As the individual becomes stronger, the 10RM will increase in weight. A progressive overload occurs with this method of training. Isometric strength training was very popular during the decade between 1955-1965. German researchers reported large gains in strength with this form of training. Isometric training involves static exercise where the muscle attempts to shorten but is not allowed to change length.
Isometric training can provide relatively quick overloading and strengthening of muscles.
However, the isometric strength is specific to the angle of the joints involved. There is little transfer of isometric strength developed at one joint angle to other joint angles or body positions. This does not allow for development of strength throughout the entire movement. The use of this form of training can develop strength in muscle groups although the training must be at several joint angles to benefit the total motion. Isometric training can be used in a rehabilitative setting to aid injured swimmers.