A Battery of Jump Tests Helps Discriminating Between Subjects With and Without Chronic Ankle Instability

The purpose of this study was to assess whether a simple and reproducible battery of jump tests can distinguish between patients affected by chronic ankle instability (CAI) and control subjects. The hypothesis was that patients with CAI would demonstrate lower performance compared to healthy subjects during jumping tasks. Twenty-one young, active adults aged 18 to 45 years affected by CAI were matched for sex, age, and body mass index (BMI) to a control group of 21 healthy subjects without history of lower limb pathology. Jumping ability was instrumentally assessed by an infrared optical acquisition system using a test battery, including mono- and bipodalic vertical squat jumps, countermovement jumps (CMJs), a drop jump (DJ), and a side-hop test. Patients with CAI had significantly worse monopodalic CMJ, DJ, and side-hop test scores in their involved limb compared to the non-dominant limb of healthy individuals. Pathological limbs of CAI patients reported inferior results compared to non-dominant limbs of healthy individuals while performing monopodalic CMJs, DJs, and side-hop tests (p < 0.05). No statistically significant differences were found between the two groups in the limb symmetry index (LSI) while performing monopodalic CMJs and DJs (p = 0.072 and p = 0.071, respectively), while a difference was found between the two groups, in favor of healthy subjects, while performing monopodalic side-hop tests (p < 0.01). A reproducible battery of jump tests performed with a simple and low-cost instrument can be applied in the clinical setting allowing for reliable measurements of functional ability of subjects with CAI. Our findings support the idea that side-hop tests could be more accurate than vertical jump tests for detecting functional deficits in patients suffering from CAI.