Acute effects of inspiratory muscle warm-up on exercise performance in competitive athletes: a systematic review and meta-analysis

The purpose of this systematic review and meta-analysis was to quantify the acute effect of inspiratory muscle warm-up (IMW) on sport-specific exercise performance in able-bodied competitive athletes and explore potential moderating effects of sport type and control condition. Para-athlete studies were not included in the eligible evidence base. We systematically searched Web of Science, PubMed, Ovid Embase, and Scopus for randomized trials comparing acute IMW with sham or standard warm-up in competitive athletes. Google Scholar was also searched to identify grey literature. A random-effects meta-analysis (Hedges’ g) was performed on performance outcomes, with a significance threshold of P < = 0.05. Eleven crossover trials (139 able-bodied athletes) were meta-analyzed. IMW produced a small beneficial effect on acute exercise performance (g = 0.285, 95% CI: 0.124 to 0.446). Sensitivity analyses assuming r = 0.3 and r = 0.7 yielded consistent results. The effect was larger for non-endurance or intermittent sports (g = 0.418, k = 6) than for endurance sports (g = 0.142, k = 5), but this subgroup contrast was treated as exploratory because the intermittent/non-endurance estimate was attenuated after excluding Lin et al. (2007) (g = 0.351, 95% CI: 0.152 to 0.551, P = 0.008, k = 5). IMW showed a small statistically significant pooled effect on acute exercise performance. However, the low certainty of evidence, limited sample base, influence of Lin et al. (2007) on the pooled estimate, and 10 of 11 individual estimates with 95% confidence intervals crossing the null mean that its practical value remains uncertain. Larger, rigorously designed trials using standardized loading protocols are needed. PROSPERO CRD420261405783.