The ulnar collateral ligament (UCL) is a prime stabilizer in the elbow against valgus force. It is also a commonly injured structure in the overhead-throwing athlete. The majority of literature to date assesses the medial elbow by adding a valgus stress or evaluates the elbow after injury has occurred. The purpose of this dissertation is to explore static changes to the medial elbow and the relationship with the overhead throw. The first investigation sought to determine if there was a bilateral difference in the medial joint space of the elbow in general population college-aged students. There was no significant difference bilaterally; suggesting that the magnitude of stress applied to the elbow by daily activities is not substantial enough to produce an anatomical change to the connective tissue. However, there was a significant gender effect with males exhibiting larger joint spaces. The second study investigated the bilateral difference in the medial joint space of the elbow in male and female overhead athletes with the same protocol from the previous study. In this study, there was a significant difference between the dominant and non-dominant arms. The third study measured the medial joint space of collegiate baseball pitchers before, after, and 48 hours following the throwing of a simulated game. This study also included measures of grip strength and ball kinematics, in order to investigate a relationship between kinetic and kinematic factors and the changes in the medial joint space. There were no significant changes in the medial joint space following pitching a simulated game, although interestingly, grip strength increased following pitching. Ball kinematics did not indicate a relationship with the changes in the medial elbow joint space.

<p> Sled towing is a common form of overload training in sports to work on muscular strength. This type of training leads to two results; chronic and acute. Acute training leads to postactivation potentiation (PAP), which is when subsequent muscle performance is enhanced following a preloading stimulus. Therefore, the purpose of the study was to determine the optimal rest intervals following sled towing on acute sprint speed. Twenty healthy recreationally trained males (age = 22.35 &plusmn; 2.41 years, height = 176.95 &plusmn; 5.46 cm, mass = 83.19 &plusmn; 11.31 kg) who were currently active in a field sport twice a week for the last six months volunteered to participate. A max 30-meter (m) pre-test BW sprint was performed followed by a 2-minute (min) recovery period. On the remaining 5 visits, participants then sprinted 30-m towing a sled at 30% BW then rested for 2, 4, 8, or 12-min. Participants were instructed to sit still during this time. After the recovery period, a max 30-m post-test BW sprint was performed. The major finding was that post sled pull bodyweight sprint times were less than baseline times on an individualized rest interval basis. This decrease occurred in the acceleration phase over the first 5-m only and was probably the result of PAP and the complex relationship between fatigue and potentiation relative to the intensity of the sled pull and rest interval.</p>

PURPOSE: To examine the influence of the Ultraman triathlon (3 days of non-continuous racing; stage 1: 10 km swim and 144.8 km cycle; stage 2: 275.4 km cycle; stage 3: 84.4 km run) on circulating plasma concentrations of whole-body (CRP, IL-6, and IL-10) and gut-specific inflammatory markers (IL-17 and IL-23) in trained participants, and determine whether these variables influence performance. METHODS: Fourteen triathletes (age: 39 ± 8 yrs; 12 men, 2 women) were evaluated pre-race and post-race for circulating concentrations of CRP, IL-6, IL-10, IL-17, and IL-23. Blood samples were drawn two days prior to stage 1 (1600 h) and one day after stage 3 (1200 h). Plasma biomarker concentrations were determined by ELISA according to manufacturer’s instructions. Data were analyzed with SPSS and significance was accepted at p < 0.05. Values are reported as means ± SD. RESULTS: Plasma CRP significantly increased from pre-race (266.27 ± 276.18 ng/mL) to post-race (25,891.94 ± 12,888.65 ng/mL; p < 0.001). Plasma IL-10 increased from pre-race (3.46 ± 2.98 pg/mL) to post-race (5.15 ± 1.89 pg/mL). Pre-race concentrations of IL-6 were below detectable limits; post-race IL-6 concentrations were 4.00 ± 3.74 pg/mL. Both pre-race and post-race concentrations of IL-17 and IL-23 were below detectable limits. Pearson’s correlation between mean finish time and post-race CRP and post-race IL-10 was 0.35 and 0.54 (p < 0.05), respectively. CONCLUSIONS: The significant increase in CRP during the race may have been due to muscle damage. The greater anti-inflammatory capacity of the athletes likely led to increased clearance of IL-6, IL-17, and IL-23 the day after the race; the increase in IL-10 concentrations during the race reflect this anti-inflammatory response. A significant positive correlation between post-race IL-10 concentrations and mean finish time may indicate that a relationship between anti-inflammatory responses and performance exists. / A Thesis submitted to the Department of Nutrition, Food and Exercise Sciences in partial fulfillment of the requirements for the degree of Master of Science. / Spring Semester 2018. / March 28, 2018. / Includes bibliographical references. / Michael Ormsbee, Professor Directing Thesis; Lynn Panton, Committee Member; Daniel Van Durme, Committee Member.

Introduction: Cold-induced changes in lactate kinetics are critically important for athletes, particularly those training and competing in the cold. Alterations in lactate production and/or clearance may result in altered blood lactate concentrations and calculated lactate threshold), which affects the exercise intensity that athletes can sustain during a race. The purpose of this study was to evaluate the effect of cold ambient temperature on lactate threshold with and without a preceding warm-up in female cyclists/triathletes. Methods: Seven well-trained female cyclists/triathletes (age: 37 ± 5.yrs; body mass: 60.08 ± 8.93kg; VO2peak :50.36 ± 3.04 ml·kg-1·min-1; peak power output: 261.43 ± 30.78W) participated in this study and completed five study visits: 1) baseline testing; 2) familiarization trial: 3) three experimental trials. The experimental visits consisted of: 1) thermoneutral temperature (20ºC, NEU); 2) cold temperature (0ºC) without an active warm-up (CNWU); 3) cold temperature (0ºC) with 25 min active warm-up (CWU). During each condition, participants performed a lactate threshold test followed by a time to exhaustion trial at 120% of the participant’s peak power output. Heart rate (HR), VO2, core temperature, skin temperature, blood lactate concentration, and rating of perceived exertion (RPE) were assessed throughout each trial. Magnitude based inferences were utilized to examine performance effects (interpreted with Hopkins’ effect sizes). Physiological and perceptual data was assessed via null-hypothesis testing. Data are presented as mean ± SD. Results: Power output at lactate threshold was 182.1 ± 26.4, 200.0 ± 22.6, and 192.9 ± 30.1 W for NEU, CNWU, and CWU, respectively. Power output at lactate threshold was 5.4 ± 2.6% lower in NEU vs. CWU (90% C. I= -10, 0.04; ES = -0.34). Power output at lactate threshold was 4.2 ± 2.7% higher in CNWU vs. CWU; this difference was likely trivial (90% C.I = -1.1, 9.8; ES = 0.25). Power output at lactate threshold in CNWU vs. NEU was 10.2 ± 2.6% greater and the effect was considered very likely small (90% C. I= 4.9, 15.8; ES= 0.59). At lactate threshold, there were no significant differences between groups in VO2, lactate concentration, heart rate or RPE (p = 0.487, 0.115, 0.841, and 0.87, respectively).There was an 11% increase in time to exhaustion at 120% peak power output VO2max between CNWU vs. CWU (73.14 ± 7.93 s, 64.86 ± 7.93 s; 90% C. I= -2.4, 26.5; ES =0.62, respectively) and this effect was likely small. Time to exhaustion was 7.8% longer in NEU condition compared to CWU (70.14 ± 10.45 s, 64.86 ± 7.93 s, 90% C. I= -6.2, 23.9; possibly small; ES =0.44, respectively). Lastly, CNWU vs. NEU had a possibly trivial (3%) increase in time to exhaustion (73.14 ± 7.93 s, 70.14 ± 10.45 s; 90% C.I =-9.1, 16.8; ES =0.18, respectively) Conclusion: These findings suggest that power output at lactate threshold and time to exhaustion at 120% of peak power output was greater and longer in CNWU compared to NEU in female cyclists/triathletes, likely resulting in a small change in performance. For female cyclists/triathletes exercising in the cold, it appears avoiding a 25 min active warm-up may improve performance at lactate threshold and time to exhaustion at 120% of peak power output. Therefore, athletes should consider the effect temperature has on lactate kinetics and determine appropriate training methods and race procedures necessary to optimize performance. / A Thesis submitted to the Department of Nutrition, Food and Exercise Sciences in partial fulfillment of the requirements for the degree of Master of Science. / Spring Semester 2018. / March 9, 2018. / cold, environmental physiology, lactate threshold, performance / Includes bibliographical references. / Michael Ormsbee, Professor Directing Thesis; Lynn Panton, Committee Member; Cathy Levenson, Committee Member.

Introduction. TeaCrine® is the pharmaceutically-produced, synthetic version to naturally occurring theacrine (1, 3, 7, 9-tetramethyluric acid) found in the leaves of the Camellia kucha tea plants. Few studies have examined the effects of TeaCrine® on cognitive function, but no research exists examining its effects on exercise performance. As such, the purpose of this study was to examine the effects of TeaCrine® on resistance exercise performance. Methods. Twelve resistance trained men (mean ± SD, age: 23.17 ± 3.10 years; height: 176.53 ± 5.89 cm, weight: 83.24 ± 7.23 kg) were recruited to participate in this study to examine the effects of TeaCrine on resistance exercise performance. Each participant performed (in order) one repetition maximum (1RM) bench press, 1RM squat, bench press reps to failure (RTF) at 70% 1RM, squat RTF at 70% 1RM, and 2km rowing time trial after the consumption one of four treatments (in random order): (1) Caffeine 300mg (CAFF300); (2) TeaCrine® 300mg (TEA300); (3) TeaCrine® + Caffeine combo (150mg/150mg) (COMBO); (4) Placebo (PLA). Visual analog scales for energy, focus, motivation to exercise, and fatigue were administered at baseline and, 90 min post-treatment. Rating of perceived exertion was also assessed after bench press and squat RTF at 70% 1RM. Magnitude based inferences were utilized to examine performance effects in 1RM and RTF for bench press and squat. Performance and perceptual data was also assessed via null-hypothesis testing. Data are presented as mean ± SD. Results. Mean bench press 1RM was 1.3%, 2.2%, and 2% higher in CAFF300 (120.08 ± 16.21 kg), TEA300 (118.94 ± 15.7 kg), and COMBO (119.89 ± 15.96 kg) compared to PLA (17.42 ± 15.52 kg), respectively. Mean squat 1RM was 150.57 ± 23.88, 148.48 ± 25.37, 149.81 ± 23.49, and 147.54 ± 20.8 kg for CAFF300, TEA300, COMBO, and PLA, respectively. Performance in CAFF300, TEA300, and COMBO were 1.8% ,0.2%, 1.3% higher compared to PLA. Mean bench press RTF was 1.4%, 5.0%, 1.5% higher in CAFF300 (12.41 ± 2.71 reps), TEA300 (12.83 ± 2.59 reps) and COMBO (12.50 ± 2.88 reps) compared to PLA (12.25 ± 2.67 reps), respectively. Mean differences in CAFF300, TEA300, and COMBO vs. PLA were 11.3% ,0.7%, 2.4%, respectively. Mean effects between all treatments for muscular strength and endurance were trivial and there were no significant differences between groups (p>0.05). CAFF300, TEA300, and COMBO were not different from PLA for 1RM and RTF in either the bench press or squat (p>0.05). There were no significant differences in peak or average power or velocity for bench press or squat. Only CAFF300 resulted in significant increases in energy (+9.8%; +15.3%), and motivation to exercise (+8.9%, +14.6%) vs. TEA300 and PLA, respectively, and increased focus (+9.6%) vs. TEA300, but no differences from COMBO. Conclusion. CAFF300, TEA300 and COMBO had no significant effect on 1RM, RTF, power or velocity in the bench press and squat. CAFF300 improved measures of focus, energy or motivation to exercise but TEA300, COMBO, and PLA did not. / A Thesis submitted to the Department of Nutrition, Food and Exercise Sciences in partial fulfillment of the requirements for the degree of Master of Science. / Spring Semester 2018. / April 3, 2018. / Caffeine, Muscular endurance, Muscular strength, Power, TeaCrine / Includes bibliographical references. / Michael J. Ormsbee, Professor Directing Thesis; Jeong-Su Kim, Committee Member; Michael Leeser, External Committee Member.

<p> Many athletes have started to specialize in a particular sport at a much younger age. To narrow down the population we looked into volleyball athletes that sport specialize at a younger age compared to those that wait until a later age. Looking into the long term effects on the athlete&rsquo;s skill level, injury and burnout rates. This cross-sectional study took two days of data collections involving 27 participants. Testing consisting of sport specific testing, anthropometrics, and surveys to investigate for volleyball history, injury and burnout in participants. Data showed that athletes that have participated for more than 3 years had a higher vertical approach and standing jump. Along with their motor development, the t-test agility test showed they were able to change direction with more ease and at a faster rate than those athletes having played less. The self-reported data showed that athletes had more ankle injuries as compared to others and 12 out of the 18 athletes reported feeling burnout from the year round sport. Concluding that the athletes that start at an earlier age have more increased motor development leading to their ability to move with ease when demonstrating the sport specific skills. More data is needed to come to a conclusion about the injury and burnout rate in the sport-specific athletes. </p><p>

<p> The purpose of this study was to investigate sartorius activity and angles of hip flexion, hip external rotation, and knee extension. These variables were evaluated during the two phases between pass&eacute; and full extension of a d&eacute;velopp&eacute; devant. Data were collected for both parallel and turned-out positions about 90&deg; of hip flexion on the preferred leg, in a sample of collegiate dancers. </p><p> Findings of the present study suggest that the sartorius experiences greater changes in muscle activity as a result of greater changes in ROM. Additionally, it can be deduced that the sartorius&rsquo;s contribution to hip external rotation might be largely responsible for the muscle&rsquo;s greater activity observed in turnout versus parallel. However, distinction of how much muscular activity is distributed towards each action of the sartorius at a given time cannot be concluded due to limitations in the equipment used. Further research is needed to understand the d&eacute;velopp&eacute; devant. </p><p>

The lungs were once thought to be over-built for exercise. However, upon further research, endurance athletes have been found to reach their maximum ventilation, demonstrating an insufficiency of the lungs to accommodate the demands of highly demanding endurance sport. This knowledge has inspired researchers to look further into the exercise ventilatory responses and, in doing so, researchers discovered that the adaptations of the pulmonary system to endurance training are still not well understood. Potential reasons for this lack of knowledge may be methodological measurement limitations, as ventilatory mechanics have been measured classically either invasively or by breathing maneuvers. These measurements are difficult to perform during high intensity exercise and in large groups of athletes. However, recent innovations in motion analysis technology have allowed for ventilatory mechanics to be measured during high intensity exercise, potentially allowing for further insight into how high intensity endurance training impacts ventilatory mechanics. The purpose of this study is to describe normal ventilatory mechanics during exercise in endurance trained and healthy untrained individuals, explore potential gender differences during exercise and investigate the impact of flow limitation during exercise on ventilatory mechanics, using a motion analysis system that allows researchers to obtain information on chest wall volume changes and chest wall compartmental interactions during high intensity exercise. This motion analysis system is called Optoelectronic Plethysmography (OEP). This dissertation is comprised of an introduction to the work and the 3 projects that comprise the dissertation along with an appendix, which includes a complete literature review. The three projects are as follows (1) an introduction to motion analysis as a tool in measuring ventilatory mechanics, (2) research determining the differences in the ventilatory mechanics in endurance athletes and healthy controls from rest to maximal exercise and (3) the differences in ventilatory mechanics between endurance trained women who demonstrate expiratory flow limitation during high intensity exercise versus endurance trained women who do not. Project 1: Optoelectronic Plethysmography (OEP) is a motion analysis tool that can be used to define exercise ventilatory mechanics by analyzing chest wall movements and calculating volume changes. By analyzing breathing mechanics by motion analysis rather than traditional breathing maneuvers, individual components of the chest wall can be analyzed and changes in volume throughout the chest wall can be assessed without altering the individual's natural breathing pattern. This review presents the history and development of OEP technology, along with a summary of the methods used and a discussion of findings to date, giving insight into exercise ventilatory mechanics never investigated before. Project 2: Differences between the ventilatory mechanics of endurance athletes and non athletes using motion analysis have not yet been described. To determine how increased ventilatory demand impacts ventilatory kinematics, we compared the total chest wall volume variations (VCW) of 18 male and female endurance-trained athletes (ET) to 14 untrained individuals (UT) during exercise. We hypothesized that training and gender would have an effect on VCW and kinematics at maximal exercise. Gender and training significantly influenced chest wall kinematics. Female ET did not change chest wall end-expiratory volume (VCW,ee) or pulmonary ribcage end-expiratory volume (VRCp,ee) with exercise, while female UT significantly decreased VCW,ee and VRCp,ee with exercise (p<0.05). Female ET significantly increased pulmonary ribcage end-inspiratory volume (VRCp,ei) with exercise (p<0.05), while female UT did not change VRCp,ei with exercise. Male ET significantly increased VRCp,ei with exercise (p<0.05); male UT did not. Men and women had significantly different VCW (p <0.05). Women demonstrated the greatest variation of VCW in the pulmonary ribcage compartment (VRCp). Men had similar volumes in the VRCp and the abdomen (VAb). In conclusion, gender and training had a significant association with ventilatory kinematics. Project 3: Research has found potential limitations of the airways to accommodate the large tidal volumes generated during high intensity exercise. This airway limitation has been defined as expiratory flow limitation (EFL) observed during high intensity exercise in a large percentage of healthy women. Because of endurance athletes' ability to exercise at high intensities for prolonged periods of time and produce greater than average tidal volumes, female endurance athletes may be particularly susceptible to EFL and the impact EFL may have on performance. The purpose of this last chapter was to investigate the ventilatory mechanics and exercise capacity parameters of female endurance athletes with and without EFL. Female competitive cyclists participated in two days of testing; day one consisted of a maximal aerobic capacity test (V ̇o2max test) with spirometry and day two involved chest wall motion analysis testing during two steady state exercise tests. Baseline flow volume loops were performed prior to exercise and repeated post exercise. During exercise participants performed flow volume loops at minutes 4, 6, 8 and last 30 seconds of exercise. EFL was considered present when the exercise flow volume loop surpassed the baseline flow volume loop. To quantify the degree of flow limitation when comparing the peak exercise flow volume loop to the baseline flow volume loop, we calculated the percent flow volume loop reserve (%FVL reserve). Two levels of submaximal constant-load exercise bouts (at 60% and 85% maximal watts) were employed to investigate if EEFL impacted ventilatory mechanics differently at different intensities. Optoelectronic plethysmography (OEP) was employed to measure VT from the pulmonary ribcage (VRCp), abdominal ribcage (VRCa) and the abdomen (VAb), as well as to measure end-expiratory volume chest wall volume (EEEV) to calculate potential dynamic hyperinflation. Comparison of participants with and without EFL was made using an ANOVA or Kruskal-Wallis test (p≤0.05). Predictors of %FVL reserve were explored with a multiple linear regression. Two participants were not included in the data analysis due to the presence of asthma (one at rest, one exercise induced) as determined by spirometry during day one testing. Out of the other 28 participants, 6 participants had definite EFL (DEFL) demonstrated by overlapping of the peak exercise flow volume loop with the pre and post exercise flow volume loop, 5 had borderline EFL (BEFL) demonstrated by an overlapping of only the pre exercise flow volume loop and 17 had no EFL (NEFL) demonstrated by no overlapping of the pre or post flow volume loops. All participants had within normal limits of the percent predicted normal reference values in resting forced expiratory volume in 1 second (FEV1), forced mid expiratory flow rates (FEF25-75L/sec), forced vital capacity (FVC) and FEV1/FVC ratio. DEFL and BEFL participants' had a significantly lower FEV1/FVC ratio compared to NEFL (p=0.003), DEFL had significantly lower FEF25-75% predicted normal reference values before and after exercise compared to NEFL (p=0.004). There were no differences in the exercise capacity values between groups. During the day two steady state tests, there was a significant interaction effect between groups and exercise intensity in the %VRCa (p=0.045) and % VAb (p=0.049). End-tidal carbon dioxide pressure, FEF25-75%, history of self reported excessive mucus with exercise and % VRCp during the 85% constant load test explained 71.6% of the variability in %FVL reserve in our regression model (p=0.002). Independent predictors of %FVL reserve were: end-tidal carbon dioxide pressure (p=0.033), FEF25-75% (p=0.010) and history of excessive mucus with exercise (0.014). In conclusion, female endurance athletes demonstrating EFL had normal but significantly different FeV1/FVC ratio and significantly different abdominal ribcage and abdomen percent contribution with increased exercise intensity, but similar exercise capacities compared to the female endurance athletes with no EFL. Also, independent predictors of %FVL reserve were found to be FEF25-75%, history of mucus production with exercise and end-tidal carbon dioxide level at peak exercise. This dissertation has provided further insight into the ventilatory mechanics of endurance athletes and how potential airway limitation can impact high intensity exercise. Further research can seek to better understand if the differences in ventilatory mechanics between endurance athletes with EFL and no EFL allow for preservation of exercise capacity in the presence of airway limitation

Neuroplasticity research suggests intervention at early developmental stages is optimal for maximizing recovery of function in children with unilateral spastic cerebral palsy (USCP). Intensive bimanual training is an effective method for improving upper-extremity function in children with USCP when provided in massed-practice day camps. Given the challenges young children face sustaining attention and their susceptibility to fatigue, adapted models using distributed practice are required. The aim of this study was to perform a randomized trial comparing home-based hand-arm bimanual intensive training (H-HABIT) with a control group receiving an intervention of equal duration, intensity, and social interaction. Twenty-four children with USCP (age range 2 yr., 6 mos. - 10 yr. 1 mos.) were randomized to participate in either 90 hours of H-HABIT (n=12) or an equivalent dose of functional lower-limb training (FLL-control; n=12). Caregivers were trained by experienced interventionists to administer either H-HABIT or FLL-control. Caregivers then performed activities with children in their own home 2 hrs./day, 5 days/week for 9 weeks (90 hrs. total). Caregivers were supervised remotely once a week for one hour using telerehabilitation. Dexterity was assessed using the Box and Blocks test. Bimanual hand function was measured using the Assisting Hand Assessment (AHA). Canadian Occupational Performance Measure (COPM) was used to assess caregiver perception (performance and satisfaction) of functional goals. All measures were assessed immediately prior to (pretest) and immediately after (posttest) the intervention and analyzed with a 2(group) x 2(session) repeated measures ANOVA. There were no statistical differences between the two groups at baseline. Children in H-HABIT showed greater improvement (pretest=9.0±5.8; posttest=14.5±7.8) than children in FLL-control (pretest=10.6±7.2; posttest=11.9±6.1) on the Box and Blocks test (for interaction, F(1,20)=18.53, p<.001). Neither group demonstrated change on the AHA (F(1,22)=0.89, p>.05) (H-HABIT=60.5 AHA units±10.1; FLL-Control=52.8 AHA units±17.1). COPM data revealed a significant test session by group interaction (F(1,22)=10.82, p<.01) with caregivers of children in H-HABIT rating higher goal performance (pretest=2.9±1.0; posttest=6.8±1.3) relative to FLL-control (pretest=2.7±1.0; posttest=4.5±1.7). Caregivers in both groups showed equal improvement between the two sessions (F(1,22)=115.63, p<.001) in ratings of satisfaction of goal performance (pretest=3.8±1.8; posttest=7.3±1.1 for H-HABIT and pretest=2.3±1.0; posttest=4.7±1.8 for FLL-control). Children in H-HABIT made greater improvements in dexterity and parent-rated goal performance. This is the first randomized trial to examine the efficacy of intensive bimanual training with caregivers as interventionists—a model which permits intervention at younger ages when there may be greater potential for improving hand function. Using caregivers as a way to implement intensive interventions provides a cost-effective alternative to expensive clinic-based interventions. Home-based models provide a valuable intervention approach to add to the repertoire of options clinicians have to chose from when developing individualized treatment programs for children and their families.

The purpose of this investigation was to determine if 8 exercise endurance training (ET) sessions over 2 weeks significantly alters cardiac autonomic modulation, as measured by heart rate variability (HRV). Twenty-four college-aged males were recruited for this study and were randomized into either an exercise group (EX; n=12) or a control group (CT; n=12). EX underwent 2 weeks of ET on a cycle-ergometer (frequency: four times/week; duration: 40 minutes; intensity 80-85% HRreserve), whereas CT was instructed not to alter their previous level of physical activity. Five-minute ECG tracings were collected for HRV under the following conditions: 5 minutes of paced breathing at a frequency of 12 breaths/minute (PB), 5 minutes of spontaneous breathing (SB1), 5 minutes of 70-degree head-up tilt on a tilt table (TILT), and a second 5-minute period of spontaneous breathing (SB2). The data were collected on 5 occasions (Test 1-Test 5) during a 2-week period. HRV was reported as the standard deviation of RR intervals, and as normalized units (NU) of the natural logarithm of high- and low-frequency power (lnHF and lnLF). A mixed-model analysis of variance (ANOVA) with repeated measures was used to evaluate any Group X Time interaction, or main effects of Group or Time on HRV. Alpha was set at 0.05. EX exhibited a significant increase in peak oxygen consumption (8%), whereas this parameter was unchanged in CT. During PB, ANOVA revealed a Group X Time interaction such that EX exhibited decreases in lnLFNU (2.89 vs. 3.45 ln%) and lnLF/lnHF (0.82 vs. 0.90) during Test 5 compared to Test 1, while there were no such differences across time in CT. Additionally, there was a Group X Time interaction during TILT such that EX exhibited lower lnLFNU (4.12 vs. 4.42 ln%) and lnLF/lnHF (1.12 vs. 1.46), and greater lnHFNU (3.52 vs. 2.53 ln%) during Test 5 compared to Test 1, while these indices were unchanged across time in CT. These data suggest that 8 ET sessions over 2 weeks increases vagal modulation of the heart. Furthermore, these data suggest that it takes at least 8 ET sessions to induce such changes.