Exploring Single-Leg Jump Testing as an Assessment of Functional Capacity in Achilles Tendinopathy: A Cross-Sectional...

Area of Science:

• Biomechanics
• Sports Medicine
• Musculoskeletal Health

Background:

• Achilles tendinopathy (AT) commonly affects runners, impacting lower limb function.
• Quantitative functional capacity measures are crucial for assessing AT.
• Single-leg jump testing offers a potential method to evaluate functional deficits.

Purpose of the Study:

• To investigate single-leg jump testing performance metrics (JPM) in Achilles tendinopathy (AT) participants versus healthy controls (CON).
• To analyze the onset of lower limb muscle activity using surface electromyography during jump tests in AT and CON groups.
• To compare limb symmetry index between AT and CON participants.

Main Methods:

• Twenty-four male runners (12 AT, 12 CON) performed vertical, reactive, and drop jumps on a force plate.
• Jump performance metrics (ground contact time, flight time, peak force, jump height, reactive strength index, net impulse) were analyzed.
• Surface electromyography measured the onset of seven lower limb muscles.

Main Results:

• No significant differences in overall JPM or limb-symmetry index were found between AT and CON groups.
• The AT group exhibited an earlier onset of the tibialis anterior muscle during reactive jumps (p=0.005).
• Descriptive analysis suggested increased variability in jump performance within the AT group.

Conclusions:

• Single-leg jump testing did not demonstrate generalized deficits in functional capacity or muscle activation timing in AT participants.
• An isolated finding of earlier tibialis anterior onset in AT during reactive jumps warrants further investigation.
• Increased performance variability in AT suggests heterogeneous compensatory strategies, necessitating individualized functional assessments.