Isokinetic resistance

Active indirect techniques are those in which the patient is asked to contract the ipsilateral antagonist muscles or the same muscles on the contralateral side. This method uses either the reciprocal inhibition or the crossed extensor reflexes to relax the muscles being treated. In these techniques, the physician typically applies isokinetic resistance to the patient s contraction, (hokinetic resistance The physician applies a resistive force such that the muscle contraction increases very little with the gradual decrease in muscle length i.e., the joint is allowed to move and the resistance is gradually increased.)... 

FIG. 26-9 Active indirect stretch of the paravertebral muscles using crossed extensor reflex (A) Starting position. (B) Midway through the maneuver, with the patient attempting to bring his chin to his right shoulder as the physician applies isokinetic resistance. (C) A passive stretch ends the technique. 

FIG. 37-17 Active indirect myofasciai technique for the thoracic region. The physician provides an isokinetic resistance to the patient s ieft arm puii. Passive stretch added at end. 

The aforementioned technique may be modified to treat the uppermost muscles by raising the ankles toward the ceiling and having the patient push down toward the floor. The legs are allowed to move against an isokinetic resistance. The patient is now contracting the muscles closest to the table to relax the uppermost muscles by reciprocal inhibition. A passive stretch may be added at the end of either of these techniques. 

Note An assistant creating an isokinetic resistive force against the medial aspect of the heels wdl increase the effectiveness of the exercise. 

In addition to chemical reactions, the isokinetic relationship can be applied to various physical processes accompanied by enthalpy change. Correlations of this kind were found between enthalpies and entropies of solution (20, 83-92), vaporization (86, 91), sublimation (93, 94), desorption (95), and diffusion (96, 97) and between the two parameters characterizing the temperature dependence of thermochromic transitions (98). A kind of isokinetic relationship was claimed even for enthalpy and entropy of pure substances when relative values referred to those at 298° K are used (99). Enthalpies and entropies of intermolecular interaction were correlated for solutions, pure liquids, and crystals (6). Quite generally, for any temperature-dependent physical quantity, the activation parameters can be computed in a formal way, and correlations between them have been observed for dielectric absorption (100) and resistance of semiconductors (101-105) or fluidity (40, 106). On the other hand, the isokinetic relationship seems to hold in reactions of widely different kinds, starting from elementary processes in the gas phase (107) and including recombination reactions in the solid phase (108), polymerization reactions (109), and inorganic complex formation (110-112), up to such biochemical reactions as denaturation of proteins (113) and even such biological processes as hemolysis of erythrocytes (114). 

Figure 31 shows the resistivity measured by the conductivity probe and the local concentration measured by the isokinetic sampling method. Measurements were made for slurries of polystyrene particles of 1.4-mm mean diameter at the pipe center and at radial positions of R = 0.8. Good agreement with calibration results is seen in these tests. Because the particles used in these experiments were large, no samples could be withdrawn from the center of the pipe at concentrations higher than 35%. Also, no voltage measurements could be taken closer to the pipe wall because particles tended to be trapped between the probe and the wall. 

Z Isokinetic. A dynamic exercise in which the speed of motion is controlled by varying the resistance. 

If, as the momerrt arm lessens, the weight in the palm corresportdingly is increased, then the resistance corrtirtually increases with flex iorr. The speed of flexion will remain con-starrt. This is an example of isokinetic exercise, which can orrly be performed by using rrtachines designed for this purpose. 

Thiistle, HG, Hislop HJ, Moffroid M. 1967. Isokinetic contraction A new concept of resistive exereise. Areh Phys MerfRehabil 1967 48 279-282. 

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