The effect of cervical spine isometric contract-relax technique on hamstring extensibility.

Objectives: To re-investigate the effect of a cervical isometric contract-relax technique on hamstring extensibility and examine the duration of any treatment effect.Methods: Forty asymptomatic participants were randomly assigned equally to either an experimental or control group. Both groups underwent pre and post hamstring extensibility measurements using passive knee extension with the thigh maintained at 90 degrees of hip flexion, with the examiner blinded to treatment allocation of the participants. Torque was measured with a hand held dynamometer to maintain consistent force in pre and post measurements. The experimental group received an upper cervical isometric contract-relax treatment. A digital camera recorded the knee extension angles and the images were computer analysed to determine hamstring extensibility.Results: A split plot ANOVA (SPANOVA) revealed no significant hamstring extensibility differences between or within the groups, immediately or at 30 minutes.Conclusion: The cervical isometric contract-relax treatment produced no significant effect to the extensibility of the hamstring. This study does not support the use of cervical techniques to alter hamstring extensibility.