Paraspinal Muscle Stiffness during Hamstring Exercise Using Shear-Wave Elastography.

Area of Science:

• Biomechanics
• Sports Medicine
• Exercise Physiology

Background:

• Soccer players use specific exercises for injury prevention.
• Understanding muscle stiffness is crucial for optimizing training and rehabilitation.
• Hamstring and paraspinal muscles play key roles in lower limb and spinal stability.

Purpose of the Study:

• To investigate the effects of hamstring exercises on paraspinal and hamstring muscle stiffness.
• To analyze changes in muscle stiffness across different knee flexion angles (0°, 45°, 90°).
• To explore the relationship between paraspinal and hamstring muscle stiffness during active and passive movements.

Main Methods:

• Utilized shear-wave elastography (SWE) and surface electromyography (sEMG).
• Measured elastic modulus and root mean square (RMS) signal in erector spinae (ES), multifidus (MF), semitendinosus (ST), and semimembranosus (SM) muscles.
• Fifteen healthy males performed passive and active knee flexion at varying angles.

Main Results:

• Passive muscle stiffness was greater at 0° knee flexion compared to 45° and 90°.
• Active contractions increased muscle stiffness, with paraspinal stiffness moderately to strongly correlated with hamstring stiffness.
• Electromyography signals indicated differences in muscle activation across conditions and angles.

Conclusions:

• Hamstring exercises can affect paraspinal muscle stiffness, indicating potential force transmission via myofascial connections.
• Findings suggest a link between lumbar spine and lower limb musculature.
• Results can inform targeted training and rehabilitation programs for improved muscle health and injury prevention in athletes.