Background <p>Sarcopenia is a progressive, age-related skeletal muscle disorder characterized by a gradual loss of muscle mass, strength, and physical function, which is highly prevalent among older adults. This study aimed to investigate the association between compliance with American College of Sports Medicine (ACSM) exercise guidelines and intervention outcomes in patients with sarcopenia.</p> Methods <p>Four electronic databases were systematically searched from inception to May 2025. Exercise interventions were evaluated for compliance with ACSM recommendations and categorized into high or low ACSM protocol compliance groups. A random-effects model was used to calculate standardized mean differences (SMD) and 95% confidence intervals (CI).</p> Results <p>Twenty-nine randomized controlled trials, comprising 1,524 patients with sarcopenia, were included. Exercise with high ACSM protocol compliance significantly improved the appendicular skeletal muscle mass index (SMD = 0.49; 95% CI 0.23, 0.76). Significant positive effects were observed for maximal voluntary contraction and the five-times sit-to-stand test performance; however, these findings remain inconclusive due to high subgroup heterogeneity and limited evidence. Grip strength demonstrated a larger effect size in the high ACSM protocol compliance group (SMD = 0.64; 95% CI 0.34, 0.94), but this was statistically significant only at the 70% threshold (<i>p</i> = 0.03), losing significance at the 75% (<i>p</i> = 0.19) and 80% (<i>p</i> = 0.24) thresholds, indicating substantial instability in the results. Subgroup differences for gait speed (<i>p</i> = 0.15) and the timed up-and-go test (<i>p</i> = 0.08) were not statistically significant. Exercise had no significant effect on body mass index or body fat percentage, and high ACSM protocol compliance was not associated with increased adverse events or dropout rates.</p> Conclusions <p>Exercise interventions with high ACSM protocol compliance significantly improved muscle mass in patients with sarcopenia. Although improvements were observed in grip strength, the five-times sit-to-stand test performance, and maximal voluntary contraction, inconsistent sensitivity analyses and high heterogeneity preclude definitive conclusions. For other outcomes, interventions with high ACSM compliance demonstrated no superior efficacy compared with other exercise protocols.</p> Trial registration <p>This systematic review was registered with PROSPERO (CRD420251104971).</p>