Resistance Training Induces Improvements in Range of Motion: A Systematic Review and Meta-Analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of controlled and randomized controlled trials
PubMed 36622555 · doi:10.1007/s40279-022-01804-x
What was done
A systematic review and meta-analysis searched four databases (PubMed, Scopus, SPORTDiscus, Web of Science) and reference lists for controlled trials or randomized controlled trials in healthy participants. Eligible studies compared chronic resistance training to a control group, stretch training, or combined resistance and stretch training versus stretch training alone. Random-effects models were used for main analyses, mixed-effects models for subgroup analyses (sex, activity level, contraction type), and meta-regressions for continuous moderators (age, frequency, duration). In total, 55 studies met inclusion criteria.
What was found
Resistance training significantly increased range of motion overall (effect size [ES] = 0.73; p < 0.001), but bodyweight-only resistance training showed no significant improvement. Flexibility gains did not differ between resistance training and stretch training (ES = 0.08; p = 0.79) or between combined resistance plus stretching versus stretch training alone (ES = -0.001; p = 0.99). Improvements were significantly greater in untrained and sedentary participants (ES = 1.042; p < 0.001) compared to trained or active individuals (ES = 0.43; p < 0.001; subgroup p = 0.005). No significant moderating effects were found for sex, contraction type, age, training duration, or weekly training frequency.
Why it matters
Resistance training with external loads matches the flexibility benefits of traditional stretch training, suggesting dedicated stretching may be unnecessary for improving range of motion when loaded resistance training is performed.
Limits
The abstract omits total participant numbers, confidence intervals, and measures of statistical heterogeneity. Non-randomized controlled trials were included alongside randomized trials, which may introduce bias. Results are limited to healthy cohorts and do not generalize to bodyweight-only resistance exercises.
Cited by
- supports Resistance training performed through a full range of motion provides flexibility benefits comparable to static stretching.