Seven days of ischemic preconditioning augments hypoxic exercise ventilation and muscle oxygenation in recreationally trained males.

This investigation sought to assess whether single or repeated bouts of ischemic preconditioning (IPC) could improve oxyhemoglobin saturation ([Formula: see text]) and/or attenuate reductions in muscle tissue saturation index (TSI) during submaximal hypoxic exercise. Fifteen healthy young men completed submaximal graded exercise under four experimental conditions: 1) normoxia (NORM), 2) hypoxia (HYP) [oxygen fraction of inspired air ([Formula: see text]) = 0.14, ∼3,200 m], 3) hypoxia preceded by a single session of IPC (IPC1-HYP), and 4) hypoxia preceded by seven sessions of IPC, one a day for 7 consecutive days (IPC7-HYP). IPC7-HYP heightened minute ventilation (V̇e) at 80% HYP peak cycling power output (Wpeak) (+10.47 ± 3.35 L·min-1, P = 0.006), compared with HYP, as a function of increased breathing frequency. Both IPC1-HYP (+0.17 ± 0.04 L·min-1, P < 0.001) and IPC7-HYP (+0.16 ± 0.04 L·min-1, P < 0.001) elicited greater oxygen consumption (V̇o2) across exercise intensities compared with NORM, whereas V̇o2 was unchanged with HYP alone. [Formula: see text] was unchanged by either IPC condition at any exercise intensity, yet the reduction of muscle TSI during resting hypoxic exposure was attenuated by IPC7-HYP (+9.9 ± 3.6%, P = 0.040) compared with HYP, likely as a function of reduced local oxygen extraction. Considering all exercise intensities, IPC7-HYP attenuated reductions of TSI with HYP (+6.4 ± 1.8%, P = 0.001). Seven days of IPC heightens ventilation, posing a threat to ventilatory efficiency, during high-intensity submaximal hypoxic exercise and attenuates reductions in hypoxic resting and exercise muscle oxygenation in healthy young men. A single session of IPC may be capable of modulating hypoxic ventilation; however, our present population was unable to demonstrate this with certainty.

The Effects of a Science-Based Community Intervention on Health Outcomes in Minority Children: The Translational Health in Nutrition and Kinesiology Program.

BACKGROUND: This study evaluated the effects of a novel nutrition and movement science after-school program integrating laboratory experiences for minority children. Laboratory experiences demonstrated how the body moves, functions, and performs in response to exercise and healthy nutrition. METHODS: A total of 76 children from 4 after-school programs that were primarily Latino and black were randomly assigned to either an experimental translational health in nutrition and kinesiology (THINK; n = 46) or standard curriculum that served as the control group (CON; n = 30). An analysis of covariance controlling for baseline values was used to compare differences between THINK and CON after the 4-month intervention. RESULTS: Following the program, THINK participants evidenced lower triceps and subscapular skinfold thickness (P < .01 and <.05, respectively). THINK students showed greater improvements in aerobic fitness, grip strength, and agility than CON (P < .01, <.01, and <.05, respectively). Participants in THINK also demonstrated higher scores on their nutrition habits/behaviors questionnaire (P < .01), nutrition science (P < .05), and exercise fitness tests (P < .001) than CON. CONCLUSION: An innovative curriculum featuring nutrition and kinesiology education interfaced with hands-on laboratory experiences and physical activities can improve physical outcomes and health-related behaviors in after-school programs serving minority children.

Perception of Physical Fitness and Exercise Self-Efficacy and Its Contribution to the Relationship between Body Dissatisfaction and Physical Fitness in Female Minority Children.

Body Dissatisfaction (BD) and low physical self-concept and exercise efficacy have been linked to poor physical fitness levels and adverse health outcomes in children. The purpose of this study was to examine the relationship between BD, physical fitness, exercise self-efficacy, and self-Perception of Physical Fitness (PFP) in Latina and Black female children. Twenty-eight Latina and Black children enrolled in an elementary afterschool program, aged 8⁻12, completed surveys evaluating body dissatisfaction, exercise efficacy, PFP, and measures of physical fitness. Subjects exhibited moderate but significant inverse relationships between BD and PFP in strength (r = −0.459), agility (r = −0.382), aerobic fitness (r = −0.354), and flexibility (r = −0.461) (p < 0.05 for all). There was a significant negative correlation between exercise efficacy and BD (r = −4.2; p < 0.05). Power (r = 0.51) and flexibility (r = 0.42) were the only physical fitness measures significantly and positively related to children’s PFP (p < 0.05). A significant medium inverse relationship was also found between BD and aerobic fitness scores (r = −0.381; p < 0.05). However, after controlling for exercise efficacy or perception of physical fitness, the relationship between BD and aerobic fitness was not significant (p > 0.05). Findings suggest that positive PFP and positive performance in several physical fitness measures are associated with lower levels of BD in minority female children. Furthermore, evidence suggests exercise efficacy and PFP can mediate the relationship body image and aerobic fitness. These findings suggest that PFP, more so than measured physical fitness, was associated with lower levels of BD in minority female children. These results have important implications for programs designed to improve physical fitness and mental health in minority children.

Beta-Alanine Does Not Enhance the Effects of Resistance Training in Older Adults.

To investigate the potential of beta-alanine to increase muscular endurance of elder individuals in specific resistance-training protocols, we randomly assigned 27 participants (60-82 years of age) to a 12-week double-blind intervention using 3.2 g/day beta-alanine or placebo with or without resistance training to determine the effects on anthropometrics, muscular performance, and activities of daily living (ADL). The endurance-based resistance-training program (ERT) was given three times per week and included two sets of 15-25 repetitions on 11 computerized pneumatic machines (alternating upper and lower body) at an intensity of 50% of maximum lifting weight (1RM). Mixed design analysis of variance (ANOVA) revealed no significant group × time interactions (p > .05) for any anthropometric or strength measures except 1RM leg press (p = .010). A post hoc analysis revealed significant improvements in 1RM leg press for both the resistance-training groups (p < .001) but no significant between-group difference attributable to beta-alanine. For the 20-repetition chest and leg press tests, no main effects of beta-alanine or group × time interactions for the exercise versus control groups were observed. Pairwise comparisons, however, did reveal significant improvements in peak and average power for both tests and fatigue index for the chest press in resistance-training groups. Although beta-alanine had no effect on any measures, the ERT program did positively affect three performance variables: 1RM, mechanical power, and fatigue patterns during muscular endurance testing. Future research should examine beta-alanine with different dosages and training programs to expand upon our findings using endurance-based resistance training.

Comparative Effect of Power Training and High-Speed Yoga on Motor Function in Older Patients With Parkinson Disease.

OBJECTIVES: To compare the effects of power training (PWT) and a high-speed yoga program on physical performances in older patients with Parkinson disease (PD), and to test the hypothesis that both training interventions would attenuate PD symptoms and improve physical performance. DESIGN: Randomized controlled trial. SETTING: A laboratory of neuromuscular research and active aging. PARTICIPANTS: Patients with PD (N=41; mean age ± SD, 72.2 ± 6.5y). INTERVENTIONS: Two high-speed exercise interventions (specifically designed yoga program and PWT) were given for 12 weeks (twice a week), and 1 nonexercise control group. MAIN OUTCOME MEASURES: Unified Parkinson Disease Rating Scale motor score (UPDRSMS), Berg Balance Scale (BBS), Mini-Balance Evaluation Systems Test (Mini-BESTest), Timed Up and Go, functional reach, single leg stance (SLS), postural sway test, 10-m usual and maximal walking speed tests, 1 repetition maximum (RM), and peak power (PPW) for leg press. RESULTS: For the posttests, both training groups showed significant improvements (P<.05) in all physical measurements except functional reach on the more affected side, SLS, and postural sway compared with the pretests, and significantly better scores for UPDRSMS, BBS, Mini-BESTest, Timed Up and Go, functional reach on the less affected side, 10-m usual and maximal walking speed tests, 1RM, and PPW than controls, with no differences detected between the yoga program and PWT. CONCLUSIONS: Both the specially designed yoga program and PWT programs can significantly improve physical performance in older persons with PD.

Ischemic preconditioning does not improve peak exercise capacity at sea level or simulated high altitude in trained male cyclists.

Ischemic preconditioning (IPC) may improve blood flow and oxygen delivery to tissues, including skeletal muscle, and has the potential to improve intense aerobic exercise performance, especially that which results in arterial hypoxemia. The aim of the study was to determine the effects of IPC of the legs on peak exercise capacity (W(peak)), submaximal and peak cardiovascular hemodynamics, and peripheral capillary oxygen saturation (SpO2) in trained males at sea level (SL) and simulated high altitude (HA; 13.3% FIO2, ∼ 3650 m). Fifteen highly trained male cyclists and triathletes completed 2 W(peak) tests (SL and HA) and 4 experimental exercise trials (10 min at 55% altitude-specific W(peak) then increasing by 30 W every 2 min until exhaustion) with and without IPC. HA resulted in significant arterial hypoxemia during exercise compared with SL (73% ± 6% vs. 93% ± 4% SpO2, p < 0.001) that was associated with 21% lower W(peak) values. IPC did not significantly improve W(peak) at SL or HA. Additionally, IPC failed to improve cardiovascular hemodynamics or SpO2 during submaximal exercise or at W(peak). In conclusion, IPC performed 45 min prior to exercise does not improve W(peak) or systemic oxygen delivery during submaximal or peak exercise at SL or HA. Future studies must examine the influence of IPC on local factors, such as working limb blood flow, oxygen delivery, and arteriovenous oxygen difference as well as whether the effectiveness of IPC is altered by the volume of muscle made ischemic, the timing prior to exercise, and high altitude acclimatization.

Improving Exercise Adherence and Physical Measures in English-Speaking Latina Women.

BACKGROUND: Epidemiological data have established that lack of physical activity increases risk factors for chronic diseases. Data also suggests that physical activity participation is lowest in minority women, particularly Latinas, and that the nature of the exercise and attitudes toward exercise may influence exercise adherence. The purpose of this study was to determine the effect of hypertrophy training (HT) or power training (PT) used concomitantly with evaluative conditioning (EC) or neutral conditioning (NC) on exercise adherence as well as in physical and psychosocial variables in Latina women. EC is a behavioral method using paired stimuli to develop and strengthen new associations in memory. METHODS: Two hundred thirty-one English-speaking Latina women (mean ± SD, age 36.8 ± 15.9 years) were randomly assigned to standard HT or high-speed circuit PT and then further stratified to receive EC or NC. RESULTS: One hundred forty-two Latina women completed pre- and posttesting. For HT, EC produced significantly greater exercise time across the training period than NC. HT and PT both significantly improved all physical, functional, and psychosocial variables, with exception of leg extension and usual gait speed (p < 0.05). CONCLUSION: EC can positively impact exercise adherence during HT in Latina women; while body composition, neuromuscular, and functional performances can be increased using HT and PT independent of psychological conditioning.

Race differences in obesity and its relationship to the sex hormone milieu.

A sexual dimorphism exists in which increased abdominal and visceral adipose tissue (VAT) - found in women and marked by low sex hormone binding globulin (SHBG) and high bioavailable testosterone (BT) - is related to the metabolic risk profile. In men, increased BT is related to decreased abdominal obesity and a decrease in the metabolic risk profile. In women, race differences have been found in androgenic sex steroids including SHBG and BT as well as central fat distribution, creating inherently greater metabolic risk for certain populations. Estrogen and estrogen receptor isoforms play a role in fat deposition and distribution and may influence the changes that occur during the menopausal transition. Androgenic sex steroids serve a mediating role, influencing VAT accumulation and its associated metabolic risk factors while VAT also serves a mediating role influencing the androgenic sex steroid-metabolic risk relationship in women. Furthermore, androgenic sex steroids and VAT may independently contribute to the variance in several metabolic variables associated with cardiovascular disease, type 2 diabetes, and their antecedent conditions such as the metabolic syndrome. Race has been shown to modify the relationship between androgenic sex steroids and metabolic variables associated with risk for diabetes in Black and White women. Further research is warranted to examine the mechanisms involved in race differences. Total adiposity and central fat distribution in accordance with changes in the hormone and metabolic milieu influence breast cancer risk, which varies by race and menopausal status. These findings have broader implications for the study of health promotion/disease prevention in women.

Comparison of inferolateral early repolarization and its electrocardiographic phenotypes in pre- and postadolescent populations.

Inferolateral early repolarization (ER) patterns on standard electrocardiogram (ECG) are associated with increased risk for cardiac and arrhythmic death in general adult population cohorts. We sought to determine the prevalence of inferolateral ER on surface ECG in multiracial pre- and postadolescent populations and to analyze its association with age, race, gender, and ST-segment patterns. A retrospective review was conducted of all ECGs recorded from preadolescent (aged 8-12 years, n = 719) and postadolescent (aged 21-25 years, n = 755) patients seen at a large academic medical center between January 1, 2009, and December 31, 2010. The overall prevalence of inferolateral ER was similar in the preadolescent and postadolescent populations (17% vs 16%, NS). The prevalence of ER increased after puberty in male patients (16% to 25%, p <0.001) and decreased in female patients (18% to 9%, p <0.001). Prevalence of ascending early repolarization (benign variant) also increased in males after puberty (15% to 23%, p <0.004) and decreased in females (11% to 4%, p <0.001). There were no differences in the prevalence of the risk-associated horizontal/descending pattern (3% in both groups). Subgroup analysis was performed on ECGs from the cohort of outpatients without cardiac disease, and the statistical trends remained the same. In conclusion, the overall prevalence of inferolateral ER was higher in pre- and postadolescent populations than in adult populations. However, the prevalence of the risk-associated horizontal/descending ST-segment pattern was only 3%, comparable to prevalence rates in the adult population. The variations in prevalence by gender and age suggest a possible influence of reproductive hormones.

National Athletic Trainers' Association position statement: safe weight loss and maintenance practices in sport and exercise.

OBJECTIVE: To present athletic trainers with recommendations for safe weight loss and weight maintenance practices for athletes and active clients and to provide athletes, clients, coaches, and parents with safe guidelines that will allow athletes and clients to achieve and maintain weight and body composition goals. BACKGROUND: Unsafe weight management practices can compromise athletic performance and negatively affect health. Athletes and clients often attempt to lose weight by not eating, limiting caloric or specific nutrients from the diet, engaging in pathogenic weight control behaviors, and restricting fluids. These people often respond to pressures of the sport or activity, coaches, peers, or parents by adopting negative body images and unsafe practices to maintain an ideal body composition for the activity. We provide athletic trainers with recommendations for safe weight loss and weight maintenance in sport and exercise. Although safe weight gain is also a concern for athletic trainers and their athletes and clients, that topic is outside the scope of this position statement. RECOMMENDATIONS: Athletic trainers are often the source of nutrition information for athletes and clients; therefore, they must have knowledge of proper nutrition, weight management practices, and methods to change body composition. Body composition assessments should be done in the most scientifically appropriate manner possible. Reasonable and individualized weight and body composition goals should be identified by appropriately trained health care personnel (eg, athletic trainers, registered dietitians, physicians). In keeping with the American Dietetics Association (ADA) preferred nomenclature, this document uses the terms registered dietitian or dietician when referring to a food and nutrition expert who has met the academic and professional requirements specified by the ADA's Commission on Accreditation for Dietetics Education. In some cases, a registered nutritionist may have equivalent credentials and be the commonly used term. All weight management and exercise protocols used to achieve these goals should be safe and based on the most current evidence. Athletes, clients, parents, and coaches should be educated on how to determine safe weight and body composition so that athletes and clients more safely achieve competitive weights that will meet sport and activity requirements while also allowing them to meet their energy and nutritional needs for optimal health and performance.

Sildenafil does not improve steady state cardiovascular hemodynamics, peak power, or 15-km time trial cycling performance at simulated moderate or high altitudes in men and women.

Sildenafil improves oxygen delivery and maximal exercise capacity at very high altitudes (≥ 4,350 m), but it is unknown whether sildenafil improves these variables and longer-duration exercise performance at moderate and high altitudes where competitions are more common. The purpose of this study was to determine the effects of sildenafil on cardiovascular hemodynamics, arterial oxygen saturation (SaO(2)), peak exercise capacity (W (peak)), and 15-km time trial performance in endurance-trained subjects at simulated moderate (MA; ~2,100 m, 16.2% F(I)O(2)) and high (HA; ~3,900 m, 12.8% F(I)O(2)) altitudes. Eleven men and ten women completed two HA W (peak) trials after ingesting placebo or 50 mg sildenafil. Subjects then completed four exercise trials (30 min at 55% of altitude-specific W (peak) + 15-km time trial) at MA and HA after ingesting placebo or 50 mg sildenafil. All trials were performed in randomized, counterbalanced, and double-blind fashion. Sildenafil had little influence on cardiovascular hemodynamics at MA or HA, but did result in higher SaO(2) values (+3%, p < 0.05) compared to placebo during steady state and time trial exercise at HA. W (peak) at HA was 19% lower than SL (p < 0.001) and was not significantly affected by sildenafil. Similarly, the significantly slower time trial performance at MA (28.1 ± 0.5 min, p = 0.016) and HA (30.3 ± 0.6 min, p < 0.001) compared to SL (27.5 ± 0.6 min) was unaffected by sildenafil. We conclude that sildenafil is unlikely to exert beneficial effects at altitudes <4,000 m for a majority of the population.

From surviving to thriving: a health and wellness colloquium for breast cancer survivors.

Recent evidence demonstrates that exercise training can provide numerous physical and psychosocial benefits for breast cancer (BCa) survivors. However, educational training programs designed to disseminate exercise training information to survivors are scarce. The From Surviving to Thriving (FST) Colloquium was a one-and-a-half-day event that featured presentations on wellness topics from fitness and health to the latest research in nutrition and exercise. Attendees filled out demographic questionnaires and feedback surveys to assess the impact of the Colloquium. Overall, the FST Colloquium was well received by BCa survivors and health care providers (HCPs). The majority of BCa survivors (84.4%) and HCPs (93.3%) rated their Colloquium experience as very good. Prior to attending the Colloquium, only 8.9% of BCa survivors rated their self-perceived knowledge of exercise and nutrition as excellent. After participation in the Colloquium, this increased to 44.4%. The Colloquium was also successful in influencing planned and actual behavior changes in BCa survivors.

The effects of an active-assisted stretching program on functional performance in elderly persons: a pilot study.

This study examined the impact of an eight-week active-assisted (AA) stretching program on functionality, mobility, power, and range of motion (ROM) in elderly residents of a residential retirement community. Seventeen volunteers (4 male, 13 female; 88.8 +/- 5.36 years) were randomly assigned to an AA or control group. The AA group performed 10 different AA stretches targeting the major joints of the body twice weekly for eight weeks. Controls attended classes requiring limited physical activity. All participants were assessed using four flexibility and six functional tests, one week before and after the eight-week training period. A fully randomized repeated-measures ANCOVA with pretest scores as a covariate was used to detect differences between groups across time. The AA group demonstrated significant increases in ROM for most of the joints evaluated (p < 0.05) and significant increases in all performance measures (p < 0.05). Controls showed no improvements in functional or ROM measures (alpha = 0.05). Additionally, the AA group showed significantly better performance outcomes across the training period than controls. We conclude that our eight-week flexibility program effectively reduces age-related losses in ROM and improves functional performance in elderly persons with insufficient physical reserves to perform higher-intensity exercises.

Peak power, ground reaction forces, and velocity during the squat exercise performed at different loads.

This study examined the changes in peak power, ground reaction force and velocity with different loads during the performance of the parallel squat movement. Twelve experienced male lifters (26.83 +/- 4.67 years of age) performed the standard parallel squat, using loads equal to 20, 30, 40, 50, 60, 70, 80, and 90% of 1 repetition maximum (1RM). Each subject performed all parallel squats with as much explosiveness as possible using his own technique. Peak power (PP), peak ground reaction force (PGRF), peak barbell velocity (PV), force at the time of PP (FPP), and velocity at the time of PP (VPP) were determined from force, velocity, and power curves calculated using barbell velocity and ground reaction force data. No significant differences were detected among loads for PP; however, the greatest PP values were associated with loads of 40 and 50% of 1RM. Higher loads produced greater PGRF and FPP values than lower loads (p < 0.05) in all cases except between loads equal to 60-50, 50-40, and 40-30% of 1RM for PGRF, and between loads equal to 70-60 and 60-50% of 1RM for FPP. Higher loads produced lower PV and VPP values than lower loads (p < 0.05) in all cases except between the 20-30, 70-80, and 80-90% of 1RM conditions. These results may be helpful in determining loads when prescribing need-specific training protocols targeting different areas of the load-velocity continuum.

Effects of sibutramine treatment in obese adolescents: a randomized trial.

BACKGROUND: Increased prevalence of adolescent obesity requires effective treatment options beyond behavior therapy. OBJECTIVE: To see whether sibutramine reduced weight more than placebo in obese adolescents who were receiving a behavior therapy program. DESIGN: 12-month, 3:1 randomized, double-blind trial conducted from July 2000 to February 2002. SETTING: 33 U.S. outpatient clinics. PARTICIPANTS: 498 participants 12 to 16 years of age with a body mass index (BMI) that was at least 2 units more than the U.S. weighted mean of the 95th percentile based on age and sex, to the upper limit of 44 kg/m2. INTERVENTIONS: Site-specific behavior therapy plus 10 mg of sibutramine or placebo. Blinded study medication dose was uptitrated to 15 mg or placebo at month 6 if initial BMI was not reduced by 10%. MEASUREMENTS: Body mass index, waist circumference, body weight, fasting lipid and glycemic variables, safety, and tolerability. RESULTS: Seventy-six percent of patients in the sibutramine group and 62% of patients in the placebo group completed the study. The estimated mean treatment group difference at month 12 (linear mixed-effects model) favored sibutramine for change from baseline in BMI (-2.9 kg/m2 [95% CI, -3.5 to -2.2 kg/m2]) and body weight (-8.4 kg [CI, -9.7 to -7.2 kg]) (P < 0.001 for both). The sibutramine group had greater improvements in triglyceride levels, high-density lipoprotein cholesterol levels, insulin levels, and insulin sensitivity (P < or = 0.001 for all). The rate of tachycardia was greater with sibutramine vs. placebo (12.5% vs. 6.2%; difference, 6.3 percentage points [CI, 1.0 to 11.7 percentage points]) but did not lead to increased withdrawal (2.4% vs. 1.5%; difference, 0.9 percentage point [CI, -1.7 to 3.5 percentage points]). LIMITATIONS: The 1-year study duration precluded assessment of long-term weight maintenance and putative health benefits and harms, and 24% and 38% of the sibutramine and placebo groups, respectively, did not complete follow-up. CONCLUSIONS: Sibutramine added to a behavior therapy program reduced BMI and body weight more than placebo and improved the profile of several metabolic risk factors in obese adolescents.

Metabolic and physiologic responses to video game play in 7- to 10-year-old boys.

OBJECTIVE: To examine the metabolic, physiologic, and hemostatic responses to action video game play in a group of young boys. DESIGN: Comparison study. SETTING: Laboratory of Clinical and Applied Physiology, University of Miami. PARTICIPANTS: Twenty-one boys aged 7 to 10 years. MAIN OUTCOME MEASURES: Blood pressure monitored before and during game play and blood glucose and lactate levels measured before and immediately after game play. Measurements were continuously recorded throughout game play. Dependent t tests were used to compare measurements recorded at baseline and during or after game play. Effect sizes using the Cohen d were examined for comparisons. RESULTS: Significant increases from baseline were found for heart rate (18.8%; P<.001), systolic (22.3%; P<.001) and diastolic (5.8%; P = .006) blood pressure, ventilation (51.9%; P<.001), respiratory rate (54.8%; P<.001), oxygen consumption (49.0%; P<.001), and energy expenditure (52.9%; P<.001). Effect sizes for these comparisons were medium or large. No significant changes were found from baseline to after video game play for lactate (18.2% increase; P = .07) and glucose (0.9% decrease; P = .59) levels. CONCLUSIONS: Video game play results in significant increases in various metabolic and physiologic variables in young children. Thus, it should not be combined with television viewing for the evaluation of sedentary activities. The magnitude of change, however, was lower than that observed during standard physical exercise and below national health recommendations. As such, video game play should not be considered a substitute for regular physical activities that significantly stress the metabolic pathways required for the promotion of cardiovascular conditioning.

Correlation analyses and regression modeling between isokinetic testing and on-court performance in competitive adolescent tennis players.

Tennis requires skill, physical attributes, and strategy. Ball velocity and placement are two of the most important components in winning the faster-paced modern game. Although isokinetic testing has been used to evaluate physical characteristics and injury potential in tennis players, few studies have compared isokinetics and on-court performance. Such a comparison would help establish links between speed-specific properties of functioning muscles and stroke production and could affect overall training strategy. This study compared isokinetic peak torque (PT), average power (AP), and total work (TW) during specific testing patterns correlated with ball velocity or stroke accuracy during the service, forehand, and backhand and developed predictive equations for each stroke using these variables. Thirty-five players, aged 13-18 years with at least 4 years playing experience, were evaluated using internal and external shoulder rotation, leg extension, and diagonal throwing motions. Ball velocity was measured using a radar gun. Accuracy was evaluated on the basis of shot position and depth. Significant correlations were found between ball velocity and a number of isokinetic variables, while no significant correlations were observed with shot accuracy. Significant isokinetic variables for each stroke were entered into regression models. One isokinetic speed sufficiently predicted ball velocity for each stroke, since no increase in predictive capacity was observed with the addition of other isokinetic parameters. We conclude that isokinetics at testing speeds between 1.57 and 4.71 rad.s(-1) can effectively predict ball velocity, but not accuracy, and that our results may be helpful in planning strategies for training and rehabilitation.

Physical, behavioral, and body image characteristics in a tri-racial group of adolescent girls.

OBJECTIVES: The purpose of this study was to evaluate physical characteristics, nutrient intake, physical activity level, and body image in white (CC), African-American (AA), and Hispanic-American (HA) female adolescents. RESEARCH METHODS AND PROCEDURES: High school volunteers were solicited for this study. Self-reported information was used to determine subject characteristics, family income, physical activity, body image, and nutrient intake. Physical evaluations were used to determine body mass index, percent body fat, fat distribution, resting heart rate, and blood pressure (BP). RESULTS: Results showed that AA girls displayed significantly higher diastolic BP than HA girls (p = 0.029). CC adolescents showed greater physical activity (p = 0.010) and lower adiposity than HA adolescents (p = 0.048), as well as lower subscapular skinfold than AA adolescents (p = 0.018). AA adolescents selected a higher ideal body size than CC girls (p = 0.038). There was also a significant difference in percentage carbohydrates (p < 0.034) and cholesterol consumed (p < 0.016) among groups, with CC girls showing the highest values for carbohydrates and lowest values for cholesterol intake among groups. DISCUSSION: Given our findings of higher adiposity and lower physical activity levels in HA adolescents and greater diastolic BP levels and subscapular skinfold in AA adolescents, more interventions should be targeted toward improving health-related variables among minority populations.

Can laboratory-based tennis profiles predict field tests of tennis performance?

The present study examined the impact of physical characteristics of adolescent competitive tennis players (13-18 years) on field tests of tennis performance. Results (n = 33) showed that boys were taller (p = 0.001), possessed greater wingspan (p = 0.030), had greater maximum oxygen consumption (p = 0.001), and performed better on isokinetic strength measurements. Multiple regression analyses controlling for age and sex showed that height (p = 0.025), maximum minute ventilation (p = 0.005), and isokinetic strength measurements significantly and positively affected ball velocity. Knee extension average power was the only variable to positively and significantly affect ball placement (p = 0.040); however, several isokinetic strength measurements negatively affected ball placement. For the nondominant side, down-the-line strokes showed reduced accuracy (p = 0.001) and ball velocity (p = 0.001) compared with cross-court strokes. Given our results, resistance training may be beneficial for the performance of on-court tennis play.

The effects of an exercise physiology program on physical fitness variables, body satisfaction, and physiology knowledge.

This study was performed to determine the effects of an exercise physiology program on physical fitness, body satisfaction, and knowledge. A total of 161 students (mean age = 16.5 +/- 0.89 years) of the Coral Gables Senior High School served as the experimental group volunteers, whereas 33 students enrolled in a standard biology course served as the control group (mean age = 15.61 +/- 0.84 years). The experimental group received exercise physiology theory coupled with active aerobic and resistance exercise. Age (p = 0.0001) and lean body mass (p = 0.023) were the only physical characteristics significantly greater in the experimental group at pretesting. An analysis of covariance controlling for pretest values showed better results in the experimental compared with the control group for sit and reach (p = 0.008), step test, recovery heart rate (p = 0.0002), overhead press (p = 0.002), bench press (p = 0.017), leg press (p = 0.012), sit-ups (p = 0.001), body satisfaction (p = 0.0009), and physiology knowledge (p = 0.0001) at posttesting. Findings indicated that a biology curriculum integrated with exercise physiology theory and exercise activities may result in significant improvements in physical fitness, body size satisfaction, and physiology knowledge in high school adolescents.