The conclusion, then, is obvious, and is drawn, not from this case alone, but from many similar experiences. When a movement is impeded by adaptive shortening and attempted increase in movement is painless, passive stretching by the use of gravity may be used as a definite curative agent. It is not, however, the best at our disposal. If, on the other hand, the movement is painful, as is usually the case when adhesions are present or when there has been septic infection, passive stretching will inevitably tend to increase the deformity unless the tension is constant (as, for instance, when elbow flexion is secured by the use of a "cuff and collar," as shown in Fig. 76, p. 150). It is the intermittent nature of the strain that is fatal to success. But if, in order to secure extension when pain is present, our correct plan of action is to train the extensor muscles, surely it is rational to suppose that this treatment will prove no less efficacious if pain is absent. And, indeed, I regard it now as a sine qua non that every movement which is deficient should be restored by training the muscles that control the movement, while, at the same time, we teach the antagonists to relax instead of trying to stretch them. Even if an adhesion is present, which when stretched is the cause of pain on extension, active contraction of the extensors and relaxation of the flexors is calculated to effect the stretching of the offending band far more readily than any amount of tension that is not constant.

In the first edition of this book I was content - though with qualms - to leave unqualified the statement made above that "a patient can perform a forced movement by utilising the force of gravity in various ways," and quoted "squatting" as an example of forced flexion of the knee, and the use of a horizontal bar for that of extension of the elbow. I now believe that this was an error, and that rarely is very much gained by either expedient in the direction desired. The former trains the quadriceps, the latter the brachialis anticus, whereas the correct way to deal with the problem is to train the hamstrings or the triceps. I have devoted much space to the elucidation of this principle, partly, perhaps, because I formerly failed to recognise its full truth, and partly because of its bearing on all remedial gymnastics. Few medical gymnasts, so far as I know, are aware of its existence; fewer still appreciate its importance.

Examples might be multiplied throughout the whole range of remedial and educational exercises and gymnastics.

3. Resistive Exercises. - The resistance may be administered by the masseur in two ways, or, as in the case of assistive exercises, the force used may be derived from mechanical apparatus, or from gravity alone. The last has already been fully dealt with; and little need be said in this connection of the use of apparatus, as the converse of the various points raised when dealing with assistive exercises by apparatus will be found to hold good.

If the masseur is supplying the resistance, a movement may be performed by the masseur while the patient resists (excen-tric), or by the patient while the masseur resists (concentric). It is plain that in performing the latter the amount of resistance given depends on the masseur, whereas in excentric the patient arranges the matter for himself. In concentric movement the muscle exercised shortens in length in the natural manner; whereas in excentric movement, although contracted, the muscle may actually lengthen.

When treating a muscle during the early stages of recovery from paralysis, excentric movement should never be employed throughout the whole range of movement. But during recovery it is sometimes found that a patient is able to offer slight resistance before any actual voluntary movement can be performed, except with the assistance of gravity or in a position in which true free movement is possible. At the same time we must bear in mind that whatever tends to stretch the muscular fibres is to be deprecated. Hence the law governing treatment of this condition is that the administration of excentric resistive exercise may be performed only in the inner half of the path of contraction. This means that the movement of the part is limited in range to the final half of the movement that can be attained by the contraction of the muscle when in health.

Concentric movement is easy in application and of the utmost service during all the earlier stages of treatment. It is of particular importance to utilise it as early as possible, when it may take its place in the middle of a prolonged assistive movement. For instance, if the brachialis anticus is very weak, it is possible that movement from the vertical to 300 may call for assistance; from 300 to 6o° there may be enough strength to raise the forearm against the resistance of gravity. By this time the muscle is shortening and gaining in power, so it may be possible to supplement the resistance of gravity up to the right angle. Soon after, perhaps, the muscle is only strong enough to continue the movement against gravity, and lastly assistance may be required to finish the last few degrees of movement. The management of the resistance obviously requires skill and care, since it starts from negative (during the assistive stage), passes zero, rises to a maximum, passes to zero again, and finally becomes negative. In a movement of wide amplitude, such as that of full flexion and extension of the elbow, the problem is fairly simple; but in dealing with a movement of small amplitude, such as rotation of a forearm, which perhaps is further limited by pathological change, the utmost delicacy of touch can alone suffice. But incontestably the best way of regulating resistance is to regulate by postural change the resistance afforded by gravity. Further details as to the technique will be found in the chapter dealing with the re-education of muscle (see Chapter XIX (The Re-Education Of Muscle).).