EMG Analysis of Lower Extremity Muscles in Three Different Squat Exercises.

Area of Science:

• Biomechanics
• Sports Medicine
• Exercise Physiology

Background:

• Anterior cruciate ligament (ACL) injuries are common in athletes.
• Previous research suggests altering the center of gravity may protect the ACL by reducing tibial translation.
• Identifying exercises that increase hamstring muscle activation is crucial for ACL injury prevention.

Observation:

• Electromyography (EMG) measured muscle activity (quadriceps, hamstring, soleus) during three squat variations in healthy female athletes.
• Subjects performed squats with modified body weight support and center of gravity.
• No significant differences in muscle activity patterns were observed across different squat tasks or knee flexion phases (0-90°).

Findings:

• Quadriceps (Vastus Medialis) activity was consistently higher than hamstring and soleus muscle activity across all tested squat variations.
• No significant differences in muscle activation were found between the three squat exercises.
• Muscle activity patterns remained similar across different phases of knee flexion.

Implications:

• The tested squat variations may not be optimal for increasing hamstring activation to enhance ACL protection.
• Further research is needed to identify exercises that effectively recruit hamstring muscles for ACL injury prevention.
• Quadriceps dominance observed in these exercises highlights potential imbalances that could influence knee joint stability.