Walking is locomotion, which results in coordinated actions of muscles of extremities and the body. This is probably the most available type of physical activity. Walking is a type of bipedal gait in which the body vaults over the stiff limb with each step. This kind of locomotion is sometimes regarded to control falling, i.e. each stem is a kind of fell that is precluded by a protrusive leg. The system that consists of the body and the extremities may be classified as the pendulum.
Walking is possible by means of conditioned and unconditioned reflexes, called a motor stereotype. Walking is a motor skill that is a chain of sequentially assigned reflexes and motor actions that can be performed automatically without consciousness. Walking must be distinguished from gait, the latter recognized as the feature of human walking, ‘way to go’.
Thus, in just one photo it is hardly possible to show the numerous actions of walking, so this is a picture of many men waking to emphasize the complexity of the walking sequence.
Normal walking is described in this paper. Walking provides important locomotive functions, such as linear translation of the body, holding vertical balance, saving energy by redistributing energy and using minimal energy consumption, smooth movement, saving gait, and resistance to possible disorders.
The Full Cycle of One Leg Movement
All the muscles of the lower limbs are essential for walking. This means that the slightest failure of one of these muscles can lead to a more or less serious disruption of gait. The full cycle of one leg is considered, keeping in mind that it is to be repeated by another one as soon as the previous cycle ends:
- Start moving forward – flexion of the hip under the contraction of musculus iliopsoas, flexion of the knee under the tension of musculus biceps femoris, flexion of the ankle by flexor muscle group of the joint (musculus tibialis anterior, the third peroneal muscles), the extension of toes by common and proprial extensor muscles.
- Initial contact with the bearing surface at the heel – end of hip flexion by the iliopsoas muscle, extension of the knee by quadriceps muscle, end of the ankle flexion by muscles of the joint, and extensors of the toes.
- Vertical support of the corresponding leg (the sole of the foot is fully in contact with the floor) – the persistent effect of the quadriceps muscle, large gluteal muscle starts contraction.
- Disequilibrium in front – the extension of the hip by the forces of the large gluteal muscle and ischio-femoral muscle, quadriceps muscle antagonism-synergism, flexion of the ankle by flexors in synergy with the large gluteal muscle.
- The first locomotive push ahead before the two legs reliance – the extension of the hip by the large gluteal muscle and ischio-femoral muscles continues, the extension of the knee with the help of quadriceps continues, the ankle is extended by the digital flexors.
- The second motor impulse (the bearing leg in full extension, while the oscillating limb is going to step on the floor) – strengthening of the quadriceps muscle in cooperation with the gluteus maximus, the ischio-femoral muscle, triceps, and toes’ flexors, especially the Flexor hallucis longus muscle.
- Beginning of oscillations (when the other limb becomes leading) – oscillating limb shortens by contracting the sciatic and femoral muscles and ankle’s flexors, iliopsoas muscle flexes the.
- Moving the limb anteriorly – iliopsoas muscle and quadriceps muscle strengthen and femoral muscles weaken, the knee joint extenses because the quadriceps muscle contracts, the toe raises as the appropriate extensors muscles act.
- The landing of the leading muscle and a new cycle begins.
More Detailed Description of the Walking Movement Process
As long as muscles of the lower extremity are of paramount importance for walking, they need to be described in more detail:
- Hip flexors are anterior to the frontal plane. They are numerous – musculus psoas (major and minor) and musculus iliacus share a common tendon. This is the strongest and the longest flexor of the coxal articulation. The muscle lies medially, but its adducting properties are doubtful. Musculus sartorius is a flexor but helps to rotate and to abduct. Musculus rectus femoris and musculus tensor fasciae latae are powerful flexors. Some smaller muscles should be remembered too – pectineus, adductor longus, and gracilis muscle.
- Hip extensors are posterior to the frontal plane. Musculus gluteus maximus is the strongest and the biggest muscle of the human body. Other muscles of this group attach to the area of the knee –biceps femoris, semitendinosus, semimembranosus muscules comprise two-thirds of the power of the gluteus maximus. These muscles also stabilize the pelvis while walking.
- Tibial flexors are in the posterior part of the hip. The muscles are biceps femoris, semitendinosus, semimebranosus, gracilis, sartorius, and popliteus muscles. Musculus gastrocnemuis is of no use to flex the shin, but serves well to extend the foot and to make the knee stable. Most of them are biarticulra, so they extend the hip at the time of contraction;
- Foot flexors must act specifically, so that it moves symmetrically without adducting and supination or abducting and pronation. These two pairs of agonists-antagonists are extensor hallucis longus and tibailis anterior muscle on one hand, and peroneus tertius and extensor digitorum longus on the other.
- Foot extensors are triceps surae, tibialis posterior, flexor hallucis longus, and flexor digitorum longus, which, as it had been noted, act by a balance of synergy and antagonism.
4 Periods of the Step Process
The step proceeds within four periods:
- Heel landing depends on friction forces of the surface – as soon as the sole of the foot touches the floor, the ankle starts its extension, which is under the impact of tibialis anterior muscle.
- Spreading the sole of the foot on the land accounts for the weight of the body when the supporting limb moves forward. Now the ankle joint flexes and plantar muscles amortize the plantar arch.
- The first motor push to motor occurs when the triceps muscle contracts, plantar muscles still resist.
- The second push lies in reducing the tension of the toes, especially by the flexor hallucis longus, while the triceps muscle is still contracting.
Articulatio coxa carries three degrees of freedom. Thus, some muscles may vary in their functional capacities depending on the position of the bones. For example, the quadriceps muscle shows remarkable changes in its function. When extension in the joint occurs, it works as the extensor; at the same time when flexion starts, it acts as an extensor.
It must be noted that the lower extremities’ muscles only do not limit actions of muscles during walking. The quadrupeds move forward symmetrically. Most animals move ahead opposite legs so that support for the body is more confident. Thus, the human gait involves flexion of the upper limb on the opposite side of the leading leg: the left upper limb moves at the same time as the right leg, and vice versa, the right upper limb moves simultaneously with the left leg. This movement pattern is usually involuntary.
Movement of the lower limbs during walking must swing the center of gravity, the pelvis. The pelvis fluctuates in two planes – vertical and lateral. In the vertical plane, the pelvis would oscillate depending on the leg elevating, and laterally at bows to the leading leg. The pelvis tilt in anterosuperior direction is accomplished by rotation of the torso around the vertical axis. This happens, because of the lower extremities alternate projections.
The rotation is due to the moves of the caput femoris. For example, when the right leg is forward, the left caput rotates inside in the articulation coxa, while the caput femoris on the right side rotates outside. As it was noted before, the upper extremities move simultaneously. Thus, the whole body torses around its own axis during walking.
List of Involved in Walking Joints
The following joints are involved in walking:
- Articulatio coxa composed of acetabula of the pelvis and caput femoris, flexes and extenses around the frontal plane, rotates around the vertical axis, and adducts or abducts around the sagittal plane.
- Articulatio genus is the biggest and the most complex of joints, composed of the distal end of the femur and the proximal end of the tibia, accomplished by meniscus medialis and lateralis. The joint flexes, extenses, and rotates. However, the latter move is limited.
- Articulatio talocruralis is composed of the tibia and fibula that block the talus. The joint allows either flexing or extending, and very minoring lateral motions.
- Articulations intertarsae – subtalaris, talocalcaneonavicularis, calcaneocuboidea, cuneonavicularis experience minor rotations inside (pronatio) and outside (supinatio).
- Articulations tarsometatarseae, metatarsophalangeae, interfalangeae are tight joints and mainly support the foot.
In conclusion, walking is the process to make the whole body move. The head is the only organ that more or less remains stable due to the fixed gaze towards the goal. The head may only perform the compensatory rotational movement at the level of the cervical spine. The small head is exposed to fluctuations in the vertical direction, parallel to the vertical displacement of the pelvis, but the movements are amortized. Nevertheless, the compensatory mechanisms are not so good to carry a stable traveling camera in hand.