Strength Measurements in Acute Hamstring Injuries: Intertester Reliability and Prognostic Value of Handheld Dynamometry
Cohort study, repeated measures.
Although hamstring strength measurements are used for assessing prognosis and monitoring recovery after hamstring injury, their actual clinical relevance has not been established yet. Handheld dynamometry (HHD) is a commonly used method of measuring muscle strength. The reliability of HHD has not been determined in athletes with acute hamstring injuries.
To determine the intertester reliability and the prognostic value of HHD strength measurement in acute hamstring injuries.
We measured knee flexion strength with HHD in 75 athletes at two visits: at baseline within five days of hamstring injury and at follow-up five to seven days after the baseline measurement. We assessed isometric hamstrings strength in 15° and 90° of knee flexion. Reliability analysis testing was performed by two testers independently at the follow-up visit. We recorded the time needed to return to play (RTP) up to 6 months follow-up.
The intraclass correlation coefficients (ICCs) of the strength measurements in injured hamstrings were between 0.75 and 0.83. There was a statistically significant but weak correlation between the time to RTP and the strength deficit at 15° of knee flexion measured at baseline (Spearman’s r=0.25, p=0.045) and at the follow-up visit (Spearman’s r=0.26, p=0.034). Up to seven percent of the variance in time to RTP is explained by this strength deficit. None of the other strength variables were significantly correlated with time to RTP.
Hamstring strength can be reliably measured with HHD in athletes with acute hamstring injuries. The prognostic value of strength measurements is limited, as there is only a weak association between the time to RTP and hamstrings strength deficit after acute injury.
Autor / Fonte:Gustaaf Reurink, Gert Jan Goudswaard, Maarten H Moen, Johannes L Tol, Jan A N Verhaar, Adam Weir Journal of Orthopaedic and Sports Physical Therapy 2016 May 12, : 1-32