What Do Upper-Extremity Physical Performance Tests Measure? Insights From a Descriptive Electromyographical Study

Physical performance tests (PPTs) require athletes to complete a physical activity essential to their sports performance. Evaluating associated electromyographical requirements enables clinicians to select appropriate tests for their athletes' specific needs.

Shoulder muscle activity differs between tests.

Descriptive laboratory study.

Level 4.

Thirty asymptomatic overhead athletes (17 women, 13 men; mean age, 20.3 ± 1.7 years) performed 4 upper-extremity PPTs: Y-balance test-upper quarter (YBT-UQ), closed kinetic chain upper extremity stability test (CKCUEST), upper limb rotation test (ULRT), and shoulder endurance test (SET). Surface electromyography, expressed as a percentage of the maximal isometric voluntary contraction, was used to measure muscle activity in upper, middle, and lower trapezius, serratus anterior, infraspinatus, and posterior deltoid on both sides. Only the supporting arm (ie, in closed chain) was considered for analysis.

During the YBT-UQ, serratus anterior and infraspinatus activity was highest during all reach directions. Serratus anterior showed the highest activity when supporting the medial and inferolateral reach (range, 72.7-95%). The infraspinatus was most active when supporting the superolateral reach (range, 92-129.2%). During the CKCUEST, all muscles were moderate to highly active, with the serratus anterior (range, 77.5-78.8%) and infraspinatus (range, 64.1-64.7%) being most active. All muscles demonstrated moderate-to-high activity during the ULRT, with the highest activity in posterior deltoid, infraspinatus, and serratus anterior. For the SET, muscle activity progressively increased with increasing speed.

Serratus anterior and infraspinatus activity was high across all tests, with the greatest activity during the YBT-UQ and CKCUEST. The ULRT elicited the highest posterior deltoid activity.

Our findings offer clinicians specific electromyographical insights, facilitating appropriate test selection for screening and return to sport.