Background and purpose: Passive stretching is widely used to increase muscle flexibility, but it has been shown that this process does not produce long-term changes in the viscoelastic properties of muscle as originally thought. The authors tested a method of lengthening hamstring muscles called "Awareness Through Movement" (ATM) that does not use passive stretching.
Subjects: Thirty-three subjects who were randomly assigned to ATM and control groups met the screening criteria and completed the intervention phase of the study.
Methods: The ATM group went through a process of learning complex active movements designed to increase length in the hamstring muscles. Hamstring muscle length was measured before and after intervention using the Active Knee Extension Test.
Results: The ATM group gained significantly more hamstring muscle length (+7.04 degrees ) compared with the control group (+1.15 degrees ).
Discussion and conclusion: The results suggest that muscle length can be increased through a process of active movement that does not involve stretching. Further research is needed to investigate this finding.