A functional MRI Exploration of Hamstring Activation During the Supine Bridge Exercise

Area of Science:

• Sports Medicine
• Biomechanics
• Exercise Physiology

Background:

• The single leg supine bridge (SLB) is a common exercise for hamstring strengthening and a clinical test for hamstring function.
• Limited research exists on the specific muscle activation patterns during the SLB exercise.

Purpose of the Study:

• To investigate the muscle activation patterns of the hamstring muscles during the single leg supine bridge (SLB) exercise.
• To determine which hamstring muscles are most activated and selectively targeted during the SLB.

Main Methods:

• Nine healthy males performed 5 sets of 10 repetitions of the SLB exercise.
• Functional magnetic resonance imaging (fMRI) was used to assess changes in transverse (T2) relaxation times in hamstring muscles (biceps femoris long and short heads, semitendinosus, semimembranosus) before and after exercise.
• T2 relaxation time changes served as an index of muscle activation.

Main Results:

• The semitendinosus showed significantly greater T2 increases compared to the biceps femoris short head and semimembranosus.
• The biceps femoris long head demonstrated a greater percentage change in T2 compared to its short head.
• The semitendinosus was the most selectively targeted hamstring muscle, and the biceps femoris long head was preferentially activated over its short head.

Conclusions:

• The SLB exercise effectively targets the semitendinosus and preferentially activates the long head of the biceps femoris.
• These findings suggest the SLB exercise can be a valuable tool in hamstring injury prevention and rehabilitation programs.