Abstract
BACKGROUND: Baseball players and coaches may not have the personnel resources to monitor the pathological declines in shoulder function throughout the season. The ArmCare Strength and Range of Motion Sensor and Mobile Application (ArmCare testing system) was designed to allow players to test and monitor their shoulder range of motion (ROM) and strength. PURPOSE: To establish the reliability and concurrent validity of the ArmCare testing system for measuring ROM and strength in high school and college baseball players. STUDY DESIGN: Cross-sectional. METHODS: Fifty-one baseball players self-tested their shoulder ROM and strength using the ArmCare testing system protocols and instructional video guidance. Participants repeated the testing following a 30-minute washout period and were blinded to their results. Intra-rater reliability measures were established by comparing ArmCare testing system scores between two same-day trials. Concurrent validity was assessed by comparing ArmCare testing system ROM and strength measures with standardized goniometric ROM and hand-held dynamometry measures performed by clinicians who were blinded to the results. Intraclass correlation coefficients (ICC) were used to assess the intra-rater reliability of the ArmCare self-testing system and Pearson correlation coefficients evaluated the concurrent validity among goniometric ROM and strength dynamometry. RESULTS: Intra-rater reliability ranged from poor to moderate (0.19 to 0.67) for AROM and moderate to good (0.73 to 0.87) for strength measures. For validity, poor overall agreement (ICC = 0.17 to 0.37) and correlation (r = 0.23 to 0.47) was found between the ArmCare testing system and all shoulder AROM measures. The ArmCare testing system demonstrated moderate to good agreement (ICC = 0.72 to 0.79) and correlation (r range = 0.72 to 0.81) compared to dynamometry for all strength measures. CONCLUSION: The ArmCare testing system may be a reasonable self-guided examination for high school and college baseball players to measure shoulder strength. However, ROM testing using the ArmCare testing system lacks consistency and accuracy warranting further investigation. LEVEL OF EVIDENCE: Level 3.