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Remote Changes of Mechanical Stiffness Following Local Stretching or Contraction: A Systematic Review with Meta-Analysis.
This systematic review and meta-analysis pooled experimental studies that tested whether doing a local muscle stretch or contraction changes the mechanica…
Signal score64Research triage score
CertaintyMixed (very low certainty for lengthening effect; moderate certainty for contraction effect) - per abstract GRADE applicationVerify in full text
PMID42228239Source identifier
Research triage, not medical advice
Do not use this summary, score, or benefit-cost estimate to diagnose, treat, prescribe, or change care without reviewing the full study and consulting qualified professionals.
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Plain-English signal
This systematic review and meta-analysis pooled experimental studies that tested whether doing a local muscle stretch or contraction changes the mechanical stiffness of remote, connected tissues (for example, whether stretching or contracting the calf affects the stiffness of the plantar fascia or back muscles). Across included studies, local muscle lengthening (stretching) produced a moderate non-local stiffness change (standardized effect Hedges' g = -0.54), but the certainty for that result was judged very low. Local muscle contraction produced a larger non-local stiffness increase (Hedges' g = -1.25) with moderate certainty. The authors report substantial differences between individual studies and possible reporting bias for both interventions, and they conclude both contraction and stretch can change stiffness at connected sites but more research is needed, especially concerning heterogeneity for stretching effects.
Why it matters
- Addresses whether local muscle actions (stretching or contraction) change mechanical stiffness at distant, structurally connected tissues - relevant to rehabilitation and exercise prescription that target myofascial chains rather than only local tissues.
- Findings could influence clinical and training decisions about whether local interventions (e.g., calf stretching or contraction) can produce measurable mechanical effects at remote sites (e.g., plantar fascia, erector spinae).
- Provides pooled quantitative estimates (Hedges' g) and certainty assessments that may alter prioritization of research or small-scale practice pilots in sports medicine and physical therapy.
Primary outcomes
- Non-local (remote) tissue mechanical stiffness following local tissue lengthening (stretch) or local muscle contraction as measured in included experimental trials.
Effect summary
From abstract: Local tissue lengthening (stretch) produced a moderate pooled non-local stiffness change (Hedges' g = -0.54; 95% CI -1.03 to -0.05; p = 0.04; 12 studies, 42 effect sizes) with very low certainty. Local muscle contraction produced a larger pooled non-local stiffness increase (Hedges' g = -1.25; 95% CI -2.15 to -0.34; p = 0.016; 7 studies, 67 effect sizes) with moderate certainty. High heterogeneity and heterogeneity differences were noted, particularly for lengthening.
Benefit-cost lens
| Quick take | Meta-analysis shows both local contraction and stretching alter non-local tissue stiffness; contraction produced larger pooled effects. Translating to benefit-cost requires baseline outcome rates, magnitude in absolute units, target population, and implementation costs. |
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| BCR anchor | 2 |
| Time horizon | 3 |
| Discount rate | 0.03 |
| Assumptions | Summary based on abstract and PubMed metadata only; assumed pooled SMDs (Hedges' g) reported are accurate. Full text needed to verify participant characteristics, outcome measurement units, clinical relevance, and harms. |
Benefit-cost fields are assumptions-based unless explicitly source-derived. Treat them as prompts for deeper economic review.
Risk of bias
| Tool | Modified Downs and Black checklist (as reported in abstract); publication-bias checks via funnel plots and Egger's test |
|---|---|
| Verdict | Some concerns |
| Notes | Authors report mostly high methodological quality scores (mean 11.3 ± 1.7) but identify possible reporting bias (Egger's test) for both contraction and lengthening and high heterogeneity (τ² reported). Assessment here is based on abstract-only information; a full risk-of-bias table from the manuscript is required for a formal judgment. |
Harms, equity, conflicts & implementation
| Implementation | Full-text review to confirm participant characteristics, measurement methods, clinical relevance, dosing of interventions, adverse events, and feasibility. Conversion of standardized effects to absolute units and stakeholder input (therapists, coaches) needed before practice change. |
|---|---|
| Equity impact | Unclear from abstract. Equity implications depend on which populations were studied (healthy volunteers vs clinical groups) and access to interventions; full text needed to assess differential effects or access barriers. |
| Harms | No harms reported in abstract. Potential adverse effects or tradeoffs (e.g., pain, injury risk from contraction/stretch protocols) are not described and require full-text check. |
| Registration | PROSPERO CRD42024615692 |
| Replication | Unknown from abstract-level triage; replication across independent samples not established in abstract. |
Source links — verify original
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