Eighteen well trained males (1RM Squat: 150.57 ± 26.79 kg) were assigned to two groups: full ROM training (control) and full ROM with partial ROM training (CP) for the seven-week training intervention. There was a significant time effect (p

The purpose of this study is to investigate the use of isometric mid-thigh pulls to determine lower-limb asymmetrical strength differences in NCAA D-I athletes. Sixty-six subjects (40 males and 26 females) performed 2 maximal effort isometric pulls over two force plates sampling at 1000 Hz each. Peak force was scaled for body weight, and rate of force development was examined from 0-200ms. Results of the study show subjects' produced significantly greater scaled force with the left leg as compared to the right leg; however, no significant differences existed for rate of force development (RFD). Men exhibited significant differences between both scaled peak force and RFD, while women only showed significant differences in scaled peak force. Of the 66 subjects tested, 6 subjects (5 men and 1 woman) exhibited percent differences of 15% or greater asymmetry for scaled peak force. The results indicate that isometric mid-thigh pulls are a way to show the presence of asymmetries in D-I athletes.

No description available.

Placebo treatments have long been used to study the psychological effects of expectancy and conditioning on an inert intervention. Interestingly, open-label placebo treatments (i.e., directly telling subjects they are receiving an inactive intervention) have recently shown promise in minimizing pain in clinical patient populations. We utilized a repeated measures design to examine the acute effects of placebo, open-label placebo, and control treatments on muscle strength and voluntary activation (Experiment #1), as well as neuromuscular fatigue (Experiment #2). Twenty-one untrained males (n=11) and females (n=10) visited the laboratory on three occasions to receive each treatment in a randomized, counter-balanced manner. All visits involved a pretest, 15-minute intervention period, and posttest. In Experiment #1, knee extensor maximal voluntary isometric contraction (MVIC) peak torque and percent voluntary activation were evaluated. In Experiment #2, subjects performed 20, six-second MVICs while surface electromyographic signals were detected from the vastus lateralis. Subjective assessments of energy and perceived exertion were also examined. In Experiment #1, no differences among interventions were demonstrated for peak torque or voluntary activation, but a main effect revealed that energy levels increased following each treatment (p = .016, η2 = .257). Experiment #2 demonstrated that placebo and open-label placebo treatments had no influence on neuromuscular fatigue, but there were main effects for declines in absolute (p = .001, η2 = .675) and normalized peak torque (p = .001, η2 = .765), electromyographic mean frequency (p = .001, η2 = .565), neuromuscular efficiency (p = .001, η2 = .585), and energy levels (p = .006, η2 = .317). Collectively, placebo and open-label placebo treatments had minimal influence on strength, voluntary activation, and fatigue resistance in untrained subjects. We speculate that our subject population and study design intricacies that are unique to placebo trials may explain our findings.

The purpose of this study was to observe physiological metrics relative to training-induced adaptations in conjunction with laboratory- and competition-based performances in a super-heavyweight weightlifter recovering from a meniscus injury. A retrospective analysis was conducted on a collegiate level male weightlifter (23.2 yrs; 131.9 kg; 187.3 cm) over the course of 21-weeks post-meniscus surgery. Body mass, body fat percentage, hydration status, vastus lateralis muscle cross-sectional area, jump performance, and isometric midthigh pull were regularly assessed as part of an ongoing athlete monitoring program. Pre-injury baseline (T0) measurements were collected relative to a major national competition (COMP1). Post-injury measurements took place at the end of sequential training blocks: strength-endurance training block 1 (T1), basic strength block 2 (T2), and transmutation block 3 (T3). The final measurement session (T4) was conducted three-days post-local competition (COMP2). Only statistically significant increases were observed from T0-T4 for muscle CSA (p=0.0367), isometric peak force (pp=0.0367), and rate of force development at 250ms (p=.0367). While non-significant changes were observed for jumping performance, jump height and net impulse did, however, return to baseline. Competition based performances also showed marked improvements from pre-to-post injury via an increase in weightlifting total (3.2%∆, +9kg) and Sinclair score (1.8%∆, +5.3au). Thus, based on these findings, implementing an evidence-based training program along with a sound athlete monitoring protocol can aid with reducing an athlete’s return-to-train timeline while improving physiological, laboratory- and competition-based performance outcomes.

This thesis investigates the effect of acute isometric handgrip exercise on cognitive function in young healthy adults / Acute whole-body exercise transiently improves cognitive function which may be mediated by increased cerebral blood flow (CBF) and arousal. Interestingly, small muscle mass exercise, like isometric handgrip exercise (IHG) may stimulate the same physiological responses as whole body-exercise and improve cognitive function. However, these effects are poorly understood, and whether sex-based differences exist in the cognitive response to IHG is unknown. Therefore, the purpose of this study was to investigate whether acute IHG improves cognitive function in young healthy adults and examine potential sex differences in the cognitive response to IHG. We hypothesized that acute IHG would improve cognitive function compared to a control condition, and that females would have greater improvements in cognitive function due to a lower exercise pressor response. To test this, 30 participants (n=15 females, mean age=23.8±3.3 years;BMI=25.3±4.1 kg/m2) completed either IHG or a control condition in a randomized-crossover design separated by at least 2 days. IHG consisted of four sets of 2-min unilateral squeezing a handgrip dynamometer at 30% maximal voluntary contraction separated by 3-min of rest. The control condition watched a nature documentary for 20-min. Hemodynamics (systolic blood pressure, diastolic blood pressure, mean arterial pressure, and heart rate) were assessed throughout. Executive function, working memory, and processing speed were assessed via the 4-Choice, Corsi Block, and N-Back tests. Arousal was assessed using the Felt Arousal Scale (FAS). Middle cerebral artery blood velocity (MCAv) was assessed using transcranial Doppler ultrasound. Compared to the control condition, IHG significantly increased MAP (∆ 26 ± 17 mmHg; P<0.001), HR(∆ 18 ±13 bpm; P<0.001), MCAv (∆ 5.27 ± 19.4 cm/s; P<0.001), cerebrovascular resistance (∆ 0.71 ±0.69 mmHg/cm/s; P=0.003), and arousal (∆ 2 ± 2 FAS score; P<0.001). Cerebrovascular resistance was calculated as MAP/MCAv. Overall, despite increases in MCAv and arousal, there was no effect of IHG on cognitive performance, and no sex differences were observed in the cognitive response to IHG. These findings stand in opposition to emerging work and suggests that increased CBF and arousal via acute IHG are an insufficient stimulus to enhance cognitive function in young adults. Furthermore, there seems to be no moderating effect of biological sex on the cognitive response to acute IHG. / Thesis / Master of Science (MSc) / It is well known that whole-body exercise, such as running, swimming, or lifting weights, improves cognitive function. Cognitive function encompasses our ability to pay attention, remember new information, and make important decisions. We sought to investigate whether isometric handgrip exercise (IHG) could improve cognitive function in young adults, because it may be a new and accessible way to improve cognitive abilities. We also wanted to know if IHG had a different effect on cognitive function in females compared to males. To test cognitivefunction, participants played computer games that measured how their cognitive abilities were affected by IHG. In particular, we examined how IHG impacted a participant’s memory, decision making, and speed to completion. Our results show that IHG increased blood flow to the brain and made participants feel more alert compared to a control condition, however, IHG did not improve performance on the computer games. Males and females also did not differ in terms of their performance on the cognitive tests. Overall, a single session of IHG did not improve cognitive function in young adults. Although IHG did not improve cognitive function in young adults, it should be investigated in other individuals, such as older adults and people with hypertension, who may stand to gain more from IHG.

Resistance exercise (RE) training is a well-known and effective method for promoting increases in muscle mass and strength. A single bout of RE induces physiological disturbances that require coordinated activation of the immune system and intramuscular signaling in order to return the tissue to homeostasis and adapt to the RE challenge. On the other hand, acute binge alcohol consumption can affect the immune response to an inflammatory challenge, intramuscular anabolic signaling, and muscle protein synthesis, and the effects of alcohol on these processes are opposite that of RE. Furthermore, individuals who report more frequent exercise also report a greater frequency of binge drinking. However, few investigations exist regarding the effects of binge alcohol consumed after a bout of RE on RE-induced physiological changes and performance recovery. Therefore, the overarching purpose of the investigations contained within this dissertation was to investigate the effect of alcohol consumed after RE on the RE-induced changes in mTOR pathway signaling, muscle protein synthesis, inflammatory capacity, strength recovery, and power recovery. Although RE increased mTOR pathway signaling and inflammatory capacity after exercise and reduced maximal strength and explosive power the day after exercise, we observed no effects of alcohol (1.09 g ethanol∙kg-1 lean body mass, designed to result in a peak blood alcohol concentration of approximately 0.12 g∙dl-1) consumed after RE on mTOR pathway signaling, 24-hour rates of muscle protein synthesis, inflammatory capacity, or strength and power recovery in resistance-trained individuals.

Surface electromyography (sEMG) and mechanomyography (MMG) are well-studied signals that can reveal information about the physiological behavior of muscles during contraction. The purpose of this study was to quantify, characterize, and analyze the electrical and mechanical muscle responses to submaximal, isometric contractions in the rectus femoris in adults. Previous studies have investigated the use of EMG to monitor muscle fatigue. However, more information appears to be needed about the use of MMG to measure muscle fatigue during submaximal isometric contraction in the rectus femoris. In this study, the utility of MMG as a measure of muscle fatigue or muscle state was investigated. After studying 10 adult subjects (6 females, 4 males) during 2 consecutive fatiguing isometric contractions at 50% MVIC, there was a total sample of 20 contractions. The RMS, frequency, and electromechanical efficiency (EME) were calculated as an average over 2s samples at the beginning, middle and end of the fatiguing contraction for both EMG and MMG. Electrical efficiency and contraction duration were also measured. EMG RMS. MMG RMS, and electrical efficiency showed significant increasing trends during fatiguing exercise (p=0.0001 and p=0.005 respectively). EMG frequency had a significant decreasing trend (p=0.0016). There was also a significant decrease in the contraction duration when fatiguing exercises were repeated in the same session (p=0.0228). EME and MMG frequency did not have significant trends. However, further studies of these parameters during different fatiguing exercises may help expand their utility in monitoring muscle state. Overall, this study suggests that sEMG and MMG may have utility in monitoring muscle fatigue in submaximal, isometric contractions in the rectus femoris. sEMG and MMG may also find future applications in monitoring patients with muscle conditions.

Self-Control Training (SCT) and Brain Endurance Training (BET) are novel training modalities designed to enhance physical endurance by building fatigue resiliency. Despite their similarities, it has yet to be examined whether combining SCT and BET provides an additive or redundant/overlapping effect on endurance exercise performance. This study investigated the effects of SCT and combined SCT+BET on performance of a maximal exertion isometric resistance endurance task (high plank) and ratings of perceived exertion (RPE). Participants (N = 33) were randomized to engage in 4 weeks (18 training sessions) of SCT (isometric handgrip; n = 13), SCT+BET (10-minute cognitively demanding task, followed by SCT; n = 10), or no-training/control (n = 10). Isometric endurance performance trials were completed at pre-, mid-, and post-training. One-way analysis of covariance (ANCOVA) models were computed for each of the mid- and post-training trials (controlling for pre-training high-plank performance) to assess effects on performance. Results showed no significant effects of training on high plank performance between groups at mid-training; however, a large and significant effect for SCT compared to control was observed at post-training (p = .044, d = .961). No significant main effects or interaction effects were found for changes in RPE over time (p’s > .05). Findings support the use of SCT as an effective training method for physical endurance performance and suggest that BET may not offer additional performance benefit compared to SCT under the training and testing conditions used in this protocol. Future research should explore potential dose-response effects of SCT on performance and moderators such as trait self-control. / Thesis / Master of Science (MSc)

<p> Hypertension is a modifiable risk factor for cardiovascular disease. The current treatment options are drug therapy and lifestyle modifications. A promising lifestyle modification therapy for the management of hypertension is isometric exercise, as several studies have demonstrated that isometric handgrip (IHG) training reduces resting arterial blood pressure (ABP) (Peters et al., 2006; Taylor et al., 2003; Wiley et al., 1992). The purpose of the present investigation was two-fold: 1) to examine the effectiveness of IHG training in reducing resting ABP in newly diagnosed hypertensive patients, in comparison to matched controls receiving advice from a physician about lifestyle modifications; and 2) to examine markers of autonomic function, specifically, heart rate variability (HRV) to determine if changes in the autonomic nervous system (ANS) existed between the two groups of hypertensive adults.</p> <p> Resting blood pressure and heart rate were assessed with an automated acquisition system before, during and after the 6-week intervention period. Also, power spectral analysis of HRV was used to assess changes in modulation of the ANS. Participants in both groups (n=14) were given lifestyle modification recommendations regarding diet, exercise and stress reduction, while participants in the training group (n=8) also completed a bilateral IHG training protocol 3 times/week at 30% maximum voluntary contraction (MVC).</p> <p> Our results demonstrate that contrary to our hypothesis, isometric exercise in combination with lifestyle modification recommendations did not result in a reduction of resting ABP or change indices of HRV. Possible explanations for these results are that unlike previous IHG training, the present study was the first to use home-based training and the small sample size of this investigation would limit our ability to identify alterations in resting ABP or HRV.</p> / Thesis / Master of Science (MSc)