Determination of Success or Failure in Dynamic (Isotonic) Movements by Isometric Methods

The results showed that failures in the dynamic task could be predicted by isometric measurements, and suggest that perhaps the controlled dynamic movement against resistance is essentially a series of isometri...

Abstract

Abstract A study was conducted to determine whether dynamic (isotonic) strength may be evaluated isometrically. A measurable task, chinning (pull-ups), was selected. A survey was first made of 128 young males to determine whether isometric testing could select and predict successful from nonsuccessful chinners (ability or inability to chin once). Isometric testing positions were used at places where failure was previously demonstrated to be frequent on the dynamic task. The results showed that failures in the dynamic task could be predicted by isometric measurements. Subjects who were unsuccessful were given special exercises. Those who eventually became successful reached the predetermined isometric strength levels necessary for success. The unsuccessful never attained those levels. The strength necessary for a dynamic movement appears to be amenable to measurement by isometric techniques. The data suggest that perhaps the controlled dynamic movement against resistance is essentially a series of isometric contractions at successive points through a given range of motion about a joint.