Hamstring flexibility unaffected by more static stretching
One page on PainSci cites Bandy 1997: The Complete Guide to Low Back Pain
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This study checked for an effect of static stretching frequency and duration on hamstring flexibility, which was measured by testing the range of motion of knee extension. The results suggest that there is nothing gained by stretching longer than 30 seconds, or doing it more than 2-3 times a day, but stretching did help ROM. ROM did not improve in the control group, which did no stretching at all.
original abstract †Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.
BACKGROUND AND PURPOSE: Frequency and duration of static stretching have not been extensively examined. Additionally, the effect of multiple stretches per day has not been evaluated. The purpose of this study was to determine the optimal time and frequency of static stretching to increase flexibility of the hamstring muscles, as measured by knee extension range of motion (ROM).
SUBJECTS: Ninety-three subjects (61 men, 32 women) ranging in age from 21 to 39 years and who had limited hamstring muscle flexibility were randomly assigned to one of five groups. The four stretching groups stretched 5 days per week for 6 weeks. The fifth group, which served as a control, did not stretch.
METHODS: Data were analyzed with a 5 x 2 (group x test) two-way analysis of variance for repeated measures on one variable (test).
RESULTS: The change in flexibility appeared to be dependent on the duration and frequency of stretching. Further statistical analysis of the data indicated that the groups that stretched had more ROM than did the control group, but no differences were found among the stretching groups.
CONCLUSION AND DISCUSSION: The results of this study suggest that a 30-second duration is an effective amount of time to sustain a hamstring muscle stretch in order to increase ROM. No increase in flexibility occurred when the duration of stretching was increased from 30 to 60 seconds or when the frequency of stretching was increased from one to three times per day.
related content
- “Extensibility of the hamstrings is best explained by mechanical components of muscle contraction, not behavioral measures in individuals with chronic low back pain,” Marshall et al, PM & R: The Journal of Injury, Function, and Rehabilitation, 2009.
- “A randomized controlled trial for the effect of passive stretching on measures of hamstring extensibility, passive stiffness, strength, and stretch tolerance,” Marshall et al, Journal of Science & Medicine in Sport, 2011.
- “Influence of static stretching on hamstring flexibility in healthy young adults: Systematic review and meta-analysis,” Medeiros et al, Physiother Theory Pract, 2016.
- “Comparison of ballistic and static stretching on hamstring muscle length using an equal stretching dose,” Covert et al, Journal of Strength & Conditioning Research, 2010.
- “The Effectiveness of PNF Versus Static Stretching on Increasing Hip-Flexion Range of Motion,” Lempke et al, Journal of Sport Rehabilitation, 2018.
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