Dynamic Posture in the Mountains
Beckett Howorth, M.D.1
WALKING and climbing are simple, primitive motions common to all of us and to many animals. Walking is usually taken for granted, as we have walked since infancy, but it is often done poorly. Climbing is often considered a special skill and hazard because it is associated with the risk of falling, and the fear of heights and of falling is deep seated in many people. Most of us can learn to walk better. All of us can learn to climb.
A baby learns to walk alone at about 14 months—his legs apart, his movements quick and uncertain, his balance poor, especially for turning and for stepping up and down. Many adults revert to the baby stage. Many children as they grow older learn to walk well, with good balance and rhythm, sure, precise movements and great adaptability to the surfaces on which they walk and to obstructions in their paths, as well as to their own changing moods and desires. Few adults retain this skill, but most can reacquire it.
The postures of the body in action, or in preparation for action, constitute “dynamic posture.” The term includes lying and sitting positions as well as standing, and also the transitions between them. It includes all the activities of our everyday lives at work and at play, as well as the special skills in arts and crafts, and in sports. There are certain fundamental principles which relate to all these activities.
Basic Standing Positions
There are three basic standing positions: the erect position, the slouch of poor posture, the crouch of dynamic posture. In the erect position the head and shoulders, hips, knees, and ankles are lined up vertically. The spine is nearly erect, the chest somewhat expanded, the abdomen flat, the legs straight and the feet parallel; but there should be no tension. Better sideways balance may be secured by separating the feet a few inches. This is a good position for standing erect and in balance, but useless for action. Try to jump in this position! Poor posture is characterized by a forward movement of the hips and pelvis, causing an S-shaped curve of the body as a whole. The head shifts forward, the chest is flat, the abdomen sags and protrudes, and the knees flex a little. It is as though man, having attained the erect posture in the process of evolution, is now going beyond it, to assume eventually a reverse position on all fours. This position is not only poor physiologically, but also useless for action. Try it.
The basic dynamic position is a slight crouch with the hips, knees and ankles flexed, the trunk and head inclined forward, the arms relaxed but slightly flexed, and the weight forward over the balls of the feet. In this position the muscles are balanced and ready for instant and powerful action, and they act as springs to absorb the shocks which occur with action. The fore-and-aft stability may be increased by advancing one foot; the sideways stability, by separating the feet. The feet thus grip the ground more securely than in the erect position, preventing slipping, and increasing the thrust for forward movement.
The basic dynamic position is used in walking rapidly or upon difficult terrain or slippery surfaces, up and down hill, and in jumping, lifting, pushing and pulling, climbing and skiing. Good dynamic posture implies the use of the body or its parts in the simplest and most effective way, using muscle contraction and relaxation, balance, coordination, rhythm and timing, as well as gravity, inertia and momentum, to optimum advantage. The smooth integration of these elements of good dynamic posture results in physical performance which is easy, graceful, satisfying and effective and represents the best in the individual physical activity as well as in the physical activity of the individual.
Gravity pulls the body or its parts toward the earth. Inertia tends to hold the body still, or to maintain its motions at a constant speed. Momentum gives the body added power or impetus. Friction, including air resistance, tends to slow the body. Gravity, inertia, momentum or friction may be overcome or reinforced by muscle action. Acceleration or deceleration may be caused by an external force such as gravity or friction, or by the internal force of muscle action. These principles are closely related to walking in mountainous country and to skiing.
A muscle may contract or relax. A contracting muscle must work against gravity in pulling or pushing the body or a weight upward; it is aided by gravity in pulling or pushing something downward. A muscle may relax and by thus letting go allow gravity to become more, or less, effective. Similarly momentum, inertia and friction may be resisted or reinforced by the proper application of muscle contraction or relaxation. Maximum power is attained by the contraction of the muscle in the most favorable relation to gravity, inertia and momentum, with a minimum of friction. The contraction need not be sustained; it should be continued just long enough to produce the desired effect. Thus tension and fatigue are avoided, and the muscle is free to perform further work. It is especially important that the normal phases of muscle relaxation be observed in walking downhill and in skiing.
Good balance is secured by maintaining the center of gravity of the body over the feet, through coordination of the eyes, the semicircular canals of the ears, and the position sense of the muscles and joints. When the body is moving forward, the center of gravity should be advanced to the balls of the feet, or in front of the feet, so that gravity will provide forward momentum. The trunk should lead the action rather than try to catch up with it, especially in glissading and in skiing, where the skis are sliding forward, causing the weight to tip back toward the heels.
Precision and smoothness are essential to good muscle action and low energy output. Timing is one of the most important and delicate phases of movement, especially of a complex and rapid one. Poor timing can reduce or invalidate the effectiveness of movement. Good timing makes the movement easier and more effective. Alternating contraction and relaxation with balanced timing produce rhythm in movement and increase the capacity for sustained action. Coordination is the smooth relationship in proper sequence of a group of muscle actions. Timing and coordination are perhaps the most important factors in skiing, jumping and glissading, but the least stressed and the hardest to teach. Precision, smoothness, timing, rhythm and coordination are the elements of good dynamic posture.
Walking is one of our simplest and most fundamental actions and may serve as an example of dynamic posture. The body is tilted slightly forward from the basic standing position and the weight thrown on the ball of the foot, while the other thigh is lifted and the leg and opposite arm are swung forward (Figure 1-B).
Various muscles, aided by inertia, maintain the body in balance on the ball of one foot until the opposite heel strikes, when the weight quickly advances to this leg with the knee extended (Figure 1-C). Momentum carries the body forward over the extended leg until it passes the perpendicular, when the thrust of the foot renews the action and the process is repeated (Figure 1-D).
The front thigh muscle contracts for only a fraction of a second, with a sort of rippling movement, in swinging the leg forward. The muscles in front of the ankle contract briefly to prevent the foot from dragging just as it swings across the ground.
As the heel strikes, all the thigh and ankle muscles quickly contract to stabilize the knee and ankle until the weight is thrust forward again by the calf.
The flexor muscles in front of the hip swing the thigh forward. Then, as the weight goes on the leg, all the hip muscles contract to stabilize the hip, particularly those on the outer side, to prevent the pelvis from falling to the inner side. The opposite arm swings forward with the leg by contraction of the shoulder and elbow flexors, then swings back by the action of their antagonists. These motions are greatly aided by the pendulum effect of the swing.
Correct walking is done with a smooth rhythm, the muscles contracting gently with a brief wavelike action and relaxing in the interval. It is characterized by free muscle and joint action, momentum, balance and rhythm. Effort becomes much greater if the speed is increased or if momentum and rhythm are disturbed.
Walking is often done badly, with the body erect and stiff, with sudden jerky movements, tense muscles, precarious balance, needless jolts and a lack of rhythm. The steps lack spring and the flexibility needed to meet unusual situations. The good walker should be able to change pace, stop, start, turn, step up or down, twist or stoop, easily and quickly, without losing balance or rhythm. A good dynamic posture and flexible healthy muscles are the basis for correct walking.
Shoes should be comfortable and of proper shape and fit. High heels and pointed toes prevent good walking. Clothing should be comfortable, not too heavy, and should allow freedom of movement. Crowded city pavements and dirty, fume-laden air usually promote bad walking posture; the varied topography and surfaces and the clean air of the country make good walking posture easier.
Walking may be affected by pain, fatigue, weakness or stiffness. Pain may be caused by an injury, such as a sprain, a bruise, a blister, a corn or arthritis. Weakness may be due to many things, such as lack of sleep, improper diet, illness, heat and humidity, a poor heart, lung disease, or nerve or muscle damage. Stiffness may be due to muscle or joint damage, tense or contracted muscles. Fatigue is due to poor physical condition, or to exceeding the capacity of the individual as to speed, distance and load, especially up and down steep and difficult slopes.
Speed may be acquired by increasing the crouch and the forward tilt, thrusting harder with the legs, and developing a longer arm swing. The length of stride should not be too great, as the effort of forcing the body to reach the forward leg becomes excessive, or too short, for energy is wasted in swinging the legs too many times. The same principles apply in running.
Walking uphill or upstairs may be made easier, safer and faster by leaning forward in a deeper crouch and forcing the body well forward on the higher step (Figure 1-G, H, I). Breathing should be deeper rather than faster and in rhythm with the other movements. There should be no tenseness of the muscles, for this results in quick fatigue. Nor should there be any disturbance in rhythm or smoothness, as one will quickly lose rather than gain in accomplishment.
Walking downhill also requires a forward lean and slight crouch to reduce the shock of each step as well as the chance of slipping. In this position the center of gravity is low (Figure 1-K, L, M) and the muscles are in position to respond to any need. The weight comes down on the whole foot, the whole step is used and the foot grips well. One can thus double up and protect oneself much easier in case of a fall. On very steep slopes a slight turning to the side or zigzagging will help. Relaxation is most important in downhill walking, especially “loose knees.” The movement then becomes almost a dance, with light quick steps, or a series of slides, similar to skiing. Small jumps may often be used. The knees are usually kept close together in this technique. The crouch brings one closer to the ground, with the muscles and joints acting as springs, minimizing the possibility and danger of a fall. Most falls are backward, with the body extended in a blind direction, the weight coming hard on the coccyx or wrists. These falls can be avoided by the method mentioned.
The pace is varied according to the difficulty of the terrain, the capacity of the walker, and the need for hurry. Most walkers do better if they adopt an easy pace and can thus maintain rhythm and relaxation. Speed is adapted to varying conditions so that the energy output is fairly uniform. Sometimes it is desirable to rush a short bit, especially with a heavy load, as considerable energy may be wasted in forcing oneself slowly up or down. Similarly, the climber may advance by quick rushes in the face of a very strong wind, especially if it is laden with snow or sleet. A rest period of five minutes every hour is usually desirable, especially if the climbing is difficult or the load heavy. If more rest is required, it should be taken more frequently rather than for a longer period. It is better to take rest lying down, unless the effort of getting up and down and of removing the load minimizes its value. It is often possible to find a boulder or other seat at thigh level for sitting, and the rucksack may be supported at the same level for a short rest without removing it. Short rests may be taken standing, leaning forward from the hips with the arms supported on the ice-axe or the advance knee; thus no energy is wasted getting up and down. The breathing should be free when resting. Rest periods may well be timed to fit in with views, photography, meals or even a swim.
Normally the whole foot should be placed on the ground. Walking on the toes reduces the strain on the front thigh muscles, but increases that on the calves and on the ankles. Toe walking is suitable for short distances steeply uphill on narrow trails or stairs; but usually it is better to turn the feet to the side, together or in herringbone fashion, and use the whole foot. Proper placement of the foot is important, so that it will be as nearly horizontal as possible, on a solid surface, and one which is not slippery. Usually bedrock is safer than grass, gravel, damp soil, slippery logs, snow or ice.
The security of the foot may be increased by increasing the area of contact, pushing into the surface perpendicularly or pushing the side of the foot against an adjacent surface. The instep may be more secure than the ball of the foot on a rounded surface; the heel is usually least secure. The hands may be used for balance or even for assistance in pulling up steep places, but the bulk of the work should normally be done by the legs. Facing out is usually best in climbing down, but in difficult climbing it may be preferable to face sideways or even inward toward the face of the ladder or steps (Figure 1-J, N).
Mountain climbing consists largely of walking, on the level and up and down hill. The basic principles of dynamic posture apply to walking on snow and ice as well as to walking on soil and rock, but consideration must be given to the softness or hardness of the surface and to the tendency to slip. The center of gravity of the body must remain over the balls of the feet or, in forward motion, in front of them. When one foot is advanced, the trunk weight must be shifted to the leading foot before the rear foot is lifted. In sidestepping on skis or herringboning on foot or on skis, the weight is shifted to the uphill foot before the lower foot is raised. Movement on treacherous surfaces must be particularly smooth, precise and light, with good timing. Keep the weight over the balls of the feet, or in front of them!
There are three exceptions. In going face downhill on snow the heel may be dug in, to make a step, by stepping hard or jumping on the heel. The weight thrust goes on the heel, but the center of gravity should still be forward. The same principle may be used in glissading down a steep slope if it is not hard. In climbing a steep face or overhang with the weight hanging partly from the arms, the toes press against the rock with the heels down and the weight back in order to prevent the feet from slipping from the face, like a bracket on the wall. The same principle applies in leaning out on a foot or ski traverse, but the trunk is leaned out and the knees inward in order to give the edge of the boot or the ski a better grip on the surface. Some of the older skiing techniques required the weight to be back on the heels, especially for turning and stopping, but have been superseded by the newer and more effective techniques with the weight well forward. However, the weight should be kept back on the heels, hips back and trunk inclined forward in walking steeply uphill on foot or on skis if the surface is slippery, in order to prevent the foot or the skis slipping backward. Similarly in snow-plowing or glissading, in changing suddenly from fast to slow snow, the weight should be kept back, as the body tends to fall forward because of the resistance of the snow. In glissading the heels are dropped as brakes in order to stop or go slower, and the weight is tilted back to prevent a fall forward; to go faster the toes are dropped so that the feet are parallel with the surface, and the weight is kept well forward.
When a weight such as a rucksack is carried on the back, the center of gravity is shifted backward; therefore the body should be tilted further forward, particularly in making a sudden forward or upward movement. Weight-lifting should be done from the crouch position, using the legs rather than the spine for the lift. Similarly, pushing or pulling a weight, such as a boulder, should be done with the body in a crouch, the weight close to the body, using the movement of the whole body, all in one direction, for the combined effect of muscle action and momentum. Falls on slippery surfaces are nearly always backward, and often result in fracture of the wrist, or even the coccyx or the spine. It is impossible to see or to double up to protect oneself in falling backward. It is almost impossible to slip on a slippery surface from the crouched position because the feet grip much more firmly. Falls from this position are forward: one can see and double up for protection. But such falls rarely occur except from tripping.
Walking a log, or along a narrow ridge, or over boulders, often involves a mental hazard which causes marked slowing of the pace. The balance is not so good at a very slow pace as at an average pace, and it may be still further disturbed by the loss of momentum. It is like riding a bicycle: it is almost impossible to balance at a very slow speed, but a little speed makes balance easy. One should not rush, however, for time is needed to see and choose footholds, and wild scrambling is precarious. It is best to note the footholds ahead, and then to proceed with a smooth, steady pace. The feet should advance straight ahead in the ordinary position, or turn moderately outward in the herringbone position if the grip of the instep is needed. The surest way to fall off a log is to turn and walk sideways. The chance of recovery by grasping the log is much poorer, too.
Jumping is done now and then in the mountains, across logs or boulders, a stream or a crevasse. The usual jump is a leap, springing from one foot and landing on the other, with a standing, stepping or running start, and a stepping or running finish. The leap may be broad, to clear a wide space, or high, to clear an obstacle or rise to a higher position. When the forward motion is to be continued on landing, the feet are used successively as in running, and the weight is kept forward. When the landing is uncertain and stationary, or after a downward leap, the landing is often made on both feet simultaneously, with one slightly ahead for greater stability and the weight slightly back for stopping. Jumping from both feet is possible, but more difficult, because there is less spring and momentum, although the initial footing is more secure. The arms aid in lifting the body by leading the movement from the crouch position, followed by the trunk, and finally the rear leg. Precise timing is most important.
An obstacle may be jumped, hurdled or vaulted, depending upon its size and stability and the ability of the jumper. The legs are drawn up and turned to one side in hurdling. The standard high jump of the track athlete, running in from the side and swinging the near leg forward and over, followed by the rear leg, may sometimes be used. The track high jump in which the body is rolled horizontally over the obstacle is unfamiliar to most mountaineers and would usually be dangerous. Vaulting may be done with one hand and arm for balance and support, directly over the obstacle or with a sideward turn resulting in an about-face of the body. Try these various jumps yourself. Become familiar with them so that you will know how far you can jump safely, and which jumps you can do best. Just before the War one of the best Italian guides lost his life by failing to clear a crevasse when he jumped. Also practice with boots and rucksack if you expect to wear them in the mountains, and remember the effect of fatigue on the ability to jump well. It may help to grasp a rucksack strap with the hand to steady and balance it. It is safer, in case of doubt, to climb rather than to jump, or to go around the obstacle, particularly if there is a definite hazard below or on the other side.
Rock climbing is similar to creeping or crawling on all fours, except that the body is nearly vertical rather than horizontal. Accordingly the weight is carried largely by the legs, and the arms are used chiefly for balance. Occasionally the weight is borne largely or entirely by the arms, when there are no footholds and the rock is vertical or overhanging. Ordinarily rock climbing is done entirely with the hands and feet, the remainder of the body being kept well out from the rock for better balance and support, wider vision and the avoidance of friction. The climbing may be done largely with the fingers and toes when the rock is steep and the holds small.
A rock surface may be a face, ridge, inside corner, crack or chimney. The face is the most common surface, but varies considerably in smoothness and angle to the horizontal. Face climbing is relatively easy. The technique is simple as long as the surface is not too smooth or too nearly vertical. Ridges are also common and the technique for climbing them is similar to that for climbing faces. A ridge consists of two rock faces at an angle between zero and 180 degrees. A narrow ridge can be straddled and the legs and arms squeezed together for firmer holds. A narrow ridge which is nearly horizontal may be sat upon astride (à cheval), but friction and the nearness of the hands interfere somewhat with movement. Such a ridge may be easily crossed by hanging from it with the hands, with the feet pressed against the face below and the hips well out from the rock, moving sideways in a hand traverse. An overhang is climbed similarly, except that the movement is upward. Often the effect of an overhang can be reduced by climbing obliquely instead of directly upward. An inside corner is the reverse of a ridge, the rock faces making an angle of about 90 degrees. The inside corner may also be straddled if there are footholds. If there are holds on only one side, the back, shoulders and hip may be pressed against the smooth side for friction holds, a modified chimney technique. A chimney is formed by two opposing rock surfaces wide enough for the body, but not too wide to reach across. It may be open on one or both sides. A chimney may be climbed astride if there are footholds, or by wedging the body between its walls for friction. The back is placed against one side, usually the smoother and more vertical, and pressure made against the opposite side with one or both hands and feet. Movement upward or downward is made in caterpillar fashion, the back being moved while pressure is made against opposite sides with opposing hands and feet. There are several variations of the basic position. A crack may be climbed by wedging or twisting some part of the body in the crack to maintain sufficient friction. Holds are maintained by pushing or pulling against the rock with the feet and hands.
Footholds usually consist of standing on a ledge of rock with all or part of the foot, gravity furnishing the pressure necessary to prevent slipping. When the hold is narrow, sloping or smooth, more inward pressure must be used to prevent slipping. This may be accomplished by moving the hips and knees away from the rock and lowering the heels. The foot, knee or elbow can be inserted in a crack and twisted to produce sufficient pressure and friction for a hold. The step upward should not be too long for much more effort is used in straightening the hip or knee when it is flexed beyond a right angle (90 degrees). The knee should rarely be used as a direct hold in place of the foot, as much of the flexibility and strength of the extremity is lost, and there is more danger of pushing off rock. Similarly one should not sit on the rock or slide the hips across it in climbing down, as a rock may be precipitated on someone below. Press or pull directly into the rock, especially when it is loose, rather than sideways, which might detach and pull it off. Climb cleanly. Keep three holds on the rock while shifting the fourth. Shift the body weight onto the advanced hold before moving the rear hold.
The mechanics of rappelling are similar to those of an overhang except that the rope replaces the handholds. The hips are kept away from the rock, the feet pressed against it at a level which produces sufficient friction. The hips and knees should be kept almost straight; if they are allowed to flex, the thigh may be pulled up against the chest when it cannot be extended. The beginner tends to lean in toward the rock and thus his feet tend to slip off. Make sure the rope is secure, and then lean out!
The body is used in snow and ice climbing in the same manner as for walking and rock climbing, the difference being due mainly to soft or loose snow and to smooth slippery ice. The climber must move softly and smoothly on soft snow, to avoid falling through, planting the weight evenly on the whole foot. The knees should be kept flexed a little to prevent the knee being suddenly forced back if the heel gives way. On smooth ice it is most important to have the footholds as nearly horizontal as possible and to center the weight over the ball of the foot.
Movement is the basis of dynamic posture. Good dynamic posture is common to such animals as the cat and the horse and often to children and primitive man, but is uncommon in adult civilized man. Watch the movements of a cat. A few individuals develop good dynamic posture naturally and instinctively, but all of us can acquire it by study and training, and apply it to all our activities. Good dynamic posture frees one from tension and gives the body a feeling of lightness, of moving through space, rather than being earthbound. The body then becomes the instrument of the individual rather than the anchor dragging at his day’s activities. The tendency to fatigue is reduced, leaving more energy for other things, more endurance. Accidents are far less common with good dynamic posture. The principles of good dynamic posture—precision, smoothness, power, balance, good timing, rhythm and coordination—may be used not only for the physical body in action, but also as an approach to life.
1Much of this material has been drawn from Dr. Howorth’s article entitled “Dynamic Posture,” which appeared in The Journal of the American Medical Association for 24 August 1946. Thanks are due to the editors of that journal for permission to use the material and the drawings.—Ed.