Muscular fitness thresholds for predicting high-quality CPR: A crossover study of two compression strategies

Specific muscular fitness indicators and their predictive thresholds for high-quality CPR have not been well established. Therefore, a randomized crossover study was designed to investigate the relationship between muscular fitness and CPR performance under continuous chest compressions and 30:2 strategies, and to identify fitness-based thresholds for predicting effective chest compressions.

Fifty-seven participants certified to perform CPR completed three muscular fitness assessments: handgrip strength, push-up, and curl-up tests. Participants performed 6 min of CPR using both continuous chest compressions and 30:2 protocols. Compression depth, force, and rate were recorded using a pressure mat and skill-reporting system. Correlation and receiver operating characteristic (ROC) analyses were conducted to determine associations between muscular fitness and CPR quality and to identify the predictive threshold of effective performance.

Among all muscular fitness indicators, handgrip strength showed the strongest correlation with both compression force (r = 0.59-0.68) and depth (r = 0.77-0.81) across all time intervals and CPR strategies. ROC analysis identified handgrip strength thresholds of 82.5 kg for high-quality CPR during the first 2 min, and 93.85 kg for sustained performance over 6 min (AUC = 0.85-0.94, p < 0.001). The 30:2 CPR consistently produced higher compression force and depth compared to continuous chest compressions, with increasing differences over time.

Handgrip strength is a robust predictor of high-quality CPR performance. The identified thresholds may inform evidence-based training, provider rotation strategies, and screening for CPR readiness, particularly in individuals at risk of fatigue-related performance decline.