Reliability and validity of 2D-video analysis to objectively assess hamstring performance during the H-test.

The H-test is commonly used during return-to-sport decisions after hamstring muscle injury. The primary aim was to evaluate the reliability of two-dimensional (2D) video analysis for the H-Test. The second aim was to assess its validity compared to an electronic gyroscope (gold standard), and the third aim was to establish normative values. We conducted a cross-sectional study including 30 healthy individuals. Mean, maximal velocities (V Mean and V max ) and range of motion (ROM) of hip flexion were captured during the H-test to evaluate inter-rater and test-retest reliability using intraclass correlation coefficient (ICC 2,1 ) and standard error of measurement (SEM). Correlation analysis ( r ) and as typical error of estimate (TEE) were used to assess the validity between the video and the gyroscope. Reliability was excellent for ROM (ICC:0.91, [95% CI:0.83-0.95]), moderate for V Mean (ICC:0.57; [95% CI:0.32-0.74]) and V Max (ICC:0.64, [95% CI:0.43-0.79]). Strong positive correlations were found between video and gyroscope for V Mean ( r  = 0.79, [95% CI:0.71-0.86]) and V Max ( r  = 0.84, [95% CI:0.77-0.89]) and very strong for ROM ( r  = 0.89, [95% CI:0.85-0.93]). Males exhibited a higher V Max ( p  < 0.001) than females, while females had a higher ROM ( p  < 0.001). 2D-video analysis is a valid and reliable method to assess ROM during the H-Test and could easily be implemented in clinical practice.