Axial muscle activation provides stabilization against perturbations while running.

Area of Science:

• Biomechanics
• Neuroscience
• Sports Medicine

Background:

• Traumatic brain injuries are a significant risk in sports due to unexpected impacts.
• Lack of muscular activation during sudden impacts may increase injury severity.
• Protective bracing through muscle activation is crucial for mitigating impact forces.

Purpose of the Study:

• To investigate the effect of warnings on axial muscle activation and body's response to perturbations.
• To determine if anticipatory muscle bracing reduces head displacement and acceleration.
• To examine the influence of perturbation timing (stance vs. flight phase) on muscle response.

Main Methods:

• Participants ran on a treadmill while experiencing fore-aft and lateral waist perturbations.
• Audio-visual warnings were provided in half of the trials (warned) and omitted in the other half (unwarned).
• Axial muscle activity (cervical, abdominal) and head kinematics were monitored during perturbations at stance and flight phases.

Main Results:

• Warned trials showed significantly less body displacement and head linear acceleration compared to unwarned trials.
• Perturbations increased axial muscle activity, with cervical and abdominal muscles showing heightened responses.
• Warnings led to reduced reflexive muscle activity, and warnings were more effective during the flight phase.

Conclusions:

• Anticipatory activation of axial muscles in response to warnings provides protective bracing.
• This neuromuscular strategy effectively reduces head injury risk from unexpected impacts in sports.
• Understanding warning effects on muscle activation can inform injury prevention strategies.