RST stands for resistive strength training. It is also known as isometric or static muscle training. It is applied to the contracting muscle, preventing it from shortening. Daily application of this technique for six seconds only, using two-thirds of maximum contractile force, results in an optimal increase of muscle strength. Progressive increase in the resistance, frequency of training, and duration of resistance enhances the effect.

It causes a rise in heart rate due to decreased vigil tone and increased discharge of cardiac sympathetic nerves therefore, requires great caution. Within a few seconds of the Start of isometric exercise, both the systolic and diastolic blood pressures rise.

The stroke volume changes relatively little, and the blood frown to the steadily contracting muscle is reduced as a result of compression of its blood vessels. The heart rate rises even when contraction is prevented by infusion of neuromuscular blocking drug locally or at the mere thought of carrying out the muscle contraction, suggesting the action of a psychic stimulus.

(a) Application of RST Exercise: According to the results of the prior medical evaluation the intensity, frequency, and duration of RST exercise must be established for each patient individually, as happens with the isotonic exercise. Since this form of training requires great caution, it may be prudent, especially in patients with cardiovascular diseases, not to extend the duration of an isometric contraction beyond six seconds. The pause between two isometric contractions should equal or exceed 20 seconds to allow time for the reconstitution of ATP. For healthy men and women, the ASCM currently recommends “at least one set of 8-12 repetitions of 8-10 RST exercises that condition the major muscle groups at least twice a week”.