The purpose of the current study was to investigate the relationship between health-related physical fitness and bone mineral density (BMD) in adolescents. One hundred forty-four adolescents (65 boys and 79 girls) between 15 and 18 years of age were recruited to this cross-sectional study. Subjects were evaluated in aerobic fitness, muscular fitness, flexibility, body composition, and maturation. BMD of the lumbar spine, total body, and proximal femur were measured by a dual-energy X-ray absorptionmeter. Pearson’s correlation and stepwise multiple regression analyses were used (p < .05). Lean body mass (LBM) and abdominal muscular fitness explained 35–40% of proximal femur BMD in whole group and boys’ total body BMD (43%); however, VO2max and LBM predicted girls’ total body BMD (23%). Lumbar spine BMD was predicted only by LBM for both genders (18% boys, 15% girls). In summary, lean body mass is the main predictor of bone mass during the end of adolescence, regardless of gender, whereas muscular fitness contributes more to bone mass among males than among females.
Rômulo Maia Carlos Fonseca, Nanci Maria de França and Emmanuel Van Praagh
Beau Kjerulf Greer, Kathleen M. Edsall and Anna E. Greer
The purpose of the current study was to determine whether expected changes in body weight via a 3-day low-carbohydrate (LC) diet will disrupt the reliability of air displacement plethysmography measurements via BOD POD. Twenty-four subjects recorded their typical diets for 3 days before BOD POD and 7-site skinfold analyses. Subjects were matched for lean body mass and divided into low-CHO (LC) and control (CON) groups. The LC group was given instruction intended to prevent more than 50 grams/day of carbohydrate consumption for 3 consecutive days, and the CON group replicated their previously recorded diet. Body composition measurements were repeated after dietary intervention. Test–retest reliability measures were significant (p < .01) and high for body fat percentage in both the LC and the CON groups (rs = .993 and .965, respectively). Likewise, skinfold analysis for body fat percentage reliability was high in both groups (rs = .996 and .997, respectively). There were significant differences between 1st and 2nd BOD POD measurements for body mass (72.9 ± 13.3 vs. 72.1 ± 13.0 kg [M ± SD]) and body volume (69.0 ± 12.7–68.1 ± 12.2 L) in the LC group (p < .05). However, there were no differences (p > .05) in BOD POD–determined body fat percentage, lean body mass, or fat mass between the 1st and 2nd trial in either group. Body composition measures via BOD POD and 7-site skinfolds remain reliable after 3 days of an LC diet despite significant decreases in body mass.
Thomas B. Walker, Jessica Smith, Monica Herrera, Breck Lebegue, Andrea Pinchak and Joseph Fischer
The purpose of this study was to investigate the ability of whey-protein and leucine supplementation to enhance physical and cognitive performance and body composition. Thirty moderately fit participants completed a modified Air Force fitness test, a computer-based cognition test, and a dual-energy X-ray-absorptiometry scan for body composition before and after supplementing their daily diet for 8 wk with either 19.7 g of whey protein and 6.2 g leucine (WPL) or a calorie-equivalent placebo (P). Bench-press performance increased significantly from Week 1 to Week 8 in the WPL group, whereas the increase in the P group was not significant. Push-up performance increased significantly for WPL, and P showed a nonsignificant increase. Total mass, fat-free mass, and lean body mass all increased significantly in the WPL group but showed no change in the P group. No differences were observed within or between groups for crunches, chin-ups, 3-mile-run time, or cognition. The authors conclude that supplementing with whey protein and leucine may provide an advantage to people whose performance benefits from increased upper body strength and/or lean body mass.
D.R. Paul, S.M. Mulroy, J.A. Horner, K.A. Jacobs and D.R. Lamb
The effects of employing a high-carbohydrate diet (carbohydrate-loading) to increase glycogen storage in skeletal muscle are not well established in female athletes. On 4 occasions—2 familiarization trials and 2 experimental trials—6 well-trained female subjects completed 6 × 15-min continuous intervals of cycling (12 min at 72% V̇O2max, 1 min at maximal effort, and 2 min at 50% V̇O2max), followed by a time trial 15 min later. The women consumed their habitual diets (HD; 6–7 g carbohydrate/kg lean body mass) for 3 days after the second familiarization trial and before the first experimental trial. During the 3 days following the first experimental trial, the subjects consumed a high-carbohydrate diet (CD; 9–10 g carbohydrate/kg lean body mass) prior to the second experimental trial. Mean (±SEM) pre-exercise muscle glycogen concentrations were greater after CD versus HD (171.9 ± 8.7 vs. 131.4 ± 10.3 mmol/kg wet weight, P < 0.003). Although 4 of the 6 subjects improved their time-trial performance after CD, mean performance for the time trial was not significantly different between diets (HD: 763.9 ± 35.6 s; CD: 752.9 ± 30.1 s). Thus, female cyclists can increase their muscle glycogen stores after a carbohydrate-loading diet during the follicular phase of the menstrual cycle, but we found no compelling evidence of a dietary effect on performance of a cycling time trial performed after 90 min of moderate-intensity exercise.
Gerasimos Terzis, Thomas Kyriazis, Giorgos Karampatsos and Giorgos Georgiadis
Although muscle mass and strength are thought to be closely related to throwing performance, there are few scientific data about these parameters in elite shot-putters. The purpose of this case report was to present longitudinal data for muscle strength and body composition in relation to performance of an elite male shot-putter.
A male national champion with the best rotational shot-put performance of 20.36 m (in 2010) was followed from 2003 to 2011 (current age: 29 y). Data regarding body composition (dual X-ray absorptiometry), as well as 1-repetition-maximum muscle strength (bench press, squat, snatch) and rotational shot-put performance, were collected every February for the last 9 y, 4 wk before the national indoor championship event.
The athlete’s personal-best performances in squat, bench press, and snatch were 175 kg, 210 kg, and 112.5 kg, respectively. His peak total lean body mass was 92.4 kg, bone mineral density 1.55 g/cm2, and lowest body fat 12.9%. His shot-put performance over these 9 years was significantly correlated with 1-repetition-maximum squat strength (r = .93, P < .01), bench press (r = .87, P < .01), and snatch (r = .92, P < .01). In contrast, shot-put performance was not significantly correlated with any of the body-composition parameters.
The results of this case study suggest that elite rotational shot-put performance may not be directly correlated with lean body mass. Instead, it seems that it is closely related with measures of muscle strength.
Annie Fex, Jean-Philippe Leduc-Gaudet, Marie-Eve Filion, Antony D. Karelis and Mylène Aubertin-Leheudre
The purpose of the current study was to examine the impact of 12 weeks of elliptical high intensity interval training (HIIT) on metabolic risk factors and body composition in pre- and type 2 diabetes patients.
Sixteen pre- (n = 8) and type 2 diabetes (n = 8) participants completed this study. Fasting blood glucose, HbA1c, anthropometric measurements, body composition (DXA), blood pressure, resting heart rate, VO2max, and dietary factors, as well as total and physical activity energy expenditure, were measured. The HIIT program on the elliptical was performed 3 times a week for 12 weeks.
After the intervention, we observed a significant improvement for fasting blood glucose, waist and hip circumference, appendicular fat mass, leg lean body mass and appendicular lean body mass, systolic blood pressure, resting heart rate, and VO2max (P < .05). In addition, we noted a lower tendency for leg fat mass (P = .06) and diastolic blood pressure (P = .05) as well as a higher tendency for total energy expenditure (P = .06) after the intervention.
The current study indicates that elliptical HIIT seems to improve metabolic risk factors and body composition in pre- and type 2 diabetes patients.
Steven A. Hawkins, Robert A. Wiswell and E. Todd Schroeder
This study examined the relationships between high-intensity resistance exercise and bone mass in postmenopausal women and serum reproductive-hormone levels and bone-mass changes in response to resistance exercise. Women 45–65 years old were assigned to an exercise or a control group. They trained 3 times weekly for 18 weeks at 90,70, and 80% of their 1-RM. Groups were not different in age, height, body mass, muscle strength, or lean body mass. Initial muscle strength increased significantly in the training group. Total hip and intertrochanter bone-mineral density (BMD) increased in the training group. Estradiol, testosterone, osteocalcin, and CrossLaps concentration did not change in either group. Serum estradiol was significantly related to change in BMD at the hip, femoral neck, and intertrochanter, as well as change in lean mass. Results suggest that high-intensity resistance exercise can increase BMD of the hip and that serum estrogen concentrations might influence bone and muscle adaptations to resistance exercise in postmenopausal women.
Eric Joseph Rosario, Rudolph Gino Villani, Jeff Harris and Rudi Klein
Aging generally results in muscle and bone atrophy, with accelerated loss in the first few years after menopause contributing to decline in strength, balance, and mobility. This investigation compared the effects of 1 of year periodized high-intensity strength training on a group of less-than-5-years (LF) postmenopausal women (n = 10, mean age 51 years) with its effects on a more-than-10-years (MT) postmenopausal group (n = 11, mean age 60 years). Mean lean body mass, strength, and balance increased over the intervention period for both groups, with no significant intergroup differences. Mean total fat mass significantly decreased for both groups, with no significant difference between groups. Total and regional bone density and mineral content did not significantly change in either group. These results indicate that even during the accelerated muscle-loss period after menopause, women can gain muscle and strength with resistance training to a similar extent as older women.
Michael R. Bracko and Gilbert W. Fellingham
Fifty-four female and 77 male hockey players ranging in age from 10–15 years volunteered for this study. Demographic data included: age (AGE) and years of playing experience (YPE). Off-ice tests included: height (HGT), body mass (BM), lean body mass (LBM), predicted body fat % (FAT%), 40-yard dash (40YD), vertical jump (VJ), push-ups/min (PUPS), sit-ups/min (SUPS), and sit-and-reach flexibility (S&R). On-ice performance skating tests included: acceleration (ACC), agility (AGL), and speed (SPD). On-ice anaerobic power (AnPow) was calculated using the formula of Watson and Sargeant (IS). Generally speaking, the females and males in this study had similar results in office fitness. The males consistently out-performed the females in the on-ice tests. It would be difficult for females to compete with or against same-aged males based on the fact that males are superior skaters.
Noelia Galiano-Castillo, Manuel Arroyo-Morales, Angélica Ariza-Garcia, Carmen Sánchez-Salado, Carolina Fernández-Lao, Irene Cantarero-Villanueva and Lydia Martín-Martín
This study examined the relationship between the 6-min walk test (6MWT) and fitness, psychological and physiologic states, quality of life, cancer-related symptoms, and body composition of 87 women with breast cancer. The assessment included the 6MWT and evaluations of Cancer Quality of Life (EORTC C-30 and EORTC BR-23), cognitive performance (Trail Making Test), the Hospital Anxiety and Depression Scale, body composition, health-related fitness (abdominal test, multiple sit-to-stand test, trunk dynamometry), and pain (Brief Pain Inventory). We observed the following correlations: moderate between 6MWT and pain interference; modest for cognitive and social functioning and the multiple sit-to-stand test; fair for several items on the Cancer Quality of Life, for anxiety, lean body mass, trunk dynamometry and pain intensity; and weak for role functioning, loss of appetite, cognitive performance and depression. Thus, the 6MWT could be used as a measure of the major components of global health in women with breast cancer.