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.
