Spry Juncture, LLC
How to Evolve Gracefully
Biceps Femoris
Region
Origin & Insertion
['Origin: Long head – ischial tuberosity; Short head – linea aspera', 'Insertion: Head of fibula']
Synergistic Muscles
['Gluteus maximus', 'Semitendinosus']
Joints
['Hip (long head)', 'Knee']
Primary Actions
['Hip extension (long head)', 'Knee flexion', 'Lateral rotation of knee']
Nerve & Spinal Segment
Long head: Tibial portion of sciatic nerve; Short head: Common fibular nerve
Sacral plexus; L5–S2
Interesting
Only hamstring with dual innervation. [Gray's]
Reversal of Action
Raise pelvis during prone extension
Common Dysfunctions
Hamstring strain, knee instability, altered gait mechanics
How to Stretch
Forward fold with IR of leg.
Trigger Points
How to Strengthen
Hip extension and knee curl drills.
Concentric Action
Hip extension and knee flexion
Applications:
Hamstring strain prevention and power in sprinting
Eccentric Action
Control leg from swing during gait
Isotonic Action
Leg curls, bridges
Related Conditions
['Hamstring tear', 'Posterior chain weakness']
Isometric Action
Hold bridge or prone knee bend
Exercise Ideas
['Nordic curls', 'RDLs', 'Hamstring sliders']