Effect of different weight-loss rates on body composition and strength related performance

Transcription

1 Effect of different weight-loss rates on body composition and strength related performance Ina Garthe, Truls Raastad, Per Egil Refsnes, Anu Koivisto, Jorunn Sundgot-Borgen

2 Background Sports that emphasise low weight and leanness have a high percentage of athletes are practicing inappropriate weight regulation strategies Recommended weight loss is kg or 1.5% of BW per week Energy restriction can lead to loss of lean body mass (LBM) and thereby impair performance In general, athletes want to lose weight fast to reduce the risk of underperforming Garthe 2004; Position stand Female athlete triad 2005; Sungot-Borgen J 2000; Torstveit MK, Sundgot-Borgen J 2004

3 Background Curvilinear relationship between initial body fat content and the proportion of weight loss consisting of LBM Strenght training combined with mild energy restriction can increase LBM in over weight untrained subjects There are no prospective randomised controlled intervention study evaluating the effect of optimal weightloss regimen for elite athletes

4 Purpose To compare the loss of fat mass, LBM and performance in two different weight-loss interventions promoting loss of 0.7% versus 1.4% of body weight per week in elite athletes

5 Hypothesis I Athletes in the Slow intervention will preserve LBM to a greater extend than athletes in the Fast intervention II Athletes in the Slow intervention will preserve performance to a greater extend than athletes in the fast intervention

6 Methods 4 days registration of dietary intake (individualised diet plan promoting the weekly body weight loss) They were supplemented with fish oil and a multivitamine-mineral supplement to ensure adequate intake Strength training program 4 times a week Periodized and emphasized hypertrophy Weekly follow-up during intervention Nutritional counselling Exercise

7 Subjects 36 Norwegian female (n=19) and male (n=17), junior and senior athletes aged years were included Junior or senior national team members/students at the Norwegian elite athlete college (Norges Toppidrettsgymnas, Wang Toppidrettsgymnas) football, volleyball, cross country skiing, judo, jujutsu, tae kwondo, waterskiing, motor-cross, cycling, track and field, kickboxing, voltage, downhill skiing, ski jump, shooting, freestyle, skating, biathlon and ice hockey Invitation letters to sport federations Invitation from the nutrition department at the Norwegian Olympic Sport Centre when athletes contacted the centre to get assistance with weight loss

8 Design

9 Design

10 Tests Blood samples (fasted) DXA LBM, fat mass, % body fat, BMD (total, spine, femur) Caliper (Skin fold measurements) Standardized meal Mental evaluation EDI, Contingent self-esteem Scale, sports specific tests (passion, identity) Performance: 1 RM in bench press, bench pull and squat, 40 m sprint and counter movement jump Exercise and nutrition diary (during intervention)

11 Results Baseline presented as mean SD SR FR Males (n=6) Females (n=7) Males (n=5) Females (n=6) Age (yrs) 24.9 ± ± ± ± 6.4 Height (cm) 177 ± ± ± ± 1 BW (kg) 78.5 ± ± ± ± 6.7 FM (kg) 13.3 ± ± ± ± 5.2 Total body fat (%) 17 ± 5 27 ± 5 16 ± 3 30 ± 5 LBM (kg) 62.3 ± ± ± ± 3.6 Experience as athletes (yrs) 13 ± ± ± ± 5.1 Training per week (h) 15.6 ± ± ± ± 5.3 Strength training last season (h week -1 ) 2.8 ± ± ± ± 1.5

12 Results Energy and nutrition variables presented as mean SE for change SD for pre and post and mean SR (n=13) FR (n=11) Diet registration Meal plan Change Diet registration Meal plan Change Energy intake (kcal) 2409 ± ± ± 61* 2514 ± ± ± 113* Energy (kcal/lbm) 45.6 ± ± ± 4.2*# 47.8 ± ± ± 2.2*# Protein (g/kgbw) 1.6 ± ± ± 0.1* 1.6 ± ± ± 0.1 Protein (E%) 19.6 ± ± ± 1.3* 18.2 ± ± 3.3 4,5 ± 1.6* CHO (g/kgbw) 4.1 ± ± ± 0.2* 4.1 ± ± ± 0.2* CHO (E%) 51.0 ± ± ± ± ± ± 1.5* Fat (E%) 30.0 ± ± ± 2.1* 31.1 ± ± ± 1.4* * p<0.05 significantly different from pre # p<0.05 significant difference between groups

13 Change (%) Body composition 10 0 Body weight Fat mass LBM * SR FR * * * # * * p<0.05 significantly different from pre # p<0.05 significant difference between groups

14 Change (%) Performance * SR FR 5 0 CMJ 40 m sprint * p<0.05 significantly different from pre # p<0.05 significant difference between groups

15 Change (%) Performance * # * * * SR FR RM Bench press 1 RM Bench pull 1 RM Squat * p<0.05 significantly different from pre # p<0.05 significant difference between groups

16 Conclusion Despite a weight loss of ~6% of body mass it is possible to increase LBM and enhance performance during a gradual weight loss in normal-weight athletes The rate of weekly weight loss and the addition of strength training are the most important factors that influencing loss of FM versus LBM and performance during weight reduction in elite athletes

17 Aknowledgements Truls Raastad Jorunn Sundgot-Borgen Per Egil Refsnes

18 Thank you for your attention! Pause