Muscle activation comparisons between elastic and isoinertial resistance: A meta-analysis

Background: Elastic resistance has been commonly used in the therapeutic and fitness setting; however, the ability of elastic resistance to overload and activate muscles has been questioned because of linear increase in elastic resistance as the device is elongated. The purpose of this meta-analysis was to examine the available literature on muscle activation associated with isoinertial and elastic resistance exercises, and to provide a quantitative summary comparing the two resistance training modes.

Methods: In a random-effects model, the Hedge's g effect size was used to calculate the biased corrected standardized mean difference between the elastic and isoinertial resistance activation of prime movers (agonist), antagonists, assistant movers and stabilizer muscles.

Findings: There was a lack of significant difference with the prime movers (effect size=-0.037, confidence interval: -0.202 to 0.128, p=0.660), antagonists (effect size=0.089, confidence interval: -0.112 to 0.290, p=0.385), synergists (effect size=-0.133, confidence interval: -0.342 to 0.076, p=0.213) and stabilizer (effect size=0.142, confidence interval: -0.006 to 0.289, p=0.060) muscle electromyography activity recorded during similar exercises using elastic and isoinertial resistance.

Interpretation: Elastic resistance provides similar prime mover, antagonist, assistant movers and stabilizer muscle activation as isoinertial resistance; contradicting the traditional criticism that the elastic band would not elicit comparable levels of muscle activation as isoinertial resistance exercise. Since development of muscle strength is closely related to the duration of muscle tension, relatively equal muscle adaptations could be expected following the two modes of training provided that equal external resistance is employed between the two exercises.

Level of evidence: 2a.