Maximal Strength Testing Using the Long-Lever Hip Adduction Squeeze Test in Youth Elite Football (Soccer) Players: A Four-Week Reliability Study.
Lasse Ishøi, Jonas Petersen, Kasper Thornton and 1 others
PMID 40469650WHAT IT FOUND
Week-to-week hip adduction strength scores in youth footballers are consistent.
However, a drop of about 22% is needed to be sure it is a real change. This helps clinicians distinguish true weakness from normal daily fluctuations.
Key findings
01The test showed good consistency from week to week, with intraclass correlation coefficients ranging from 0.916 to 0.933.
02The minimal detectable change for an individual player was between 21.2% and 24%, meaning smaller drops could be measurement error.
03There was no significant difference in average strength scores between the testing weeks.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study did not control for training load or match minutes played between tests, which may have introduced random error. Pain ratings were not anonymized, so some players may have underreported pain and remained in the analysis. The sample was limited to elite male youth footballers in a specific academy setting, so results may not generalize to female players, recreational athletes, or senior professionals. The high minimal detectable change (21-24%) means the test may miss subtle early signs of weakness associated with injury risk.
Declared interests
The authors report no financial conflicts of interest, but two authors (LI and MDD) provided feedback on the development of the testing device used in the study.
The easy way to misread this
Do not use a 10% drop in strength as a definitive red flag for injury. The study shows that a change must exceed roughly 22% to be statistically distinct from measurement error. Relying on smaller thresholds may lead to unnecessary sidelining of players.