The purpose was to compare changes in lean tissue mass, strength, and myof-brillar protein catabolism resulting from combining whey protein or soy protein with resistance training. Twenty-seven untrained healthy subjects (18 female, 9 male) age 18 to 35 y were randomly assigned (double blind) to supplement with whey protein (W; 1.2 g/kg body mass whey protein + 0.3 g/kg body mass sucrose power, N = 9: 6 female, 3 male), soy protein (S; 1.2 g/kg body mass soy protein + 0.3 g/kg body mass sucrose powder, N = 9: 6 female, 3 male) or placebo (P; 1.2 g/kg body mass maltodextrine + 0.3 g/kg body mass sucrose powder, N = 9: 6 female, 3 male) for 6 wk. Before and after training, measurements were taken for lean tissue mass (dual energy X-ray absorptiometry), strength (1-RM for bench press and hack squat), and an indicator of myofbrillar protein catabolism (urinary 3-methylhistidine). Results showed that protein supplementation during resistance training, independent of source, increased lean tissue mass and strength over isocaloric placebo and resistance training (P < 0.05). We conclude that young adults who supplement with protein during a structured resistance training program experience minimal beneficial effects in lean tissue mass and strength.
Darren G. Candow, Natalie C. Burke, T. Smith-Palmer and Darren G. Burke
Stacy D. Hunter, Mandeep S. Dhindsa, Emily Cunningham, Takashi Tarumi, Mohammed Alkatan, Nantinee Nualnim and Hirofumi Tanaka
Obesity is associated with arterial stiffening and diminished quality of life. Bikram yoga may be a feasible alternative to traditional exercise among obese individuals. Accordingly, the purpose of this study was to investigate the impact of Bikram yoga, a heated style of hatha yoga, on arterial stiffness in normal and overweight/obese adults.
Forty-three (23 normal body mass index or BMI; 20 overweight/obese) apparently healthy participants completed an 8-week Bikram yoga intervention. Body composition was estimated via dual energy x-ray absorptiometry, arterial stiffness was measured via brachialankle pulse wave velocity, and health-related quality of life was assessed via RAND 36-Item Short Form survey at baseline and at the end of the 8-week intervention.
After the intervention, brachial-ankle pulse wave velocity decreased (P < .05) in overweight/obese participants while no such changes were observed in normal BMI participants. In the quality of life measures, emotional well-being improved (P < .05) in both groups, and general health improved (P < .05) only in the normal weight BMI group.
Bikram yoga ameliorates arterial stiffness in overweight/obese adults and can positively impact quality of life regardless of BMI.
Ann L. Gibson, Vivian H. Heyward, Christine M. Mermier, Jeffrey M. Janot and M. Virginia Wilmerding
The authors used 3-component (3C) Db-mineral-model (Lohman, 1986) reference measures to cross-validate Siri’s (1961) 2-component (2C) conversion formula and dual-energy X-ray absorptiometry (DXA) estimates of relative body fat (%BF) for physically active adults. Participants varied in age (18 to 59 y), body fatness, ethnicity (black, Hispanic, white), and physical activity level. The 3C Db-mineral model was used to obtain reference measures of %BF (%BF3C) for comparison with body-composition measures from DXA and hydrodensitometry. For men (n = 110) and women (n = 110), %BF3C (14.0% BF and 24.4% BF, respectively) was more accurately estimated by Siri’s 2C formula (%BFSiri; men, r = 0.97, SEE = 1.77% BF; women, r = 0.98, SEE = 1.56% BF) than by DXA (%BFDXA; men, r = 0.86, SEE = 3.54% BF; women, r = 0.88, SEE = 3.73% BF). The average %BFSiri (men, 15.8% BF; women, 24.7% BF) and %BFDXA (men, 16.2% BF; women, 26.0% BF) differed significantly (P < 0.001) from %BF3C. Siri’s 2C model estimated the average %BF3C in this sample more accurately than DXA did.
Gary Slater, David Jenkins, Peter Logan, Hamilton Lee, Matthew Vukovich, John A. Rathmacher and Allan G. Hahn
This investigation evaluated the effects of oral β-Hydroxy-β-Methylbutyrate (HMB) supplementation on training responses in resistance-trained male athletes who were randomly administered HMB in standard encapsulation (SH), HMB in time release capsule (TRH), or placebo (P) in a double-blind fashion. Subjects ingested 3 g · day−1 of HMB or placebo for 6 weeks. Tests were conducted pre-supplementation and following 3 and 6 weeks of supplementation. The testing battery assessed body mass, body composition (using dual energy x-ray absorptiometry), and 3-repetition maximum isoinertial strength, plus biochemical parameters, including markers of muscle damage and muscle protein turnover. While the training and dietary intervention of the investigation resulted in significant strength gains (p < .001) and an increase in total lean mass (p = .01), HMB administration had no influence on these variables. Likewise, biochemical markers of muscle protein turnover and muscle damage were also unaffected by HMB supplementation. The data indicate that 6 weeks of HMB supplementation in either SH or TRH form does not influence changes in strength and body composition in response to resistance training in strength-trained athletes.
Han C.G. Kemper
This paper reviews the growth and development of skeletal mass in youth and the effects of physical activity upon the bone mass in young people. The different methods to measure the bone mass are described such as anthropometrics, radiographics, dual energy X-ray absorptiometry, quantitative computed tomography, and ultrasound. Two different mechanisms are important for the formation and plasticity of bone: a central hormonal mechanism (with estrogen production) and a local mechanism (based on mechanical forces of gravity and muscle contractions). This local mechanism is closely connected to physical activity patterns and therefore discussed in more detail. Thereafter the natural course of the development of the bone mass during youth is described, taking into account the pubertal stages of boys and girls and also the age at which the maximal bone mass (peak bone mineral density) will be reached. The last part is devoted to the effects of physical activity on bone mass based on results of randomized controlled trials. Although the number of experimental studies are scarce, significant effects of weight bearing activity and high impact strength training programs are shown on the side specific bone mineral density in both boys and girls.
Sakiho Miyauchi, Satomi Oshima, Meiko Asaka, Hiroshi Kawano, Suguru Torii and Mitsuru Higuchi
The purpose of this study was to determine whether overfeeding and high-intensity physical training increase organ mass. We examined this question using cross-sectional and longitudinal studies in which we measured collegiate male American football players. Freshman (n = 10) and senior players in their second and third years of college (n = 17) participated in the cross-sectional study. The same measurements of the same freshman players (n = 10) were assessed after the one-year weight gain period in the longitudinal study. Fat-free mass (FFM), skeletal muscle, and adipose tissue mass were obtained using dual-energy X-ray absorptiometry. Liver, kidney, brain, and heart volumes were calculated using magnetic resonance imaging or echocardiography. Compared with the freshman players, the senior players had 10.8 kg more FFM, and 0.29 kg, 0.08 kg, and 0.09 kg greater liver, heart, and kidney mass, respectively. In the longitudinal study, FFM, liver, heart, and kidney mass of the freshman players increased by 5.2 kg, 0.2 kg, 0.04 kg, and 0.04 kg, respectively, after one year of overfeeding and physical training. On the other hand, the organ-tissue mass to FFM ratio did not change, except for the brain, in either the cross-sectional or longitudinal studies. Our results indicated that the organtissue masses increased with overfeeding and physical training in male collegiate American football players.
Deborah Fearnley, Louise Sutton, John O’Hara, Amy Brightmore, Roderick King and Carlton Cooke
The Vendée Globe is a solo round-the-world sailing race without stopovers or assistance, a physically demanding challenge for which appropriate nutrition should maintain energy balance and ensure optimum performance. This is an account of prerace nutritional preparation with a professional and experienced female racer and assessment of daily nutritional intake (NI) during the race using a multimethod approach. A daily energy intake (EI) of 15.1 MJ/day was recommended for the race and negotiated down by the racer to 12.7 MJ/day, with carbohydrate and fluid intake goals of 480 g/day and 3,020 ml/day, respectively. Throughout the 99-day voyage, daily NI was recorded using electronic food diaries and inventories piloted during training races. NI was assessed and a postrace interview and questionnaire were used to evaluate the intervention. Fat mass (FM) and fat-free mass (FFM) were assessed pre- (37 days) and postrace (11 days) using dual-energy X-ray absorptiometry, and body mass was measured before the racer stepped on the yacht and immediately postrace. Mean EI was 9.2 MJ/day (2.4–14.3 MJ/day), representing a negative energy balance of 3.5 MJ/day under the negotiated EI goal, evidenced by a 7.9-kg loss of body mass (FM –7.5 kg, FFM –0.4 kg) during the voyage, with consequent underconsumption of carbohydrate by ~130 g/day. According to the postrace yacht food inventory, self-reported EI was underreported by 7%. This intervention demonstrates the practicality of the NI approach and assessment, but the racer’s nutrition strategy can be further improved to facilitate meeting more optimal NI goals for performance and health. It also shows that evaluation of NI is possible in this environment over prolonged periods, which can provide important information for optimizing nutritional strategies for ocean racing.
Robyn S. Mehlenbeck, Kenneth D. Ward, Robert C. Klesges and Christopher M. Vukadinovich
Calcium intake in adolescent and young adult female athletes often is inadequate to optimize peak bone mass, an important determinant of osteoporosis risk. The purpose of this study was to determine if calcium supplementation in eumenorrheic female collegiate athletes increases intake to recommended levels and promotes increases in bone mineral density (BMD). Forty-eight eumenorrheic female athletes from several college teams (15 soccer, 7 crosscountry, 8 indoor track, and 18 basketball) were randomized at the beginning of a competitive season to receive either an oral calcium supplement (1000 mg calcium citrate/400 I.U. Vitamin D) or placebo daily throughout the training season (16 weeks). Self-reported daily pill intake was obtained every 2 weeks to assess adherence. Calcium intake was evaluated using the Rapid Assessment Method, and total body and leg BMD was measured at pre-, mid-, and postseason using dual energy x-ray absorptiometry (DEXA; Hologic QDR-2000). Pre-season calcium intake was lower than national recommendations for this age group (12), averaging 842 mg/d (SD = 719) and was lower in the placebo group compared to the supplemented group (649 ± 268 vs. 1071 ± 986 mg/d, respectively; p = .064). Adherence to supplementation was good, averaging 70% across the training season. Supplementation boosted total calcium intake to a mean of 1397 ± 411 mg/d, which is consistent with recommended levels for this group (37). Supplementation did not influence BMD change during this 16-week intervention. Across teams, a small increase of 0.8% was observed in leg BMD. Change in total body BMD was modified by team, with a significant increase of 1.5% observed in basketball players. These results indicate that providing calcium supplements of 1000 mg/d is adequate to boost total intake to recommended levels during athletic training. Longer intervention trials are required to determine whether calcium supplementation has a positive effect on BMD.
Joseph M. Kindler, Hannah L. Ross, Emma M. Laing, Christopher M. Modlesky, Norman K. Pollock, Clifton A. Baile and Richard D. Lewis
Assessment of physical activity in clinical bone studies is essential. Two bone-specific physical activity scoring methods, the Bone Loading History Questionnaire (BLHQ) and Bone-Specific Physical Activity Questionnaire (BPAQ), have shown correlations with bone density and geometry, but not architecture. The purpose of this study was to determine relationships between physical activity scoring methods and bone architecture in non-Hispanic white adolescent females (N = 24; 18-19 years of age). Bone loading scores (BLHQ [hip and spine] and past BPAQ) and energy expenditure (7-day physical activity recall) were determined from respective questionnaires. Estimates of trabecular and cortical bone architecture at the nondominant radius and tibia were assessed via magnetic resonance imaging. Total body and regional areal bone mineral density (aBMD), as well as total body fat mass and fat-free soft tissue (FFST) mass were assessed via dual energy X-ray absorptiometry. Pearson’s correlations and partial correlations adjusting for height, total body fat mass, and FFST were performed. Hip BLHQ scores were correlated with midtibia cortical volume (r = .43; p = .03). Adjusted hip and spine BLHQ scores were correlated with all midtibia cortical measures (r = .50-0.58; p < .05) and distal radius apparent trabecular number (r = .46-0.53; p < .05). BPAQ scores were correlated with all midtibia cortical (r = .41-0.51; p < .05) and most aBMD (r = .47-0.53; p < .05) measures. Energy expenditure was inversely associated with femoral neck aBMD only after statistical adjustment (r = .49, p < .05). These data show that greater load-specific physical activity scores, but not energy expenditure, are indicative of greater midtibia cortical bone quality, thus supporting the utility of these instruments in musculoskeletal research.
David Travis Thomas, Laurie Wideman and Cheryl A. Lovelady
To examine the effect of yogurt supplementation pre- and postexercise on changes in body composition in overweight women engaged in a resistance-training program.
Participants (age = 36.8 ± 4.8 yr) with a body-mass index of 29.1±2.1 kg/m2 were randomized to yogurt supplement (YOG; n = 15) or isoenergetic sucrose beverage (CONT; n = 14) consumed before and after exercise for 16 wk. Participants were also instructed to reduce energy intake daily (–1,046 kJ) during the study. Body composition was assessed by dual-energy X-ray absorptiometry, waist circumference, and sagittal diameter. Strength was measured with 1-repetition maximum. Dietary recalls were obtained by a multipass approach using Nutrition Data System software. Insulin-like growth factor-1 and insulin-like growth-factor-binding protein-3 were measured with ELISA.
Significant weight losses of 2.6 ± 4.5 kg (YOG) and 1.2 ± 2.5 kg (CONT) were observed. Total lean weight increased significantly over time in both YOG (0.8 ± 1.2 kg) and CONT (1.1 ± 0.9 kg). Significant reductions in total fat (YOG = 3.4 ± 4.1 kg vs. CONT = 2.3 ± 2.4 kg) were observed over time. Waist circumference, sagittal diameter, and trunk fat decreased significantly over time without group differences. Both groups significantly decreased energy intake while maintaining protein intake. Strength significantly increased over time in both groups. No changes over time or between groups were observed in hormone levels.
These data suggest that yogurt supplementation offered no added benefit for increasing lean mass when combined with resistance training and modest energy restriction.