Weight categorized athletes use a variety of techniques to induce rapid weight loss (RWL) in the days leading up to weigh in. This study examined the fluid and electrolyte balance responses to 24-hr fluid restriction (FR), energy restriction (ER) and fluid and energy restriction (F+ER) compared with a control trial (C), which are commonly used techniques to induce RWL in weight category sports. Twelve subjects (six male, six female) received adequate energy and water (C) intake, adequate energy and restricted water (~10% of C; FR) intake, restricted energy (~25% of C) and adequate water (ER) intake or restricted energy (~25% of C) and restricted (~10% of C) water intake (F+ER) in a randomized counterbalanced order. Subjects visited the laboratory at 0 hr, 12 hr, and 24 hr for blood and urine sample collection. Total body mass loss was 0.33% (C), 1.88% (FR), 1.97% (ER), and 2.44% (F+ER). Plasma volume was reduced at 24 hr during FR, ER, and F+ER, while serum osmolality was increased at 24 hr for FR and F+ER and was greater at 24 hr for FR compared with all other trials. Negative balances of sodium, potassium, and chloride developed during ER and F+ER but not during C and FR. These results demonstrate that 24 hr fluid and/or energy restriction significantly reduces body mass and plasma volume, but has a disparate effect on serum osmolality, resulting in hypertonic hypohydration during FR and isotonic hypohydration during ER. These findings might be explained by the difference in electrolyte balance between the trials.
Lewis J. James and Susan M. Shirreffs
Stewart J. Laing, Samuel J. Oliver, Sally Wilson, Robert Walters, James L.J Bilzon and Neil P. Walsh
The aim was to investigate the effects of 48 hr of fluid, energy, or combined fluid and energy restriction on circulating leukocyte and lymphocyte subset counts (CD3+, CD4+, and CD8+) and bacterially stimulated neutrophil degranulation at rest and after exercise. Thirteen healthy men (M ± SEM age 21 ± 1 yr) participated in 4 randomized 48-hr trials. During control (CON) participants received their estimated energy (2,903 ± 17 kcal/day) and fluid (3,912 ± 140 ml/day) requirements. During fluid restriction (FR) they received their energy requirements and 193 ± 19 ml/day water to drink. During energy restriction (ER) they received their fluid requirements and 290 ± 6 kcal/day. Fluid and energy restriction (F+ER) was a combination of FR and ER. After 48 hr, participants performed a 30-min treadmill time trial (TT) followed by rehydration (0–2 hr) and refeeding (2–6 hr). Circulating leukocyte and lymphocyte counts remained unchanged for CON and FR. Circulating leukocyte, lymphocyte, CD3+, and CD4+ counts decreased by ~20% in ER and ~30% in F+ER by 48 hr (p < .01), returning to within 0-hr values by 6 hr post-TT. Circulating neutrophil count and degranulation were unaltered by dietary restriction at rest and after TT. In conclusion, a 48-hr period of ER and F+ER, but not FR, decreased circulating leukocyte, lymphocyte, CD3+, and CD4+ counts but not neutrophil count or degranulation. Circulating leukocyte and lymphocyte counts normalized on refeeding. Finally, dietary restriction did not alter circulating leukocyte, lymphocyte, and neutrophil responses to 30 min of maximal exercise.
Renee A. Dalton, Janet Walberg Rankin, Don Sebolt and Frank Gwazdauskas
The effect of acute carbohydrate consumption on performance and metabolism of resistance-trained males was determined. Twenty-two subjects, assigned to either carbohydrate (C, n = 8), placebo (P, n - 8), or control (N, n = 6), performed standardized workouts every other day for a week prior to testing and throughout the testing period. Three of these workouts (Tl, T2, and T3) were the performance test in that the last bouts of leg extension and bench press were done to failure at 80% of 10 repetition maximum. A carbohydrate or placebo beverage was consumed 30 min prior to T3. Blood samples were drawn before and after T2 and T3. There was no effect of carbohydrate or energy restriction on number of repetitions done during the leg extension performance test. Carbohydrate intake prior to a resistance exercise bout done in negative energy balance state did not affect performance or evidence of muscle damage.
Ina Garthe, Truls Raastad and Jorunn Sundgot-Borgen
When weight loss (WL) is needed, it is recommended that athletes do it gradually by 0.5–1 kg/wk through moderate energy restriction. However, the effect of WL rate on long-term changes in body composition (BC) and performance has not been investigated in elite athletes.
To compare changes in body mass (BM), fat mass (FM), lean body mass (LBM), and performance 6 and 12 mo after 2 different WL interventions promoting loss of 0.7% vs. 1.4% of body weight per wk in elite athletes.
Twenty-three athletes completed 6- and 12-mo postintervention testing (slow rate [SR] n = 14, 23.5 ± 3.3 yr, 72.2 ± 12.2 kg; fast rate [FR] n = 9, 21.4 ± 4.0 yr, 71.6 ± 12.0 kg). The athletes had individualized diet plans promoting the predetermined weekly WL during intervention, and 4 strength-training sessions per wk were included. BM, BC, and strength (1-repetition maximum) were tested at baseline, postintervention, and 6 and 12 mo after the intervention.
BM decreased by ~6% in both groups during the intervention but was not different from baseline values after 12 mo. FM decreased in SR and FR during the intervention by 31% ± 3% vs. 23% ± 4%, respectively, but was not different from baseline after 12 mo. LBM and upper body strength increased more in SR than in FR (2.0% ± 1.3% vs. 0.8% ± 1.1% and 12% ± 2% vs. 6% ± 2%) during the intervention, but after 12 mo there were no significant differences between groups in BC or performance.
There were no significant differences between groups after 12 mo, suggesting that WL rate is not the most important factor in maintaining BC and performance after WL in elite athletes.
Ina Garthe, Truls Raastad, Per Egil Refsnes, Anu Koivisto and Jorunn Sundgot-Borgen
When weight loss (WL) is necessary, athletes are advised to accomplish it gradually, at a rate of 0.5–1 kg/wk. However, it is possible that losing 0.5 kg/wk is better than 1 kg/wk in terms of preserving lean body mass (LBM) and performance. The aim of this study was to compare changes in body composition, strength, and power during a weekly body-weight (BW) loss of 0.7% slow reduction (SR) vs. 1.4% fast reduction (FR). We hypothesized that the faster WL regimen would result in more detrimental effects on both LBM and strength-related performance. Twenty-four athletes were randomized to SR (n = 13, 24 ± 3 yr, 71.9 ± 12.7 kg) or FR (n = 11, 22 ± 5 yr, 74.8 ± 11.7 kg). They followed energy-restricted diets promoting the predetermined weekly WL. All athletes included 4 resistance-training sessions/wk in their usual training regimen. The mean times spent in intervention for SR and FR were 8.5 ± 2.2 and 5.3 ± 0.9 wk, respectively (p < .001). BW, body composition (DEXA), 1-repetition-maximum (1RM) tests, 40-m sprint, and countermovement jump were measured before and after intervention. Energy intake was reduced by 19% ± 2% and 30% ± 4% in SR and FR, respectively (p = .003). BW and fat mass decreased in both SR and FR by 5.6% ± 0.8% and 5.5% ± 0.7% (0.7% ± 0.8% vs. 1.0% ± 0.4%/wk) and 31% ± 3% and 21 ± 4%, respectively. LBM increased in SR by 2.1% ± 0.4% (p < .001), whereas it was unchanged in FR (–0.2% ± 0.7%), with significant differences between groups (p < .01). In conclusion, data from this study suggest that athletes who want to gain LBM and increase 1RM strength during a WL period combined with strength training should aim for a weekly BW loss of 0.7%.
Alan C. Utter, David C. Nieman, Elizabeth M. Shannonhouse, Diane E. Butterworth and Cathy N. Nieman
The purpose of this study was to measure the influence of diet, exercise, or both on body composition and cardiorespiratory fitness in obese women. Ninety-one obese subjects were randomized into one of four groups: diet (D) (4.19–5.44 MJ or 1,200–1,300 kcal/day), exercise (E) (five 45-min sessions at 78.5 ± 0.5% maximum heart rate), exercise and diet (ED), and controls (C). Maximal aerobic power and body composition were measured in all subjects before and after a 12-week diet intervention period. Subjects in D and ED lost 7.8 ± 0.7 and 8.1 ± 0.6 kg body mass, with no significant change for E relative to C. Losses of percent body fat and fat mass were significantly greater in D and ED but not in E relative to C. The change in VO2max was greater in ED and E but not D when compared to C. Results indicate that moderate aerobic exercise training during a 12-week period has no discernible effects on body composition but does improve cardiorespiratory fitness in dieting obese women.
Lindy M. Rossow, David H. Fukuda, Christopher A. Fahs, Jeremy P. Loenneke and Jeffrey R. Stout
Bodybuilding is a sport in which competitors are judged on muscular appearance. This case study tracked a drug-free male bodybuilder (age 26–27 y) for the 6 mo before and after a competition.
The aim of this study was to provide the most comprehensive physiological profile of bodybuilding competition preparation and recovery ever compiled.
Cardiovascular parameters, body composition, strength, aerobic capacity, critical power, mood state, resting energy expenditure, and hormonal and other blood parameters were evaluated.
Heart rate decreased from 53 to 27 beats/min during preparation and increased to 46 beats/min within 1 mo after competition. Brachial blood pressure dropped from 132/69 to 104/56 mmHg during preparation and returned to 116/64 mmHg at 6 mo after competition. Percent body fat declined from 14.8% to 4.5% during preparation and returned to 14.6% during recovery. Strength decreased during preparation and did not fully recover during 6 months of recovery. Testosterone declined from 9.22 to 2.27 ng/mL during preparation and returned back to the baseline level, 9.91 ng/mL, after competition. Total mood disturbance increased from 6 to 43 units during preparation and recovered to 4 units 6 mo after competition.
This case study provides a thorough documentation of the physiological changes that occurred during natural bodybuilding competition and recovery.
Amy J. Hector and Stuart M. Phillips
al., 1997 ), but sensitizes skeletal muscle to the anabolic effects of protein ingestion, resulting in a synergistic rise in MPS that, when performed repeatedly, can result in a gain of LBM over time. During dietary energy restriction, rates of MPS are reduced in the fasted and fed conditions ( Areta et
Oliver C. Witard, Ina Garthe and Stuart M. Phillips
track and field athletes are familiar with the concept of high-quality weight loss ( Sundgot-Borgen & Garthe, 2011 ), which describes the loss of fat mass while preserving, or even increasing, fat-free mass (i.e., muscle tissue) during a voluntary period of energy restriction. Many athletes engage in
intake of 1.4–1.6 g/kg was advised. Research has shown that athletes who consume a higher protein diet (approximately 2 g/kg) recorded reduced losses of LBM compared with a control group who consumed less protein (approximately 1 g/kg) during a period of energy restriction ( Mettler et al., 2010 ). Daily