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Humans can complete movements successfully because their postures compensate for forces exerted during movements. For example, a person would fall toward a heavy door during the process of opening it if muscles in the back of the legs and trunk did not contract and thus stabilize the body. These postural compensations are essential, but are frequently absent in dysfunctional neuromuscular systems. Posture and movement are thus coordinated, but the details of how this is accomplished are only beginning to be understood. In the past, research on postural control has looked mostly at postural shifts following external challenges such as jostling of the supporting surface. However, maintenance of upright stance, essential for many voluntary movements, is a more common task of postural coordination and is the subject of current study. Postural control strategies have been classified as: postural reactions, which are minute adjustments occurring quickly after an action; postural preparations, with which athletes and posturally unstable people prepare by improving the support base and by tensing muscles; and postural accompaniments, small adjustments which occur just before or during the motion. This article reviews postural regulation of the upright position during limb and trunk movement. A model by which the brain coordinates postural responses to movement is proposed. A limited set of prestructured postural reactions is argued to be available to regulate upright stance. The models used by the brain in reaction to movement are developed as particular movements are repeatedly performed. Possible brain regions which may integrate movement intentions with feedback about body stability and success of the movement are postulated. Adjustment of the movement models, or learning, can occur when the expected and actual movements differ, a process important in learning novel movements or relearning tasks following brain or nervous system injury. (Consumer Summary produced by Reliance Medical Information, Inc.), Movement is performed against a background of subtle postural adjustments that counteract destabilizing forces imposed by the movement. Despite the importance of these postural adjustments to the safe and efficient performance of movement, little is known about the properties of these postural accompaniments. The purpose of this article is twofold. First, it provides a review of properties of postural adjustments that accompany a variety of limb and trunk movements. Second, a schema for the coordination of posture and movement is proposed. This schema suggests that a central nervous system model of body dynamics is essential to anticipatory control of posture during movement. [Frank JS, Earl M. Coordination of posture and movement. Phys Ther. 1990;70:855-863.], Coordination of Posture and Movement Movement is performed against a background of subtle postural adjustments that often go unnoticed by the performer. Movement perturbs posture by imposing forces on adjoining [...]

The frequency of falls significantly contributes to illness and death in the elderly population. Studies which address this problem have implicated different aspects of locomotion (walking) in falls, but research has chiefly looked at quiet standing and balance in the elderly. This is inappropriate, as the challenges to maintenance of balance posed by walking differ from those involved in standing. In standing, the goal is to maintain the center of gravity within the base of support, while during walking, the center of gravity is continually moved outside the base of support, and both feet are never flat on the ground simultaneously. Thus, walking comprises a pattern of repeatedly losing and regaining balance. Challenges to balance and central nervous system coordination during locomotion include safe swing of the foot with clearance above the floor and then gentle placement of the foot, with dynamic balance of the head, arms, and trunk. Complete gait analysis, that is, documentation of how the head, arms, trunk, legs, and feet are individually moved, has not previously been done in healthy elderly subjects. The gait of 15 active elderly individuals was analyzed and compared with that of younger adults so as to identify major or subtle changes that would signal degeneration or compensation, and to provide a database against which to compare patients with suspected problems. Several alterations in gait were found among the elderly, as compared with younger adults. Walking velocity (speed) was significantly less, which was due to reduced stride length, and was accompanied by an increase in the amount of double-support (both feet on floor) stance time. Pushoff (the force which provides power for swinging the foot out from the standing position) was less vigorous, and landings were more flat-footed, both of which are stabilizing changes. Any one of these changes may have been a primary alteration, with the others being a related compensation. The study indicates that knowledge of normal elderly gait is necessary before accurate identification of disorders that may lead to falling in the elderly can occur. (Consumer Summary produced by Reliance Medical Information, Inc.), A descriptive study of the biomechanical variables of the walking patterns of the fit and healthy elderly compared with those of young adults revealed several significant differences. The walking patterns of 15 elderly subjects, selected for their active life style and screened for any gait- or balance-related pathological conditions, were analyzed. Kinematic and kinetic data for a minimum of 10 repeat walking trials were collected using a video digitizing system and a force platform. Basic kinematic analyses and an inverse dynamics model yielded data based on the following variables: temporal and cadence measures, heal and toe trajectories, joint kinematics, joint moments of force, and joint mechanical power generation and absorption. Significant differences between these elderly subjects and a database of young adults revealed the following: the same cadence but a shorter step length, an increased double-support stance period, decreased push-off power, a more flat-footed landing, and a reduction in their "index of dynamic balance." All of these differences, except reduction in index of dynamic balance, indicate adaptation by the elderly toward a safer, more stable gait pattern. The reduction in index of dynamic balance suggests deterioration in the efficiency of the balance control system during gait. Because of these significant differences attributable to age alone, it is apparent that a separate gait database is needed in order to pinpoint falling disorders of the elderly. [Winter DA, Patla AE, Frank JS, et al. Biomechanical walking pattern changes in the fit and healthy elderly. Phys Ther. 1990;70:340-347] Key Words: Equilibrium; Geriatrics; Kinesiology/biomechanics, gait analysis; Posture, tests and measurements., Biomechanical Walking Pattern Changes in the Fit and Healthy Elderly The reduction of frequency of falls among the elderly is the goal of many researchers addressing the resultant injuries, death, [...]