Multifactorial hamstring assessment protocol including ultrasound, strength, and running kinematics parameters

Purpose To present a protocol comprising a combination of measurements related to hamstring strain injuries (HSIs) and to report on its feasibility, advantages, limitations, and interpretation of findings. Methods The protocol consists of a sequence of tests totalling about 60 min. After collecting participant data, an evaluation of hamstring muscle architecture (fascicle length, muscle thickness, pennation angle, and cross-sectional area) is performed using extended field of view ultrasound. Participants then complete knee flexion isometric and Nordic eccentric peak torque evaluations. Following a standardized warm-up consisting of 5 min of low-intensity aerobic activity and 8 min of dynamic mobility work, participants undergo a running linear and angular kinematics assessment composed of 15 30-m trials at 80% of their maximum speed on a treadmill. Parameters such as stride length, cadence, and trunk and pelvic angles during running are then derived from this assessment. The players’ maximum speed can be determined using match data. The treadmill assessment is followed by repeated isometric and eccentric torque measurements. We estimate that sample sizes of 21 and at least 120 players would be required to establish reliability and the diagnostic ability of a composite risk measure based on this protocol, respectively. Conclusions The presented protocol is designed to explore potential underlying HSI mechanisms, with the aim of moving beyond simply identifying who may be at risk. It presents some limitations in terms of material requirements and personnel skills, which may limit its applications in settings with lower resources. The value of this protocol for identifying HSI risk patterns should be confirmed in further studies.