Passive/Active Exercise

Regular exercise is essential for health, but for those who can walk no more than a few steps at a time, or not at all, such exercise can be difficult to obtain.

Over the past few years, a new method for exercising limbs that have full or partial disability has evolved in conjunction with a new class of machine called a passive/active exerciser. Powered by an electric motor, this compact, portable machine is located in front of the individual, who is seated in a wheelchair or a lounge chair. The feet are strapped into foot plates; simple controls set direction of rotation and speed.

With a passive/active exerciser, the person can relax as the slow, predictable, orbital motion is provided entirely by the electric motor. Such exercise is known as passive exercise, and can be enjoyed even while watching TV. People find it psychologically satisfying, even soothing, to see their legs moving in a predictable manner. According to many users, there is often a reduction in limb pain and swelling (which is often caused by inactivity), and improved flexibility in muscles and tendons. Also reported are better bowel and bladder control and function, as well as improved ability to sleep.

Active exercise occurs in a muscle when nerve impulses cause individual muscle cells to contract against a load. This is the kind of exercise that improves the strength of muscle cells. For many people with disabilities, however, conventional exercise is not possible. Thus it is very difficult to maintain the minimum strength level required to weight-bear or get out of a chair, for example.

Passive/active exercisers provide the link between no exercise and the level of exercise that could be obtained with an exercise bicycle. These machines are designed to cover both passive exercise requirements and the possibility of active exercise, if desired. The machine providing the exercise alternates easily back and forth between active and passive mode. For instance, as the legs are being orbited in the passive mode, an individual with some muscle power in one or both legs can use this ability to assist the motion, thereby slightly reducing the amount of power required by the motor. When tiredness sets in, the machine automatically falls into passive mode until the next attempt at active exercise.

To reinforce production of active exercise, biofeedback can be very useful. Some exercisers provide this. An example is Tecogics Scientific Limited’s Ex ’N’ Flex line of passive/active exerciser. Its biofeedback indicator is a light display that is on at all times during use. Its starting point is in a median position. If active exercise is produced at some time during the exercise period, the light indicator will be reduced below the median while active exercise is taking place, thus giving immediate feedback.

For users with excessive tone or spasticity in their muscles, the biofeedback indicator also gives a visual output of the amount of resistance encountered by the motor to the orbiting legs. In this case, the light indicator will adopt a level above the median. As tone and spasticity in the legs decrease due to the exercise, the reading decreases back to the median.

The passive/active facility ensures that working muscles can be strengthened, while inoperative muscles are kept flexible. Thus any muscle strength that is available is not partially depleted in overcoming stiffness in inoperative muscles.

Passive/active exercise is ideally suited for daily home use as a means to satisfy the body’s need for movement. Many individuals have assured us that the pleasure of this movement does not diminish with time.

(Dr. R. Errol Gray is President of Tecogics Scientific Ltd., which manufactures a line of passive/active exercisers.)