Presentation on theme: "Progression: The basic objective of the locomotor system is to move the body forward from the current site to a new location so the hands and head can."— Presentation transcript:
Progression: The basic objective of the locomotor system is to move the body forward from the current site to a new location so the hands and head can perform their functions. The initial step: How does body weight fall forward??
This result in forward falling of body weight which is considered the prime propelling force of human gait. A second propelling force of lesser magnitude is the momentum of the forward swinging limb (explained later). The progression cycle: Advancement of the body depends an stance limb mobility. This cycle consists of 5 parts: 1- Heel rocker, 2- Ankle rocker, 3- Forefoot rocker, 4- Swing phase hip flexion, 5- Swing phase knee extension.
1- Heel rocker is controlled by muscular action, which muscles? What type of contraction? Does this affect tibia, knee, and hip? This is how body weight falling downward is converted to body weight falling forward.
2- Ankle rocker: once the forefoot contacts the floor, progression occurs at the ankle by forward movement of the tibia into dorsi-flexion. As body moves forward so does the GRF moving anterior to the ankle and causing dorsi-flexion that is controlled by which muscle?? 3- Forefoot rocker: once GRF reaches the meta-tarsal heads, the heel rises making the meta-tarsal heads rounded which serve as the forefoot rocker. At this point the lever arm is at its longest, and body weight falls unrestrained producing the greatest propelling force during the whole gait cycle.
4- Swing phase hip flexion: helps the weight bearing limb during the first part of mid-stance. 5- Swing phase knee extension: knee extension adds weight forward to the body providing momentum to the stance limb and aiding it to progress forward. Shock absorption: the body is in a state of free fall for a short period of time. Several mechanisms are involved in shock absorption: 1- Resilient tissues of the heel pad, 2- Controlled ankle plantar flexion during loading response, 3- Controlled sub-talar joint eversion during loading response, 4- Controlled knee flexion during loading response
5- Controlled contralateral pelvic drop during loading response and early mid-stance. 2- Controlled PF: (which rocker is this?) decelerated and controlled PF slows foot fall towards the floor and thus reduce force of impact. Muscle action absorbs part of the force, how?? Which muscles?? 4- Controlled knee flexion: occurs due to???? It is the greatest shock absorbing mechanism. Muscles absorb part of the shock, which muscles? Contraction? 5- Rate of pelvic drop is restrained by which muscles?? Contraction? Pelvis fall is absorbed by muscle