Effects of isometric vs. dynamic resistance training on muscle performance and body composition: Protocol for a pilot...

Isometric resistance training (ISO-RT) has gained renewed attention for its potential to elicit muscular adaptations and enhance athletic performance. Unlike dynamic resistance training (DYN-RT), ISO-RT involves no joint movement or eccentric loading, making it particularly suitable for individuals with joint pathologies or those undergoing rehabilitation. Despite increasing interest, the comparative effectiveness of ISO-RT versus DYN-RT across various outcomes, including strength, hypertrophy, endurance, and recovery, remains inadequately explored.

This study aims to evaluate and compare the effects of multi-angle ISO-RT and traditional DYN-RT on muscle performance, body composition, and recovery-related indicators in healthy adults.

In this pilot randomised controlled trial, 20 healthy adults (≥18 years) will be randomly assigned to either the ISO-RT or DYN-RT group (n ​= ​10 per group). Both groups will complete a full-body resistance training program twice weekly for six weeks. The key distinction lies in the execution of the chest press and leg press exercises-performed isometrically in the ISO-RT group and dynamically in the DYN-RT group. All outcomes will be assessed at baseline and post-intervention.

Primary outcomes include dynamic and isometric strength. Secondary outcomes encompass muscular power, dynamic and isometric endurance, body composition (via dual-energy X-ray absorptiometry), muscle oxygenation (via near-infrared spectroscopy), and subjective recovery indicators such as sleep quality and delayed onset muscle soreness. Between-group comparisons will be conducted using appropriate inferential statistical tests to determine effect estimates and feasibility metrics.

This trial will offer preliminary insights into the physiological and perceptual adaptations elicited by ISO-RT versus DYN-RT. The findings will inform the design of larger-scale trials and contribute to developing tailored, evidence-based resistance training guidelines for both clinical and athletic populations.