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Title: Mathematical Modeling of Heart Rate Deflection Point in Relation to Respiratory Compensation and Treadmill Running Performance.
Creator: Baker, Kayla, Fukuda, David, Hoffman, Jay, Stout, Jeffrey, University of Central Florida
Abstract / Description: Heart rate deflection point (HRDP), identified as the second breakpoint in the (")intensity / heart rate(") relationship, is indicative of the anaerobic threshold (AT). This point can be determined via bi-segmental linear regression (2SEG) or through use of the maximal distance model (D-max); however, the relationship between these methods has yet to be investigated 2. Purpose: To compare the use of 2SEG and D-max methods to determine HRDP and to examine the relationship between these values...
Show moreHeart rate deflection point (HRDP), identified as the second breakpoint in the (")intensity / heart rate(") relationship, is indicative of the anaerobic threshold (AT). This point can be determined via bi-segmental linear regression (2SEG) or through use of the maximal distance model (D-max); however, the relationship between these methods has yet to be investigated 2. Purpose: To compare the use of 2SEG and D-max methods to determine HRDP and to examine the relationship between these values with a metabolic threshold, respiratory compensation point (RCP), as well as running performance [5,000 meter treadmill time trial (5Ktime)]. Methods: Nineteen recreationally active men (n=9, 25.56(&)#177;3.17 y, 1.77(&)#177;0.05 m, 83.52(&)#177;6.77 kg, 48.98(&)#177;7.37 ml(&)#183;kg(&)#183;min-1) and women (n=10, 22.78(&)#177;2.11 y, 1.64(&)#177;0.07 m, 62.28(&)#177;6.20 kg, 42.32(&)#177;4.13 ml(&)#183;kg(&)#183;min-1) were recruited for this study. Participants completed two experimental trials, consisting of a graded exercise test to exhaustion (GXT) and 5,000m time trial on the treadmill. Estimates of HRDP and RCP were calculated from data collected during the GXT. One-way repeated measures analysis of variance was used to compare HRDP found through 2SEG (HRDP2SEG), HRDP found through D-max (HRDPD-max), and RCP. Pearson product moment correlations were used to examine the relationship between variables (HRDP2SEG, HRDPD-max, RCP, and 5Ktime). Results: No differences were found between HRDP2SEG (176.70(&)#177;9.40 bpm), HRDPD-max (178.18(&)#177;6.85 bpm), and RCP (176.92(&)#177;6.63 bpm) (p = 0.533). Strong correlations were found between HRDP2SEG and HRDPD-max (r = 0.831, p (<) 0.0001), RCP and HRDP2SEG (r = 0.650, p = 0.003), and RCP and HRDPD-max (r = 0.619, p = 0.005). No relationship was found between 5Ktime and HRDP2SEG (r = 0.419, p = 0.074), HRDPD-max (r = 0.241, p = 0.321), or RCP (r = 0.193, p = 0.429). Similar limits of agreement were found for all comparisons (HRDP2SEG and RCP, p = 0.070; HRDPD-max and RCP, p = 0.868; HRDP2SEG and HRDPD-max, p = 0.029), however, systematic bias was found between HRDP2SEG and HRDPD-max. Conclusion: Based on these results, HRDP2SEG and HRDPD-max could potentially be used interchangeably as methods to determine HRDP. However, the potential for systematic bias must be taken into consideration. Additionally, the results indicate that RCP and HRDP may provide similar estimates of the anaerobic threshold, but none of these thresholds appear to be related to 5Ktime on a treadmill.
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Date Issued: 2016
Identifier: CFE0006070, ucf:50944
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006070

Title: Effects of an Acute High-Volume Isokinetic Intervention on Circulating Levels of TNF-? and STNFR: Influence of Age.
Creator: Arroyo Delgado, Eliott, Wells, Adam, Hoffman, Jay, Stout, Jeffrey, Fukuda, David, University of Central Florida
Abstract / Description: The immune system has been implicated in recovery and muscle regeneration following exercise. In response to muscle damage, the immune system responds with an increase in circulating pro-inflammatory cytokines with the goal of recruiting leukocytes to the damaged area. Tumor Necrosis Factor-alpha (TNF-?), in particular, has been shown to be implicated in both muscle regeneration and muscle wasting. However, it remains unclear whether TNF-? is responsible for the age-related losses in muscle...
Show moreThe immune system has been implicated in recovery and muscle regeneration following exercise. In response to muscle damage, the immune system responds with an increase in circulating pro-inflammatory cytokines with the goal of recruiting leukocytes to the damaged area. Tumor Necrosis Factor-alpha (TNF-?), in particular, has been shown to be implicated in both muscle regeneration and muscle wasting. However, it remains unclear whether TNF-? is responsible for the age-related losses in muscle size and function. Also, due to the high clearance rate of TNF-? from circulation, analyzing the circulating levels of soluble TNF-? receptors 1 and 2 (STNFR1 and STNFR2) may provide a better indication of inflammatory events. Therefore, the purpose of this study was to compare changes in circulating levels of TNF-?, STNFR1, and STNFR2 following an acute muscle damaging intervention in young age (YA) and middle-aged (MA) males. Recreationally active young (YA; N=9, 21.8 (&)#177; 2.2 y, 179.5 (&)#177; 4.9 cm, 91.2 (&)#177; 12.2 kg, 21.8 (&)#177; 4.3% BF) and middle-aged (MA; N=10, 47.0 (&)#177; 4.4 y, 176.8 (&)#177; 7.6 cm; 96.0 (&)#177; 21.5 kg, 25.4 (&)#177; 5.3% BF) males completed an acute muscle damaging protocol (MDP). Blood samples were obtained at baseline (BL), immediately (IP), 30 minutes (30P), 60 minutes (60P), 120 minutes (120P), 24 hours (24H), and 48 hours (48H) post-MDP. Lower body performance was analyzed via isokinetic dynamometer at BL, IP, 120P, 24H, and 48H. No significant group x time interactions or main group effects were observed for TNF-?, STNFR1, STNFR2 or any marker of muscle damage. When collapsed across groups, plasma lactate was significantly elevated at IP (p (<) 0.001) and 30P (p = 0.003); serum myoglobin was increased at 30P (p = 0.002), 60P (p = 0.001), and 120P (p = 0.007); creatine kinase was elevated at 24H (p = 0.001) and 48H (p = 0.005). Plasma concentrations of TNF-? were unchanged following MDP. With both groups combined, serum STNFR1 was decreased at 30P (p = 0.001) and increased at 48H (p = 0.028). Serum STNFR2 was decreased at 30P (p = 0.008), 60P (p = 0.003), and 120P (p = 0.002). The results of this study indicate that the TNF-? and STNFRs response to exercise is similar between young and middle-aged males. Measuring STNFRs may be a more appropriate method of assessing the acute inflammatory response to muscle damage. In addition, an acute bout of exercise may attenuate ectodomain shedding of TNFR1 and TNFR2.
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Date Issued: 2017
Identifier: CFE0006561, ucf:51350
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006561

Title: The Effects of Sprint Interval Training and Maturity Status on Metabolic and Neuromuscular Fatigue Thresholds in Adolescents.
Creator: Beyer, Kyle, Fukuda, David, Hoffman, Jay, Stout, Jeffrey, Fragala, Maren, University of Central Florida
Abstract / Description: Purpose: To examine the maturity-related differences in the adaptations to systemic and localized fatigue thresholds (FTs) in response to sprint interval training (SIT) amongst adolescent male athletes. Methods: Twenty-seven adolescent male athletes, 11-17 years of age, completed pre-testing, six weeks of SIT, and post-testing. Participants were grouped according to their number of years from peak height velocity (PHV), an estimation of somatic maturity status, into PRE (()+1.5yr) PHV groups....
Show morePurpose: To examine the maturity-related differences in the adaptations to systemic and localized fatigue thresholds (FTs) in response to sprint interval training (SIT) amongst adolescent male athletes. Methods: Twenty-seven adolescent male athletes, 11-17 years of age, completed pre-testing, six weeks of SIT, and post-testing. Participants were grouped according to their number of years from peak height velocity (PHV), an estimation of somatic maturity status, into PRE ((<)-1.5yr), PERI (between -1.5 to +1.5yr) and POST ((>)+1.5yr) PHV groups. Each testing session consisted of a ramp exercise protocol on a cycle ergometer. During the protocol, three systemic FTs, gas exchange threshold, ventilatory threshold, and respiratory compensation point were calculated from gas exchange and ventilatory parameters. Also, three localized FTs, neuromuscular fatigue threshold (NFT), deoxyhemoglobin breakpoint (HHbBP), and oxygenation deflection point (OxDP) were calculated from electromyography (NFT) and near-infrared spectroscopy signals (HHbBP and OxDP) from the vastus lateralis of both legs. Data were plotted versus oxygen consumption and 30-second moving averages were calculated. All FTs were determined using the maximal distance method. Localized FTs were averaged between the two legs. The six weeks of SIT consisted of repeated 20-second (")all-out(") sprints on a cycle ergometer against a load equivalent to 7.5% of body mass with 4-minute rest periods. Maturity-related differences to the adaptations to SIT were assessed with mixed-factorial ANOVA and magnitude-based inferences. Results: During training, POST and PERI completed significantly greater relative work (p=0.003 and p=0.002, respectfully) and peak power (p=0.025 and p=0.023, respectfully) per session than PRE. Furthermore, POST achieved significantly greater peak rotations per minute than PRE (p=0.001) and PERI (p=0.042) during the first training session. No significant group(&)#215;time interactions existed for absolute V?O2max (p=0.386), relative V?O2max (p=0.341) or maximum workload (p=0.593). However, there was a significant group(&)#215;time interaction (p=0.030) for FTs, with POST having significantly greater changes than PRE (p=0.026) and PERI (p=0.023), and was the only group to experience a significant improvement in FTs from training (p(<)0.001). In addition, magnitude based inferences revealed that POST had Likely improvements in all measures of maximal aerobic performance, while PERI only had Likely improvements in maximum workload and PRE experienced Trivial changes. Furthermore, all measured FTs experienced Likely or Very Likely improvements amongst POST; however, PRE and PERI only had improvements in NFT and HHbBP. Conclusion: SIT improved maximal aerobic performance and FTs in POST, but had limited affects in PRE and PERI. The maturity-related differences in the adaptations to SIT may be due to the differences in performance during the training program or underlying physiological changes that occur with maturation.
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Date Issued: 2017
Identifier: CFE0006934, ucf:51644
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006934

Title: Intramuscular TNF-alpha signaling in response to resistance exercise and recovery in untrained males.
Creator: Townsend, Jeremy, Stout, Jeffrey, Hoffman, Jay, Fukuda, David, Roberts, Michael, University of Central Florida
Abstract / Description: INTRODUCTION: The nuclear factor kappa B (NF-??) signaling cascade is responsible for mediating stress-activated catabolic effects of Tumor Necrosis Factor Alpha (TNF-?) downstream of the TNF receptor (TNFR1). NF-?? transcription factor remains inhibited in the cytosol of the muscle and can be stimulated for translocation and transcription by a variety of external stimuli, most notably by pro-inflammatory cytokines and oxidative stress. Nevertheless, currently there is a gap in the literature...
Show moreINTRODUCTION: The nuclear factor kappa B (NF-??) signaling cascade is responsible for mediating stress-activated catabolic effects of Tumor Necrosis Factor Alpha (TNF-?) downstream of the TNF receptor (TNFR1). NF-?? transcription factor remains inhibited in the cytosol of the muscle and can be stimulated for translocation and transcription by a variety of external stimuli, most notably by pro-inflammatory cytokines and oxidative stress. Nevertheless, currently there is a gap in the literature with regard to the time course effect of NF-?? signaling following acute resistance exercise in humans. PURPOSE: To observe the effects of an acute lower-body resistance exercise protocol and subsequent recovery on intramuscular NF- ?? signaling. METHODS: Twenty-eight untrained males were assigned to either a control (CON; n=11) or exercise group (EX; n=17) and completed a lower-body resistance exercise protocol consisting of the back squat, leg press, and leg extension exercises. Skeletal muscle microbiopsies were obtained from the vastus lateralis pre-exercise (PRE), 1-hour (1HR), 5-hour (5HR), and 48-hours (48HR) post-resistance exercise. Multiplex signaling assay kits (EMD Millipore, Billerica, MA, USA) were used to quantify the total protein (TNFR1, c-Myc) or phosphorylation status of proteins (IKKa/b, NF- ??, IkB) specific to apoptotic signaling pathways using MAGPIX(&)#174; (Luminex, Austin, TX, USA). Repeated measures ANOVA analysis was used to determine the effects of the exercise bout on intramuscular signaling at each timepoint. Additionally, change scores were analyzed by magnitude based inferences to determine a mechanistic interpretation. RESULTS: Repeated measures ANOVA indicated a trend for a two way interaction between the EX and CON Group (p=0.064). Magnitude based inferences revealed a (")Very Likely(") increase in total c-Myc from PRE-5H and a (")Likely(") increase in IkB phosphorylation from PRE-5H. CONCLUSION: Results indicate that c-Myc transcription factor and phosphorylation of IkB are elevated following acute intense resistance exercise in untrained males. These data suggest that NF- ?? signaling plays a role in ribosome biogenesis and skeletal muscle regeneration following resistance exercise in young untrained males.
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Date Issued: 2016
Identifier: CFE0006191, ucf:51089
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006191

Title: The effect of training volume and intensity on improvements in muscular strength and size in resistance-trained men.
Creator: Mangine, Gerald, Hoffman, Jay, Fukuda, David, Stout, Jeffrey, Ratamess, Nicholas, University of Central Florida
Abstract / Description: The magnitude of improvements in muscular strength and size are influenced by the volume and intensity of a resistance training program. While it is clearly advantageous for resistance-trained individuals to utilize programming specific to these goals, it not clear which is more important. Therefore the purpose of the present investigation was to determine the effect of focusing on training volume versus intensity on changes in muscle size and strength. Changes in muscular strength and size...
Show moreThe magnitude of improvements in muscular strength and size are influenced by the volume and intensity of a resistance training program. While it is clearly advantageous for resistance-trained individuals to utilize programming specific to these goals, it not clear which is more important. Therefore the purpose of the present investigation was to determine the effect of focusing on training volume versus intensity on changes in muscle size and strength. Changes in muscular strength and size were examined in 29 resistance-trained men following 8 weeks of resistance training. Participants were randomly assigned to either a high volume (VOL, n = 14, 4 x 10 (-) 12RM, 1min rest) or high intensity (INT, n = 15, 4 x 3 (-) 5RM, 3min rest) resistance training program. Lean body mass, lean arm and leg mass, were assessed by dual energy X-ray absorptiometry, while ultrasound images (VL-vastus lateralis, RF-rectus femoris, PM-pectoralis major, and TB-triceps brachii) were used to assess changes in muscle cross-sectional area (CSA) and thickness (MT). Strength was measured by one repetition-maximum (1RM) squat (SQ) and bench press (BP). Changes in muscular (RF (&) VL) activation in response to increases in submaximal SQ intensity (40-, 60-, 80-, (&) 100%-1RM) were assessed via surface electromyography. Blood samples were collected at baseline, immediately post, 30min post, and 60min post-exercise at week 3 (WK3) and week 10 (WK10), to assess plasma/serum testosterone, growth hormone (GH), insulin-like growth factor-1 (IGF1), cortisol (CORT), and insulin. Area under the curve analysis revealed a greater (p (<) 0.05) increase for VOL (WK3: GH (&) CORT; WK10: CORT) compared to INT. Compared to WK3, WK10 showed reduced responses for VOL (GH and CORT) and INT (IGF1). Significant group differences were observed for changes in lean arm mass (INT: 5.2 (&)#177; 2.9%, VOL: 2.2 (&)#177; 5.6%) and BP 1RM (INT: 14.8 (&)#177; 9.7%, VOL: 6.9 (&)#177; 9.0%). Over the course of 8 weeks, our data indicate that trained men would benefit more when focusing on training intensity, rather than volume, for strength and size improvements.
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Date Issued: 2015
Identifier: CFE0005658, ucf:50179
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005658

Title: Determination of Critical Rest Interval using Repeated Sprint Ability Testing.
Creator: Lamonica, Michael, Fukuda, David, Hoffman, Jay, Stout, Jeffrey, Fragala, Maren, University of Central Florida
Abstract / Description: The critical power (CP) concept has been used to determine the appropriate rest interval during intermittent exercise through the investigation of critical rest interval (CRI). Repeated sprint ability (RSA) testing has been developed to define the athlete's ability to recover and maintain maximal effort during successive bouts. The CP model has been used to understand the physiological responses involved with intermittent exercise delineating between severe and heavy exercise intensity...
Show moreThe critical power (CP) concept has been used to determine the appropriate rest interval during intermittent exercise through the investigation of critical rest interval (CRI). Repeated sprint ability (RSA) testing has been developed to define the athlete's ability to recover and maintain maximal effort during successive bouts. The CP model has been used to understand the physiological responses involved with intermittent exercise delineating between severe and heavy exercise intensity domains. The primary purpose of this study was to determine the CRI from the work-time relationship given by RSA testing using varying work to rest ratios. The secondary purpose was to determine the validity of CRI by evaluation of physiological responses above and below estimated rest interval values during intermittent cycling.Twelve recreationally trained males (mean (&)#177; SD; age 24.1 (&)#177; 3.6yr; height 175.8 (&)#177; 7.0cm; weight 77.6 (&)#177; 12.8kg; V?O2peak 43.3 (&)#177; 5.6ml/kg/min; Body Fat (%) 24.5 (&)#177; 4.4) were recruited for this study. Participants performed a graded exercise test to determine V?O2peak and peak heart rate. Eight participants completed the same three RSA protocols with 6s maximal sprints and varying rest intervals (12-24s) on a cycle ergometer. Intermittent critical power (ICP) was calculated through the linear total work (TW) and time-to-exhaustion (TTE) relationship, whereas CRI was estimated using the average work per sprint and ICP. Seven subjects completed trials above and below estimated CRI to evaluate the validity of this estimate through the examination of the physiological responses. Breath-by-breath oxygen consumption (V?O2) and heart rate (HR) values were recorded during the validation trials. One-way repeated measures analysis of variance (ANOVA) was used to analyze the variables from the RSA trials. Paired samples t-tests were performed to compare performance and physiological variables above or below CRI during the validation trials. Two-way repeated measures ANOVA was used to examined the changes in oxygen consumption (V?O2), HR, mean power (MP), and TW throughout the validation trials. Significant differences (p (<) 0.1) were found for the number of intervals completed, TTE, average work per sprint, peak and mean V?O2 between RSA protocols. Linearity between TW and TTE was r2 = 0.952 (&)#177; 0.081. During the validation trials, TTE was significantly greater in the above versus the below CRI trial (2270.43 (&)#177; 941.15s vs. 1511.00 (&)#177; 811.0s). Furthermore, blood lactate concentration (8.94 (&)#177; 4.89mmol/L vs. 6.56 (&)#177; 3.45mmol/L), AveV?O2 (2.05 (&)#177; 0.36L/min vs. 1.78 (&)#177; 0.26L/min), V?O2peak (2.84 (&)#177; 0.48L/min vs. 2.61 (&)#177; 0.43L/min), and AveHR (151.14 (&)#177; 18.46bpm vs. 138.14 (&)#177; 17.51L/min) were significantly greater in the below CRI trial when compared to the above CRI trial. Significant interactions were found between above and below trials within minimal V?O2 response (F = 6.886, p = 0.024, ?2 = 0.534) to the recovery intervals and maximal HR (F = 4.51, p = 0.016, ?2 = 0.429) response to the work intervals. During the above CRI trial, minimal V?O2 response decreased over time (51-43%V?O2 peak) while maximal HR response achieved a steady state level (81-84%HRpeak). Conversely, minimal V?O2 response during the below CRI trial achieved a steady state level (54-58%V?O2 peak), whereas maximal HR response increased over time (84-90%HRpeak).The relationship between TW and TTE is appropriate for use with RSA testing with varying rest intervals. The differing physiological response during the validation trials may reflect changes in energy system contribution. In conclusion, CRI distinguished between physiological responses related to exercise intensity domains in a manner similar to CP estimates determined from other testing and exercise modalities.
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Date Issued: 2014
Identifier: CFE0005645, ucf:50168
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005645

Title: CRITICAL VELOCITY IS ASSOCIATED WITH COMBAT SPECIFIC PERFORMANCE MEASURES IN A SPECIAL FORCES UNIT.
Creator: Hoffman, Mattan, Stout, Jeffrey, Fukuda, David, Fisher, Thomas, University of Central Florida
Abstract / Description: Over recent years, military research has focused on ways of being able to predict operational success and readiness through the development of simulated operational tasks measuring the physical limits of the soldier. Therefore, to properly prepare the tactical athlete for the demands and rigor of combat, accurate assessment of baseline physical abilities and limitations are necessary. Currently, western armies use a basic physical fitness test, which has been heavily argued to have no bearing...
Show moreOver recent years, military research has focused on ways of being able to predict operational success and readiness through the development of simulated operational tasks measuring the physical limits of the soldier. Therefore, to properly prepare the tactical athlete for the demands and rigor of combat, accurate assessment of baseline physical abilities and limitations are necessary. Currently, western armies use a basic physical fitness test, which has been heavily argued to have no bearing on operational readiness, thus they are in the process of transitioning to a more specific combat readiness test. However, specific assessments to predict operational success/readiness are inefficient or lacking. A single test that requires minimal time, but provides simultaneous assessment of the necessary physical characteristics (i.e. aerobic and anaerobic capacities) may provide a unique opportunity to enhance soldier performance assessment. The 3-min all-out run, is a relatively new test that has been recently validated. It provides two performance estimates, critical velocity (CV) and anaerobic distance capacity (ADC). CV provides a measure of the individual's aerobic capacity, while the ADC is an indicator of anaerobic capacity. The purpose of this study, therefore, is to examine the relationship between CV and ADC from the 3-min all-out run and combat specific tasks (2.5-km run, 50-m casualty carry, and repeated sprints with rush shooting) in an elite special force unit. Eighteen male soldiers (age: 19.9 (&)#177; 0.8 years; height: 177.6 (&)#177; 6.6 cm; body mass: 74.1 (&)#177; 5.8 kg; BMI: 23.52 (&)#177; 1.63) from an elite combat special force unit of the Israel Defense Forces (IDF) volunteered to complete a 3-min all-out run, while wearing a global positioning system (GPS) unit, and a battery of operational CST (2.5-km run, 50-m casualty carry and 30-m repeated sprints with (")rush(") shooting (RPTDS)). Estimates of CV and ADC from the 3-min all-out run were determined from the downloaded GPS data with CV calculated as the average velocity of the final 30 s of the run and ADC as the velocity-time integral above CV. CV exhibited significant negative correlations with the 2.5-km run time (r = - 0.62, p (<) 0.01), and RPTDS time (r = - 0.71p (<) 0.01). However, CV (r = - 0.31) or ADC (r = 0.16) did not show any correlation with the 50-m casualty carry run. In addition, CV was positively correlated with the average velocity during the 2.5- km run (r = 0.64, p (<) 0.01). Stepwise regression identified CV as the most significant performance measure associated with the 2.5-km run time, and BMI and CV measures as significant predictors of RPTDS time (R2= 0.67, p (<) 0.05). Our main findings indicate that CV was highly related to performance during CST, including the 2.5-km run and RPTDS, but not the 50-m casualty carry. Using the 3-min all-out run as a testing measurement offers a more efficient and simpler way in assessing both aerobic and anaerobic capabilities (CV and ADC) with-in a relatively large sample. In this regard, this method of testing may be conducive to a military type environment whether for selection purposes, to predict combat readiness, to prescribe a training program or just a need analysis for the company commander
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Date Issued: 2015
Identifier: CFE0005628, ucf:50227
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005628

Title: Intramuscular anabolic signaling and endocrine response following different resistance exercise protocols in trained men.
Creator: Gonzalez, Adam, Hoffman, Jay, Stout, Jeffrey, Fukuda, David, Willoughby, Darryn, University of Central Florida
Abstract / Description: The mammalian/mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway appears to be the primary regulator of protein synthesis and growth. While resistance exercise paradigms are often divided into hypertrophy (HYP) and strength (STR) protocols, it is unknown whether these protocols differentially stimulate mTORC1 signaling. The purpose of this study was to examine mTORC1 signaling in conjunction with circulating hormone concentrations following a typical lower-body HYP and STR...
Show moreThe mammalian/mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway appears to be the primary regulator of protein synthesis and growth. While resistance exercise paradigms are often divided into hypertrophy (HYP) and strength (STR) protocols, it is unknown whether these protocols differentially stimulate mTORC1 signaling. The purpose of this study was to examine mTORC1 signaling in conjunction with circulating hormone concentrations following a typical lower-body HYP and STR resistance exercise protocol. Ten resistance-trained men (24.7(&)#177;3.4y; 90.1(&)#177;11.3kg; 176.0(&)#177;4.9cm) performed each resistance exercise protocol in a random, counterbalanced order. Blood samples were obtained at baseline (BL), immediately (IP), 30 minutes (30P), 1 hour (1H), 2 hours (2H), and 5 hours (5H) post-exercise. Fine needle muscle biopsies were completed at BL, 1H, and 5H. Electromyography of the vastus lateralis was also recorded during each protocol. HYP and STR produced a similar magnitude of muscle activation across sets. Myoglobin and lactate dehydrogenase concentrations were significantly greater following STR compared to HYP (p=0.01-0.02), whereas the lactate response was significantly higher following HYP compared to STR (p=0.003). The GH, cortisol, and insulin responses were significantly greater following HYP compared to STR (p=0.0001-0.04). No significant differences between protocols were observed for the IGF-1 or testosterone response. Intramuscular anabolic signaling analysis revealed a significantly greater (p=0.03) phosphorylation of IGF-1 receptor at 1H following HYP compared to STR. Phosphorylation status of all other signaling proteins including mTOR (mammalian target of rapamycin), p70S6k (ribosomal S6 kinase 1), and RPS6 (ribosomal protein S6) were not significantly different between trials. Despite significant differences in markers of muscle damage and the endocrine response following STR and HYP, both protocols appeared to elicit similar mTORC1 activation in resistance-trained men.
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Date Issued: 2015
Identifier: CFE0005621, ucf:50203
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005621

Title: Endocrine and Contralateral Muscle Responses to Short-term Unilateral Resistance Training.
Creator: Boone, Carleigh, Fragala, Maren, Hoffman, Jay, Stout, Jeffrey, Fukuda, David, University of Central Florida
Abstract / Description: PURPOSE: The purpose of this study was to examine the effects of short-term lower body unilateral resistance training on hormonal, muscle morphological, and performance measures in young men. METHODS: Seventeen healthy, untrained young men (Age: 22.8 (&)#177; 3.7 y; BMI: 26.5 (&)#177; 4.9 kg/m2) were randomly assigned to one of two groups (UT: 22.9 (&)#177; 4.6 y, 25.3 (&)#177; 4.2 kg/m2; CON: 24.0 (&)#177; 4.6 y, 27.7 (&)#177; 5.1 kg/m2). Resistance training consisted of 4 weeks of...
Show morePURPOSE: The purpose of this study was to examine the effects of short-term lower body unilateral resistance training on hormonal, muscle morphological, and performance measures in young men. METHODS: Seventeen healthy, untrained young men (Age: 22.8 (&)#177; 3.7 y; BMI: 26.5 (&)#177; 4.9 kg/m2) were randomly assigned to one of two groups (UT: 22.9 (&)#177; 4.6 y, 25.3 (&)#177; 4.2 kg/m2; CON: 24.0 (&)#177; 4.6 y, 27.7 (&)#177; 5.1 kg/m2). Resistance training consisted of 4 weeks of unilateral lower body and bilateral upper body exercises on 3 days per week. Each training session entailed unilateral countermovement jumps (3 (&)#215; 8), unilateral leg press (LP), bilateral chest press (CP), unilateral leg extension (LE), and bilateral low row (LR). Strength exercises were performed for 3 sets of 8-10 repetitions; lower body exercises were performed with the dominant leg only. Muscle thickness (MT), pennation angle (PA), cross-sectional area (CSA), and echo-intensity (EI) of the vastus lateralis (VL) and rectus femoris (RF) muscles of both legs was assessed via ultrasound. Fascicle length (FL) was calculated as [MT / sin(PA)]. Maximal dynamic unilateral LP and LE strength was assessed during one-repetition maximum (1RM) testing; CP and LR 1RM strength was estimated as [repetition weight/(1.0278-0.0278)(reps)]. Maximal isometric knee extensor strength was isolaterally assessed via maximal voluntary contraction (MVC) testing. Mean and peak power output (Watts) was quantified during unilateral countermovement jumps via accelerometry. Fasting concentrations of total testosterone and growth hormone were obtained at baseline (PRE), immediately post (IP), 30-minutes post (30P), and 60-minutes post (60P) during both testing exercise sessions (Pre and Post). Following the 4-week intervention, all participants' maximal dynamic and isometric strength, mean and peak power output, muscle morphology, and hormonal responses were reassessed. Performance, ultrasound, and area under the curve data were analyzed using ANCOVA to observe between-group comparisons while controlling for baseline (PRE) values. Endocrine data were analyzed using a two-way, mixed-factorial repeated-measures ANOVA. RESULTS: Participants in the UT group experienced significant strength improvements of the trained (28 to 150%) and untrained legs (12 to 160%). Training did not elicit significant improvements in maximal isometric strength or power output of the trained or untrained leg. The trained RF experienced significant increases in CSA and MT. The trained VL experienced a significant increase in CSA. Muscle size of the untrained leg was not significantly augmented. Training did not elicit changes in the acute hormonal response to exercise. CONCLUSIONS: Four weeks of unilateral lower body resistance training using the dominant leg appears sufficient to evoke strength gains of both the ipsilateral and contralateral legs. However, meaningful morphological changes were observed in the trained leg only. Differences in acute hormonal responses to resistance exercise did not appear to explain the observed differences. In addition, unilateral lower body resistance training did not appear to augment the acute endocrine response to an acute bout of resistance exercise. Current findings suggest that the cross-educational strength transfer during the early stage of training is attributable to factors other than changes in muscle morphology and circulating hormones.
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Date Issued: 2014
Identifier: CFE0005307, ucf:50538
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005307

Title: The Cross Education of Neuromuscular Economy.
Creator: Beyer, Kyle, Fukuda, David, Hoffman, Jay, Stout, Jeffrey, Fragala, Maren, University of Central Florida
Abstract / Description: Cross education is the phenomenon by which the untrained limb will experience a gain in strength following a unilateral resistance training program. However, little is known as to the underlying adaptation occurring in the untrained limb. Purpose: To examine the effect of dynamic unilateral resistance training on the strength and neuromuscular adaptations of both the trained and untrained legs. Methods: Eight previously untrained males (22.38(&)#177;2.92 y, 1.73(&)#177;0.08 m, 75.26(&)#177;14...
Show moreCross education is the phenomenon by which the untrained limb will experience a gain in strength following a unilateral resistance training program. However, little is known as to the underlying adaptation occurring in the untrained limb. Purpose: To examine the effect of dynamic unilateral resistance training on the strength and neuromuscular adaptations of both the trained and untrained legs. Methods: Eight previously untrained males (22.38(&)#177;2.92 y, 1.73(&)#177;0.08 m, 75.26(&)#177;14.53 kg) completed a four-week unilateral resistance training program, while another eight untrained males (24.00(&)#177;4.57 y, 1.84(&)#177;0.05 m, 94.21(&)#177;16.14 kg) served as controls. Isometric leg extension strength, leg press 1 repetition maximum (1RM), leg extension 1RM, root mean square of the maximal electromyographic amplitude (EMG), submaximal EMG, dynamic neuromuscular economy (NME) and the slope of NME-power output relationship were determined before and after training to assess the changes in strength and neuromuscular adaptations of the vastus lateralis (VL) and rectus femoris (RF) in both the trained and untrained legs. The unilateral resistance training program was conducted on the dominant leg (DOM) in the unilateral resistance training group (URT) and was compared to the dominant leg of the control group (CON). Cross education was measured in the nondominant leg (NON) for both groups. The unilateral resistance training program was completed three days per week for a total of twelve training sessions. Exercises included in the training program were unilateral leg press, unilateral leg extension, bilateral chest press and bilateral low row. All data was analyzed using one-way analysis of covariance of the post-testing values using the pre-testing values as the covariate. Further analysis of the EMG and NME data was performed using magnitude-based inferences. Results: The URT group improved their isometric (DOM:11.03%, NON:4.98%), leg press (DOM:77.63%, NON:64.88%) and leg extension (DOM:46.76%, NON:16.43%) strength after the four weeks of resistance training. There was no difference between the groups in isometric strength in the dominant (p=0.188) or nondominant (p=0.948) leg. For leg extension 1RM, there was a significant difference between groups in the dominant leg (p=0.018), but not the nondominant leg (p=0.482). However, there were significant group differences in both the dominant (p=0.003) and nondominant (p=0.034) leg for leg press 1RM. In terms of maximal EMG, the training groups improved in the vastus lateralis (DOM:29.81%, NON:31.44%) and rectus femoris (DOM:20.71%, NON:6.26%) individually, as well as in total EMG (DOM:24.78%, NON:17.57%). There was a Likely Positive or Very Likely Positive effect of unilateral resistance training on the changes in maximal EMG of the vastus lateralis and rectus femoris in both the dominant and nondominant legs. There was a Likely Positive effect of unilateral resistance training on the submaximal EMG of the dominant vastus lateralis at 75 and 125 watts. Conversely, in the rectus femoris, there was Unclear effects of unilateral resistance training on the submaximal EMG of the dominant leg. There was no consistent effect of unilateral resistance training on submaximal EMG values of the vastus lateralis in the nondominant leg. However, the rectus femoris in the nondominant leg experienced a Likely Positive effect of unilateral resistance training on submaximal EMG. NME improved in the URT group in the VL at 75 (DOM:9.73%, NON:13.42%), 100 (DOM:8.76%, NON:8.21%), and 125(DOM:24.26%, NON:12.8%) watts and in the RF at 75 (DOM:22.25%, NON:15.73%), 100(DOM:24.85%, NON:17.05%) and 125 (DOM:30.99%) watts. In terms of neuromuscular economy, there was a Likely Positive or Very Likely Positive effect of unilateral resistance training on most measures of NME on both the vastus lateralis and rectus femoris in both the dominant and nondominant legs. In terms of NME slope, there was only a Likely Positive effect of unilateral resistance training on the dominant vastus lateralis. Conclusion: Based on these results, it appears that the cross education of strength from unilateral resistance training is modality-specific. Furthermore, the NME of both the vastus lateralis and rectus femoris in both legs appear to improve following unilateral resistance training. However, in the nondominant leg, the improvement in NME appears to be due solely to the increase in maximal EMG, whereas the improved NME in the dominant leg is due to both an increase in maximal EMG and a decrease in submaximal EMG.
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Date Issued: 2014
Identifier: CFE0005305, ucf:50537
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005305

Title: Acute Pro-inflammatory Immune Response Following Different Resistance Exercise Protocols in Trained Men.
Creator: Wells, Adam, Hoffman, Jay, Stout, Jeffrey, Fukuda, David, Oliveira, Leonardo, University of Central Florida
Abstract / Description: The successful regeneration of muscle tissue is dependent upon the infiltration of phagocytic CD14++CD16- monocytes that support the proliferation and differentiation of myogenic precursor cells. Physiologically, the magnitude of the cellular response following resistance exercise is dictated by the level of receptor expression on the plasma membrane of the monocyte, as well as the secretion of their cognate ligands from tissue resident cells. However, it remains unclear whether the innate...
Show moreThe successful regeneration of muscle tissue is dependent upon the infiltration of phagocytic CD14++CD16- monocytes that support the proliferation and differentiation of myogenic precursor cells. Physiologically, the magnitude of the cellular response following resistance exercise is dictated by the level of receptor expression on the plasma membrane of the monocyte, as well as the secretion of their cognate ligands from tissue resident cells. However, it remains unclear whether the innate pro-inflammatory immune response varies with different resistance training protocols, and how it may impact recovery and the muscle remodeling process. Therefore, the purpose of this investigation was to examine temporal changes in the expression of chemotactic and adhesion receptors following an acute bout of high-volume, moderate-intensity (VOL) versus high-intensity, low-volume (HVY) lower-body resistance exercise in experienced, resistance trained men. Changes in receptor expression were assessed in conjunction with plasma concentrations of MCP-1, TNF?, and cortisol. Ten resistance-trained men (90.1 (&)#177; 11.3 kg; 176.0 (&)#177; 4.9 cm; 24.7 (&)#177; 3.4 yrs; 14.1 (&)#177; 6.1% body fat) performed each resistance exercise protocol in a random, counterbalanced order. Blood samples were obtained at baseline (BL), immediately (IP), 30 minutes (30P), 1 hour (1H), 2 hours (2H), and 5 hours (5H) post-exercise. Analysis of target receptor expression on CD14++CD16- monocytes was completed at BL, IP, 1H, 2H and 5H time points via flow cytometric analysis. Plasma concentrations of myoglobin, and LDH AUC were significantly greater following HVY compared to VOL (p = 0.003 and p = 0.010 respectively). Changes in plasma TNF?, MCP-1, and expression of CCR2, CD11b, and GCR on CD14++CD16- monocytes were similar following HVY and VOL. When collapsed across groups, TNF? was significantly increased at IP, 30P, 1H and 2H post-exercise (p = 0.001 (-) 0.004), while MCP-1 was significantly elevated at all post-exercise time points (p = 0.002 (-) 0.033). CCR2 expression was significantly lower at IP, 1H, 2H and 5H post-exercise (p = 0.020 (-) 0.040). In contrast, CD11b receptor expression was significantly greater at 1H relative to BL (p = 0.001), while GCR expression was not significantly different from baseline at any time point. As expected, plasma cortisol concentrations were significantly higher following VOL compared to HVY (p = 0.001), although this did not appear to be related to changes in receptor expression. Plasma testosterone concentrations and TNFr1 receptor expression did not appear to be affected by resistance exercise. Our results do not support a role for cortisol in the modulation of CCR2 receptors in vivo, while the degree of muscle damage does not appear to influence plasma concentrations of TNF?, or MCP-1. It is therefore likely that both HVY and VOL protocols constitute an exercise stimulus that is sufficient enough to promote a robust pro-inflammatory response, which is similar in timing and magnitude.
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Date Issued: 2015
Identifier: CFE0005736, ucf:50088
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005736

Title: A mixed-methods approach to understanding the relationship between mental toughness and the effect of music on exercise performance.
Creator: Baker, Kayla, Garcia, Jeanette, Stout, Jeffrey, Fukuda, David, Fisher, Thomas, Dawson, Nicole, University of Central Florida
Abstract / Description: Previous research has investigated the use of music as an ergogenic aid for exercise performance; however, the effect of music on exercise may differ between individuals of varying levels of mental toughness (MT). Purpose: The purpose of this study is to examine the moderating effect of MT on the effect of listening to music during exercise. Methods: The current study used a counter-balanced design, utilizing a mixed-methods approach. Thirty-one recreationally-active individuals (22.13 (&)...
Show morePrevious research has investigated the use of music as an ergogenic aid for exercise performance; however, the effect of music on exercise may differ between individuals of varying levels of mental toughness (MT). Purpose: The purpose of this study is to examine the moderating effect of MT on the effect of listening to music during exercise. Methods: The current study used a counter-balanced design, utilizing a mixed-methods approach. Thirty-one recreationally-active individuals (22.13 (&)#177; 2.11 yrs, 1.73 (&)#177; .10 m, 75.68 (&)#177; 14.67 kg, 42.89 (&)#177; 5.31 mL(&)#183;kg(&)#183;min-1; 65.5% males) were recruited for this study. Participants completed an initial visit to complete a MT questionnaire and create a personalized music playlist of at least 15 songs. Participants completed two familiarization trials and a VO2max test on the treadmill, all on separate days. The experimental trials consisted of two separate conditions: 1) no music (NM); and 2) self-selected music (SSM). For each experimental trial, participants performed a time-to-exhaustion (TTE) run at 80% of their VO2max, separated by at least 48 hours, followed by a post-study interview. Pearson product-moment correlations were used to investigate relationships between performance variables and MT. Moderated regression analysis was used to determine a potential order effect, as well as a potential moderating effect of MT on change in performance between NM and SSM groups. Linear regression analysis was used to determine a potential relationship between MT and change in performance between NM and SSM groups. An alpha level of p ? 0.05 was used to determine statistical significance. All qualitative data from post-study interviews was transcribed, coded, and categorized into primary themes. All statistical analyses was conducted via the Statistical Package for Social Science (SPSS) software for Windows version 21 (SPSS Inc., Chicago, IL). Results: Averages were calculated for MT (156.39 (&)#177; 9.38), TTESSM (14.18 (&)#177; 4.79 minutes), and TTENM (12.23 (&)#177; 5.24 minutes). Correlations were found between VO2max and TTESSM, TTENM, and MT (r = 0.390, p = 0.030; r = 0.519, p = 0.003; r = 0.404, p = 0.024; respectively). Moderated regression analysis revealed a non-significant interaction between MT, music, and order, indicating no order effect (? = -0.416, p = 0.735). Independent samples t-tests revealed no significant difference in MT, performance, or VO2maz between groups of participants who received music first or music second, indicating no effect of order (F = 0.388; p = 0.538; F = 0.537; p = 0.470; F = 0.070; p = 0.794; respectively. Moderated regression analysis, via linear regression, determined no significant moderating effect of MT on the change in performance between trials (?TTE) (F (3, 58) = 0.958, r = 0.217, p = 0.498). Linear regression, however, revealed a significant main effect of MT, indicating an inverse relationship between MT and ?TTE (F (1, 29) = 4.417, r = -0.634, p = 0.044). Discussion: The results from the current study indicate that greater levels of MT were associated with less change between the two performance trials, however, there were no significant relationships between MT or performance with self-selected music. This finding suggests that individuals with greater MT may demonstrate consistent patterns of performance, irrespective of the presence of external factors. Understanding the effects of MT and how external and internal stimuli affect performance may allow exercise professionals to tailor their training or rehabilitation programs to each individual, therefore increasing exercise performance and adherence.
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Date Issued: 2019
Identifier: CFE0007428, ucf:52736
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007428

Title: Comparative Analysis of The Effects Of Virtual Reality Active Video Game And Controller-Free Active Video Game Play On Physiological Response, Perceived Exertion, And Hedonic Experience.
Creator: Wooden, Shanon, McCauley, Pamela, Rabelo, Luis, Karwowski, Waldemar, Fukuda, David, University of Central Florida
Abstract / Description: Over 60% of US adults are overweight or obese. Sedentary lifestyles are considered major contributors to the high rates and increasing prevalence of obesity. Physical activity is a critical component in shifting from sedentary lifestyles. Studies indicate that less than half of U.S. adults meet the CDC/ACSM physical activity recommendations. Interactive video games can increase PA, but no study has yet assessed physiologic effort, hedonics, and perceived exertion for playing immersive virtual...
Show moreOver 60% of US adults are overweight or obese. Sedentary lifestyles are considered major contributors to the high rates and increasing prevalence of obesity. Physical activity is a critical component in shifting from sedentary lifestyles. Studies indicate that less than half of U.S. adults meet the CDC/ACSM physical activity recommendations. Interactive video games can increase PA, but no study has yet assessed physiologic effort, hedonics, and perceived exertion for playing immersive virtual reality (VR) and controller-free screen-based active video games (AVGs), compared to treadmill walking and resting. We ran 25 subjects (9 female, 16 male) in 10-minute sessions of five conditions. Head Mounted Display VR: Oculus (Fruit Ninja and Boxing), Screen-based AVG: Kinect (Fruit Ninja and Boxing), and Treadmill walking at 3 mph. One, six-condition (Rest, Treadmill 3.0, Kinect Boxing, Kinect Fruit Ninja, Oculus Boxing, Oculus Fruit Ninja) repeated-measures ANOVA was used to examine differences in HRmean. Three, five-condition (Treadmill 3.0, Kinect Boxing, Kinect Fruit Ninja, Oculus Boxing, Oculus Fruit Ninja) repeated-measures ANOVA were used to examine differences in HRpeak, ratings of perceived exertion (RPE) and Hedonics (Liking). Post hoc analyses using pairwise comparisons were used to further assess significant main effects of the condition. A Pearson's product-moment correlation was run to assess the relationship between activity condition HRmean and RPE VR Boxing elicited the greatest physiological effort, producing vigorous-intensity PA. There was no significant difference in average heart rate for the Treadmill, Kinect Fruit Ninja, Kinect Boxing, and VR Fruit Ninja. Thus, the Kinect and VR sport and casual games are comparable to treadmill walking PA levels and qualify as moderate-intensity activity. The VR Fruit Ninja, VR Boxing, Kinect Fruit Ninja were the most enjoyed activities. Despite having the highest Heart rate and the highest self-reported Rating of Perceived Exertion (RPE), VR Boxing was significantly more enjoyable than Treadmill Walking. There was no statistically significant correlation between Activity Condition HRmean and RPE.Both casual and sports VR and AVG activities are enjoyable activities for adults, stimulating moderate-to-vigorous activity through a traditionally sedentary medium. This research extends previous works in active video gaming effects on physiological cost, perceived exertion and hedonics and fills the gap relating virtual reality active video games. The significance of the research outcomes is that this analysis provides a scientifically validated approach to support the establishment of physical activity level goals and guidelines in the development of active video games as a response and/or remedy to address the sedentary lifestyles that are contributing to American and global obesity.
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Date Issued: 2018
Identifier: CFE0007383, ucf:52065
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007383

Title: Exploring the Self-Reported Dietary Habits and Physical Activity Between Athletes and Non-Athletes in Four Central Florida Public High Schools.
Creator: Redd, Alison, Valdes, Anna, Stout, Jeffrey, Fisher, Thomas, Garcia, Jeanette, Fukuda, David, University of Central Florida
Abstract / Description: The federal reimbursable meals offered in American school cafeterias have recently been revised with improved nutrition standards yet may not meet the needs of student athletes who require additional energy intake. While many epidemiological studies report high numbers of adolescents who are overweight or obese, there are close to eight million high school students involved in interscholastic sports(-)more now than ever before. Therefore, the purpose of this research is to establish...
Show moreThe federal reimbursable meals offered in American school cafeterias have recently been revised with improved nutrition standards yet may not meet the needs of student athletes who require additional energy intake. While many epidemiological studies report high numbers of adolescents who are overweight or obese, there are close to eight million high school students involved in interscholastic sports(-)more now than ever before. Therefore, the purpose of this research is to establish participation rates in the federal school meals programs in a local Central Florida school district between athlete and non-athlete high school populations. Additionally, the study aimed to establish athlete and non-athlete participation rates in the federal free/reduced lunch program and determine the average number of hours spent in physical activity between athlete and non-athletes in one week. An online questionnaire was developed to assess students' self-reported energy intake and energy expenditure through sport participation and physical activity acquired during leisure time. Results of the study revealed no significance difference in federal school breakfast or lunch consumption rates between athletes and non-athletes. The study also revealed similar participation rates in the free and reduced lunch program between athlete and non-athletes when purchasing school lunches. Additionally, while non-athletes reported more average hours acquiring physical activity in their leisure time than athletes did, athletes accrued more average hours of overall physical activity due to time spent in interscholastic sport practice. Lastly, results determined significant differences in Body Mass Index (BMI) with athletes having lower BMIs than non-athletes. If meals policies evolve to be more accurately reflective of energy intake needs of athletes and non-athletes, school meals could appropriately fuel student performance in the classroom, the athletic field, and beyond.
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Date Issued: 2018
Identifier: CFE0007239, ucf:52230
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007239

Title: Mechanical and physical characteristics of knee flexors and extensors following different warm up protocols in collegiate male soccer athletes.
Creator: Redd, Mike, Fukuda, David, Stout, Jeffrey, Garcia, Jeanette, Wells, Adam, Stock, Matt, University of Central Florida
Abstract / Description: PURPOSE: To compare potential differences in mechanical and physical characteristics of knee flexors and extensors in collegiate male soccer players following different warm up protocols.METHODS: Sixteen collegiate male soccer players (20.33 (&)#177; 1.33 years, 176.97 (&)#177; 6.72 cm, and 78.43 (&)#177; 7.42 kg) participated in this study. A small sided games warm up (SSG), a dynamic warm up (DYN), and a plyometric warm up (PLY) were completed using a randomized crossover design....
Show morePURPOSE: To compare potential differences in mechanical and physical characteristics of knee flexors and extensors in collegiate male soccer players following different warm up protocols.METHODS: Sixteen collegiate male soccer players (20.33 (&)#177; 1.33 years, 176.97 (&)#177; 6.72 cm, and 78.43 (&)#177; 7.42 kg) participated in this study. A small sided games warm up (SSG), a dynamic warm up (DYN), and a plyometric warm up (PLY) were completed using a randomized crossover design. Tensiomyography (TMG) was used to assess contraction time (Tc), delay time (Td) and maximal displacement (Dm) of the rectus femoris (RF) and biceps femoris (BF) of both legs before (PRE) and after (POST) each warm up. POST assessment included: TMG of the RF and BF, countermovement jump height (CMJ-h), CMJ flight time (CMJ-ft), 20m sprint time (20m), T-test time, and sit and reach (SR) distance. All TMG measures were analyzed using a three-way [condition (&)#215; time x leg] analysis of variance (ANOVA). All performance variable data were analyzed with a repeated measures ANOVA.RESULTS: There was no difference between warm up protocols for T-test, CMJ-h, or CMJ-ft. 20m significantly improved following SSG (p=0.020) compared to DYN and PLY. SR was significantly greater following PLY (p=0.022). Three-way ANOVA did not reveal a significant interaction for any of the measured TMG variables. However, main effects of time were seen PRE to POST for BF-Tc (p=0.035), RF-Td (p(<)0.001) and BF-Td, (p=0.008) and a main effect of condition was seen for RF-Tc (p=0.038).CONCLUSION: Warm-up specific improvements were demonstrated in sprint speed and flexibility measures following SSG and PLY, respectively. While no differences were shown between the examined protocols, the present study revealed PRE to POST changes in certain TMG measures (RF-Td, BF-Td, and BF-Tc) following a warm up in male collegiate soccer athletes.
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Date Issued: 2018
Identifier: CFE0007240, ucf:52224
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007240

Title: The effect of moderate altitude on high intensity running performance during a game with collegiate female soccer players.
Creator: Bohner, Jonathan, Hoffman, Jay, Fragala, Maren, Stout, Jeffrey, Fukuda, David, University of Central Florida
Abstract / Description: Competition often requires teams that reside at sea level to compete against opponents whose residence is at a moderate altitude. This may pose a potential competitive disadvantage considering that moderate altitude may cause decrements in VO2max, distance covered, and time to exhaustion in endurance athletes. The purpose of this study was to examine the effect of altitude on game performance measures. Six NCAA Division I female soccer players (20.33 (&)#177; 1.21 y; 168 (&)#177; 6.45 cm; 62...
Show moreCompetition often requires teams that reside at sea level to compete against opponents whose residence is at a moderate altitude. This may pose a potential competitive disadvantage considering that moderate altitude may cause decrements in VO2max, distance covered, and time to exhaustion in endurance athletes. The purpose of this study was to examine the effect of altitude on game performance measures. Six NCAA Division I female soccer players (20.33 (&)#177; 1.21 y; 168 (&)#177; 6.45 cm; 62.5 (&)#177; 6.03 kg) were retrospectively examined. Comparisons were made between two competitions that were played at sea level (SL) within two weeks of a game played at a moderate altitude (1840 m) on game characteristics including high intensity running (HIR) and total distance covered (TDC). Analysis was performed on these six players who met a threshold of playing sixty or more minutes in each competition. A 10-Hz global positioning system (GPS) was used to measure distance and velocity. The rate of TDC and HIR during the game (m?min-1) and percentage of time at HIR during competition were evaluated. The two games at SL were averaged to establish baseline performance and the mean results were compared with the single game played at altitude. Paired samples t-tests were performed to determine if any mean differences existed between performance at altitude and sea level.Significant differences (p (<) 0.05) were seen in minutes played between the games at SL (74.23 (&)#177; 2.93 min) versus altitude (83.24 (&)#177; 5.27 min). The relative distance rate during the game at altitude was lower at altitude (105.77 (&)#177; 10.19 m?min-1) than at SL (120.55 (&)#177; 8.26 m?min-1). HIR rate was greater at SL (27.65 (&)#177; 9.25 m?min-1) compared to altitude (25.07 (&)#177; 7.66 m?min-1). The percent of time spent at high intensity was not significantly different (p = 0.064), yet tended to be greater at sea level (10.4 (&)#177; 3.3%) than when they performed at altitude (9.1 (&)#177;2.2%).Soccer performance at a moderate altitude appears to reduce the rate at which players run throughout the competition, as well as their rate at a high intensity. Results suggest that teams that reside at SL may be at a competitive disadvantage when competing at altitude.
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Date Issued: 2014
Identifier: CFE0005134, ucf:50716
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005134

Title: The Effect of Repeated Sprint Training in Hypoxia and Beta-Alanine Supplementation On Exercise Performance.
Creator: Wang, Ran, Hoffman, Jay, Fukuda, David, Stout, Jeffrey, Kang, Jie, University of Central Florida
Abstract / Description: The primary objective of this study was to evaluate the synergistic effects of repeated sprint training in hypoxia (RSH) and beta-alanine supplementation on performance in recreationally active men. Participants were randomly assigned to one of the following groups: hypoxia + beta-alanine (HB, n = 10), hypoxia + placebo (HP, n = 9), normoxia + beta-alanine (NB, n = 11) and normoxia + placebo (NP, n = 8). All participants completed a total of 8 training sessions (each consisting of 3 sets of 5...
Show moreThe primary objective of this study was to evaluate the synergistic effects of repeated sprint training in hypoxia (RSH) and beta-alanine supplementation on performance in recreationally active men. Participants were randomly assigned to one of the following groups: hypoxia + beta-alanine (HB, n = 10), hypoxia + placebo (HP, n = 9), normoxia + beta-alanine (NB, n = 11) and normoxia + placebo (NP, n = 8). All participants completed a total of 8 training sessions (each consisting of 3 sets of 5 (&)#215; 10-s sprints at a resistance of 7.5% of body mass, with 20-s rest intervals between sprints) over 4 weeks on a cycle ergometer either in hypoxia (Oxygen fraction: FiO2 = 14.2%) or normoxia (FiO2 = 20.9%). Participants were instructed to consume a daily dosage of 6.4g (two 800 mg tablets ingested 4 times per day at 3-4 hour intervals) of either beta-alanine or placebo. Changes in performance in a graded exercise test (GXT), repeated sprint test (RST) and 3-min all-out test (3MT) were examined before and after 28-days of training and supplementation. Aerobic performance was measured by maximal oxygen consumption (VO2max), peak power output (PPO). Exercise intolerance was assessed from critical power (CP), oxygen consumption (VO2RCP) and power output (PRCP) at respiratory compensation point. Exercise capacity was measured by total work (TW) during 3MT. Anaerobic capacity was evaluated via anaerobic working capacity (AWC), heart rate response to RST (RST_HR60) and lactate responses to RST (RST_La) and 3MT (3MT_La). Repeated sprint performance was estimated through average power output of the last sprint (RST_AP5) and all sprints (RST_AP). No between-group differences were observed for training volume or supplementation compliance. Anthropometric and hematological measures remain unchanged before and after intervention in all groups. A main effect of altitude was shown for VO2RCP, PRCP, RST_AP5, RST_HR60, and TW, with post-intervention values in the hypoxia groups significantly (p (<) 0.05) higher (lower for RST_HR60) than the normoxia groups. A main effect of beta-alanine was detected in AWC, with post-intervention values in the beta-alanine groups being significantly (p (<) 0.05) higher than the placebo groups. Results of this investigation demonstrated that RSH and beta-alanine benefit performance from different perspectives. RSH improved aerobic performance, exercise tolerance, cardiovascular recovery and exercise capacity, while beta-alanine supplementation maintained anaerobic working capacity in recreationally-trained men during the four-week repeated sprint training intervention.
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Date Issued: 2017
Identifier: CFE0006961, ucf:51633
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006961

Title: Resistance Exercise Elicits Selective Mobilization and Adhesion Characteristics of Granulocytes and Monocyte Subsets.
Creator: Jajtner, Adam, Hoffman, Jay, Stout, Jeffrey, Fukuda, David, Radom-Aizik, Shlomit, University of Central Florida
Abstract / Description: Resistance exercise eliciting muscle damage results in an immune response, leading to increases in circulating cytokines, and immune cell mobilization. Classical monocytes respond to muscle damage, however, little is known about the intermediate or nonclassical monocyte response to resistance exercise. Moreover, the impact of polyphenol supplementation in conjunction with resistance exercise on the innate immune response is unknown. The purpose of this study was to examine the immune response...
Show moreResistance exercise eliciting muscle damage results in an immune response, leading to increases in circulating cytokines, and immune cell mobilization. Classical monocytes respond to muscle damage, however, little is known about the intermediate or nonclassical monocyte response to resistance exercise. Moreover, the impact of polyphenol supplementation in conjunction with resistance exercise on the innate immune response is unknown. The purpose of this study was to examine the immune response following resistance exercise with (PPB) and without (PL) polyphenol supplementation. Thirty-nine untrained men were randomized into three groups: PPB (n=13, 21.8(&)#177;2.5yrs, 171.2(&)#177;5.5cm, 71.2(&)#177;8.2kg), PL (n=15, 21.6(&)#177;2.5yrs, 176.5(&)#177;4.9cm, 84.0(&)#177;15.7kg) or a control group (CON) (23.3(&)#177;4.1yrs, 173.6(&)#177;12.0cm, 77.8(&)#177;15.6kg). Blood samples were obtained pre- (PRE), immediately- (IP), 1- (1H), 5- (5H), 24- (24H), 48- (48H) and 96- (96H) hours post-exercise (PPB/PL). CON rested for one hour between PRE and IP blood draws. Changes in granulocyte and monocyte subset proportions and adhesion characteristics (CD11b) were assessed via flow cytometry, while plasma cytokine concentrations and markers of muscle damage were analyzed via multiplex and spectrophotometric assays, respectively. Creatine Kinase and myoglobin were elevated at each time point for PPB and PL (p (<) 0.050). Monocyte chemoattractant protein-1 was significantly elevated at IP in PPB (p = 0.005) and PL (p = 0.006) and significantly greater than CON at 5H (PPB: p (<) 0.001; PL: p = 0.006). Granulocyte proportions were elevated at 1H (p (<) 0.001), 5H (p (<) 0.001) and 24H (p = 0.005; p = 0.006) in PPB and PL, respectively. Classical monocyte proportions were lower in PPB (p = 0.008) and PL (p = 0.003) than CON at IP, and significantly greater than CON at 1H (PPB: p = 0.002; PL: p = 0.006). Nonclassical monocyte proportions were significantly greater in PPB (p = 0.020) and PL (p = 0.028) than CON at IP. Intermediate monocyte proportions were significantly greater in PPB (p = 0.034) and PL (p = 0.001) than CON at IP, and significantly lower than CON at 1H (PPB: p = 0.003; PL: p = 0.008). Intermediate monocyte proportions were also significantly greater in PPB than CON at 24H (p = 0.016) and 48H (p = 0.007). At PRE, CD11b expression was significantly lower in the PPB group than CON and PL for intermediate (p = 0.017; p = 0.045) and nonclassical (p (<) 0.001, p = 0.019) monocytes, respectively. When groups were combined, CD11b expression was significantly elevated from PRE at IP (p (<) 0.001) and 1H (p = 0.015) on granulocytes. CD11b expression on classical monocytes was significantly elevated compared to PRE at 1H (p (<) 0.001), 5H (p = 0.033) and 24H (p = 0.004) when groups were combined. CD11b expression on intermediate monocytes was significantly elevated compared to PRE at 1H (p (<) 0.001) when groups were combined. Intermediate and nonclassical monocyte proportions also showed significant positive correlations with markers of muscle damage (r = 0.361 to 0.775, p(<)0.05). Results indicated that resistance exercise in novice lifters may elicit a selective mobilization of intermediate monocytes at 24h and 48H, and that muscle damage may be related to increases in intermediate and nonclassical monocytes. In addition, polyphenol supplementation appeared to suppress CD11b expression on monocytes to resistance exercise.
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Date Issued: 2016
Identifier: CFE0006119, ucf:51177
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006119

Title: Do Changes in Muscle Architecture Effect Post- Activation Potentiation.
Creator: Reardon, Danielle, Hoffman, Jay, Fragala, Maren, Stout, Jeffrey, Fukuda, David, University of Central Florida
Abstract / Description: Purpose: To examine the effect of three muscle potentiation protocols on changes in muscle architecture and the subsequent effect on jump power performance. Methods: Maximal (1RM) squat strength (Mean SD=178.3 (&)#177; 36.6kg), vertical jump power, and muscle architecture were obtained in 12 resistance trained men (25.2(&)#177;3.6y; 90.67(&)#177;12.7kg). Participants randomly completed three squatting protocols at 75% (3 x 10 reps), 90% (3 x 3 reps) or 100% (1 x 1) of their 1RM, or no workout...
Show morePurpose: To examine the effect of three muscle potentiation protocols on changes in muscle architecture and the subsequent effect on jump power performance. Methods: Maximal (1RM) squat strength (Mean SD=178.3 (&)#177; 36.6kg), vertical jump power, and muscle architecture were obtained in 12 resistance trained men (25.2(&)#177;3.6y; 90.67(&)#177;12.7kg). Participants randomly completed three squatting protocols at 75% (3 x 10 reps), 90% (3 x 3 reps) or 100% (1 x 1) of their 1RM, or no workout (CON), with each protocol being separated by one week. During each testing session ultrasound and vertical jump testing were assessed at baseline (BL), 8min post (8P) and 20min post (20P) workout. Ultrasound measures of the rectus femoris (RF) and vastus lateralis (VL) muscles included; cross sectional area (CSA) and pennation angle (PNG). Following each ultrasound, peak (PVJP) and mean (MVJP) vertical jump power (using hands for maximum jump height) were measured using an accelerometer. Results: Magnitude based inferences analysis indicated that in comparison to CON, 75% resulted in a likely greater change in RF-CSA and VL-CSA (BL-8P and BL(-)20P), 90% resulted in a likely greater RF-CSA and VL-CSA (BL(-)20P), and 100% resulted in a very likely or likely decrease in VL-PNG at BL-8P and BL(-)20P, respectively). Meanwhile, changes in PVJP and MVJP for the 75% trial was likely decreased at BL-8P and BL(-)20P; and for the 90% trial MVJP was likely decreased at BL-8P and BL(-)20P. Analysis of the magnitude of the relationships indicated a likely negative relationship between VL-PNG and MVJP (r = -0.35; p (<) 0.018) at BL-8P, while at BL(-)20P, a negative relationship was observed between PVJP and RF-CSA (r = -0.37; p (<) 0.014). Conclusion: Acute increases in muscle size and acute decreases in pennation angle did not result in any potentiation in vertical jump power measures. Although the inverse relationships observed between muscle architecture variables and power suggests a potential effect, the change in position (i.e. movement from standing to supine for ultrasound measures) may negate, as a result of potential fluid shifts or muscle relaxation, the potentiating effects of the exercise. It is also possible that the fatiguing nature of the squat protocols in trained but not competitive participants may have also contributed to the results.
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Date Issued: 2013
Identifier: CFE0005048, ucf:49963
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005048

Title: The Effects of High-Intensity Interval Training and 28 days of [Beta]-Hydroxy-[Beta]-Methybutyrate Supplementation on Measures of Aerobic Power and Metabolic Thresholds.
Creator: Robinson, Edward, Stout, Jeffrey, Hoffman, Jay, Fragala, Maren, Fukuda, David, Ferguson, Matthew, University of Central Florida
Abstract / Description: Purpose: To examine the effects of 28 days of ?-hydroxy-?-methylbutyrate free acid (HMB) and high-intensity interval training (HIIT) on maximal oxygen consumption (VO2peak), ventilatory threshold (VT), respiratory compensation point (RCP) and time to exhaustion (Tmax) in college-aged men and women. Methods: Healthy men and women (n=34, age and V ?O2peak= 22.7+3.1yr and 39.3+5.0 mL.kg-1.min-1, respectively) participated in this study. All participants completed a series of tests prior and...
Show morePurpose: To examine the effects of 28 days of ?-hydroxy-?-methylbutyrate free acid (HMB) and high-intensity interval training (HIIT) on maximal oxygen consumption (VO2peak), ventilatory threshold (VT), respiratory compensation point (RCP) and time to exhaustion (Tmax) in college-aged men and women. Methods: Healthy men and women (n=34, age and V ?O2peak= 22.7+3.1yr and 39.3+5.0 mL.kg-1.min-1, respectively) participated in this study. All participants completed a series of tests prior and subsequent to treatment. A maximal oxygen consumption test was performed on a cycle ergometer to assess VO2peak, Tmax, VT, and RCP. The peak power output (Ppeak), power at VT (PVT) and power at RCP (PRCP) were also recorded from this test. Twenty-six subjects completed 12 HIIT (80-120% maximal workload) exercise sessions consisting of 5-6 bouts of a 2:1 minute cycling work to rest ratio protocol over a four-week period, while eight served as controls (CTL). In double-blind fashion, the HIIT groups were assigned into either a placebo (HIIT) or 3g per day of HMB (HMB-HIIT). Body composition was measured with dual energy x-ray absorptiometry (DEXA). Outcomes were assessed by ANCOVA with posttest means adjusted for pretest differences. Results: The HMB-HIIT intervention showed significant (p(<)0.05) gains in VO2peak, VT, and PVT versus the CTL and HIIT group. Both HIIT and HMB-HIIT treatment groups demonstrated significant (p(<)0.05) improvement over CTL for Ppeak, Tmax, RCP, and PRCP with no significant difference between the treatment groups. There were no significant differences observed for any measures of body composition. An independent-samples t-test confirmed that there were no significant differences between the training volumes for the HIIT and HMB-HIIT groups. Conclusion: These findings suggest that the addition of HMB supplementation may result in greater changes in VO2peak and VT than HIIT alone. Therefore, in college-aged men and women, the use of HMB supplementation may enhance the benefits of HIIT on aerobic performance measures.
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Date Issued: 2014
Identifier: CFE0005240, ucf:50604
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005240

Electromyography (4)	+ -
Inflammation (4)	+ -
Resistance Training (3)	+ -
Autism Spectrum Disorder (2)	+ -
Critical Power (2)	+ -

Muscle Damage (2)	+ -
fatigue threshold (2)	+ -
knee extensors (2)	+ -
neuromuscular fatigue (2)	+ -
physical activity (2)	+ -
repeated sprint ability (2)	+ -
running performance (2)	+ -
soccer (2)	+ -
ultrasound (2)	+ -
3-min all-out run (1)	+ -
5000m running (1)	+ -
5k running (1)	+ -
?-Hydroxy-?-Methylbutyrate (1)	+ -
Active Video Games (1)	+ -
Adhesion (1)	+ -
Aerobic (1)	+ -
Aging (1)	+ -
Altitude (1)	+ -
Autism (1)	+ -
BDNF (1)	+ -
C-C Chemokine Receptor 2 (1)	+ -
CD11b (1)	+ -
Center of pressure (1)	+ -
Chemokines (1)	+ -
Chemotaxis (1)	+ -

ETD Collection (36)	+ -
Honors Collection (4)	+ -

University of Central Florida (40)	+ -
Fukuda, David (37)	+ -
Stout, Jeffrey (34)	+ -
Hoffman, Jay (24)	+ -
Fragala, Maren (9)	+ -

Wells, Adam (7)	+ -
Garcia, Jeanette (6)	+ -
Fisher, Thomas (3)	+ -
Fukuda, David H. (3)	+ -
Garcia, Jeanette M. (3)	+ -
Stock, Matt (3)	+ -
Baker, Kayla (2)	+ -
Beyer, Kyle (2)	+ -
Boone, Carleigh (2)	+ -
Lamonica, Michael (2)	+ -
Mangine, Gerald (2)	+ -
Varanoske, Alyssa (2)	+ -
Arroyo Delgado, Eliott (1)	+ -
Barnes, Demani Barak (1)	+ -
Bohner, Jonathan (1)	+ -
Burrell, Auckland J (1)	+ -
Church, David (1)	+ -
Dawson, Nicole (1)	+ -
Ferguson, Matthew (1)	+ -
Girts, Ryan (1)	+ -
Gonzalez, Adam (1)	+ -
Gordon, Joseph (1)	+ -
Harat, Idan (1)	+ -
Hoffman, Mattan (1)	+ -
Jajtner, Adam (1)	+ -

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