Biomechanical upper-extremity performance tests and isokinetic shoulder strength in collision and contact athletes

ABSTRACT

The aim of this study was threefold (1) to assess the reliability of three upper-extremity performance tests: a countermovement push up, press jump and drop box land, performed on a set of dual-force plates (2) to examine whether there was an association between isokinetic dynamometry and the performance tests in a non-injured cohort of collision/contact athletes and (3) to establish a normal descriptive profile of the vertical ground reaction forces from the performance tests, in a cohort of contact/collision athletes. The study was split into two sub-sections; the inter-day reliability of three upper-extremity performance tests (n = 21) and a descriptive, correlation study investigating the relationship between isokinetic dynamometry and performance tests metrics (n = 39). We used intraclass correlation coefficients (absolute agreement, 2-way mixed-effects model) with 95% confidence intervals to quantify inter-day reliability of all variables. We used Pearson correlation coefficients to investigate associations between isokinetic strength and vertical ground reaction force asymmetry variables. Inter-day reliability was moderate-to-excellent for the upper-extremity performance tests (ICC 0.67–0.97). There was no statistically significant correlation between external and internal rotational peak torque and the variables of CPMU, PJ and BDL (r range = .02–.24).These upper-extremity tests are reliable for use with male contact/collision athletes.

KEYWORDS:

• Shoulder
• return to sport criteria
• upper-extremity performance tests
• isokinetic dynamometry
• contact athletes
• collision athletes

Practical implications

• The countermovement push up, press jump and drop box land tests performed on a set of dual-force plates offer a reliable way to identify modifiable (trainable) variables of strength that may help collision athletes prepare for return to sport.

• The tests poorly correlate with isokinetic dynamometry and therefore have the potential to add new insight into an athlete’s upper body function and readiness to return to sport.

• The tests should form part of a cluster of tests of shoulder function, including assessment of rotational strength, ROM and joint position sense, to ensure a multifaceted approach for return to sport screening following shoulder stabilization in contact and collision athletes.

Data availability request

The data that support the findings of this study are available from the corresponding author upon request

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.