Wrist Flexion Exercise Increases the Width of the Medial Elbow Joint Space During a Valgus Stress Test

Objectives The medial elbow is stabilized during valgus loading by the ulnar collateral ligament, the flexor pronator mass (FPM), and the radial head. Impairment of the FPM can occur as a result of repeated wrist flexion activity. The purpose of this study was to determine the effect of repeated elbow flexion exercise on medial elbow stability. Methods Thirty volunteers were included in this study. Ultrasound images of the medial joint space of the nondominant elbow of the participants were collected during a valgus stress test. The images were collected before and immediately after a wrist flexion exercise protocol. Results The wrist flexion strength measure decreased (7.5%) after the exercise protocol (t = 3.840; P = .001). The medial elbow width increased between unstressed (mean ± SD, 2.8 ± 0.1 mm) and stressed (3.6 ± 0.1 mm) conditions (P