This study assessed the effect of resistive training (RT), with or without high-dose chromium picolinate (Cr-pic) supplementation, on body composition and skeletal muscle size of older women. Seventeen sedentary women, age range 54-71 years. BMI 28.8±2.4 kg/m2. were randomly assigned (double-blind) to groups (Cr-pic. n = 9; Placebo, n = 8) that consumed either 924 μg Cr/d as Cr-pic or a low-Cr placebo (<0.2 μg Cr/d) during a 12-week RT program (2 day/ week, 3 sets · exercise−1 · d1,80% of 1 repetition maximum). Urinary chromium excretion was 60-fold higher in the Cr-pic group, compared to the Placebo group (p < .001), during the intervention. Resistive training increased maximal strength of the muscle groups trained by 8 to 34% (p < .001), and these responses were not influenced by Cr-pic supplementation. Percent body fat and fat-free mass were unchanged with RT in these weight-stable women, independent of Cr-pic supplementation. Type I and type II muscle fiber areas of the m. vastus lateralis were not changed over time and were not influenced by Cr-pic supplementation. These data demonstrate that high-dose Cr-pic supplementation did not increase maximal strength above that of resistive training alone in older women. Further, these data show that, under these experimental conditions, whole body composition and skeletal muscle size were not significantly changed due to resistive training and were not influenced by supplemental chromium picolinate.
Wayne W. Campbell, Lyndon J.O. Joseph, Richard A. Anderson, Stephanie L. Davey, Jeremy Hinton and William J. Evans
Conall F. Murtagh, Christopher Nulty, Jos Vanrenterghem, Andrew O’Boyle, Ryland Morgans, Barry Drust and Robert M. Erskine
. Therefore, the present soccer talent selection models are limited. Subsequently, the aims of this study were to (1) investigate the differences in muscle strength, size, architecture, and activation between elite and nonelite soccer players and (2) determine the contribution of muscle size, architecture
Kevin R. Short and K. Sreekumaran Nair
Loss of muscle mass, strength, and oxidative capacity accompanies normal aging in humans. The mechanisms responsible for these changes remain to be clearly defined. Muscle protein mass and function depend on protein turnover. Synthesis rate of the major muscle contractile protein, myosin heavy chain (MHC), and transcript levels of fast MHC isoforms decrease in association with strength reductions, while mitochondrial protein synthesis rate declines in parallel with activities of mitochondrial enzymes and maximal oxidative capacity (V̇O2max). Resistance exercise training increases the synthesis rate of MHC and transcript levels of the slow MHC isoform in older humans, along with increasing muscle strength. The relationship between the synthesis of muscle proteins, and muscle size and function, with aging and exercise training are discussed in this review.
Krissy D. Weisgarber, Darren G. Candow and Emelie S. M. Vogt
To determine the effects of whey protein before and during resistance exercise (RE) on body composition and strength in young adults.
Participants were randomized to ingest whey protein (PRO; 0.3 g/kg protein; n = 9, 24.58 ± 1.8 yr, 88.3 ± 17.1 kg, 172.5 ± 8.0 cm) or placebo (PLA; 0.2 g/kg cornstarch maltodextrin + 0.1 g/kg sucrose; n = 8, 23.6 ± 4.4 yr, 82.6 ± 16.1 kg, 169.4 ± 9.2 cm) during RE (3 sets of 6–10 repetitions for 9 whole-body exercises), which was performed 4 d/wk for 8 wk. PRO and PLA were mixed with water (600 ml); 50% of the solution containing 0.15 g/kg of PRO or PLA was consumed immediately before the start of exercise, and ~1.9% of the remaining solution containing ~0.006 g/kg of PRO or PLA was consumed immediately after each training set. Before and after the study, measures were taken for leantissue mass (dual-energy X-ray absorptiometry), muscle size of the elbow and knee flexors and extensors and ankle dorsiflexors and plantar flexors (ultrasound), and muscle strength (1-repetition-maximum chest press).
There was a significant increase (p < .05) in muscle size of the knee extensors (PRO 0.6 ± 0.4 cm, PLA 0.1 ± 0.5 cm), knee flexors (PRO 0.4 ± 0.6 cm, PLA 0.5 ± 0.7 cm) and ankle plantar flexors (PRO 0.6 ± 0.7 cm, PLA 0.8 ± 1.4 cm) and chest-press strength (PRO 16.6 ± 11.1 kg, PLA 9.1 ± 14.6 kg) over time, with no differences between groups.
The ingestion of whey protein immediately before the start of exercise and again after each training set has no effect on muscle mass and strength in untrained young adults.
Thomas W. Balon, Jeffrey F. Horowitz and Karen M. Fitzsimmons
Bodybuilders have used different carbohydrate loading regimens in conjunction with resistance exercise prior to competition in the belief that this would result in increased muscle size. To investigate this possibility, muscle girth measurements were obtained from nine weight-trained males before and after a control (standard isocaloric diet) and an experimental trial (carbohydrate loading). The latter regimen consisted of 3 days of intense weight-lifting while the subjects ingested a diet of 10% carbohydrate (CHO), 57% fat (F), and 33% protein (P), followed by 3 days of light weight-lifting and a day of rest while ingesting a diet of 80% CHO, 5% F, and 15% P. The control trial consisted of an identical weight-lifting regimen while subjects ingested an isocaloric (45 kcal/kg BWIday) diet. Body weight and girths (forearm, upper arm, chest, thigh, waist, and calf) were obtained before and after each trial in a relaxed and flexed state. The results indicated that an exercise/carbohydrate loading regimen had no significant effect on muscle girth as compared to the control trial. It is concluded that CHO loading has no additional advantage to enhancing muscle girth in bodybuilders over weight-lifting alone.
years later, it would seem that this is a novel idea given the recent discussion on the absence of contribution of muscle size on strength. 2 , 3 Some time later, in the earlier 1990s, we were very lucky because Mr Rotea started the first course for coaches of the Spanish Olympic Committee. The teacher
Ryan P. Durk, Esperanza Castillo, Leticia Márquez-Magaña, Gregory J. Grosicki, Nicole D. Bolter, C. Matthew Lee and James R. Bagley
disease populations ( Smith et al., 2013 ), the growing body of literature on physical activity and gut health may help to inform future bacterial therapeutic interventions attempting to restore microbial homeostasis and preserve physiological systems (e.g., aging skeletal muscle size and function
Eduardo Lusa Cadore, Miriam González-Izal, Rafael Grazioli, Igor Setuain, Ronei Silveira Pinto and Mikel Izquierdo
, studies have reported greater increases in muscle size following eccentric training compared with concentric training, 11 , 13 , 14 while others have found similar muscle hypertrophy after concentric and eccentric training. 12 , 15 , 16 However, comparisons of the effects of CON and ECC training on the
Rafael Sabido, Jose Luis Hernández-Davó and Gabriel T. Pereyra-Gerber
-series study . Phys Ther Sport . 2011 ; 12 ( 1 ): 43 – 48 . doi:10.1016/j.ptsp.2010.10.003 21256449 10.1016/j.ptsp.2010.10.003 9. Norrbrand L , Fluckey JD , Pozzo M , Tesch PA . Resistance training using eccentric overload induces early adaptations in skeletal muscle size . Eur J Appl Physiol
Dean Ritchie, Justin Keogh, Steven Stern, Peter Reaburn, Fergus O’Connor and Jonathan D. Bartlett
(predominately skill-based drills with the addition of top-up running) was completed in the morning followed by a RT session in the afternoon. The aim of the RT program was designed to increase muscle size and strength both throughout preseason and in-season. To prevent participants becoming accustomed to any of