Saturday, March 31, 2012

QM vs. Climbing

In QM, the hands or forearms interact with the surface of contact through simple pressing, possibly with a light clawing to improve traction. When the hands start grabbing the surface they're on, the movement becomes a form of climbing. In a sense, climbing is just a specialized form of QM! In both, the arms are used as much if nt more than the legs, however in climbing the arms are pulling and pushing, while QM only involves pushing movements. Note that the pushing of the arms, using triceps and back shoulder muscles, is generally easier than the pulling, with biceps and deltoid.

When progressing on a slope, QM and climbing can sometimes merge. QM movements on a slope upward are made easier as the hips are lower, decreasing the effort of the arms. The body can be spread further. On downward slopes it is the opposite: one must shorten the distance between the limbs in order to maintain a vertical alignment of the joints and contact points. On steep slopes, it is much advantageous to turn around and progress backward, feet first. In general it is best to keep the head toward the upper part of the slope and the front of the body facing it. To avoid or slow down a fall, the quadrupedist can always drop to the ground and move by crawling, thus increasing the area of contact with the slope. Going sideways can be good to progress up and down a slope, either as a crab or using a sideways posture halfway between crawling and regular QM.

Wednesday, March 21, 2012

Stride and strike

When walking, running or jumping in QM, the efficiency of movement depends first on the general posture of the four limbs, then on the coordination of the limbs in motion and their contact with the ground, and last on the smoothness, power and amplitude of the arm stride.

A balanced posture with the feet and hands under the hips and shoulders is best at rest, with the limbs going in "point" (feet/hands equally spaced around the upper joint) during motion. The relative height of the hip and shoulder is directly related to the achievable QM speed. Many running quadrupeds have an almost balanced limb length with slightly longer hind legs. In that regard, we are more closely related to smaller quadrumane monkeys (e.g. Capuchin monkeys) than to great apes which have longer arms and much shorter legs, and have limited QM speed.

Like the foot, the hand can strike the ground in different ways. Like for the foot, striking directly with the heel of the hand at the wrist propagates shock through the arm, while striking with the ball of the hand with some stabilizing help from the fingers enables to better absorb any downward momentum. In slow QM walk, it is not much of an issue, but it becomes fundamental to achieving good speed and fluidity in running and jumping. The hands and feet shouldn't cross or even touch during movement, except maybe for long QM jumps. The balance of speed and amplitude in classical running stride applies identically to the arms in QM: longer stride and then faster movement.