Investigation the Force-Related Fatigability of Gymnasts and Untrained Girls in Different Age Groups According to Tanner Stage

The purpose of this cross-sectional present study was to investigate the force-related fatigability in gymnast and untrained girls according to tanner stage. 60 gymnasts and untrained girls were divided into the three subgroups of children, adolescents and adults according to Tanner's scale. Subjects were referred to the laboratory in three separate sessions for familiarity and initial measurements, maximal test, and fatigue test, respectively. For the maximal test, each subject performed three maximum isometric contractions of the knee extensor at five different angles to determine the optimal angle of force production. The fatigue test included repeating five-second maximum contractions with five seconds of rest to reach 60% of maximum torque. The electrical activity of the rectus femoris muscle was recorded using an electromyography to measure mean power frequency (MPF). Two-way ANOVA was used for data analysis. There was a significant difference between the number of repetitions to fatigue in children compare to adolescent and adult (P<0.05), this difference (between children with adolescents and adults) was not significant in gymnast groups (p>0.05). However, the normalization of the torque drop based on the initial productive force (peak torque) showed a similar pattern in children and adults. This may indicate the importance of the peak torque in explaining fatigability between children and adults. It seems gymnastic training in pre-puberty period may shift the fatigability pattern toward adulthood pattern.