Effects of Maturation on Plantar Flexor Activity and Achilles Tendon Stiffness in Vertical Jumping: Sex Differences.

The aim of this study was to investigate the effect of maturation on vertical jumping performance, in adolescent boys and girls, concerning plantar flexor activity and Achilles tendon (AT) stiffness. Thirty-nine adolescents were tested in a counter-movement jump (CMJ) at three different time points: 18 and 9 months before peak height velocity (PHV) and at PHV. The EMG activity of the medialis gastrocnemius (MG) and tibialis anterior (TA) muscles was evaluated, in relation to jump height.

Postural control in adolescent boys and girls before the age of peak height velocity: Effects of task difficulty.

Background: Adolescent children experience a critical developmental period marked by rapid biological changes. Research question To describe the longitudinal changes in postural control that occur in adolescent boys and girls before the age of peak height velocity (PHV).

Methods: Here, to address the gap of knowledge, we compared the postural control and activation strategies of the muscles that control the ankle joint in twenty-three boys (age 12.