English abstract
The research aimed to study the evolution of muscle power, elastic and reactive strength indexes (EI and RSI, respectively) during growth phases and to identify the nature of their relationship with anthropometric measures in females' students. 103 female students (11-14 year-old) voluntary to participate in this study. They were divided into four groups according to growth phases [-2?-1]? ]-1?0[? ]0?+1]? ]+1?+2] years from peak height velocity (PHV). All students performed squat jump (SJ), countermovement jump (CMJ), and drop Jump (DJ) tests. EI and RSI were also calculated. No significant differences were recorded between group which belongs to phase [-2?-1] (SJ: 12.0?3.4 cm? CMJ: 15.1?4.4cm? DJ: 11.4?4.3cm? RSI: 40.2?15.8cm/sec) and group belonging to phase ]-1?0[ (SJ: 12.0?3.8 cm? CMJ: 14.9?3.8cm? DJ: 11.6?3.5cm? RSI: 41.1?16.9cm/sec) in one hand and between group which belongs to phase ]0?+1] (SJ: 16.2?5.3 cm? CMJ: 19.0?5.9cm? DJ: 15.4?5.0cm? RSI: 54.4?21.8cm/sec) and group belonging to ]+1?+2] (SJ: 16.3?4.0cm? CMJ: 19.3?4.2cm? DJ: 14.8?3.3cm? RSI: 52.6?17.1cm/sec) in the other hand. Whereas, significant differences were recorded between pre- and post-PHV groups. EI was not significantly different between the 4 groups. Significant negative correlations between body mass index in one side, SJ, CMJ, DJ performance and RSI in the other side were recorded for females which belong to pre- and post-PHV groups. These results are of great importance to girl coaches from an early age and physical education teachers in leg muscle power assessment and development of stretch-shortening cycle using plyometric exercises.
