The result of isometric training on strength development was first reported to provide a 5% per week increase (12), but later it was reported as 1.8% per week in their subsequent publications. There was some outcry as to the accuracy of the work by Hettinger and Muller (13,14).
1n 1962, against mounting criticism, Muller argued that strength increases depended upon an individual’s current state of conditioning, with those who were less fit, gaining more rapidly, and those who were more fit, less rapidly.
The weekly gains vary from 12% (2.4% per session) assuming five training sessions per week for those in a poorer state of health to less than 2% (0.4% per session) for those close to their limiting strength.
Therefore, according to Muller, even for the untrained, very few weeks are needed to reach limiting strength. Muller believed the results depicted in the Table explained why the results of other studies may have been at variance with his own: “Contrary findings are distorted by comparing unequal states of training.”
They (Hettinger and Muller) later defined the training state operationally: the state of training of a muscle is its initial strength (Pi) expressed as a percentage of its end strength (Pe). Limiting strength is defined as the final value to which strength can reach at its maximum potential regardless of how long training goes on, i.e., training can go on forever, but it is believed that strength increases have a limit.
So the final value depends on two things: 1) the strength capacity of the muscle and 2) the efficiency of the training method adopted. Therefore, if the training program chosen is of little value, then end strength would occur rather quickly since the method cannot serve to increase strength because of its ineffectiveness.
There is an inherent weakness to assessing strength in this manner and certainly one way around this is to establish a database of age and sex-related norms to qualify an individual’s initial fitness status.
Basically what we’re saying is isometrics is the best way to gain strength!
The biggest advantage to this type of training is twofold.
First, by forcing your muscles to hold a position for a certain length of time, your body starts to recruit more and more motor units to help maintain this contraction. Motor units that are rarely exercised within a muscle are now brought into use, perhaps for the first time.
Second, the motor units that are recruited are forced to contract continuously, time after time, until your muscles achieve a state of maximum intensity safely and effectively.
The end result is that the entire muscle matures very quickly.
Resistance band training with an isometric strategy adds additional benefits to the athlete beyond traditional isometrics. Read more at http://www.isoinsane.com/isometric-strengthening-effect/