The influence of a 6 month intervention on self-perceived fatigue, body composition and handgrip performance in obese boys

Introduction: The main goals of obesity intervention programs are decreasing body weight, fat mass and increasing lean mass. It is generally accepted that fat mass decreases with weight loss, but results on lean mass are inconsistent. The relation between weight-loss induced changes in body composition and fatigue sensations in obese adolescents remain unexplored. This study examined the effect of a 6 months weight loss program on self-perceived fatigue, grip performance and body composition.Methods: 81 obese boys (15±2 years) were examined for body composition (DXA), maximal grip strength, fatigue resistance (the time during which grip strength decreased to 50% of its maximum value during sustained maximal contraction), grip work (calculated as fatigue resistance x 0.75 x maximal grip strength, corresponding to the area under the curve) and self-perceived fatigue (Multidimensional Fatigue Inventory, MFI-20). The boys were divided into 2 groups; a high weight loss group (HWL, >20% body weight) and a low weight loss group (LWL, <20% body weight).Results: At baseline HWL and LWL showed similar weight, BMI and grip parameters. HWL improved significantly for all grip and self-perceived fatigue parameters whereas LWL improved only for fatigue resistance and grip parameters corrected for body weight. Both LWL and HWL lost significant fat mass, but the HWL also lost significant lean mass and significantly more fat mass compared to LWL.Conclusion: After a 6 month multidimensional weight loss program, HWL showed significantly improvements in self-perceived fatigue and grip performance despite the fact that they also lost more lean mass.