Effect of weight gain and weight loss on performance and body composition in elite athletes
1) The weight loss strategy recommended is a gradual weight-loss due to moderate energy restriction promoting a weekly weight-loss of 0.5-1 kg. However, a decrease in body mass due to energy restriction can lead to loss of lean body mass (LBM) and thereby impair performance. Purpose: To compare the loss of fat mass, LBM and performance in two different weight-loss interventions. 2) Because muscle mass is an important determinant of performance in sports dependent on high muscle strength or power (e.g. weight lifting, alpine skiing), there is a need for effective muscle mass gaining protocols. The most important factors promoting an increase in muscle mass is strength training combined with positive energy balance, and an increase in body mass of 0.25-0.5 kg per week may be possible depending on genetics and the resistance-training history of the athlete (1,2). For Elite athletes with heavy training loads, competitions and limited time for proper nutrition strategies, it can be a difficult task to increase lean body mass (LBM) or to maintain LBM during the competitive season. Thus, a significant number of these athletes are using excessive supplementation and diets high in saturated fat. Purpose: To evaluate the effect of nutritional guidance in a 10-12 weeks weight-gain period in elite athletes.
1) Methods: 30 male and female elite athletes where randomized into two groups, “slow reduction” (SR, n=14, 23.53.3 y, 72.212.2 kg) and “fast reduction” (FR, n=16, 22.34.9 y, 72.211.2kg). All athletes followed a 6-12 week energy restriction period depending on the intervention and desired weight loss. Diets were recorded by 4-day weighed food records and each athlete followed an individualized diet plan promoting weekly body weight-loss of 0.7% or 1.4%. All athletes continued training their sport as usual (14.63.5h per week), and in addition all included four resistance-training sessions per week to emphasize muscle hypertrophy. Measurements done pre and post intervention were: body weight (BW), dual energy x-ray absorptiometry (DEXA), 1 RM tests (squat and bench press) and vertical jumping test. 2) Methods: 39 male and female elite athletes where randomized into two groups, “nutritional guidance group” (NG, n=21, 19.1±2.9 y, 70.9±8.9 kg) and “ad libitum group” (ALG, n=18, 19.6±2.7 y, 75.0±5.9kg). The Athletes in NG followed a strict meal plan based on a 4-day weighed food registration, providing a positive daily energy intake corresponding to 544±143 kcal whereas the athletes in the ALG had an ad libitum energy intake with no nutritional guidelines. All athletes continued their normal sport specific training (16.7±5.4h per week), and in addition all included four resistance-training sessions per week to emphasize muscle hypertrophy. Assessments done pre and post intervention were: body weight (BW), dual energy x-ray absorptiometry (DEXA), 1 RM tests (squat and bench press and bench pull).