Hamstring muscle kinematics and activation during overground sprinting.

Area of Science:

• Sports Medicine
• Biomechanics
• Exercise Physiology

Background:

• Hamstring muscle strain injuries are prevalent in sports like soccer, rugby, and track and field.
• These injuries often occur during high-speed running activities, particularly sprinting.
• The exact mechanisms leading to hamstring injuries during sprinting are not fully understood.

Purpose of the Study:

• To investigate the mechanisms of hamstring muscle strain injuries during overground sprinting.
• To analyze hamstring muscle-tendon kinematics and muscle activation during sprinting.
• To identify critical phases within the sprinting gait cycle associated with injury risk.

Main Methods:

• Collected 3D videographic and electromyographic (EMG) data from 20 male athletes during maximal overground sprinting.
• Analyzed hamstring muscle-tendon lengths, elongation velocities, and EMG data throughout the running gait cycle.
• Focused analysis on the dominant leg during a complete gait cycle.

Main Results:

• Hamstring muscles demonstrated eccentric contractions in both the late stance and late swing phases of sprinting.
• Peak eccentric contraction speeds were significantly higher in the late swing phase compared to the late stance phase.
• Maximum hamstring muscle-tendon lengths did not significantly differ between the late stance and late swing phases.

Conclusions:

• Hamstring muscle strain injury risk is present during both the late stance and late swing phases of overground sprinting.
• The late swing phase exhibits higher eccentric contraction speeds, potentially increasing injury risk.
• Further research into muscle-tendon behavior during these critical phases can inform injury prevention strategies.