Reference Values and Construct Validity for 4 Upper Limb Physical Performance Tests in Junior Tennis Players.

Abstract

Background: Upper extremity physical-performance-tests are gaining interest for screening overhead athletes in view of injury prevention, individual performance, and return to play after injury. However, at present, no reference data are available for these tests in a junior tennis population. In addition, the construct validity of these tests with respect to shoulder strength is still unclear.

Hypothesis: Junior tennis players will exhibit differences in test performance based on age, sex, and side. Shoulder strength will be moderately to highly correlated with the seated medicine ball throw (SMBT) and the modified-closed-kinetic-chain-upper-extremity test (M-CKCUEST), but not with shoulder endurance test (SET) and the Y-balance-test-upper-quadrant (YBT-UQ).

Study design: Descriptive study, cross-sectional design.

Level of evidence: Level 3.

Methods: Four commonly used physical performance tests (PPTs) (YBT-UQ, M-CKCUEST, SMBT, and SET) were executed by 99 junior tennis players aged 9 to 18 years. In addition, isometric external and internal rotation strength was measured, using a hand-held dynamometer. Descriptive reference values were reported, and correlations between the PPTs and strength values were calculated.

Results: A linear regression model with backwards stepwise regression was used to identify possible age, sex, and side differences regarding PPTs and strength. Some, but not all reached statistical significance. Moderate-to-high correlations (Pearson correlation coefficients) were found between the M-CKCUEST, SMBT, and SET and strength measurements, establishing acceptable construct validity with respect to strength. No significant correlation was found between the YBT-UQ and strength.

Conclusion: Junior tennis players exhibit differences in test performance based on age, sex, and side. The MCKCUEST, SMBT, and SET may be valuable alternatives for strength testing in the clinical setting.

Clinical relevance: These tests may provide a valuable, user-friendly alternative for strength measurements in junior tennis players.