Different visual stimuli affect muscle activation at the knee during sidestepping

Area of Science:

• Sports Medicine
• Biomechanics
• Kinesiology

Background:

• Anterior cruciate ligament (ACL) injuries are common in sports involving sidestepping.
• Appropriate knee muscle activation is crucial for maintaining knee stability and reducing ACL injury risk.
• Differences in muscle activation strategies may exist between high-level and low-level athletes in response to varying stimuli.

Purpose of the Study:

• To investigate how different visual stimuli (game-realistic vs. non-realistic) and expertise levels influence knee muscle activation during sidestepping.
• To determine if quasi game-realistic scenarios enhance anticipatory muscle activation for knee stability.
• To compare muscle activation patterns between high-level and low-level athletes under different sidestepping conditions.

Main Methods:

• Eleven high-level and 10 low-level soccer players performed sidestepping tasks under four conditions: arrow-planned (AP), one-defender scenario (1DS), two-defender scenario (2DS), and arrow-unplanned (AUNP).
• Electromyography measured the activation of eight knee muscles during pre-contact and weight-acceptance phases.
• Knee flexor-extensor co-activation ratios were calculated to assess muscle coordination strategies.

Main Results:

• Overall muscle activation increased by approximately 27% in the 1DS condition for both athlete groups.
• High-level athletes demonstrated an earlier shift from flexor to extensor dominance during weight-acceptance in the 2DS.
• Quasi game-realistic stimuli (1DS) promoted anticipatory muscle activation when time demands were low, irrespective of skill level.

Conclusions:

• Game-realistic visual cues can enhance anticipatory knee muscle activation, potentially reducing ACL injury risk.
• High-level athletes exhibit superior ability to interpret complex game-realistic information (2DS) for optimized muscle activation timing, particularly for single-leg landings.
• Training interventions should consider incorporating game-realistic scenarios to improve neuromuscular control and knee stability in athletes.