Effect of Two Different Weight-Loss Rates on Body Composition and Strength and Power-Related Performance in Elite Athletes
Abstract and Figures
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%.
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... Previously, studies have shown that nutrition by itself can decrease FM to lose weight (Benito et al., 2017;Foster-Schubert et al., 2012). Other studies show that if a diet is incorporated into an exercise intervention then decreases in FM are observed (Campbell et al., 2018;Garthe et al., 2011). Regional FM was also analyzed in our study but no significant differences were observed compared to baseline. ...
Manual Resistance Training (MRT) is a mode of Resistance Training (RT) primarily used as a training method for improving muscular strength and body composition. MRT is a form of training that requires minimal equipment due to the use of a partner who provides external resistance. The purposes of this study were 1) to investigate the effects of an 8-week MRT intervention on body composition and muscular strength, and 2) to compare the changes observed in MRT to a traditional Weight Resistance Training (WRT) and control groups. Thirty young adults (n = 30) were randomly assigned to either a MRT (n = 10), WRT (n = 10) or control (n = 10) group. The MRT and WRT groups engaged in twice-a-week training for 1 hour with 2 circuits composed of 3 exercises per circuit while the control group was instructed not to engage in any exercise for 8 weeks. Body composition was measured via Dual-energy X-ray Absorptiometry and Muscular Strength was measured via Isokinetic Knee Extension/Flexion, Isometric Bench Press, Isometric Mid-thigh Pull, One-Repetition Maximum (1RM) Bench Press (1RMBP), and 1RM Leg Press (1RMLP) before and after the intervention. The MRT and WRT groups showed no change in body composition from pre to post-testing. However, an increase in Strength was seen in MRT through 1RMLP (p < 0.01) and in WRT through 1RMBP (p < 0.01) and 1RMLP (p < 0.01) from pre to
post-testing. No changes in the control group were observed for any of the variables of interest (p > 0.05). An 8week MRT or WRT intervention increases muscle strength without changes in body composition.
... kcal/d) may have provided different insights, they would have been influenced by an unequal number of observations. Helms and colleagues (18) speculated that protein intake should scale with energy deficit severity while acknowledging that energy deficit magnitude may be more important for FFM retention than protein intake (13,34). During large energy restriction, any increase in dietary protein necessarily reduces dietary carbohydrate or fat, with potential for low dietary carbohydrate negatively affecting RT volume performance (27) and low dietary fat compromising sex hormone concentrations (23,69). ...
Individuals often restrict energy intake to lose fat mass (and body mass [BM]) while performing resistance training (RT) to retain fat-free mass (FFM). Therefore, the aim of the present systematic review with meta-regression was to explore (a) the pattern and strength of the dose-response relationship between daily dietary protein intake and FFM change, and (b) whether intervention duration, energy deficit magnitude, baseline body fat percentage (BF%), and participant sex influence this relationship. Studies were included if they involved a standardized RT protocol with nonobese, energy-restricted (experiencing fat mass loss) individuals with a minimum of 3 months RT experience. Of 916 retrieved studies, data were extracted from a total of 29 studies. Bayesian methods were used to fit linear and nonlinear meta-regression models and estimate effect sizes, highest density credible intervals, and probabilities. Results suggest a >97% probability of a linear dose-response relationship between daily protein intake [g/kgBM: β = 0.07 (95% highest density interval [HDI]: −0.01 to 0.14), and g/kg/FFM: β = 0.06 (95% HDI: 0.01 to 0.12)] and favorable FFM changes. The relationship is stronger when protein intake is expressed relative to FFM, in interventions longer than 4 weeks, in men, and when BF% is lower. Overall, the heterogeneity between studies renders our findings exploratory.
... While the athlete prioritized minimizing muscle loss while pursuing competition objectives, no resting metabolic rate test was performed. As a result, practical adjustments had to be applied in an attempt to effectively monitor caloric deficits and track progress throughout the preparation period [5,[19][20][21]. As in previous bodybuilding case studies, body mass decreased, but the muscle-to-fat ratio differed. ...
Citation: Michailidis, K.; Zaras, N.; Balampanos, D.; Avloniti, A.; Stampoulis, T.; Protopapa, M.; Pantazis, D.; Retzepis, N.-O.; Smilios, I.; Chatzinikolaou, A. Assessment of Body Composition, Bone Density, and Biochemical Markers of a Natural Bodybuilder During Contest Preparation. Appl. Sci. 2025, 15, 79. Abstract: This case study aimed to evaluate the body composition and several biochemical markers during a 7-month pre-competition training period of a natural male bodybuilder. The athlete monitored his nutrition, training variables, and daily physical activity during the preparation phase. At the beginning (W31), in the middle (W18), and one week before the contest (W1), measurements included body composition via DEXA, testosterone and cortisol hormonal concentrations, and lipid, blood, and liver biochemical markers via an automated hematology analyzer. A gradual decrease in energy intake (−27.6%) and increased daily activity (169.0%) was found. Fat mass decreased from 17.9 kg (W31) to 13.1 kg (W18) and 4.2 kg (W1), while lean body mass decreased from 69.9 kg (W31) to 68.2 kg (W18) and 66.7 kg (W1). Bone density decreased linearly, and bone mass decreased from W31 to W1 by 1.7%. Testosterone decreased from 5.4 ng·mL −1 (W31) to 5.3 ng·mL −1 (W18) and 4.4 ng·mL −1 (W1), while cortisol increased from 21.3 µg·dL −1 (W31) to 20.3 µg·dL −1 (W18) and 24.4 µg·dL −1 (W1). In conclusion, a slow rate of weight loss and training with repetitions nearly to failure, combined with weekly monitoring of training and nutrition, may significantly improve body composition. However, hormone concentration and bone mass will experience mild negative effects.
... Evidence indicates that a more gradual loss of body mass helps to preserve lean mass while losing body fat (14) (15). This phenomenon seemed to play out in the present case study. ...
This study assessed a male competitive powerlifter over a 6-month period that encompassed his pre-contest preparation and post-contest recovery. We conducted the following monthly assessments: multi-frequency bioelectrical impedance analysis (MF-BIA), B-mode ultrasound evaluation of muscle thickness (MT), body circumferences, handgrip strength, vertical jump height, isometric lower body strength, and questionnaires for perceived mood and sleep. The athlete undertook a 3-month pre-contest preparatory period that included an extreme energy-restricted diet intended to sufficiently reduce body mass. This period also included an 8-week pre-contest training regimen with a 10-day taper intended to promote peak strength increases in the target lifts for competition. During the pre-competition period, the athlete experienced rapid and substantial losses of body mass (10.3%), body fat (6.5%) and lean mass (3.3%), the majority of which was regained in the 2-month post-competition recovery phase. The athlete's isometric knee extension strength rose sharply during the initial month of the pre-competition phase (336.4 Nm), followed by consistent declines (299 to 262.2 to 283 Nm) over the next 3 months, eventually returning close to baseline values 2 months post- competition Jump height remained steady in the 3 months in the pre-contest phase but increased (+1.4 cm) in the 2 months post-competition while handgrip strength increased during the months preceding the competition (47.5 kg to 49 kg) but decreased to 42.3 cm post-competition. Overall, the athlete did not seem to have any marked sleep disturbances. The most notable changes in mood parameters were increased tension, anger, and depression immediately preceding the competition.
... During the pre-competition period, bodybuilders aim to reduce body fat while preserving muscle mass [10][11][12] . To maintain lean body mass, it is recommended to achieve a gradual rate of body mass loss ranging from 0.5-1% per week 9,13,14 . In our study, the rate of weekly body mass loss was 0.57% for IL bodybuilders and 0.81% for NL bodybuilders; however, both groups achieved similar absolute body mass loss (about 9.6 kg). ...
Objectives
To compare the pre-competition nutrition practices of Lithuanian elite international-level (IL) and national-level (NL) bodybuilders.
Methods
Sixteen male bodybuilders (n=8 per group) were enrolled. The IL group comprised individuals achieving 1st to 4th place in the World and European Championships organized by the IFBB, whereas the NL group ranked between 1st and 6th place in the national championships. Body mass and diet data were obtained via a questionnaire. A repeated-measures ANOVA was performed using time as a within factor and group as a between factor.
Results
Both groups experienced a reduction in body mass during the pre-competition phase (p<0.001), which was slower in the IL than in the NL group (p=0.048). Both groups exhibited a reduction in caloric (p<0.001), carbohydrate (p<0.001), and fat (p=0.006) intake relative to body mass, but not in protein intake. Nevertheless, the IL group had a higher intake of calories (p=0.015), protein (p<0.001), but not carbohydrates relative to body mass vs. the NL group.
Conclusions
The Lithuanian IL and NL bodybuilders both reduced calories by cutting fat and carbohydrates during pre-competition. The IL group maintained higher calorie and protein intake, resulting in similar body mass loss but at a slower rate than the NL group.
... This indicates that greater muscle mass significantly contributes to higher performance in these strength measures, underscoring the importance of muscular development in elite judo athletes. These results align with previous studies showing a significant correlation between body composition and strength, particularly explosive and isometric strength [32,33]. A similar study on Polish national and international rank competitors found a statistically significant correlation between lean body mass and handgrip strength [31]. ...
This study aimed to determine the influence of body composition on the muscle fitness of selected judokas. This study was conducted on a sample of 23 judokas (cadets n = 12, juniors n = 11), members of the male national team of Serbia. The assessment of body composition was performed using the InBody 720 (Biospace Co., Ltd., Seoul, Republic of Korea) and calipers. Muscle fitness was assessed using “Optojump” (Microgate, Bolzano, Italy), Fitrodine Premium (Fitronic, Bratislava, Slovakia), and a digital force instrument IMADA Z2H-1100 (Imada Inc., Northbrook, IL, USA). Regression analysis revealed a notable association between muscle mass and measures of explosive strength (countermovement jump (CMJ) p = 0.023; drop jump (DJ) p = 0.026). Moreover, this study’s results showed that back extension (p = 0.006; R2 = 0.61) and hand grip (p = 0.009; R2 = 0.52) provide a strong positive association with muscle mass. The findings suggest that tailored training and nutritional strategies that improve muscle mass might significantly enhance muscle fitness in young judokas, optimizing their performance.
... On the other hand, even this combined approach may have drawbacks (20) (21), including muscle loss ( which can result in compromising strength and performance) (22), and hormonal disruptions (which can cause reductions in testosterone, IGF-1, and thyroid hormones), particularly when coupled with severe calorie restriction (4). In addition, increasing training volume, which can lead to overtraining, may have significant effects on oxidative stress and inflammation. ...
Background: Maintaining an optimal weight is essential for wrestlers, given their competition in weight-classified categories. However, many wrestlers resort to unhealthy methods of rapid weight loss, such as drastic caloric restriction and dehydration, which can adversely affect their overall wellbeing. Objective: This study aimed to examine the impact of a two-week increase in exercise volume on weight loss, serum oxidative stress, and inflammation in young wrestlers. Methods and Materials: Twenty wrestlers (aged 15-19, weight 63.47 kg) participated in a 2-week exercise intervention in addition to their regular weekly wrestling drills. The intervention consisted of resistance training, high-intensity interval training, and speed training. Wrestlers weighed daily over 2-week span. The participants' superoxide dismutase (SOD), malondialdehyde (MDA), total antioxidant capacity (TAC), and serum interleukin-6 (IL-6) were measured both before and after the intervention. Data were analyzed using the paired t-test conducted through SPSS software, with a significant level set at p < 0.05. Results: The 2-week intervention resulted in significant weight loss (p<0.001). Within group comparisons found serum levels of IL-6, SOD, and TAC significantly increased from pre-to-post testing, but MDA did not change significantly. Conclusion: In conclusion, the present study demonstrates that a two-week increase in exercise volume can be an effective strategy for promoting weight loss and reducing oxidative stress in young wrestlers. The findings suggest that the improvement in antioxidant status is likely a result of the body's response to increased inflammation, as indicated by changes in inflammatory markers.
This mini review explores the psychological factors associated with weight cutting practices among combat sport athletes. We overviewed combat sport athletes' extrinsic and intrinsic motivations for their sport participation and performance expectations and goals associated with weight cutting. Next, we reviewed the extant research on psychological risk factors associated with weight cutting with a particular focus on combat sport athletes' relationship with food, societal expectations concerning body image, and disordered eating. Finally, we examined how applying task-oriented strategies and Goal Attainment Theory aligns with combat sport athletes' motivation for sport participation. We called for further research into exploring how promoting gradual weight loss may promote psychological resilience with the goal of promoting healthier weight management strategies among combat sport athletes.
Background:
Chronic diseases are the leading cause of mortality and morbidity worldwide. Much of this burden can be prevented by adopting healthy behaviours and reducing chronic disease risk factors. Settings-based approaches to address chronic disease risk factors are recommended globally. Sporting organisations are highly prevalent, and engage many people in many countries. As such, they represent an ideal setting for public health interventions to promote health. However, there is currently limited evidence of their impact on healthy behaviour and health outcomes as previous systematic reviews are either limited in their scope (e.g. restricted to professional sporting organisations), or are out of date.
Objectives:
Primary: to assess the benefits and harms of interventions implemented through sporting organisations to promote healthy behaviours (including physical activity, healthy diet) or reduce health risk behaviours (including alcohol consumption, tobacco use). Secondary: to assess the benefits and harms of these interventions to promote health outcomes (e.g. weight), other health-related behaviours (e.g. help-seeking behaviour) or health-related knowledge; to determine whether benefits and harms differ based on the characteristics of the interventions, including target population and intervention duration; to assess unintended adverse consequences of sporting organisation interventions; and to describe their cost or cost-effectiveness.
Search methods:
We searched CENTRAL, MEDLINE, Embase, one other database and two clinical trial registries, from inception to May 2024, to identify eligible trials. We searched Google Scholar in May 2024. We did not impose language or publication status restrictions. We also searched reference lists of included trials for other potentially eligible trials.
Selection criteria:
We included randomised controlled trials (RCTs), including cluster-RCTs, of any intervention conducted within or using a sporting organisation for access to a target group, that aimed to improve a health behaviour primary outcome or a secondary review outcome, and had a parallel control group (no intervention, alternative intervention). Eligible participants were any individual exposed to an intervention involving a sporting organisation, including players, members, coaches, and supporters.
Data collection and analysis:
We used standard methodological procedures expected by Cochrane. We conducted random-effects meta-analyses to synthesise results where we could pool data from at least two trials. Where we could not conduct meta-analysis, we followed Cochrane guidance for synthesis using other methods and reported results according to the Synthesis Without Meta-analysis (SWiM) guidance.
Main results:
We included 20 trials (42 trial arms, 8179 participants) conducted in high-income countries, and identified four ongoing trials and four trials awaiting classification. There was considerable heterogeneity in the type of participants, interventions and outcomes assessed across trials. Included trials primarily targeted sporting organisation members (eight trials) or supporters (eight trials), males only (11 trials) and adults (14 trials). Football clubs (e.g. soccer, American football, Australian football league) were the most common intervention setting (15 trials), and interventions targeted various combinations of health behaviours, knowledge and health outcomes. Fourteen trials (10 RCTs and four cluster-RCTs) assessed the impact of a sporting organisation intervention on a primary outcome: physical activity (nine trials); diet (six trials); alcohol consumption (11 trials); and tobacco use (two trials). For RCTs, we assessed the risk of bias for primary outcomes (physical activity, diet, alcohol consumption) and unintended adverse consequences as being at low risk of bias (four outcomes), some concerns (one outcome) or high risk of bias (32 outcomes), due to outcomes being self-reported. For cluster-RCTs, we assessed the risk of bias for all primary outcomes (alcohol consumption, tobacco use) as high risk (eight outcomes), due to outcomes being self-reported. Sporting organisation interventions versus control probably have a small positive effect on the amount of physical activity per day, equivalent to approximately 7.4 minutes of moderate-to-vigorous physical activity (MVPA) per day (standardised mean difference (SMD) 0.36, 95% confidence interval (CI) 0.22 to 0.49; I2 = 3%; 4 trials, 1213 participants; moderate-certainty evidence) and may not reduce sedentary behaviour (mean difference (MD) -15.18, 95% CI -30.82 to 0.47; I2 = 0%; 2 trials, 1047 participants; low-certainty evidence). Sporting organisation interventions versus control may have a moderate positive effect on fruit and vegetable consumption, equivalent to a score increase of 1.25 points on a 12-point scale for frequency of fruit and vegetable consumption (SMD 0.50, 95% CI 0.35 to 0.65; I2 = 0%; 5 trials, 1402 participants; low-certainty evidence). Sporting organisation interventions versus control may reduce sugary drink consumption (equivalent to a reduction of sugary drink consumption by 0.8 times per day), but the evidence is very uncertain (SMD -0.37, 95% CI -0.64 to -0.10; I2 = 0%; 2 trials, 225 participants; very low-certainty evidence). Sporting organisation interventions versus control may have little to no effect on alcohol consumption (equivalent to a reduction of 0.38 units of alcohol consumed per week), but the evidence is very uncertain (MD -0.38, 95% CI -1.00 to 0.24; I2 = 78%; 7 trials, 2313 participants; very low-certainty evidence). Two trials that could not be synthesised reported equivocal findings on tobacco use (low-certainty evidence). The evidence is very uncertain about the effect of sporting club interventions on unintended adverse consequences. Five trials assessed this outcome, with two reporting that there were no adverse consequences, one reporting only non-serious adverse consequences, and two reporting that there were serious unintended adverse consequences in less than 1% of participants.
Authors' conclusions:
Overall, sporting organisation interventions probably increase MVPA by 7.4 minutes per day, may result in little to no difference in sedentary behaviour, and may increase fruit and vegetable consumption. The evidence is very uncertain about whether sporting organisation interventions decrease sugary drink and alcohol consumption. Findings for tobacco use and unintended adverse consequences were equivocal in the few trials reporting these; thus, the evidence was very uncertain. These findings should be interpreted in the context of the heterogeneity of the interventions, participants and sporting organisations for some outcomes.
The EDI-2 manual is currently out of print but the attached file provides the table of contents for the EDI-3 which includes all of the EDI-2 items as well as the updated scale structure and scoring system for the EDI-3
Aims:
To examine the effects of rapid weight loss on mood and performance among amateur boxers.
Methods:
Participants were 16 experienced amateur boxers. In stage 1, structured interviews were used to assess the type of strategies that boxers used to reduce weight and the value of performing at their desired weight in terms of performance. In stage 2, boxers completed a 4 x 2 minute (1 minute recovery) circuit training session. Boxers completed the circuit training session on three different occasions with a week between each. The first test was used to familiarise the boxers with the circuit training task; the second and third tasks were at their training weight and championship weight, respectively. Participants were given one week to reduce their body weight to their championship weight using their preferred weight making strategies; boxers reduced their body weight by an average of 5.16% of body weight.
Results:
Boxers typically lost weight by restricting fluid and food intake in the week leading to competition. Repeated measures multivariate analysis of variance results indicated that rapid weight loss among boxers was associated with poor performance, increased anger, fatigue, and tension, and reduced vigour.
Conclusions:
Strategies used to make weight by boxers are associated with poor performance and a negative mood profile.
The aim of the present study was to examine the effects of a combination of gradual and rapid body mass loss on the physical performance and psychological state of elite judo athletes. Participants were divided into two groups: the experimental (diet) group needed to reduce body mass by 2-6%, whereas the control group did not need to lose body mass. Body mass, percentage of body fat, vertical jump, repetitions of judo movements, rowing with additional loads, and the Profile of Mood States were assessed at 4 weeks before a championship and again one day before the same championship. Compared with 4 weeks before the championship, the experimental group showed a significant decrease in body mass (-4 +/- 1.1%, P < 0.05), estimated body fat (-10 +/- 4.0%, P < 0.05), and judo movement repetitions over 30 s (-4.5 +/- 2.7, P < 0.05), and an increase in scores for confusion (-14.6 +/- 7.9, P < 0.05) and tension (-10.1 +/- 12.5, P < 0.05), but a decrease in vigour (11.3 +/- 8.5, P < 0.05), one day before the championship. There was no difference in squat jump or countermovement jump performance or in judo movement repetitions over 5 s. Our results show that for the experimental group some aspects of performance were impaired one day before a competition, but performance of judo movements over 5 s was not affected.
The diet-induced thermogenesis of 12 healthy males of normal body weight was measured by means of indirect calorimetry over 6 h after test meals of 1, 2 or 4 MJ protein (white egg, gelatin, casein), carbohydrate (starch, hydrolyzed starch) or fat (sunflower oil, butter). The totals of the thermic responses proved to be dependent on the type of nutrient supplied as much as on its quantity. The effect of 1 MJ protein was at least three times as large as that of an isocaloric carbohydrate supply. The investigated dietary fats produced no evident thermic response. The doubling of the energy intake of either casein or hydrolyzed starch led to the approximate doubling of the thermic effect.
The purpose of this study was to examine the physiological effects of a weight-loss dietary regimen with or without exercise.
Thirty-five overweight men were matched and randomly placed into either a control group (C; N = 6) or one of three dietary groups; a diet-only group (D; N = 8), a diet group that performed aerobic exercise three times per week (DE; N = 11); and a diet group that performed both aerobic and strength training three times per week (DES; N = 10).
After 12 wk, D, DE, and DES demonstrated a similar and significant (P < or = 0.05) reduction in body mass (-9.64, -8.99, and -9.90 kg, respectively) with fat mass comprising 69, 78, and 97% of the total loss in body mass, respectively. The diet-only group also demonstrated a significant reduction in fat-free mass. Maximum strength, as determined by 1-RM testing in the bench press and squat exercise was significantly increased for DES in both the bench press (+19.6%) and squat exercise (+32.6%). Absolute peak O2 consumption was significantly elevated in DE (+24.8%) and DES (+15.4%). There were no differences in performance during a 30-s Wingate test for the DE and DES, whereas D demonstrated a significant decline in peak and mean power output. Resting metabolic rate (RMR) (kcal x d(-1)) was not significantly different for any of the groups except for the DE group. There were no significant changes in basal concentrations of serum glucose, BUN, cortisol, testosterone, and high density lipoprotein (HDL) cholesterol for any of the groups. Serum total cholesterol and low density lipoprotein (LDL) cholesterol were significantly decreased for all dietary groups. Serum triglycerides were significantly reduced for D and DES at week 6 and remained lower at week 12 for D, while triglycerides returned to baseline values for DES.
These data indicate that a weight-loss dietary regimen in conjunction with aerobic and resistance exercise prevents the normal decline in fat-free mass and muscular power and augments body composition, maximal strength, and maximum oxygen consumption compared with weight-loss induced by diet alone.
Athletes engage in a number of dietary and weight control practices which may influence metabolism, health, and performance. This paper reviews the literature on these factors with special emphasis on athletes who show large, frequent, and rapid fluctuations in weight (wrestlers) and athletes who maintain low weight and low percent body fat (e.g., distance runners, gymnasts, and figure skaters). A theory is presented which relates these weight patterns and the accompanying dietary habits to changes in body composition, metabolism, metabolic activity of adipose tissue, and the distribution of body fat. Changes in these physiological variables may be manifested in enhanced food efficiency (weight as a function of caloric intake) as the body seeks to protect and replenish its energy stores. This may explain the surprisingly low caloric intakes of some athletes. The health status of the athlete is a concern in this regard because there may be changes in fat distribution, risk factors for cardiovascular disease, and hormonal factors associated with reproductive functioning in both females and males. Amenorrhea in female athletes may be mediated at least in part by regional fat distribution; depletion of femoral fat depots (lactational energy reserves) may be the stimulus for cessation or disruption of menses.
Athletes reduce bodyweight for several reasons: to compete in a lower weight class; to improve aesthetic appearance; or to increase physical performance. Rapid bodyweight reduction (dehydration in 12 to 96 hours), typically with fluid restriction and increased exercise, is used by athletes competing in weight-class events. Gradual bodyweight reduction (over >1 week) is usually achieved by cutting energy intake to 75 to 130 kJ/kg/day. An intake of 100 kJ/kg/day results in a weekly bodyweight loss of roughly 1kg. Aerobic endurance capacity decreases after rapid bodyweight reduction, but might increase after gradual bodyweight reduction. Maximal oxygen uptake (V̇O2max) measured as L/min is unchanged or decreased after bodyweight loss, but V̇O2max measured as ml/kg/min may increase after gradual bodyweight reduction. Anaerobic performance and muscle strength are typically decreased after rapid bodyweight reduction with or without 1 to 3 hours rehydration. When tested after 5 to 24 hours of rehydration, performance is maintained at euhydrated levels. A high carbohydrate diet during bodyweight loss may help in maintaining performance. Anaerobic performance is not affected and strength can increase after gradual bodyweight reduction. Reductions in plasma volume, muscle glycogen content and the buffer capacity of the blood explain decreased performance after rapid bodyweight reduction. During gradual bodyweight loss, slow glycogen resynthesis after training, loss of muscle protein and stress fractures (caused by endocrinological disorders) may affect performance. Athletes’ bodyweight goals should be individualised rather than by comparing with other athletes. If the time between weigh-in and competition is
Six successful members of the British Women's Lightweight Rowing Team were assessed before and after two-month (1990) and four-month (1991) periods of weight-reduction controlled by reduced caloric intake, while engaged in their normal physical training. Fat free mass (FFM) was calculated from body weight (BW) by utilising total body potassium measurements. Maximal oxygen intake (VO2max), respiratory anaerobic threshold (Tvent), upper body anaerobic peak power (PP) and mean power (MP) outputs, and knee flexor (KF) and extensor (KE) isokinetic peak torques were among the physiological parameters assessed. No statistical differences were noted between the data obtained prior to the two weight-reduction periods, and both periods resulted in lower BW (p < 0.001) and FFM (p < 0.05); approximately 50% of the lost BW was FFM. At the end of the two-month weight-reduction period Tvent (p < 0.02) and KF (p < 0.02) decreased. In contrast, a similar BW loss during the four-month period was associated with higher VO2max (p < 0.01) and PP (p < 0.05) compared with values prior to weight reduction. Comparisons between the percentage changes pre to post BW loss showed that the longer weight-reduction period was associated with significantly improved VO2max (p < 0.01), Tvent (p < 0.005), PP (p < 0.05) and KF (p < 0.05). We conclude: a) the proportion (50%) of weight lost as FFM in the present elite rowers is higher than the suggested optimal figure of 22%, and b) compared to four months, 6-7% of BW loss over two months may adversely influence fitness-related parameters in international lightweight oarswomen.
This study examined risk factors and triggers for eating disorders in female athletes. Subjects included were all of the elite female athletes in Norway (N = 603), ages 12-35 yr, representing six groups of sports: technical, endurance, aesthetic, weight dependent, ball games, and power sports. The Eating Disorder Inventory was used to classify individuals at risk for eating disorders. Of the 117 athletes defined at risk, 103 were administered a structured clinical interview for eating disorders. A comparison group was also interviewed, consisting of 30 athletes chosen at random from a pool not at risk and matched to the at-risk subjects on age, community of residence, and sport. Ninety-two of the at-risk athletes met criteria for anorexia nervosa, bulimia nervosa, or anorexia athletica. The prevalence of eating disorders was higher in sports emphasizing leanness or a specific weight than in sports where these are less important. Compared with controls, eating disordered athletes began both sports-specific training and dieting earlier, and felt that puberty occurred too early for optimal performance. Trigger factors associated with the onset of eating disorders were prolonged periods of dieting, frequent weight fluctuations, a sudden increase in training volume, and traumatic events such as injury or loss of a coach.
In most situations involving a significant change in body weight, both fat-free body mass (FFM) and body fat participate, but the relative contribution of FFM and fat to the total weight change is influenced by the initial body fat content. Overfeeding: In experiments of at least 3-weeks' duration, the weight gain of thin people comprises 60-70% lean tissues, whereas in the obese it is 30-40%. Underfeeding: In humans, there is an inverse curvilinear relationship between initial body fat content and the proportion of weight loss consisting of lean tissue. The same trend holds for animals and birds, including loss during hibernation. Another factor is the magnitude of the energy deficit: as energy intake is reduced, lean tissue makes up an increasing fraction of the total weight loss. Exercise: If individuals lose much weight with exercise, the result is usually some loss of lean tissue as well as fat, and once again the proportion of lean loss to total weight loss is greater in thin people than in those who have larger body fat burdens. Members of twin pairs often differ in weight. In thin individuals, lean accounts for about half of the intrapair weight difference, whereas in the obese it accounts for only one quarter. Body fat content must be taken into account in evaluating body composition changes induced by nutrition and exercise.