Dry Needling for Hamstring Flexibility: A Single-Blind Randomized Controlled Trial.

CONTEXT: Hamstring muscle tightness is one of the most common problems in athletic and healthy people. Dry needling (DN) was found to be an effective approach for improving muscle flexibility, but there is no study to compare this approach with static stretching (SS) as a common technique for the increase of muscle length. OBJECTIVE: To compare the immediate effects of DN and SS on hamstring flexibility in healthy subjects with hamstring tightness. STUDY DESIGN: A single-blind randomized controlled trial. SETTING: A musculoskeletal physiotherapy clinic at Tehran University of Medical Sciences. SUBJECTS: Forty healthy subjects (female: 32, age range: 18-40 y) with hamstring tightness were randomly assigned into 2 groups of DN and SS. INTERVENTION: The DN group received a single session of DN on 3 points of the hamstring muscles, each for 1 minute. The SS group received a single session of SS of the hamstrings, consisting of 3 sets of 30-second SS with a 10-second rest between sets in the active knee extension test (AKET) position. MAIN OUTCOME MEASURES: The AKET, muscle compliance, passive peak torque, and stretch tolerance were measured at the baseline, immediately, and 15 minutes after the interventions. RESULTS: Improvements in all outcomes was better for the DN group than for the SS group. DN increased muscle compliance significantly 15 minutes after the intervention, but it did not improve in the SS group. CONCLUSION: DN is effective in improving hamstring flexibility compared with SS. One session of DN can be an effective treatment for hamstring tightness and increase hamstring flexibility. The improvements suggest that DN is a novel treatment for hamstring flexibility.

Immediate Effects of Dry Needling as a Novel Strategy for Hamstring Flexibility: A Single-Blinded Clinical Pilot Study.

CONTEXT: There are numerous studies on the benefits of dry needling (DN) for pain relief. No studies exist examining the effects of DN on hamstring flexibility. OBJECTIVE: To determine the immediate effects of DN on hamstring flexibility in healthy subjects with shortened hamstrings. DESIGN: A single-blinded, pretest-posttest clinical pilot study. SETTING: A university physiotherapy clinic. SUBJECTS: A total of 15 healthy subjects (female = 11; age = 23.26 [4.3] y) with shortened hamstrings participated in this study. INTERVENTION: Subjects received a single session of DN. Three locations on the hamstring muscle group were needled, each for 1 minute. MAIN OUTCOME MEASURES: The active knee extension test, muscle compliance, passive peak torque, and stretch tolerance were measured at baseline, immediately, and 15 minutes after DN. RESULTS: There were statistically significant improvements in all outcome measures immediately after DN and at the 15-minute follow-up. The effect sizes for all outcome measures were large (Cohen's d ≥ 0.8). No serious adverse events were observed with DN. CONCLUSIONS: This is the first study that demonstrates the beneficial effects of DN on hamstring flexibility, muscle compliance, and stretch tolerance without added stretching. The beneficial effects of DN should encourage clinicians to use DN as a novel strategy for increasing muscle flexibility.