Calculation of Resistive Loads for Elastic Resistive Exercises

Area of Science:

• Biomechanics
• Exercise Physiology
• Rehabilitation Science

Background:

• Determining the appropriate resistive load for elastic resistance training is often subjective, relying on clinician estimates and patient feedback.
• Objective evidence is lacking to guide the initial intensity for elastic resistance exercises aimed at strength gain.

Purpose of the Study:

• To establish an objective measure for the starting resistive load in elastic resistance training.
• To determine the average percentage of maximal isometric force that can be used to initiate strengthening exercises with elastic resistance.

Main Methods:

• A cohort of 34 subjects underwent isometric strength testing using an isometric dynamometer to measure force (Newtons) and calculate Test Torque.
• Exercise Load in pounds was derived from Test Torque, considering the point of force application relative to the joint's center of rotation.
• The average exercise load, expressed as a percentage of individual Test Torque for each exercise, was recorded.

Main Results:

• The average percentage of maximal isometric force used to initiate elastic resistance exercises was found to be 30% (±7%) of the measured test torque.
• Torque produced during exercises was normalized to body weight for further analysis.

Conclusions:

• This study provides clinicians with an objective target load (30% of test torque) for initiating elastic resistance training.
• Utilizing a load cell during elastic resistance exercises allows for objective documentation of exercise progression, despite expected individual variations.