Late swing knee mechanics in elite rugby union players and trained sprinters

Hamstring injuries are highly prevalent in running-based sports such as sprinting and rugby union, and are thought to occur during the late swing phase where the hamstrings are under great load and strain. The aim of this study was to investigate the knee mechanics of elite rugby players and speed-matched sprinters during the late swing phase of maximum effort over-ground running. Elite rugby players demonstrated reduced knee extension velocity through late swing, which was associated with a smaller maximum knee flexion angle during the mid-swing phase. As rugby players displayed a greater absolute knee flexion moment, power absorption and negative work, we suggest that the kinematic differences displayed by rugby players may be an adaptation to reduce the velocity of hamstring stretch and load on the hamstring muscles during late swing.