Objective To evaluate the acute intervention and training intervention effects of variable resistance training on maximal strength and power, and to provide strong evidence for the scientific application of performing variable resistance training.

Methods A literature search was conducted by using the PubMed, Web of Science, SPORTDiscus and CNKI electronic databases. A modified version of quality scoring system by Brughelli was used to assess each study. The data combining, subgroup analyses, forest plot, heterogeneity, meta-regression, publication bias were used and assessed with Stata 16.0 version.

Results 8 studies were included on acute intervention. Compared to constant resistance training, variable resistance training significantly induced larger PAP (SMD=0.37, 95%CI: 0.18-0.56, P<0.001). PAP in 4-7 min recovery intervals tended to be significant (P=0.05), PAP in 8-12 min recovery intervals was significantly larger (P<0.001). The larger contribution of variable resistance could be more beneficial in inducing PAP (P=0.064). 12 studies were included on training intervention. Compared to constant resistance training, variable resistance training significantly improved maximal strength (SMD=0.25, 95%CI: 0.05-0.45, P<0.05); the intervention duration <7 weeks (P=0.04) and using chains as the variable resistance equipment (P=0.01) had a significantly larger effect on maximal strength. Variable resistance training could be more beneficial in improving power performance (SMD=0.26, 95% CI: −0.03-0.55, P=0.08), and the same relative load scheme and elastic band as the variable resistance equipment could be even better (P=0.08).

Conclusions When manipulating variable resistance training, the same load and larger contribution of variable resistance was an optimal strategy to induce PAP, and the 4-12 min recovery interval was a better choice. Utilizing shorter than 7-week intervention and chains as the variable resistance equipment was an ideal strategy in improving maximal strength performance. Using the same load scheme and elastic band may be an ideal strategy in improving power performance, but the contribution of variable resistance should not be too large.