Neck strength imbalance correlates with increased head acceleration in soccer heading

Area of Science:

• Sports Medicine
• Neurology
• Biomechanics

Background:

• Soccer heading involves direct head-ball contact, crucial for gameplay but raises concerns about potential neurologic deficits.
• Repetitive head impacts and accelerations during heading are linked to cumulative subclinical brain injury.
• Understanding the role of neck muscles in stabilizing the head is vital for injury prevention.

Purpose of the Study:

• To investigate the correlation between neck strength imbalance and head acceleration during soccer heading.
• To determine if neck muscle symmetry influences head impact forces in collegiate soccer players.

Main Methods:

• An observational laboratory study involving 16 collegiate soccer players.
• Motion capture technology (14-camera Vicon MX system) recorded player movements during heading.
• Neck flexor and extensor strength were measured using a clinical dynamometer.

Main Results:

• A positive correlation was found between the mean neck strength difference and angular head acceleration (P = 0.05).
• A trend towards significance was observed for linear head acceleration (P = 0.057).
• Ball velocity during heading averaged 5.48 m/s.

Conclusions:

• Symmetrical neck flexor and extensor strength appears to reduce head acceleration in collegiate soccer players during low-velocity heading.
• Balanced neck strength may mitigate cumulative subclinical brain injury.
• Neck strength is a measurable and trainable factor, representing a modifiable intrinsic risk for heading-related injuries.