Neuromuscular Control Mechanisms During Single-Leg Jump Landing in Subacute Ankle SprainPatients: A Case Control Study

Background
Optimal neuromuscular control mechanisms are essential for preparing, maintaining, and restoring functional joint stability during jump landing and to prevent ankle injuries. In subacute ankle sprain patients, neither muscle activity nor kinematics during jump landing has previously been assessed.

Objective
To compare neuromuscular control mechanisms and kinematics between subacute ankle sprain patients and healthy persons before and during the initial contact phase of a 25‐cm single‐leg jump.

Design
Case‐control study.

Setting
University hospital.

Patients
Fifteen patients with grade I or II acute ankle sprains were followed up after 4 weeks of conservative management not involving physical therapy.

Methods
Subjects performed alternately 3 single‐leg forward jumps of 25 cm (toe‐to‐heel distance) barefoot. Their results were compared with the data of 15 healthy subjects.

Main Outcome Measurements
Electromyographic (EMG) activity of the musculus (m.) gastrocnemius lateralis, m. tibialis anterior, and m. peroneus longus as well as kinematics for ankle, knee, and hip joint were recorded for pre–initial contact (IC) phase, post–initial contact phase, and reflex‐induced phase.

Results
The results showed that EMG activity of the 3 muscles did not differ between ankle sprain patients (n = 15) and healthy persons (n = 15) for any of the analyzed time intervals (all P > .05). However, during the pre‐IC phase, ankle sprain patients presented less plantar flexion, as well as during the post‐IC phase after jump landing, compared to healthy persons (P < .05).

Conclusion
Taken together, these kinematic alterations of the ankle joint can lead to neuromuscular control mechanism disturbances through which functional instability might arise.

Level of Evidence
III.