Abstract
Purpose: This study examined the interday reliability of a predetermined and a self-determined isometric-squat test among youth soccer players. Familiarization effects were evaluated to determine the minimum number of trials necessary to obtain consistent outputs. Finally, differences between protocols were evaluated.
Methods: Thirty-one youth soccer players (mean [SD] age: 13.2 [1.0] y; body mass: 54.1 [3.4] kg; stature: 166.3 [11.2] cm; percentage of estimated adult height: 92.6% [3.6%]) from a top-tier professional academy completed 4 experimental sessions for each protocol: familiarization 1, familiarization 2, test, and retest sessions. Peak force; relative peak force; impulse from 0 to 50 milliseconds, 0 to 100 milliseconds, 0 to 150 milliseconds, and 0 to 200 milliseconds; and rate of force development from 0 to 50 milliseconds, 0 to 100 milliseconds, 0 to 150 milliseconds, and 0 to 200 milliseconds were measured.
Results: Both protocols displayed acceptable (intraclass correlation coefficient >=.75 and coefficient of variation ≤10%) reliability statistics for all metrics apart from rate of force development of any time epoch. Differences were found between familiarization 2 and both test and retest sessions for peak force (P = .034 and .021, respectively) and relative peak force (P = .035 and .005, respectively) across both protocols.
Conclusions: The isometric-squat test is a reliable test among youth soccer players. Two familiarization sessions seem to be sufficient to ensure data stabilization. Outputs between the self-determined and predetermined are comparable; however, the latter seems preferable due to improved testing time efficiency.
Methods: Thirty-one youth soccer players (mean [SD] age: 13.2 [1.0] y; body mass: 54.1 [3.4] kg; stature: 166.3 [11.2] cm; percentage of estimated adult height: 92.6% [3.6%]) from a top-tier professional academy completed 4 experimental sessions for each protocol: familiarization 1, familiarization 2, test, and retest sessions. Peak force; relative peak force; impulse from 0 to 50 milliseconds, 0 to 100 milliseconds, 0 to 150 milliseconds, and 0 to 200 milliseconds; and rate of force development from 0 to 50 milliseconds, 0 to 100 milliseconds, 0 to 150 milliseconds, and 0 to 200 milliseconds were measured.
Results: Both protocols displayed acceptable (intraclass correlation coefficient >=.75 and coefficient of variation ≤10%) reliability statistics for all metrics apart from rate of force development of any time epoch. Differences were found between familiarization 2 and both test and retest sessions for peak force (P = .034 and .021, respectively) and relative peak force (P = .035 and .005, respectively) across both protocols.
Conclusions: The isometric-squat test is a reliable test among youth soccer players. Two familiarization sessions seem to be sufficient to ensure data stabilization. Outputs between the self-determined and predetermined are comparable; however, the latter seems preferable due to improved testing time efficiency.
| Original language | English |
|---|---|
| Pages (from-to) | 718-725 |
| Number of pages | 8 |
| Journal | International Journal of Sports Physiology and Performance |
| Volume | 18 |
| Issue number | 7 |
| Early online date | 19 May 2023 |
| DOIs | |
| Publication status | Published - 31 Jul 2023 |
Keywords
- strength
- power
- assessment
- self-determination
- autonomy