Abstract: Objective: To explore the influence of different ankle stability on the landing posture stability strategy and neuromuscular control of vertical jump during the intervention of visual cognitive task. Methods: 36 male college high-level athletes were selected as subjects, with an average age of (20.23±2.05) yrs., an average height of (179.28±4.61) cm and an average weight of (72.62±4.59) kg. According to the degree of ankle instability, they were divided 12 subjects into CON group, 12 subjects into LAT group and 12 subjects into CAI group. All subjects performed the drop-vertical jump+visual task in a random order. The kinematics, dynamics and EMG parameters of each group in landing stage were compared by one-way ANOVA and Scheffe method. Results:(1) the movement range of APSI (CAI & LAT>CON), VSI and DPSI (CON>CAI) of COM were significant; (2) at the initial landing phase, the angles of ankle(CAI>CON), knee valgus (CON>LAT & CAI), hip flexion(CON & LAT>CAI) and abduction (CAI>CON) were significant, while the angle of ankle plantarflexion (CON & LAT>CAI) was significant at the lowest point of squat, and the range of motion of ankle flexion(CON & LAT>CAI), extension, valgus (CAI>CON & LAT) and the peak value of ankle valgus angle velocity (CAI>CON) were significant; (3) the landing load rate (CON>CAI) was significant at 50 ms; (4) in pre-landing phase, TA (CAI>LAT & CON), PL (CON>CAI) and MG (CAI>CON) were significant; there were significant differences in RF(LAT>CON & CAI), PL (CON>LAT & CAI), MG (CAI>CON) at the initial landing; in descending phase, GM (CON>CAI), PL (CON>LAT & CAI), MG (CAI>CON) were significant, while the rate of BF / RF (CON>LAT & CAI), S / TA (CAI>LAT & CON), MG / TA (CAI & LAT>CON) co-contraction were significant; in propulsion phase, GM (CON>CAI), VM (CON>CAI), BF (CON>LAT & CAI) , S (CON>CAI) were significant, while the rate of TA / S (CON>CAI) co-contraction were significant; in stability phase, VM (CON>LAT & CAI), S (CON>CAI) were significant. Conclusion: Hip flexion and abduction, more ankle valgus and muscle co contraction are important mechanisms to stabilize the joints of CAI athletes, and the earlier and faster ankle valgus speed is the key factor of repeated sprains of CAI athletes; the ability of hip abduction can be improved by strengthening the gluteus medius muscle, and the peroneal longus muscle can be trained to improve ankle protection.

Key words: ankle sprain, neuromuscular control, visual task interference, landing and buffering, posture stability, vertical jump.