Reliability, Familiarization Effect, and Comparisons Between a Predetermined and a Self-Determined Isometric-Squat...

Area of Science:

• Sports Science
• Biomechanics
• Youth Athlete Performance

Background:

• Assessing physical performance in young athletes is crucial for training and talent identification.
• The isometric-squat test is a common tool, but its reliability and optimal protocol in youth soccer players require further investigation.

Purpose of the Study:

• To evaluate the interday reliability of predetermined and self-determined isometric-squat tests in youth soccer players.
• To determine the number of familiarization trials needed for reliable isometric-squat test data.
• To compare the outcomes between predetermined and self-determined isometric-squat testing protocols.

Main Methods:

• Thirty-one youth soccer players underwent four sessions per protocol: two familiarization, one test, and one retest.
• Measurements included peak force, relative peak force, impulse, and rate of force development across various time epochs.
• Intraclass correlation coefficient and coefficient of variation were used to assess reliability.

Main Results:

• Both predetermined and self-determined protocols demonstrated acceptable reliability for most metrics, except rate of force development.
• Two familiarization sessions were sufficient to stabilize data for peak force and relative peak force.
• Familiarization 2 showed significant differences compared to test and retest sessions for peak force and relative peak force.

Conclusions:

• The isometric-squat test is a reliable measure for youth soccer players.
• Two familiarization sessions are adequate to ensure data consistency.
• While both protocols are comparable, the predetermined isometric-squat test is more time-efficient.