The current recommendations by the American Heart Association for health promotion are that all persons should partake in regular physical activity in order to reduce the risk of cardiovascular disease. Regular physical exercise reduces blood pressure and is an important component of the management of hypertension. It is therefore important that patients with hypertension participate in habitual physical exercise. Many hypertensive patients who exercise will require anti-hypertensive medication. However, some antihypertensive agents cause fatigue during exercise. In order for patients to gain the full benefits of an active lifestyle, it is important that the prescribed antihypertensive agent does not prevent them performing and enjoying sustained exercise. It has been well documented that β-blockers cause premature fatigue during physical exercise. The effects on exercise performance of other first line antihypertensive medications, such as calcium channel antagonists have not been extensively investigated. In particular, the effects of these agents on prolonged submaximal exercise endurance have not been well studied. The object of this thesis was to compare the effects of isradipine, a dihydropyridine calcium channel antagonist, to those of atenolol, a β₁-selective antagonist, on maximal and submaximal exercise performance and on short duration high-intensity exercise in physically active hypertensive patients. The study design was a crossover trial where drug treatments were double blinded and randomised. Physically active volunteers with mild to moderate hypertension were recruited. 11 subjects performed i) progressive exercise to exhaustion for determination of maximal oxygen consumption (VO₂max), maximal work load and cardiorespiratory responses to maximal exercise, ii) prolonged submaximal exercise for determination of exercise endurance, cardiorespiratory responses and ratings of perceived exertion (APE), and iii) short duration, high intensity exercise consisting of a 30 second maximal exercise test (Wingate test) to determine skeletal muscle power output, following 4 weeks ingestion of isradipine (2.5mg bd), atenolol (50mg bd) or placebo. Diastolic blood pressure at rest was reduced by both atenolol and isradipine, but was lowered to a greater extent by atenolol (83.3 vs 89.0 vs 96.1 mmHg, atenolol vs isradipine vs placebo, p<.0005). Systolic blood pressure at rest tended to be similarly reduced by both agents, but was significantly reduced during maximal and submaximal exercise by atenolol only (p<.001, atenolol vs isradipine, placebo). Heart rate at rest and during maximal and submaximal exercise was decreased by atenolol only (p<.0005, atenolol vs isradipine, placebo). Maximal exercise performance was reduced after atenolol ingestion compared to placebo but not after isradipine ingestion. Peak workload achieved during the maximal exercise test was decreased after atenolol but unchanged after isradipine ingestion (214 vs 243 W, atenolol vs placebo, p<.01). Similarly, VO₂max was reduced after atenolol compared to placebo but was unchanged after isradipine ingestion (33.6 vs 36.4, 33.6 vs 36.1 mlO₂/kg/min, atenolol vs placebo, atenolol vs isradipine, p<.05). Both atenolol and isradipine ingestion reduced submaximal endurance time compared to placebo (27.8 vs 46.4, 34.4 vs 46.4 min, atenolol vs placebo, isradipine vs placebo, p<.005), and increased rating of perceived exertion (APE) after 30 min of submaximal exercise (p<.05). Submaximal oxygen consumption (VO₂), ventilation, respiratory exchange ratio (REA) and blood lactate, glucose and free fatty acid concentrations were not altered after the ingestion of either agent. Neither agent influenced peak skeletal muscle power, total work done, or rate of fatigue during the Wingate test compared to placebo. The results of these studies indicate that impaired performance and increased RPE during submaximal exercise after ingestion of either atenolol or isradipine is not due to alterations of ventilation, VO₂, RER, or blood lactate, glucose and free fatty acid concentrations during prolonged submaximal exercise. Similarly, reduced submaximal exercise performance after atenolol or isradipine ingestion is not due to factors which would also limit the ability of skeletal muscle to perform short duration, high intensity exercise before a bout of prolonged exercise. This study demonstrates that prolonged submaximal exercise testing can reveal an impairment in exercise performance after ingestion of antihypertensive medication which is not evident during maximal exercise testing. This finding is important as prolonged submaximal exercise is the form of exercise which most hypertensive patients actually perform. Further research is required on the effects of anti-hypertensive medications on submaximal exercise performance before firm recommendations can be made regarding medications most suitable for the physically active hypertensive patient. The results of these and other studies indicate that it is not yet possible to make claims that the calcium channel antagonist agents are without effect on physical exercise performance in physically active hypertensive patients.

The purpose of this study was to compare core muscle activity during resistance exercises performed on stable ground versus an unstable surface and to examine whether lifting at different relative intensities affects core muscle activity levels. Twelve trained men performed four different movements including the deadlift, back squat, military press, and curl. Surface electromyography (EMG) was utilized to assess the activity of the rectus abdominis, external oblique, transversus abdominis, and erector spinae muscles. Participants performed each movement under three separate conditions including standing on stable ground with 50% of their one repetition maximum (1-RM), standing on a BOSU balance trainer with 50% of their 1-RM and, standing on stable ground with 75% of their 1-RM. The following muscles exhibited greater activity during the 75% 1-RM condition than all other conditions: the transversus abdominis (TA) and external oblique (EO) muscles during the deadlift; the rectus abdominis (RA) during the squat; the TA, RA, and EO during the press, and TA and erector spinae (ES) during the curl. The ES muscle during the press movement and EO during the squat movement were more active during the BOSU 50% 1-RM condition than the stable 50% 1-RM condition. Healthy individuals might consider performing the military press, curl, squat and deadlift movements with higher intensity resistances while standing on stable ground to incur higher widespread muscle activity of the core region.

RED-S is a syndrome that stems from low energy availability (LEA) in athletes. It can impact numerous physiological and psychological functions, as well as negatively affect performance. Because RED-S is a relatively new syndrome, there are few studies showing the impact of RED-S on performance and physiological factors. The aim of this systematic review was to examine the consequences of induced LEA in relation to RED-S in male athletes. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, Five studies were deemed eligible based on inclusion and exclusion criteria. Studies measured risk of RED-S through body composition, bone mineral density, clinical biomarkers, and performance. Studies ranged in duration from 2- 8 weeks with a decrease in energy availability of 50% or 25%. Of the five studies investigated, data showed significant changes lactate metabolism and IGF-1,non-significant changes in body composition, and inconclusive changes in performance.

Cancer is the second leading cause of death, with about approximately 1.9 million Americans being diagnosed each year. Yet, it has high survival rates with the help of advancing treatments like radiation therapy. Cancer patients and survivors are contingent on experiencing a decline in physical functioning, quality of life, and physiological parameters. Treatment is effective and can prolong life expectancy but can be deleterious to a patient’s health. Parallel with cancer's impact on Americans is cardiovascular disease. Cardiovascular disease is responsible for 1 in 4 deaths. The development of cardiovascular disease is not spread accordantly among all ethnicities. Hispanics are more likely to have a type of cardiovascular disease. Structured exercise has consistently been established to be an effective countermeasure for diminishing cardiovascular risk factors, adverse side effects, and symptoms of cancer and cancer treatment. The purpose of this thesis is to evaluate the effect of structured exercise to address 3 questions with limited data. The evaluation included the incidence of cardiovascular disease in at-risk Hispanics, physiological adaptions to a structured exercise program, and the effect of radiation therapy on exercise outcomes. Subjects for each study were enrolled in a 6 10-week structured exercise program consisting of aerobic, resistance, and flexibility exercises. Conclusions were no difference in exercise benefits in ethnicity but exercise did improve cancer survivors’ physical functioning in all domains.

The purpose of this study is to determine if there is a relationship between rapid weight loss and physical performance in combat sports athletes. The inclusion criteria were rapid weight loss and physical performance effects among combat sports researched in the last 20 years. Phrases, as well as keywords, were searched using multiple databases. The keywords included mixed martial arts (MMA), judo, wrestling, taekwondo, boxing, studies that looked at multiple disciplines at once, and unspecified disciplines. Results of the literature review indicate that there are negative effects on performance due to rapid weight loss and dehydration in combat sports. Appendix I summarizes the data found. However, other literature has suggested no physical performance effects following a period of rapid weight loss. Determination at what percentage of body mass loss unequivocally affects physical performance measures and the threshold in which a certain athlete is likely to experience these effects is key. Factors that seem to influence the magnitude of measured performance effects include the length of recovery time following the period of rapid weight loss, the magnitude of body mass lost, as well as methods used to achieve weight loss. The results of this study may help provide insight into areas of research that are lacking data on this subject and may also provide helpful guidelines for combat sports athletes and trainers alike.

The effects of short-term resistance training on performance and health variables associated with prolonged sedentary lifestyle and metabolic syndrome (MS) were investigated. Resistance training may alter a number of health-related, physiological, and performance variables. As a result, resistance training can be used as a valuable tool in ameliorating the effects of a sedentary lifestyle including those associated with MS. Nineteen previously sedentary subjects (10 with MS and 9 with nonmetabolic syndrome [NMS]) underwent 8 weeks of supervised resistance training. Maximum strength was measured using an isometric midthigh pull and resulting force-time curve. Vertical jump height (JH) and power were measured using a force plate. The muscle cross-sectional area (CSA) and type were examined using muscle biopsy and standard analysis techniques. Aerobic power was measured on a cycle ergometer using a ParvoMedics 2400 Metabolic system. Endurance was measured as time to exhaustion on a cycle ergometer. After training, maximum isometric strength, JH, jump power, and V_ O2peak increased by approximately 10% (or more) in both the metabolic and NMS groups (both male and female subjects). Over 8 weeks of training, body mass did not change statistically, but percent body fat decreased in subjects with the MS and in women, and lean body mass increased in all groups (p # 0.05). Few alterations were noted in the fiber type. Men had larger CSAs compared those of with women, and there was a fiber-specific trend toward hypertrophy over time. In summary, 8 weeks of semiblock free-weight resistance training improved several performance variables and some cardiovascular factors associated with MS

The purpose of this study was to determine the differences in kinetic, kinematic, and metabolic variables between an acute normal dead stop squat (NDS) protocol and an acute accentuated eccentric loaded squat (AEL) protocol. Eight collegiate weightlifters were performed the 2 squat protocols. Eccentric and concentric kinetic and kinematic data were collected via synchronized force plate and linear position transducer. Metabolic parameters assessed were oxygen consumption (VO2 ) using open circuit spirometry, testosterone (T) and cortisol (C) via blood draw from antecubital vein, and lactate (La) values via finger prick blood draw. The following are major findings of the dissertation. No statistical differences were observed for concentric variables between AEL and NDS work sets or between warm-up at 55% (WUP55) and postset at 55% (POST55) sets. Differences were found in the speed and duration of the eccentric portion of the lifts. Results indicate that there are no meaningful biomechanical differences when performing AEL squats in this manner and that the intensity and volume executed did not result in PAP. Oxygen uptake was statistically different during sets with the additional eccentric load (set 4, 5, 6, 7) and the subsequent down set (set 9). Lactate was greater during AEL squatting than NDS after set 7 and set 8 for the whole group. T exhibited no statistically significant changes. C was greater immediately following the AEL protocol compared to NDS 30 minutes post-AEL squat protocol yielded a statistically significant difference from immediately post and a return to near baseline measures. These acute changes may have meaningful effects on long- term gains in hypertrophy and strength. The findings of this dissertation show the potential benefits of AEL dead-stop squats for long-term hypertrophy and strength development. However, because this dissertation was the first to explore dead-stop squats with an additional eccentric load, further research is required on both the potential benefits of dead-stop squats and typical squats with no dead-stop using an AEL protocol.

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.

In recent years physical inactivity among students has become a matter of great concern. Nearly 65% of students do not meet the daily recommended level of physical activity, which is 60 minutes or more of moderate to vigorous physical activity each day, with 50% of that time being spent in moderate to vigorous levels of activity (CDC, 2010b). As a result, the 21st century has shown to be a time of many health problems such as, obesity, diabetes, and heart disease. In fact, nearly one third of all children are considered obese or overweight (Slawta & DeNeui, 2009). Researchers suggest that these health problems are directly related to students' sedentary lifestyles (Pate et al., 2006). Schools play a pivotal role in addressing and increasing physical activity during the school day. The purpose of this research study was to measure levels of physical activity in elementary students during school hours. Specifically, the study sought to discover if there were increased levels of physical activity while students were using a cross-curricular adventure playground, as compared to when they were engaged in free play or physical education class. The study also compared the different measurement types (pedometers, accelerometers, and the observational method) used to assess physical activity, to indicate which measurement types were most feasible in the elementary school setting. Schools are ideal locations for assessing levels of physical activity, as 95% of all children are enrolled in these learning institutions (National Center for Educational Statistics, 2005). The data indicate that physical education provided for the highest levels of moderate to vigorous activity, while both free play and cross-curricular activity still rendered adequate levels of physical activity. After studying the different measurement protocols (pedometers, accelerometers, and the observational method) used in this study, results suggested the pedometer to be the most feasible device to use for measuring children in these types of physical activity settings. One implication for practice was implementing cross-curricular physical activity as a supplement to other physical activities or as an addition to physical education classes in an effort to allow more time for academic instruction while having students engaged in physical activity. Another recommendation for practice was to use pedometers as a cost-effective physical activity measurement device for elementary students.

The purpose of this study was to investigate the alterations and relationships among training variables, performance variables, and physiological variables. Nine (9) D-1 collegiate throwers and 4 control subjects participated in the study. The throwers participated in an 11-week periodized resistance training and throws program. Volume load was recorded throughout the study. Measurements of maximal strength (isometric mid-thigh pull), vertical jumping ability, dynamic mid-thigh pulls (across a spectrum of loads), hormones (testosterone and cortisol), and adipokines (adiponectin, leptin, and resistin) were taken at weeks 1, 7, and 11. The throwers demonstrated several statistically significant alterations over time for performance variables. The throwers realized increases across time in maximum strength and peak power output. Hormone values did not exhibit statistically significant changes across time; however, there were trends across time for cortisol, the testosterone:cortisol ratio and adiponectin. These alterations would indicate a more anabolic environment and less obesity associated inflammation.