Methods: Five professional soccer teams sent 20 players with and without histories of hamstring injury for assessment of their lumbo-pelvic mechanisms (subjects=20, of which 15 were Hamstring group and 5 were controls, i.e. one control from each club). Each player followed the same procedure; first, their lumbo-pelvic mechanics were manually assessed using a standardized evaluation by the same blinded manual therapist; second, each player was assessed on a Cybex Norm dynamometer for trunk flexion–extension values. The data were analysed, and subsequently, the medical histories of the players were revealed.
Results: Manual assessment revealed higher levels of lumbo-pelvic dysfunction in the hamstring group—particularly in players with recurrent strains (though not statistically significant). Cybex assessment appeared to be less sensitive than manual assessment. However, for subjects who had a greater time period out of competitive play, the dynamometry was more sensitive; indicating its use in assessing deconditioning syndromes. There was no statistical correlation between manual and dynamometer assessment results. Statistical evaluation proved insignificant, but was hampered by low subject number, and more importantly by lack of normative data and contamination of the control group.
Conclusion: Further research is required to provide statistical validity for this clinically acceptable and highly evidenced hypothesis: hamstring strain can be associated with lumbo-pelvic dysfunction.