# Resistance Training Induces Improvements in Range of Motion: A Systematic Review and Meta-Analysis

## TL;DR

This study finds that resistance training can improve joint flexibility as effectively as stretching, especially when using external weights.

## Contribution

The first comprehensive meta-analysis on resistance training's effect on range of motion, including moderating variables.

## Key findings

- Resistance training with external loads significantly increases range of motion (ES = 0.73).
- Stretching before or after resistance training does not provide additional flexibility benefits.
- Untrained individuals show greater range of motion improvements compared to trained individuals.

## Abstract

Although it is known that resistance training can be as effective as stretch training to increase joint range of motion, to date no comprehensive meta-analysis has investigated the effects of resistance training on range of motion with all its potential affecting variables.

The objective of this systematic review with meta-analysis was to evaluate the effect of chronic resistance training on range of motion compared either to a control condition or stretch training or to a combination of resistance training and stretch training to stretch training, while assessing moderating variables.

For the main analysis, a random-effect meta-analysis was used and for the subgroup analysis a mixed-effect model was implemented. Whilst subgroup analyses included sex and participants’ activity levels, meta-regression included age, frequency, and duration of resistance training.

Following the systematic search in four databases (PubMed, Scopus, SPORTDiscus, and Web of Science) and reference lists, 55 studies were found to be eligible.

Controlled or randomized controlled trials that separately compared the training effects of resistance training exercises with either a control group, stretching group, or combined stretch and resistance training group on range of motion in healthy participants.

Resistance training increased range of motion (effect size [ES] = 0.73; p < 0.001) with the exception of no significant range of motion improvement with resistance training using only body mass. There were no significant differences between resistance training versus stretch training (ES = 0.08; p = 0.79) or between resistance training and stretch training versus stretch training alone (ES = − 0.001; p = 0.99). Although “trained or active people” increased range of motion (ES = 0.43; p < 0.001) “untrained and sedentary” individuals had significantly (p = 0.005) higher magnitude range of motion changes (ES = 1.042; p < 0.001). There were no detected differences between sex and contraction type. Meta-regression showed no effect of age, training duration, or frequency.

As resistance training with external loads can improve range of motion, stretching prior to or after resistance training may not be necessary to enhance flexibility.

The online version contains supplementary material available at 10.1007/s40279-022-01804-x.