Time of day effect in postural control in young soccer players: Field dynamic assessment

This study aimed to examine the reliability and the time-of-day variability on standing long jump (SLJ), three hop test (THT) speed (5-m, and 20-m sprint), and balance (Y balance test [Y-BT]) in prepuberal male soccer players. Data were gathered from two phases, using 105 soccer players. Reliability was investigated in phase 1. Time of day effect on SLJ, THT, 5-m, and 20-m speed and Y-BT tests was investigated in phase 2. Phase 1 showed non-significant bias between the two applications of the SLJ, THT, 5-m, and 20-m speed, and Y-BT tests . The SLJ, THT, 5-m, and 20-m speed, and Y-BT scores showed high relative and absolute reliability. The usefulness analysis showed that the SLJ, THT, 5-m and 20-m speed, and Y-BT tests could detect small changes in performance (SEM < SWC for all tests). Phase 2 showed that leg power, speed, and postural control are affected by time of day. A significantly better (p< 0.05) leg power, speed, and postural control were observed at the end of the afternoon than at morning hours. Time-of-day may be considered as a factor in designing leg power, speed, and postural control training programmes and intervention studies for prepuberal male soccer players.