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Context: Studies developed the frail elderly handgrip strength (HGS) diagnostic criteria using multiple types of handgrip dynamometers. If different handgrip dynamometers report different values, then this would have the potential to misclassify people into the wrong diagnostic category. Objective: To examine the characteristics of HGS measured by 2 standard handgrip dynamometers and to investigate the influence of hand size on HGS. Setting: University research laboratory. Participants: A total of 87 young and middle-aged adults between the ages of 20 and 60 years participated in this study. Main Outcome Measures: Standard methods of HGS measurements were used for hydraulic and Smedley spring-type dynamometers, although the participants were instructed to maintain an upright standing position in both tests. Results: Test–retest reliability of hydraulic and Smedley dynamometers provided comparable results to that observed with previous studies. However, the difference in HGS between the 2 dynamometers (Hydraulic–Smedley difference) was positively associated (r = .670, P 45 kg) produced greater strength values with the hydraulic compared with the Smedley. The hand and palm lengths were weakly correlated (r = .349 and r = .358, respectively, both Ps Conclusions: Test–retest reliability of hydraulic and Smedley dynamometers provides comparable results to previous studies. However, the difference in HGS between the 2 dynamometers was positively associated with the mean of the 2 dynamometers. This Hydraulic–Smedley difference would not affect persons who have relatively low HGS (at least

Functional limitations persist in obese patients after total knee arthroplasty (TKA). This study assessed the effect of an exercise program (EP) and fitness trackers (FT) in obese patients with TKA. Sixty patients 1 year after orthopedic surgery were recruited and received a 16-week tailored EP; half were randomized to receive an FT. FT had no measurable effect compared with EP alone. EP improved knee range of motion, strength, and quality-of-life scores. This study provides preliminary evidence that a 16-week EP in obese individuals 1 year post TKA is feasible and effective in improving function and quality of life.

Obese patients are more likely to have osteoarthritis and total knee arthroplasty (TKA). This investigation sought to evaluate physical function, activity level, and quality of life (QOL). Obese participants near 1-year postsurgical follow-up appointment were recruited. Evaluation included QOL and activity questionnaire, medical histories, anthropometrics, strength, and aerobic capacity. Sixty participants completed assessments. Obese TKA patients have physical performance limitations and low physical activity levels 1 year after surgery and completion of postoperative rehabilitation.

An equation published by Loftin, Waddell, Robinson, and Owens (2010) was cross-validated using ten normal-weight walkers, ten overweight walkers, and ten distance runners. Energy expenditure was measured at preferred walking (normal-weight walker and overweight walkers) or running pace (distance runners) for 5 min and corrected to a mile. Energy expenditure per mile was predicted using the Loftin et al. (2010) equation yielding a mean predicted value of 99.7 ± 13.8 kcal · mile−1. This was significantly different (p < .05) than the mean actual value from the cross-validation group (107.8 ± 15.5 kcal · mile−1), although the difference was within the published standard error of estimate. A Chow test revealed no significant differences between regression coefficients of the original equation and the cross-validation group equation. It appears the Loftin et al. (2010) regression equation is useful for exercise prescription of energy expenditure for walking or running a mile in normal-weight and overweight adults.

Aim To test the hypothesis that static balance is associated with site-specific loss of muscle mass in older adults. Methods A total of 57 active women aged 52–83 years had their muscle thickness (MTH) measured by ultrasound at four sites on the anterior and posterior aspects of their upper- and lower-leg. MTH ratios were calculated to assess the site-specific muscle loss. One-leg standing balance with eyes open and maximum isometric knee extension/flexion strength were measured. Daytime physical activity was also measured. The participants were separated into three groups based on achieved timed one-leg balance test: less than 60 s (n = 19, G1), 60–120 s (n = 12, G2) and over 120 s (n = 26, G3). Results Age was inversely correlated to the upper-leg (A50 : P70) MTH ratios (r = −0.389, P

Dual-energy X-ray absorptiometry (DXA) is an attractive method for evaluating sarcopenia, age-related loss of skeletal muscle mass and function, using appendicular lean tissue (aLT) mass for criteria of diagnosis, although minimal radiation is exposed. Skeletal muscle (SM) mass can be estimated by using ultrasound-measured muscle thickness (MTH). However, the association between these two methods is unclear. To examine the relationship between DXA-derived aLT mass and total body SM mass estimated by ultrasound, thirty-six healthy adults (18 men and 18 women) aged 19 - 65 years participated in this study. Ultrasound-measured muscle thickness was used to estimate the total SM mass. DXA was used to estimate whole body and regional body composition, and aLT mass was considered equivalent to the sum of lean tissue in both the right and left arms and legs. Total SM mass (26.3 ± 4.4 kg for men and 15.7 ± 2.6 kg for women) estimated by ultrasound was similar to DXA-estimated aLT mass (24.5 ± 3.8 kg for men and 15.7 ± 2.7 kg for women). There was a strong correlation between DXA-measured aLT mass and total SM mass estimated by ultrasound in men (r = 0.927, n = 18) and women (r = 0.931, n = 18) as well as overall sample (r = 0.975, n = 36). The ratio of total SM mass to aLT mass was 1.07 for men and 1.00 for women. These results suggest that DXA-derived aLT mass can be accurately predicted from ultrasound estimated total SM mass, although the predicted value may underestimate in men (approximately 7% at the group level).

The incidence of breast cancer is increasing worldwide, and this seems to be related to an increase in lifestyle risk factors, including physical inactivity and overweight/obesity. We have reported previously that exercise induced a circulating angiostatic phenotype characterized by increased soluble fms-like tyrosine kinase-1 (sFlt-1) and endostatin and decreased unbound vascular endothelial growth factor (VEGF) in men. However, there are no data on women. The present study determines the following: (a) whether moderate exercise increased sFlt-1 and endostatin and decreased unbound VEGF in the circulation of adult female volunteers and (b) whether overweight/obese women have a higher plasma level of unbound VEGF than lean women. A total of 72 African American and White adult women volunteers ranging in age from 18 to 44 years were enrolled in the exercise study. All the participants walked on a treadmill for 30 min at a moderate intensity (55-59% heart rate reserve), and oxygen consumption (VO(2)) was quantified utilizing a metabolic cart. We obtained blood samples before and immediately after exercise from 63 participants. ELISA assays showed that the plasma levels of sFlt-1 were 67.8±3.7 pg/ml immediately after exercise (30 min), significantly higher than the basal levels, 54.5±3.3 pg/ml, before exercise (P

It is unknown whether severe sarcopenia produces unfavorable effects on cardiovascular risk factors. To examine the influence of severe and moderate sarcopenia on selected cardiovascular risk factors, 687 men were screened; those exhibiting clinically relevant diseases and higher body fat percentage (25% fat) were excluded. A total of 410 men aged 40-76 years (mean age 56.0 years) were used for data analyses.Sarcopenia was defined as a skeletal muscle mass (SM) index (muscle mass/height squared) of 1-2 standard deviations (SD) below (moderate) or2 SDs below (severe) the mean for young adult men. Ultrasound-measured subcutaneous fat and muscle thicknesses were used to estimate the SM, percent body fat, and fat-free mass. Serum total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C) levels were determined using fasting blood samples. Systolic blood pressure and diastolic blood pressure were also measured.HDL-C was similar among the groups, but TC was lower in severe and moderate sarcopenia groups compared to the normal group. As a result, the TC:HDL-C ratio was lower in the moderate and severe sarcopenia groups than in the normal group. After adjusting for age, body mass index (BMI), waist circumference, and percent body fat, HDL-C was lower in both sarcopenia groups compared to the normal group, but other parameters were similar among the groups. A low prevalence of high HDL-C and high prevalence of moderate HDL-C were observed in the severe and the moderate sarcopenia groups.Our results suggest that moderate and severe sarcopenia may influence the HDL-C level, although the values are still maintained in the clinically normal range.

The purpose of this study was to investigate the time course of hypertrophic adaptations in both the upper arm and trunk muscles following high-intensity bench press training. Seven previously untrained young men (aged 25±3 years) performed free-weight bench press training 3 days (Monday, Wednesday and Friday) per week for 24 weeks. Training intensity and volume were set at 75% of one repetition maximum (1-RM) and 30 repetitions (3 sets of 10 repetitions, with 2–3 min of rest between sets), respectively. Muscle thickness (MTH) was measured using B-mode ultrasound at three sites: the biceps and triceps brachii and the pectoralis major. Measurements were taken a week prior to the start of training, before the training session on every Monday and 3 days after the final training session. Pairwise comparisons from baseline revealed that pectoralis major MTH significantly increased after week-1 (p=0.002), triceps MTH increased after week-5 (p=0.001) and 1-RM strength increased after week-3 (p=0.001) while no changes were observed in the biceps MTH from baseline. Significant muscle hypertrophy was observed earlier in the chest compared to that of the triceps. Our results indicate that the time course of the muscle hypertrophic response differs between the upper arm and chest.

The purpose of this study was to examine changes in physical activity and fitness variables in members of 8 volunteer families after 3 months of home use of the Wii Fit™ interactive video game. Pre and postintervention measurements were obtained from 21 subjects relative to physical activity (5 days of accelerometry), aerobic fitness (graded treadmill test), muscular fitness (push-ups), flexibility (sit-and-reach test), balance (composite equilibrium score), and body composition (body mass index and % body fat). Use characteristics of the Wii Fit™ device were also determined. A series of 2 (age group) × 2 (time) repeated measures analyses of variance were conducted to assess changes over time and between adults and children. Three months of home Wii Fit™ use revealed no significant age group × time interactions or main effects of group or time for daily physical activity, muscular fitness, flexibility, balance, or body composition. An age group × time interaction (p = 0.04) was observed in peak VO2 (ml·kg(-1)·min(-1)) with children displaying a significant (p = 0.03) increase after 3 months of Wii Fit™ use, whereas adults showed no significant (p = 0.50) change. Daily Wii Fit™ use per household declined by 82% (p < 0.01) from 21.5 ± 9.0 min·d(-1) during the first 6 weeks to 3.9 ± 4.0 min·d(-1) during the second 6 weeks. Most measures of health-related fitness in this exploratory study remained unchanged after 3 months of home use of the popular Wii Fit™ whole-body movement interactive video game. Modest daily Wii Fit™ use may have provided insufficient stimulus for fitness changes.

The purpose of this study was to compare heart rate peak in obese (n=43) and normal weight (n=45) female youth. Heart rate (HR) peak was significantly lower (p2 (L min-) peak similar between groups (1.77±20.53, 1.97±0.60). Bivariate correlations for heart rate peak with body weight, percent fat, and body mass index yielded the following: -0.53, -0.54, and -0.57. These findings agree with the adult data indicating low HR peak in obese individuals. Further research is needed to explore physiologic factors that may lead to reduced HR peak in obese female youth.

The aim of the study was to objectively determine whether the Nutrition and Physical Activity Self-Assessment for Child Care (NAP SACC) program improved physical activity levels during the school day.The study compared the physical activity levels of subjects from 26 daycare centers, randomized into treatment (N=13) and control (N=13) groups. The subjects were 3 to 5 year olds (N=209, 104 males and 105 females; age [years]=3.85±0.8 [mean±standard deviation]), and accelerometry was used to determine the subjects' physical activity levels. Accelerometers were attached to each subject for 2 days before and immediately after a 6-month intervention. Height, mass, and waist were also measured.Regression analyses indicated that the treatment group demonstrated significant increases in moderate and vigorous physical activity, as compared to the control group (F(1, 207)=6.3, p0.05, Cohen's d=0.30; F(1, 207)=4.7, p0.05, Cohen's d=0.25, respectively). The treatment group also showed significant increases in total physical activity (F(1, 218)=12.4; p0.05) from pre- to post-test with significant increases in moderate and vigorous intensity physical activity (F(1, 218)=18.6, p0.05; F(1, 218)=23.3, p0.05, respectively). Regression analyses revealed significant increases in height for both groups from pre- to post-tests, but no differences were noted between groups.Implementation of the NAP SACC program in treatment daycare facilities resulted in significant increases in objectively measured physical activity levels, compared to the control group, demonstrating physical activity improvement in the treatment daycare centers.

AB Purpose: Childhood cancer survivors (CCS) experience late effects that interfere with physical function. Limitations in physical function can affect CCS abilities to actively participate in daily activities. The purpose of this investigation was to evaluate the concordance between self-reported physical performance and clinically evaluated physical performance among adult CCS. Methods: CCS 18 yr or older and 10 yr or older from diagnosis who are participants in the St. Jude Lifetime cohort study responded to the physical function section of the Medical Outcome Survey Short Form (SF-36). Measured physical performance was evaluated using the Physical Performance Test and the 6-Minute Walk Test. Results: Individuals (N = 1778, 50.8% female) with a median time since diagnosis of 24.9 yr (range = 10.9-48.2) and a median age of 32.4 yr (range = 19.1-48.2) completed testing. Limitations in physical performance were self-reported by 14.1% of participants. The accuracy of self-report physical performance was 0.87 when the SF-36 was compared with the 6-Minute Walk Test or the Physical Performance Test. Reporting inaccuracies most often involved reporting a physical performance limitation. Poor accuracy was associated with previous diagnosis of a bone or CNS tumor, lymphoma, older age, and large body size. Conclusions: These results suggest that self-report, using the physical performance subscale of the SF-36, correctly identifies CCS who do not have physical performance limitations. In contrast, this same measure is less able to identify individuals who have performance limitations.

Exercise mode and intensity/duration are important factors for influencing muscle morphology and function as well as bone. However, it is unknown whether masters cyclists who undergo regular moderate- to high-intensity exercise maintain lower-body skeletal muscle mass (SM) and function and bone health when compared with young adults. The purpose of this study was to compare SM, areal bone mineral density (aBMD), and gait performance between masters cyclists and young adults. Fourteen male masters cyclists (aged 53-71 years) and 13 moderately active young men (aged 20-30 years, exercising less than twice a week) volunteered. The masters cyclists were all training actively (four to five times per week, ∼200 miles per week) for on average the last 17 years (range 7-38 years). Thigh SM was estimated from an ultrasound-derived prediction equation using muscle thickness (MTH). Appendicular lean mass (aLM) and aBMD were also estimated using dual-energy X-ray absorptiometry. There were no significant differences (p0.05) in thigh SM, anterior and posterior thigh MTH ratio, or aLM between masters cyclists and young men. Maximum straight and zigzag walking times were also similar between groups. Lumbar spine (L1-L4) aBMD was not different between groups, but femoral neck aBMD was lower (p0.05) in the cyclists than in the young men. Our results suggest that appendicular as well as site-specific thigh muscle loss with aging were not observed in masters cyclists. This maintenance of muscle mass in masters cyclists may preserve walking performance to similar levels as moderately active young adults. However, long-term cycling does not preserve femoral neck aBMD.

OBJECTIVE The conventional ratio method (milliliters O(2) per mass) typically is used to express VO(2) peak. The goal of the current study was to compare VO(2) peak of obese girls with normal-weight girls by ratio and allometric scaling methods. RESEARCH METHODS AND PROCEDURES We compared VO(2) peak by ratio and allometric methods in 46 obese and 47 normal-weight girls. Indirect calorimetry was used to measure VO(2) peak during either treadmill running or walking. Regression analysis was used to determine coefficients for mass and stature for each group with ANOVA used to compare data between groups. RESULTS The obese girls were taller and had higher values of body fatness (p < or = 0.05). Absolute VO(2) peak (liters per minute) was similar between groups; however VO(2) peak relative to mass was 50% lower (p < or = 0.05) in the obese girls. When VO(2) peak (milliliters per minute per kilogram) and mass were correlated, r = -0.48 was found in the obese group. Allometric scaling of logarithmic transformed stature and mass reduced this to r = -0.002, thus eliminating the bias associated with the ratio method. Adjusting VO(2) peak allometrically scaled for mass, stature, and the combination of mass and stature reduced the difference between groups from 50% (ratio method) to 10% to 11% (p < or = 0.05) with higher values found in the normal-weight girls. DISCUSSION These results demonstrate the bias associated with the ratio method when comparing VO(2) peak in obese girls with VO(2) peak in normal-weight girls. Allometric scaling eliminated the bias and thus may reflect a truer comparative response.

Background: Safe and effective exercise programs are needed to prevent and treat chronic diseases in childhood. In particular, preadolescent obese children should participate in activities that are specific to their special needs. Resistance or strength training has been prescribed for adult obese persons. Research is limited concerning the use of resistance training in programs that treat obese preadolescents. Methods: Nineteen treatment subjects (7-12 years of age) were enrolled in a 1 O-week weight management program which included diet, behavior modification, and aerobic and flexibi lity exercises. Forty-eight control subjects (7-12 years of age) participated in the diet, behavior modification program, and a thrice-a-week walking program. The efficacy of the overall weight management program was examined by anthropometry at 10 weeks and 1 year. Results: Fifteen treatment subjects completed the 10-week program (retention rate, 78.9%). Thereafter compliance decreased by approximately 33% for the long-term study. Seventeen control subjects completed the program (retention rate, 35%). Weight, percent of ideal body weight, and body mass index were reduced significantly at 10 weeks (P and did not increase significantly at 1-year follow-up in both treatment and control groups. Height increased significantly at 1 year in both treatment and control subjects. In the treatment subjects, percent fat decreased significantly (p P > 0.05). Conclusions: A resistance-training program may be included safely in a multidisciplinary weight management program for obese preadolescent male and female children. The addition of specific exercise regimes such as resistance training may improve program retention especially in severely obese youth.

Peak cardiorespiratory responses, physical activity patterns, and the association of VO2peak and physical activity were examined in 16 elementary (ES) and 16 high school (HS) females. Peak responses were assessed during treadmill running, and physical activity patterns were examined over two 12-hour weekdays. Results indicated similar relative VO2peak responses between groups (ES: M = 46.8 ml · kg−1 · min−1;HS:M = 46.6 ml · kg−1 · min−1). No statistical differences (p ≤ .05) were noted when moderate to vigorous physical activity (MVPA) and vigorous physical activity (VPA) were compared. Also, a three-way (Group × HR level × Sustained minutes) ANOVA revealed no statistical differences. A median correlation (r = .27) was found from 8 independent correlations of habitual physical activity and VO2peak. ES and HS appeared similar in regard to VO2peak, accumulative and sustained MVPA and VPA. Low levels of sustained MVPA and VPA (≥ 10 min) were evident in both groups.

The purpose of this study was to compare the prevalence of severe sarcopenia detected by total skeletal muscle mass (SM) index and of site-specific thigh sarcopenia for differing age groups in men and women. Japanese nonobese men and women aged 20 to 85 (n = 1,994, 55 % women) had muscle thickness (MTH) measured by ultrasound at six sites on the anterior and posterior aspects of the body. SM was estimated from ultrasound-derived prediction equations. Site-specific thigh sarcopenia was calculated using ultrasound-measured MTH at the anterior and posterior aspects of the thigh (MTH ratio, anterior 50 %/posterior 50 % thigh MTH (A50/P50 MTH)). Sarcopenia was defined as a SM index (SM divided by height2) of >2 standard deviations (SD) below the mean for young adults. Site-specific thigh sarcopenia was defined as a ratio of A50/P50 MTH of >2 SD below the mean for young adults. Age was inversely correlated to SM index and A50/P50 MTH in men (r = −0.480 and r = −0.522) and women (r = −0.243 and r = −0.516). The prevalence rate of sarcopenia was less than 3 % for women under the age of 60, 7 % for ages 60–69, and 24 % for ages 70–80. In men, the prevalence rate of sarcopenia was less than 7 % under the age of 50, 18 % for ages 50–59, 33 % for ages 60–69, and 47 % for ages 70–85. Compared to the sarcopenia estimated by SM index, there was a higher prevalence of site-specific thigh sarcopenia observed in both sexes. These results suggest that site-specific thigh sarcopenia appears before it is able to be detected at the whole body level.

The multidisciplinary, four-phase approach, which includes PSMF, BEM, and MPE is successful in treating mild, moderate, and severe degrees of childhood and adolescent obesity. The MPE program is appropriate for use with PSMF and BEM due to its progressive nature, variety of options, and moderate intensity level. In addition, the MPE program is of sufficient intensity, duration, and frequency to promote a significant increase in estimated aerobic capacity (VO2max) and to promote the maintenance of lean body mass and resting energy expenditure. The short-term intervention of PSMF, BEM, and MPE also results in an improvement in body composition, lipid profiles, and IGF-1 and T3 levels. The 1200-calorie balanced diet, MPE, and BEM also provide a successful method of weight maintenance in children and adolescents, as indicated by further improvement in body composition at the 26-week measure. Additional studies are needed to assess the contribution of exercise to the maintenance of lean body mass and resting energy expenditure in obese children and adolescents. In addition, it will be important to assess long-term weight maintenance in obese adolescents who effectively lose weight in this multidisciplinary program.

We compared the energy expenditure to walk or run a mile in adult normal weight walkers (NWW), overweight walkers (OW), and marathon runners (MR). The sample consisted of 19 NWW, 11 OW, and 20 MR adults. Energy expenditure was measured at preferred walking speed (NWW and OW) and running speed of a recently completed marathon. Body composition was assessed via dual-energy x-ray absorptiometry. Analysis of variance was used to compare groups with the Scheffe's procedure used for post hoc analysis. Multiple regression analysis was used to predict energy expenditure. Results that indicated OW exhibited significantly higher (p0.05) mass and fat weight than NWW or MR. Similar values were found between NWW and MR. Absolute energy expenditure to walk or run a mile was similar between groups (NWW 93.9 ± 15.0, OW 98.4 ± 29.9, MR 99.3 ± 10.8 kcal); however, significant differences were noted when energy expenditure was expressed relative to mass (MRNWWOW). When energy expenditure was expressed per kilogram of fat-free mass, similar values were found across groups. Multiple regression analysis yielded mass and gender as significant predictors of energy expenditure (R = 0.795, SEE = 10.9 kcal). We suggest that walking is an excellent physical activity for energy expenditure in overweight individuals that are capable of walking without predisposed conditions such as osteoarthritis or cardiovascular risk factors. Moreover, from a practical perspective, our regression equation (kcal = mass (kg) × 0.789 - gender (men = 1, women = 2) × 7.634 + 51.109) allows for the prediction of energy expenditure for a given distance (mile) rather than predicting energy expenditure for a given time (minutes).

Five men and five women from a university cross‐country team were tested during the first 2 weeks and at the conclusion of a 7‐week cross‐country season. Maximal and submaximal cardiorespiratory responses, body composition, and performance variables were compared for seasonal and gender differences by analysis of variance and analysis of covariance. Male runners had significantly less (p ≤0.05) body fat, more fat‐free body (FFB) mass, a larger cardiorespiratory capacity, and ran more economically and faster than female runners. The difference in cardiorespiratory capacity and performance may have been due to a larger FFB (muscularity) and the increased training volume practiced by the male runners. Several gender but no seasonal differences were observed during a running economy test (214 m·min−1). A difference in oxygen uptake (VO2; ml·min−1‐kg BW−1) during the running economy test between male and female runners was unexpected and may have been due to fatigue in the female runners since their late seaso...

Purpose:The aim of this investigation was to compare gender differences in physiologic and perceptual responses during a 1-h run at recent marathon pace and running economy at three speeds in recreational marathon runners.Methods:In a counterbalanced design, 10 men and 10 women completed a 1-h treadmill run and a running economy test. Treadmill speed for the 1-h run ranged from 141 to 241 m·min−1 and 134, 168, and 188 m·min−1 for running economy. Physiologic parameters (oxygen uptake, carbon dioxide production, pulmonary ventilation, and heart rate) and perceived exertion were measured. Repeated-measures ANOVA was used to compare any gender differences (P < .05) during the 1-h run and a two-way ANOVA was used to compare running economy. With this sample, estimated marathon energy expenditure, body composition, and maximal physiologic function was reported.1Results:With the exception of an allometric expression of VO2 (mL·min−1·kg BW−0.75), similar gender physiologic and perceptual responses were found during the 1-h run. Although not significant, the females exercised at a higher percent VO2max (8% to 9%) during the run. Similar gender differences were also noted during the running economy tests.Conclusions:Although the male runners completed a recent marathon significantly faster than the females, similar gender physiologic and perceptual responses were generally found during the 1-h treadmill run and the running economy tests.

The purpose of the study was to investigate the seasonal relationship of athletic amenorrhea and body composition in elite, adolescent, cross-country runners. The participants consisted of 28 female adolescent cross-country runners (mean age ± SD = 15.4 ± 1.5 years); 17 eumenorrheics and 11 amenorrheics. The participants’ body composition was measured pre- and postseason using dual-energy X-ray Absorptiometer (DXA). The eumenorrheics’ postseason BMD was significantly greater than the amenorrheics’ postseason BMD (F(1,54) = 16.22, p < .05, partial η2 = .231). The eumenorrheics’ postseason bodyweight (F(1,54) = 7.65, p < .05, partial η2 = .124), BF (F(1,54) = 8.56, p < .05, partial η2 = .137), and BMC (F(1,54) = 8.52, p < .05, partial η2 = .136) were significantly greater than the amenorrheic subgroup. There was also a significant seasonal increase in BMD (t(27) = –4.01, p < .05) for the overall group and the eumenorrheic subgroup (t(16) = –3.90, p < .05). Bodyweight best predicted BMD (F(1,26) = 46.434, p < .05, R2 = .641). In the study, athletic amenorrhea was highly associated with lower levels of BMD in the participants, and crosscountry running was highly associated with increased BMD.

The purpose of this study was to examine exercise intensity while perceptually pacing at 12 to 14 (somewhat hard) on the Borg scale during outdoor running. Maximal oxygen uptake (VO2max), ventilatory threshold, and related variables were measured during treadmill running. Submax VO2 was collected during a 1.6 km run while pacing between 12 and 14 on the Borg scale. In order to collect expired gases during this run, a Douglas bag was fitted to a backpack frame and data were collected during the last 0.4 km of the 1.6 km run. To minimize pacing errors, three 2.4 km runs while perceptually pacing were completed. VO2max averaged 41.3 ml‐min‐1.kg‐1 and ventilatory threshold was 64.4% of VO2max. The submax VO2 while perceptually pacing was 71.2% of VO2max. This value was slightly, although nonsignificantly (p > 0.05), higher than the percentage of VO2max at ventilatory threshold. The results indicate that distance run pacing at 12 to 14 on the Borg scale is near ventilatory threshold and within the acceptable e...

This study examined energy expenditure and physiologic determinants for marathon performance in recreational runners. Twenty recreational marathon runners participated (10 males aged 41 +/- 11.3 years, 10 females aged 42.7 +/- 11.7 years). Each subject completed a V(.-)O2max and a 1-hour treadmill run at recent marathon pace, and body composition was indirectly determined via dual energy X-ray absorptiometry. The male runners exhibited higher V(.-)O2max (ml x kg(-1) x min(-1)) values (52.6 +/- 5.5) than their female counterparts (41.9 +/- 6.6), although ventilatory threshold (T-vent) values were similar between groups (males: 76.2 +/- 6.1 % of V(.-)O2max, females: 75.1 +/- 5.1%). The male runners expended more energy (2,792 +/- 235 kcal) for their most recent marathon as calculated from the 1-hour treadmill run at marathon pace than the female runners (2,436 +/- 297 kcal). Body composition parameters correlated moderately to highly (r ranging from 0.50 to 0.87) with marathon run time. Also, V(.-)O2max (r = -0.73) and ventilatory threshold (r = -0.73) moderately correlated with marathon run time. As a group, the participants ran near their ventilatory threshold for their most recent marathon (r = 0.74). These results indicate the influence of body size on marathon run performance. In general, the larger male and female runners ran slower and expended more kilocalories than smaller runners. Regardless of marathon finishing time, the runners maintained a pace near their T-vent, and as T-vent or V(.-)O2max increased, marathon performance time decreased.

The primary aim of this study was to examine the effects of exercise intensity and duration on choice reaction time with a secondary aim to examine the influence of aerobic fitness on choice reaction time. Fifteen college-aged men enrolled in a physical fitness activity course participated. We observed a cubic trend ( r =.99) across exercise intensity that ranged from unloaded cycling to 90% of physical working capacity (PWC). However, no significant differences were noted across intensity (medium effect size) or duration (small effect size). The fastest choice reaction time occurred at 75% of PWC, which was near the ventilatory threshold (72.6% of VO2max). Aerobic fitness was average for college-aged men (39.3 ml/kg/min.) and was poorly correlated with choice reaction time across exercise intensity. Further research is needed to compare choice reaction time in high to low fitness groups across exercise intensity.

Over 15% of children 6–11 yr old and adolescents 12–19 yr old in the United States are overweight (17). Among adolescent girls, the prevalence of overweight was reported as 15.5% in the 1999–2000 National Health and Nutrition Examination Survey (NHANES), compared with 9.7% in NHANES III (1988–1994) (17). Boys are generally more likely to be overweight and at risk than girls (11). However, African American girls have significantly higher rates of overweight than boys, and in Native American children no gender differences are apparent (6). In the simplest terms, overweight occurs when there is an imbalance between energy intake and energy expenditure. However, because physical activity is a highly variable component of energy expenditure, its relationship to weight status is not clearly understood, especially in female youth. Regardless, it is generally well accepted that lower than desirable energy expenditure, because of low physical activity, is a contributing factor to the recent increase in childhood overweight and obesity. Previous studies have examined the relationship between childhood weight or body composition and physical activity (9,10,15,16). Higher levels of physical activity were associated with lower levels of weight or body fat in several studies (9,16,24). Physical activity estimated by a questionnaire, but not activity energy expenditure (derived by doubly labeled water), was inversely related to body fat in children (10). The findings across studies likely differ because of differences in measurement techniques for body composition, physical activity and energy expenditure, and whether the focus is on an estimate of total physical activity or the energy cost of activity. Overweight/obesity can be determined by simple anthropometric measures (body mass and height) or by body composition techniques (e.g., skinfolds, bioelectric impedance, or dual-energy x-ray absorptiometry). Physical activity can be measured through self-reports (diaries and questionnaires) or more objectively, by accelerometry or doubly-labeled water. Accelerometers can quantify total activity over several days, and intensity can be characterized by utilizing previously established accelerometer thresholds for sedentary, light, moderate, and vigorous activity (26). Combining measures of body composition with accelerometry provides a unique way to explore relationships among body fatness, fat-free mass, and physical activity. Our purpose for the present analysis was to examine the nature of the relationship (linear, curvilinear) of body composition (size, fat mass, fat-free mass) to physical activity as assessed in sixth grade girls. Because physical activity is the primary outcome in the TAAG trial, we wanted to establish baseline relationships between physical activity (dependent variable) and body composition (independent variable). Specifically, we examined whether components of body composition were associated to moderate-to-vigorous physical activity (MVPA), vigorous physical activity (VPA), and MET-weighted physical activity using a large sample of girls from across the United States. This paper presents the baseline body composition and physical activity (as measured by accelerometry) of girls enrolled in The Trial of Activity for Adolescent Girls (TAAG), a multisite school- and community-based intervention designed to prevent the decline in physical activity in adolescent girls.

Clinical, epidemiological and basic research evidence clearly supports the inclusion of regular physical activity as a tool for the prevention of chronic disease and the enhancement of overall health. In children, activities of a moderate intensity may enhance overall health, and assist in preventing chronic disease in at-risk youth. The numerous health benefits of regular exercise are dependent on the type, intensity and volume of activity pursued by the individual. These benefits include reduction of low density lipoproteins while increasing high density lipoprotein; improvement of glucose metabolism in patients with type II diabetes; improved strength, self esteem and body image; and reduction in the occurrence of back injuries. In addition, a progressive, moderate-intensity exercise program will not adversely effect the immune system and may have a beneficial effect on the interleukin-2/natural killer cell system. Furthermore, by decreasing sedentary behaviors and, thus, increasing daily physical activity, individuals may experience many stress-reducing benefits, which may enhance the immune system. Conclusion Moderate intensity exercise of a non-structured nature seems to facilitate most of the disease prevention goals and health promoting benefits. With new guidelines promoting a less intense and more time-efficient approach to regular physical activity, it is hoped that an upward trend in the physical activity patterns, and specifically children at risk for chronic disease, will develop in the near future.

The purpose of the study was to examine the relationship and comparisons of athletic amenorrhea and bone mineral density in adolescent, cross-country runners. Subjects: Twenty-eight female adolescent cross-country runners (Mean Age + SD = 15.0 + 1.3 years); consisting of seventeen eumenorrheics & eleven amenorrheics. Design: The design consisted of a sixmonth longitudinal design in which the subjects were measured before and after cross-country season for height, weight, and lean tissue (LT), body fat (BF), bone mineral content (BMC), and bone mineral density (BMD) using whole-body scan densitiometry with a Lunar Dual-energy X-ray Absorptiometer (DXA). Run performance, weekly training volumes, menstrual dysfunction, menarchal age, nutritional information, and stress fractures were reported by the subjects. Statistical analyses consisted of Pearson product-moment and partial correlations to examine the associations of the variables, paired t-tests to measure seasonal body composition changes, multivariate analysis (MANOVA & MANCOVA) to investigate the subgroup differences of variables, and simple linear regression to determine the best body composition predictor variable for BMD. Results: The eumenorrheic subgroup's BMD was significantly greater than the amenorrheic subgroup's BMD (F(1, 54) = 16.22, p

Researchers have investigated the effect of exercise on reducing subjects' responsiveness to stress. Results from the initial studies were positive, yet these studies often did not use objective measures of fitness. This investigation applied more rigorous methodology than past experiments to assess the relationship between fitness and reactivity to stress. Maximal oxygen consumption was measured to indicate the fitness of recreational cyclists who were then exposed to three stressful situations (mental subtraction, speech preparation, and the cold pressor test). Heart rate, frontalis electromyographic (EMG) levels, and self-report of tension were monitored during the stress-inducing tasks. Physical fitness was significantly related to heart rate taken during the subtraction and cold pressor tasks, with EMG during subtraction, and with self-report during all three stressor tasks. These results further support the hypothesized association of physical fitness and reducing response to stress.