Knee Flexor Eccentric Strength, Hamstring Muscle Volume and Sprinting in Elite Professional Soccer Players with a...

Area of Science:

• Sports Medicine
• Biomechanics
• Exercise Physiology

Background:

• Hamstring strain injuries (HSIs) are common in professional soccer.
• Understanding the long-term effects of HSIs on muscle strength, volume, and performance is crucial for effective prevention and rehabilitation.

Purpose of the Study:

• To investigate bilateral differences in knee flexor eccentric strength and hamstring muscle volume in professional soccer players with a history of HSI.
• To compare sprinting performance between players with and without a history of HSI.

Main Methods:

• Forty-six male professional soccer players were assessed at the start of preseason.
• Measurements included eccentric knee flexor strength, hamstring muscle volume via MRI, and 20-m sprint tests with 5-m and 10-m split times.

Main Results:

• Players with prior HSIs demonstrated greater eccentric knee flexor strength in previously injured limbs compared to uninjured players' limbs.
• Previously injured limbs showed potentially larger biceps femoris short head (BFSh) and semitendinosus (ST) muscle volumes.
• Players with a history of HSI were possibly slower in 5-m sprints, with unclear differences in 10-m and 20-m sprint times.

Conclusions:

• Professional soccer players with a prior HSI exhibit enhanced eccentric knee flexor strength and possibly hypertrophied hamstring muscles (ST and BFSh).
• These players may have reduced sprinting performance over short distances (5m).
• Findings suggest implications for designing secondary hamstring injury prevention strategies.