The validity of Nordic hamstring in Iranian football and track and field athletes

Abstract

Context: Isokinetic dynamometry is a golden standard test for hamstring injury risk assessment. Limitations such as time and cost lead to explore field-based tests. Recently, Nordic hamstring test (NHT) has been introduced as a field-based test. The aims of this study were to (1) Validate NHT in football and track and field athletes and (2) to assess the effect of hip joint position on correlations obtained. Design: Validation study. Setting: University biomechanical laboratory. Participants: 44 male athletes including two groups (22 football players and 22 track and field athletes) were recruited for this study. Intervention: Eccentric peak torque of hamstring, angle of peak torque, angle of crossover and hamstring to quadriceps ratios were extracted from isokinetic dynamometry in two seated and lying positions. The Nordic breakpoint angle was gained from video analysis of NHT. Main Outcome Measure: Nordic breakpoint angle, hamstring eccentric peak torque, angle of peak torque, angle of crossover, hamstring to quadriceps ratio. Results: In both groups, there were significant correlations between eccentric hamstring peak torque and Nordic break-point in both groups (P < 0.001). The correlations in Lying positions were higher than seated positions. Angle of crossover had significant correlation with eccentric hamstring peak torque (P < 0.001). While no correlation for Hamstring to quadriceps ratio. Conclusion: The results of this study revealed that NHT is a valid test in football and track and field athletes. Angle of crossover is a better way to knee muscle balance assessment. Hip joint position is an important factor and should be considered in future studies regarding hamstring strain.