Biceps Femoris Exercises: Strengthen Your Outer Hamstring

The biceps femoris is the hamstring muscle on the outside of your thigh. With two distinct heads, it plays crucial roles in knee flexion, hip extension, and—uniquely—external rotation of the lower leg. Understanding this muscle can help you address hamstring imbalances, prevent injuries, and improve athletic performance.

Understanding the Biceps Femoris

Location: Back and outer side of the thigh

Two Heads:

• Long head: Originates from the ischial tuberosity (sit bone)—crosses both hip and knee
• Short head: Originates from the back of the femur—crosses only the knee

Insertion: Head of the fibula (outer lower leg bone)

Key Feature: The only hamstring that inserts on the lateral (outer) side of the knee

Functions of the Biceps Femoris

Long Head:

• Hip extension (pushing leg backward)
• Knee flexion (bending the knee)
• External rotation of the hip

Short Head:

• Knee flexion only
• External rotation of the lower leg when knee is bent

Both Heads Together:

• Decelerate the leg during running
• Stabilize the knee, especially during rotation
• Control forward momentum

Why the Biceps Femoris Matters

Injury Prevention

• Most commonly strained hamstring muscle
• Critical for sprinting and high-speed running
• Weakness increases ACL injury risk

Knee Stability

• Protects the lateral knee
• Works with ACL to prevent anterior tibial translation
• Important for rotational control

Athletic Performance

• Powerful hip extensor for sprinting
• Essential for jumping and change of direction
• Key muscle for posterior chain strength

Common Biceps Femoris Problems

Biceps Femoris Strain

• Most common hamstring injury, especially in sprinters
• Often occurs during high-speed running
• Pain at back of thigh, usually upper portion
• May feel pop during injury

Biceps Femoris Tendinopathy

• Pain at outer knee where tendon inserts
• Common in runners and cyclists
• Gradual onset, worse with activity
• Tender to touch at fibular head

Proximal Hamstring Tendinopathy

• Pain at sit bone
• Common in runners and those who sit a lot
• Long head involved along with other hamstrings

Exercises for the Biceps Femoris

General Hamstring Exercises

Romanian Deadlift

1. Stand holding weight with slight knee bend
2. Hinge at hips, pushing hips back
3. Lower weight along legs until hamstrings stretch
4. Drive hips forward to stand
5. Perform 3 sets of 10-12 repetitions

Nordic Hamstring Curl

1. Kneel with ankles secured under sturdy object
2. Slowly lower body forward with control
3. Catch yourself with hands and push back up
4. Perform 3 sets of 5-8 repetitions Excellent for injury prevention

Glute-Ham Raise

1. Position in GHD machine
2. Lower torso toward floor
3. Curl back up using hamstrings
4. Perform 3 sets of 8-10 repetitions

Biceps Femoris-Focused Exercises

Lying Leg Curl with Feet Turned Out

1. Lie face down in leg curl machine
2. Turn feet slightly outward (external rotation)
3. Curl weight toward buttocks
4. Lower with control
5. Perform 3 sets of 12 repetitions External rotation emphasizes biceps femoris

Swiss Ball Leg Curl (Feet Out)

1. Lie on back with heels on Swiss ball
2. Turn feet outward 30-45 degrees
3. Lift hips and curl ball toward buttocks
4. Extend legs and repeat
5. Perform 3 sets of 12 repetitions

Single-Leg Romanian Deadlift

1. Stand on one leg
2. Hinge forward while extending other leg behind
3. Keep slight knee bend in standing leg
4. Return to standing
5. Perform 3 sets of 10 repetitions each leg Single-leg work challenges lateral stability

Slider Leg Curl (Single-Leg)

1. Lie on back with one heel on slider
2. Lift hips into bridge position
3. Curl slider toward buttocks
4. Extend and repeat
5. Perform 3 sets of 10 repetitions each leg

Eccentric Emphasis (Injury Prevention)

Eccentric Nordic Curl

1. Focus only on the lowering phase
2. Take 4-5 seconds to lower
3. Use hands to help return to start
4. Perform 3 sets of 5-6 repetitions

Eccentric Single-Leg Romanian Deadlift

1. Lower slowly (4 seconds) into position
2. Return to standing at normal speed
3. Perform 3 sets of 8 repetitions each leg

Eccentric Leg Curl

1. Curl weight up with both legs
2. Lower with one leg only (4-5 seconds)
3. Perform 3 sets of 8 repetitions each leg

Stretching the Biceps Femoris

Because the biceps femoris is on the lateral side and externally rotates, you can target it specifically:

Seated Hamstring Stretch (Internal Rotation)

1. Sit with one leg extended
2. Turn toes slightly inward (internal rotation)
3. Reach toward toes, keeping back straight
4. Feel stretch on outer hamstring
5. Hold 30-45 seconds each side

Standing Hamstring Stretch with Rotation

1. Place heel on elevated surface
2. Turn toes inward
3. Lean forward from hips
4. Feel stretch along outer thigh
5. Hold 30-45 seconds each side

Supine Hamstring Stretch with Strap

1. Lie on back, loop strap around foot
2. Lift leg toward ceiling
3. Gently rotate leg inward
4. Feel stretch on lateral hamstring
5. Hold 30-45 seconds each side

Sport-Specific Considerations

Sprinting

• Biceps femoris highly active during late swing phase
• Eccentric strengthening crucial for prevention
• Progress running speed gradually
• Nordic curls reduce hamstring injuries by up to 50%

Soccer/Football

• High-speed running and kicking stress biceps femoris
• Include both concentric and eccentric work
• Address any strength asymmetries between legs

Running

• Repetitive loading requires endurance
• Include single-leg exercises
• Monitor for early signs of tendinopathy

Cycling

• Biceps femoris active during power phase
• May develop lateral knee pain from tendinopathy
• Ensure proper bike fit

Preventing Biceps Femoris Injuries

1. Progressive loading: Gradually increase training intensity
2. Eccentric training: Nordic curls and eccentric deadlifts
3. Address imbalances: Compare strength between legs
4. Adequate warm-up: Dynamic stretching before high-speed work
5. Don't ignore tightness: Address hamstring flexibility
6. Manage fatigue: Most injuries occur when tired
7. Proper running mechanics: Avoid overstriding

Rehabilitation Principles

If you've injured your biceps femoris:

Acute Phase (Days 1-5):

• Protect from further injury
• Pain-free range of motion
• Gentle walking as tolerated
• Avoid stretching into pain

Subacute Phase (Days 5-14):

• Progressive range of motion
• Begin isometric exercises
• Light resistance training
• No high-speed movements

Remodeling Phase (Weeks 2-6+):

• Eccentric strengthening emphasis
• Progressive loading
• Sport-specific drills
• Gradual return to running

Return to Sport:

• Full strength compared to other leg
• No pain with sport-specific movements
• Completed running progression
• Typically 2-8 weeks depending on severity

When to Seek Help

Consult a healthcare provider if you experience:

• Sudden pop with immediate pain and weakness
• Significant bruising
• Unable to bear weight
• Pain that doesn't improve with rest
• Recurrent hamstring strains

Summary

The biceps femoris is a critical muscle for athletic performance and knee stability. Its location on the lateral hamstring and unique rotational functions make it especially important for high-speed activities. Prioritize eccentric training for injury prevention, include exercises that emphasize external rotation to target this muscle specifically, and address any strength imbalances between legs. Whether you're an athlete or simply want healthy, functional hamstrings, giving the biceps femoris proper attention will pay dividends in performance and injury resilience.