Pinpoint
Muscles/Thigh

Thigh

biceps femoris

BY-seps FEM-or-iss

The biceps femoris is the lateral hamstring on the back of the thigh, with long and short heads forming a thick band from hip to knee. It flexes the knee, extends the hip, and rotates the leg outward, vital for running, jumping, and deadlifts. Key for posterior chain power and injury prevention.

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Common Pain & Injury

Hamstring pain feels like a pull or tear in the back thigh, worse with sprinting or bending knee. Chronic ache from strains. See doctor for swelling, bruising, or inability to walk.

Anatomy & Function

Origin

Long head: ischial tuberosity (sit bone); Short head: linea aspera of femur (thigh bone shaft)

Insertion

Head of fibula (outer knee bone)

Actions

  • Knee flexion (bending knee)
  • Hip extension (straightening hip)
  • Leg external rotation

Innervation

Tibial nerve (long head, L5-S2); Common fibular nerve (short head)

Muscle Relationships

Antagonists

Quadriceps femorisTensor fasciae latae

Synergists

SemitendinosusSemimembranosus

Trigger Points

Mid-posterior thigh; refer to back of knee or calf.

Stretches

1Seated hamstring stretch
2Forward fold with knee straight
3Lying hamstring stretch with strap

Common Conditions

Biceps femoris strainHamstring tendinopathyProximal hamstring avulsion

Anatomical Parts

Long head of right biceps femorisShort head of right biceps femorisLong head of left biceps femorisShort head of left biceps femoris

FAQ

What does biceps femoris do?

Flexes knee, extends hip, and rotates tibia outward for sprinting and squats.

Biceps femoris pain running?

Common strain from sudden acceleration; grade 1-3 severity.

How to stretch biceps femoris?

Straight-leg forward bends target it best.

Biceps femoris tear?

Popping sensation, bruising, knee flexion weakness.

Exercises for biceps femoris

20
90/90 Hamstring position 1
90/90 Hamstring position 2

90/90 Hamstring

beginner·Bodyweight
Alternating Hang Clean position 1
Alternating Hang Clean position 2

Alternating Hang Clean

intermediate·kettlebells
Ball Leg Curl position 1
Ball Leg Curl position 2

Ball Leg Curl

beginner·exercise ball
Band Good Morning position 1
Band Good Morning position 2

Band Good Morning

beginner·bands
Band Good Morning (Pull Through) position 1
Band Good Morning (Pull Through) position 2

Band Good Morning (Pull Through)

beginner·bands
Box Jump (Multiple Response) position 1
Box Jump (Multiple Response) position 2

Box Jump (Multiple Response)

beginner·other
Box Skip position 1
Box Skip position 2

Box Skip

beginner·other
Chair Leg Extended Stretch position 1
Chair Leg Extended Stretch position 2

Chair Leg Extended Stretch

beginner·other
Clean position 1
Clean position 2

Clean

intermediate·barbell
Clean Deadlift position 1
Clean Deadlift position 2

Clean Deadlift

beginner·barbell
Double Kettlebell Alternating Hang Clean position 1
Double Kettlebell Alternating Hang Clean position 2

Double Kettlebell Alternating Hang Clean

intermediate·kettlebells
Dumbbell Clean position 1
Dumbbell Clean position 2

Dumbbell Clean

intermediate·dumbbell
Floor Glute-Ham Raise position 1
Floor Glute-Ham Raise position 2

Floor Glute-Ham Raise

intermediate
Front Box Jump position 1
Front Box Jump position 2

Front Box Jump

beginner·other
Front Leg Raises position 1
Front Leg Raises position 2

Front Leg Raises

beginner·Bodyweight
Glute Ham Raise position 1
Glute Ham Raise position 2

Glute Ham Raise

intermediate·machine
Good Morning position 1
Good Morning position 2

Good Morning

intermediate·barbell
Good Morning off Pins position 1
Good Morning off Pins position 2

Good Morning off Pins

intermediate·barbell
Hamstring-SMR position 1
Hamstring-SMR position 2

Hamstring-SMR

beginner·foam roll
Hamstring Stretch position 1
Hamstring Stretch position 2

Hamstring Stretch

beginner

Also Works biceps femoris

10
Advanced Kettlebell Windmill position 1
Advanced Kettlebell Windmill position 2

Advanced Kettlebell Windmill

intermediate·kettlebells
Alternate Leg Diagonal Bound position 1
Alternate Leg Diagonal Bound position 2

Alternate Leg Diagonal Bound

beginner
Atlas Stone Trainer position 1
Atlas Stone Trainer position 2

Atlas Stone Trainer

intermediate·other
Atlas Stones position 1
Atlas Stones position 2

Atlas Stones

expert·other
Axle Deadlift position 1
Axle Deadlift position 2

Axle Deadlift

intermediate·other
Backward Drag position 1
Backward Drag position 2

Backward Drag

beginner·other
Balance Board position 1
Balance Board position 2

Balance Board

beginner·other
Barbell Deadlift position 1
Barbell Deadlift position 2

Barbell Deadlift

intermediate·barbell
Barbell Full Squat position 1
Barbell Full Squat position 2

Barbell Full Squat

intermediate·barbell
Barbell Glute Bridge position 1
Barbell Glute Bridge position 2

Barbell Glute Bridge

intermediate·barbell

Related Thigh Muscles

gracilis
Long, thin medial thigh muscle adducting and flexing knee. Aids cutting movements in soccer, stabilizing in squats.
iliotibial tract
The iliotibial tract (IT band) is a thick fibrous band down the outer thigh from hip to knee, stabilizing the leg during running and single-leg stands. Tight ITB causes knee pain in runners; mobility work prevents issues.
rectus femoris
The rectus femoris is the central quad muscle crossing both hip and knee, visible as the teardrop above your knee. It flexes the hip and extends the knee, powering sprints, jumps, and squats. Balanced development prevents knee pain in athletes.
sartorius
The sartorius is the longest muscle in the body, spiraling from hip to inner knee, forming a 'tailor's muscle' for crossing legs. It flexes, abducts, and rotates the hip plus flexes the knee, key for soccer kicks and agility drills. Balances quad-dominant training.
semimembranosus
The semimembranosus is a posterior thigh hamstring forming the teardrop at knee back, flexing knee and extending hip. Powers deadlifts, lunges, and deceleration in sports. Prevents ACL strains by stabilizing.
semitendinosus
Semitendinosus is the slender medial hamstring with a long tendon, flexing knee and extending hip. Aids in medial knee stability for cutting sports. Complements semimembranosus for balanced posterior chain.
vastus intermedius
Deep central quad muscle under rectus femoris, extends knee powerfully. Core quad for squats and jumps.
vastus lateralis
Largest quad on outer thigh, massive knee extender for lateral stability in lunges and sprints.

Thigh Pain Guide

Common causes and relief

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Activities & Sports

See which activities use biceps femoris

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Pinpoint·Interactive 3D Anatomy & Exercise Guide