In proprioception, the brain is communicating with the muscles as to the specific level of involvement required to achieve the movement objective. The importance of this neuromuscular relationship becomes most obvious as the deterioration of the muscle tissue occurs. Older adults will adapt their movements to compensate for their muscular weaknesses. While single joint action or muscle isolation exercises are helpful, they cannot match the total neuromuscular involvement of a multi-joint or gross motor movement. Walking is an example of a gross motor movement which is vital to the older adult.
There are two phases of a normal walking gait cycle. Stance is the interval in which the foot of the reference extremity is in contact with the ground. Swing is that portion in which the reference extremity does not contact the ground. The normal gait cycle is 60% stance and 40% swing. Two additional components of the cycle are double limb support and stride length. Double limb support refers to the two intervals in the gait cycle during which body weight transfers from one foot to the other while both feet are in contact with the ground. Stride length is the distance of a full gait cycle from the point of heel strike of one extremity to the point of heel strike of the same extremity. Normal stride length is approximately 1.5 meters.
Weakness in different muscle groups will affect the gait in different ways. Decreased stride length reflects instability during single limb support of the opposite leg. Lack of stabilization will also lead to increased step width and to increased double limb support time, because less muscle tissue is available for balance control. The older adult then further compromises the gait pattern with side to side swaying and with shuffling of the feet. He or she typically fears that any wrong move may lead to a fall.
As the sedentary lifestyle continues, an inverse relationship is created: as caution regarding normal movement increases, the ambition for any movement decreases. Thus, lean muscle tissue proceeds down a spiral of progressive decline, ultimately leading to the requirement of a walker, motorized chair, or even nursing care because the individual is simply too weak to get out of bed and function in "real life."
Although this is a painfully common scenario in our society, the good news is that it is definitely not inevitable. Stabilization techniques to build functional muscle strength and ensure a continued lifestyle of autonomy are easy to perform.
First, it is important to understand that an exercise program must be established based on some prerequisite information. The current level of function should be identified after medical clearance to exercise is given by a physician. This functional assessment is not to be confused with the typical tests for strength commonly used in the fitness industry. Regarding the older adult, much can be learned about his or her present lifestyle through a verbal interview process and through observation of selected gross motor movements. For example, have the individual sit in a chair, stand up, and sit down again. After performing the activity two or three times, does the individual need assistance? Does he or she manipulate other body parts to be successful at the maneuver? Can the individual perform the movement without swaying or needing to take a step for correction of balance when rising to the standing position? The answers to these and similar questions can provide definitive information as to which muscles need to be conditioned to perform the task properly.