Effects of isometric vs. dynamic resistance training on isometric and isokinetic muscular strength: a systematic review with meta-analysis

Backgrounds: Both isometric resistance training (ISO-RT) and dynamic resistance training (DYN-RT) are commonly used interventions to improve muscular strength. Unlike DYN-RT, which involves producing force through a joint range of motion, ISO-RT generates force without joint movement. However, their relative effectiveness for improving strength remains unclear, making it essential to clarify these differences to better guide exercise prescription across diverse populations and training goals. Objectives: This systematic review and a meta-analysis investigated the effects of ISO-RT versus a non-exercise control (CTRL) or DYN-RT on isometric and isokinetic muscular strength in healthy adults. Methods: Four databases (PubMed/MEDLINE, SPORTDiscus, Embase, and Scopus) were searched up to May 2025. Randomised and non-randomised controlled trials, including adults (18–45 years), were eligible for inclusion. Random-effects meta-analyses were conducted, with outcomes reported as standardised mean differences (SMD) and 95 % confidence intervals (CIs). Results: A total of 32 studies involving 621 participants were included. ISO-RT significantly improved combined isometric and isokinetic strength compared to CTRL (SMD = 0.65; 95 % CI: 0.52–0.77; p < 0.0001) and DYN-RT (SMD = 0.35; 95 % CI: 0.21–0.48; p < 0.0001). Subgroup analyses revealed greater isometric strength gains with ISO-RT compared to DYN-RT (SMD = 0.43; p < 0.0001), whilst no statistically significant difference was observed for isokinetic strength between these RT modalities (SMD = − 0.20; p = 0.24). Conclusions: Overall, our findings indicate that ISO-RT resulted in greater isometric strength gains compared to DYN-RT and CTRL, whilst isokinetic strength gains were similar between these RT modalities. These findings indicate that ISO-RT may be an effective modality for enhancing muscular strength and could be considered a viable alternative or complement to DYN-RT.