knee, gait, stairs, walking

Modified hinge joint

The classification of the knee joint, which bends back and forth and has a complex rotational component during flexion and extension.

Cartilage

The material inside the joint providing shock absorption during weight-bearing activities like walking or climbing stairs.

Femur

The bone commonly known as the thigh bone.

Tibia

The bone commonly known as the shin bone.

Patella

The bone commonly known as the kneecap, which protects the joint and slides in the femoral groove.

MCL

The Medial collateral ligament; it limits sideways motion from the inner side and is the most commonly injured knee ligament.

LCL

The Lateral collateral ligament; it limits sideways motion from the outer side.

ACL and PCL

The Anterior and Posterior cruciate ligaments; they limit the forward motion of the knee bones.

Menisci

Two structures between the femur and tibia that act as cushions or shock absorbers.

Articular cartilage

A smooth and slick material covering the bone ends, femoral groove, and underside of the patella to ensure smooth movement.

Quadriceps tendon

Connects the quadriceps muscles to the top of the patella and becomes the patellar tendon.

Patellar tendon

Also called a ligament, it connects the patella to the front of the tibia.

Screw home mechanism

A locking action at the end of extension involving external rotation of the tibia occurring during the last 20 degrees of extension.

Knee Extensors

A group of four muscles known as the Quadriceps, including the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius.

Vastus intermedius

The only quadriceps muscle that is not superficial or palpable.

Knee Flexors

A group of muscles including the sartorius, biceps femoris, semitendinosus, semimembranosus, and gracilis.

Sartorius

A muscle that performs three combined movements: hip flexion, hip external rotation, and knee flexion.

ACL injury

Usually caused by a non-contact pivoting/twisting movement with the foot planted, sudden deceleration, or hyperextension.

Medial meniscus injury

A tear that is three times more likely to occur than a lateral meniscus tear, often caused by rotational force on a flexed knee.

Valgus blow

A direct sideways blow that typically causes damage to the MCL, common in football, soccer, and hockey.

Gait: Stance phase

The part of walking consisting of heel strike (foot strike), mid-stance, and push off (toe off).

Gait: Swing phase

The part of walking consisting of acceleration, mid-swing, and deceleration.

CON

Abbreviation for concentric contraction.

ECC

Abbreviation for eccentric contraction.

ISO

Abbreviation for isometric contraction.

Stairs Ascent

Involves extension of the hip, knee, and plantar flexion of the ankle using concentric muscular action.

Stairs Descent

Involves flexion of the hip and knee and dorsiflexion of the ankle using eccentric muscular action.

Hip Movement (Stair Ascent)

Extension

Muscular Action Type (Stair Ascent)

Concentric (con)

Hip Muscular Action (Stair Ascent)

Gluteus maximus, Biceps femoris, Semimembranosus, and Semitendinosus

Knee Movement (Stair Ascent)

Extension

Knee Muscular Action (Stair Ascent)

rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius

Ankle Movement (Stair Ascent)

Plantar flexion

Ankle Muscular Action (Stair Ascent)

Gastrocnemius, Soleus, Peroneus longus, Peroneus brevis, plantaris, flexor hallucis longus, flexor digitorum longus, and tibialis posterior

Hip Movement (Stair Descent)

Flexion

Muscular Action Type (Stair Descent)

Eccentric (Ecc)

Hip Muscular Action (Stair Descent)

Gluteus maximus, Biceps femoris, Semimembranosus, and Semitendinosus

Knee Movement (Stair Descent)

Flexion

Knee Muscular Action (Stair Descent)

rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius

Ankle Movement (Stair Descent)

Dorsiflexion

Ankle Muscular Action (Stair Descent)

Gastrocnemius, Soleus, Peroneus longus, Peroneus brevis, plantaris, flexor hallucis longus, flexor digitorum longus, and tibialis posterior

Walking

Accomplished by the alternating action of the two lower extremities.

Stride

The sequence from heel contact of one leg to the next heel strike with the same leg.

Step

Starts with the heel strike of one leg and ends with the heel strike of the contralateral leg.

Stance phase

The phase of walking that includes heel-strike, mid-stance, and toe-off.

Swing phase

The phase of walking that includes acceleration, mid-swing, and deceleration.

Heel-strike (Hip Action)

$\text{Controlled Flexion (ECC) to Extension}$ utilizing the Gluteus maximus, Biceps femoris, Semimembranosus, and Semitendinosus.

Heel-strike (Knee Action)

$\text{Extension (slight flexion ECC)}$ utilizing the Rectus femoris, Vastus lateralis, vastus medialis, and vastus intermedius.

Heel-strike (Ankle Action)

$\text{Plantar flexion (ECC)}$ utilizing the Tibialis anterior, Extensor digitorum longus, and Extensor hallucis longus.

Mid-stance (Ankle Action)

$\text{Neutral to control dorsi flexion (ECC)}$ utilizing the Gastrocnemius, Soleus, flexor hallucis longus, flexor digitorum longus, tibialis posterior, Peroneus longus, Peroneus brevis, and plantaris.

Toe-off (Hip Action)

$\text{Extension}$ utilizing the Gluteus maximus, Biceps femoris, Semimembranosus, and Semitendinosus.

Toe-off (Knee Action)

$\text{Extension (extending to push)}$ involving the Rectus femoris, Vastus lateralis, vastus medialis, and vastus intermedius.

Toe-off (Ankle Action)

$\text{Plantar flexion}$ utilizing the Gastrocnemius, Soleus, flexor hallucis longus, flexor digitorum longus, tibialis posterior, Peroneus longus, Peroneus brevis, and plantaris.

Acceleration (Hip Action)

$\text{Flexion}$ utilizing the Rectus femoris, Iliopsoas, Sartorius, and pectineus.

Acceleration (Knee Action)

$\text{Flexion}$ utilizing the Biceps femoris, Semimembranosus, Semitendinosus, Sartorius, and gracilis.

Acceleration (Ankle Action)

$\text{Dorsi flexion (CON)}$ utilizing the Tibialis anterior, Extensor digitorum longus, and Extensor hallucis longus.

Mid-swing (Ankle Action)

$\text{Dorsi flexion (ISO)}$ utilizing the Tibialis anterior, Extensor digitorum longus, and Extensor hallucis longus.

Deceleration (Hip Action)

$\text{Flexion (slow down ECC)}$ utilizing the Gluteus maximus, Biceps femoris, Semimembranosus, and Semitendinosus.

Deceleration (Knee Action)

$\text{Extension (slow down and then initiate ECC)}$ involving the Biceps femoris, Semimembranosus, Semitendinosus, Sartorius, and gracilis.

Deceleration (Ankle Action)

$\text{Dorsi flexion (ISO)}$ utilizing the Tibialis anterior, Extensor digitorum longus, and Extensor hallucis longus.

Iliopsoas

A muscle showing high activity (***) during Forward swing.

Gluteus Maximus activity

A muscle showing high activity (*) during Deceleration and moderate activity () during Footstrike.

Plantar Flexors activity

Muscles showing high activity (***) specifically during the Toe-off phase.

Quadriceps activity

Muscles showing high activity (*) during Footstrike and moderate activity () during Midsupport.