Obesity-related differences in neuromuscular fatigue in adolescent girls

The aim of this study was to investigate the effect of obesity on neuromuscular fatigue in adolescent girls. Twelve lean (13.6 +/- A 0.8 years) and 12 obese (13.9 +/- A 0.9 years) girls repeated 5-s maximal voluntary contractions (MVC) of the knee extensors until the generated torque reached 55 % of its initial value. Magnetic stimulations were delivered to the femoral nerve every five MVCs to follow the course of voluntary activation (VA) and potentiated twitch torque (Qtw(pot)). Torque reached 55 % of its initial value after 52.6 +/- A 20.4 and 74.9 +/- A 22.8 repetitions in obese and lean girls, respectively (p < 0.01). Furthermore, the decline of VA was smaller in obese girls (p < 0.001). In contrast, Qtw(pot) decreased to a greater extent in obese girls (p < 0.05). Obese girls fatigue faster than their lean counterparts. The peripheral factors mainly account for fatigue in obese girls, whereas central factors are mainly involved in lean girls.