Muscle function and body composition profile in adolescents with restrictive anorexia nervosa: does resistance training help?

PURPOSE: The aim of this study was to analyze the effects of short-term resistance training on the body composition profile and muscle function in a group of Anorexia Nervosa restricting type (AN-R) patients.

METHODS

The sample consisted of AN-R female adolescents (12.8 ± 0.6 years) allocated into the control and intervention groups (n = 18 each). Body composition and relative strength were assessed at baseline, after 8 weeks and 4 weeks following the intervention.

RESULTS

Body mass index (BMI) increased throughout the study (p = 0.011). Significant skeletal muscle mass (SMM) gains were found in the intervention group (p = 0.045, d = 0.6) that correlated to the change in BMI (r = 0.51, p < 0.031). Meanwhile, fat mass (FM) gains were significant in the control group (p = 0.047, d = 0.6) and correlated (r > 0.60) with change in BMI in both the groups. Significant relative strength increases (p < 0.001) were found in the intervention group and were sustained over time.

CONCLUSIONS

SMM gain is linked to an increased relative strength when resistance training is prescribed. Although FM, relative body fat (%BF), BMI and body weight (BW) are used to monitor nutritional progress. Based on our results, we suggest to monitor SMM and relative strength ratios for a better estimation of body composition profile and muscle function recovery. Implications for Rehabilitation Anorexia Nervosa Restricting Type (AN-R) AN-R is a psychiatric disorder that has a major impact on muscle mass content and function. However, little or no attention has been paid to muscle recovery. High intensity resistance training is safe for AN-R after hospitalization and enhances the force generating capacity as well as muscle mass gains. Skeletal muscle mass content and muscular function improvements are partially maintained for a short period of time when the exercise program ceases.