REF-985 · Takeuchi et al., 2023 · Scandinavian Journal of Medicine & Science in Sports, Vol. · Paper · PubMed

Long-term static stretching can decrease muscle stiffness: A systematic review and meta-analysis

A-fairly strong evidenceMeasured on a mixed groupWritten before October 2026, being re-checked

Stretch training increases a joint's range of motion, yet why it does so is poorly understood, and an earlier meta-analysis pooling different stretching types found no change in muscle stiffness with long-term stretch training. This review asked how long-term static stretch training (≥2 weeks) affects muscle stiffness.

Searches of PubMed, Web of Science and EBSCO covered papers published before December 28, 2022; 10 papers qualified for the meta-analysis. Compared with a control condition, 3-12 weeks of static stretch training moderately reduced muscle stiffness. The effect did not differ by sex, by how stiffness was assessed, or with total stretching duration.

Participants

10 papers; participant numbers, ages and training status are not given in the abstract. Subgroups by sex were male vs. mixed sex.

Protocol

Sources: PubMed, Web of Science and EBSCO, published before December 28, 2022.
Inclusion: long-term (≥2 weeks) static stretching training with muscle stiffness as outcome, compared to a control condition.
Analysis: mixed-effect model; subgroups compared men-only vs. mixed-sex samples, and stiffness measured via shear modulus vs. calculated from the muscle-tendon junction; a meta-regression tested total stretching duration.

Key Results

Against a control condition, 3-12 weeks of static stretch training lowered muscle stiffness moderately (effect size -0.749; p < 0.001; heterogeneity I2 = 56.245).
No significant difference between sexes (p = 0.131).
No significant difference between types of muscle stiffness assessment (p = 0.813).
How long people stretched in total was not significantly related to muscle stiffness (p = 0.881).

Practical Application

"If I stretch for weeks, does the muscle actually get less stiff?" Pooling 10 papers, the meta-analysis found that 3-12 weeks of static stretch training made muscles moderately less stiff than in a control condition (effect size = -0.749), and total stretching duration was unrelated to the size of the effect. Pooled, static stretching does change the tissue measure, not only stretch tolerance.
This qualifies the single trial in REF-382, where six weeks of static stretching raised range of motion with stiffness unchanged: one trial found no change, the pooled estimate across ten papers is a moderate decrease.
No dose can be taken from this: total stretching duration did not predict the effect, and the abstract gives no per-session or weekly prescription.
What was not measured in the abstract: perceived tightness, soreness, performance, injury. Less stiffness is not shown to be better for an endurance athlete.
Not from this paper; the base's own practice: what to do about tight legs, and what stretching is and is not for, is SYNTH-11; recovery between sessions is SYNTH-70.

Limitations

Ten papers; moderate heterogeneity (I2 = 56.245).
Participants, muscles studied and stretching doses are not described in the abstract.
Outcome is muscle stiffness only; no functional, perceptual or injury outcome.
An earlier meta-analysis across stretching types found no change; this one is restricted to static stretching.
Written from the abstract and record metadata only (full text not read).
How this entry was checked and changed
Why this level

meta-analysis of 10 papers with moderate heterogeneity (I2 = 56.245)