Optimal duration of stretching exercise in patients with chronic myofascial pain syndrome: A randomized controlled trial.

OBJECTIVE

To explore the effect of variable durations of stretching on neural function, pain, and algometric pressure in patients with chronic myofascial pain syndrome.

DESIGN

Randomized controlled trial.

PATIENTS

A total of 100 participants diagnosed with chronic myofascial pain syndrome were randomly assigned to a control group or 1 of 3 intervention groups.

METHODS

The 3 experimental groups received different durations of cervical spine stretching: 15, 30 or 60 s. The control group did not stretch. Primary outcome measures included peak-to-peak somatosensory-evoked potential for dermatomes C6, C7 and C8. Secondary outcome measures included central somatosensory conduction time (N13-N20), pain intensity, and pressure-pain threshold algometric measurements. All outcome measures were assessed immediately after and 2 h after the treatment session.

RESULTS

Post hoc analysis indicated that stretching for 60 s significantly decreased the dermatomal amplitude for C6, C7 and C8 (p < 0.001) and significantly increased the central conduction time, indicating negative effect (p < 0.001). Stretching for 30 and 60 s resulted in greater improvement in pain intensity and algometric pressure than stretching for 15 s or no stretch (control) p < 0.001.

CONCLUSION

Stretching cervical muscles involved in chronic myofascial pain syndrome for 30 s was optimal in achieving stretching benefits and minimizing the negative effects on the neural function of the involved nerve roots and central nervous system.