Muscle Function

Vastus Intermedius

Isolated Function: Concentrically accelerates knee extension. Integrated Function: Eccentrically decelerates knee flexion, adduction, and internal rotation. Isometrically stabilizes the knee.

Vastus Lateralis

Isolated Function: Concentrically accelerates knee extension. Integrated Function: Eccentrically decelerates knee flexion, adduction, and internal rotation. Isometrically stabilizes the knee.

Vastus Medialis

Isolated Function: Concentrically accelerates knee extension. Integrated Function: Eccentrically decelerates knee flexion, adduction, and internal rotation. Isometrically stabilizes the knee.

Biceps Femoris - Long Head

Isolated Function: Concentrically accelerates knee flexion and hip extension. Tibial external rotation. Integrated Function: Eccentrically decelerates knee extension. Eccentrically decelerates hip flexion. Eccentrically decelerates tibial internal rotation at mid-stance of the gait cycle. Isometrically stabilizes the lumbo-pelvic-hip complex and knee.

Gluteus Minimus

Isolated Fuction: Concentrically accelerates hip abduction and internal rotation. Integrated Function: Eccentrically decelerates hip adduction external rotation. Isometrically stabilizes the lumbo-pelvic-hip complex.

Anterior Tibialis

Isolated Function: Concentrically accelerates Xdorsiflexion and inversion. Integrated Function: Eccentrically decelerates plantarflexion and eversion. Isometrically stabilizes the arch of the foot.

Gluteus Medius

Isolated Function: Concentrically accelerates hip abduction and internal rotation (anterior fibers). Concentrically accelerates hip abduction and external rotation (posterior fibers). Integrated Function: Eccentrically decelerates hip adduction and external rotation (anterior fibers). Eccentrically decelerates hip adduction and internal rotation (posterior fibers). Isometrically stabilizes the lumbo-pelvic-hip complex.

Adductor Magnus - Anterior Fibers

Isolated Function: Concentrically accelerates hip adduction, flexion, and internal rotation. Integrated Function: Eccentrically decelerates hip abduction, extension, and external rotation. Dynamically stabilizes the lumbo-pelvic-hip complex.

Adductor Brevis

Isolated Function: Concentrically accelerates hip adduction, flexion, and internal rotation. Integrated Function: Eccentrically decelerates hip abduction, extension, and external rotation. Isometrically stabilizes the lumbo-pelvic-hip complex.

Adductor Longus

Isolated Function: Concentrically accelerates hip adduction, flexion, and internal rotation. Integrated Function: Eccentrically decelerates hip abduction, extension, and external rotation. Isometrically stabilizes the lumbo-pelvic-hip complex.

Pectineus

Isolated Function: Concentrically accelerates hip adduction, flexion, and internal rotation. Integrated Function: Eccentrically decelerates hip abduction, extension, and external rotation. Isometrically stabilizes the lumbo-pelvic-hip complex.

Adductor Magnus - Posterior Fibers

Isolated Function: Concentrically accelerates hip adduction, flexion, and internal rotation. Integrated Function: Eccentrically decelerates hip abduction, flexion, and internal rotation. Isometrically stabilizes the lumbo-pelvic-hip complex.

Gracilis

Isolated Function: Concentrically accelerates hip adduction, flexion, and internal rotation. Assists in tibial internal rotation. Integrated Function: Eccentrically decelerates hip abduction, extension, and external rotation. Isometrically stabilizes the lumbo-pelvic-hip complex and knee.

Piriformis

Isolated Function: Concentrically accelerates hip external rotation, abduction, and extension. Integrated Function: Eccentrically decelerates hip internal rotation, adduction, and flexion. Isometrically stabilizes the hip and sacroiliac joints.

Iliacus

Isolated Function: Concentrically accelerates hip flexion and external rotation. Integrated Function: Eccentrically decelerates hip extension and internal rotation. Isometrically stabilizes the lumbo-pelvic-hip complex.

Psoas

Isolated Function: Concentrically accelerates hip flexion and external rotation. Concentrically extends and rotates lumbar spine. Integrated Function: Eccentrically decelerates hip internal rotation. Eccentrically decelerates hip extension. Isometrically stabilizes the lumbo-pelvic-hip complex.

Tensor Fascia Latae

Isolated Function: Concentrically accelerates hip flexion, abduction, and internal rotation. Integrated Function: Eccentrically decelerates hip extension, adduction, and external rotation. Isometrically stabilizes the lumbo-pelvic-hip complex.

Sartorius

Isolated Function: Concentrically accelerates hip flexion, external rotation, and abduction. Concentrically accelerates knee flexion and internal rotation. Integrated Function: Eccentrically decelerates hip extension and internal rotation. Eccentrically decelerates knee extension and external rotation. Isometrically stabilizes the lumbo-pelvic-hip complex and knee.

Rectus Femoris

Isolated Function: Concentrically accelerates knee extension and hip flexion. Integrated Function: Eccentrically decelerates knee flexion, adduction, and internal rotation. Decelerates hip extension. Isometrically stabilizes the lumbo-pelvic-hip complex and knee.

Biceps Femoris - Short Head

Isolated Function: Concentrically accelerates knee flexion and tibial external rotation. Integrated Function: Eccentrically decelerates knee extension. Eccentrically decelerates tibial internal rotation. Isometrically stabilizes the knee.

Semitendinosus

Isolated Function: Concentrically accelerates knee flexion, hip extension, and tibial internal rotation. Integrated Fuction: Eccentrically decelerates knee extension. Eccentrically decelerates hip flexion. Eccentrically decelerates tibial external rotation. Isometrically stabilizes the lumbo-pelvic-hip complex and knee.

Semimebranosus

Isolated Function: Concentrically accelerates knee flexion, hip extension, and tibial internal rotation. Integrated Function: Eccentrically decelerates knee extension. Eccentrically decelerates hip flexion. Eccentrically decelerates tibial external rotation. Isometrically stabilizes the lumbo-pelvic-hip complex and knee.

Posterior Tibialis

Isolated Function: Concentrically accelerates plantarflexion and inversion of the foot. Integrated Function: Eccentrically decelerates the dorsiflexion and eversion of the foot. Isometrically stabilizes the arch of the foot.

Gastrocnemius

Isolated Function: Concentrically accelerates plantarflexion. Integrated Function: Decelerates ankle dorsiflexion. Isometrically stabilizes the foot and ankle complex.

Soleus

Isolated Function: Concentrically accelerates plantarflexion. Integrated Function: Decelerates ankle dorsiflexion. Isometrically stabilizes the foot and ankle complex.

External Oblique

Isolated Function: Concentrically accelerates spinal flexion, lateral flexion, and contralateral rotation. Integrated Function: Eccentrically decelerates spinal extension, lateral flexion, and rotation. Isometrically stabilizes the lumbo-pelvic-hip complex.

Internal Oblique

Isolated Function: Concentrically accelerates spinal flexion, lateral flexion, and ipsilateral rotation. Integrated Function: Eccentrically decelerates spinal extension, rotation, and lateral flexion. Isometrically stabilizes the lumbo-pelvic-hip complex.

Rectus Abdominis

Isolated Function: Concentrically accelerates spinal flexion, lateral flexion, and rotation. Integrated Function: Eccentrically decelerates spinal extension, lateral flexion, and rotation. Isometrically stabilizes the lumbo-pelvic-hip complex.

Peroneus Longus

Isolated Function: Concentrically plantarflexes and everts the foot. Integrated Function: Decelerates ankle dorsiflexion. Isometrically stabilizes the foot and ankle complex.

Gluteus Maximus

Isolates Function: Concentrically accelerates hip extension and external rotation. Integrated Function: Eccentrically decelerates hip flexion and internal rotation. Decelerates tibial internal rotation via the iliotibial band. Isometrically stabilizes the lumbo-pelvic-hip complex.