Predicting the Clean Movement Technique in Crossfit (R) Athletes Using an Optimal Upper-Limb Range of Motion: A Prospective Cohort Study

Background: The aim of this study was to determine the optimal upper-limb range of motion (ROM) profile for the catch phase of the clean movement (CPCM) and to identify the key ROMs for performing the CPCM in CrossFit (R) athletes. Methods: A prospective cohort study of twenty CrossFit (R) athletes aged 20-36 years was conducted. Data were collected regarding age, anthropometrics, CrossFit (R) training experience and upper-limb ROM. The ROM was measured using the ROM-SPORT method. After 7 months, athletes performed a clean movement with a load of 80% one repetition maximum. A Bayesian Student's t-analysis, binary logistic regression analysis and Receiver Operating Characteristic analysis were performed. Results: The optimal upper-limb ROM profile that predicted correct CPCM performance was 78 degrees in shoulder extension, 173 degrees in shoulder flexion, 107 degrees in shoulder external rotation, 89 degrees in shoulder internal rotation, 153 degrees in elbow flexion, 99 degrees in elbow pronation and 92 degrees in wrist extension (area under the curve >= 651; positive predictive value >= 80%). Shoulder external rotation, elbow pronation and wrist extension were found to be the most important ROMs for the efficient and safe performance of CPCM (area under the curve >= 854; positive predictive value >= 85.7%). Conclusion: The upper-limb ROM profile is associated with proper clean performance. Further studies are warranted to determine whether improving flexibility on upper-limb ROM may improve proper clean movement performance.