The Effect Of Eccentric Strength Testing On Delayed-onset Muscle Pain

Abstract

Eccentric training is increasingly being recommended due to decreased ratings of perceived exertion and increased strength gains. Eccentric strength testing is required to evaluate eccentric training programs, but such testing may cause muscle adaptation in and of itself. PURPOSE This investigation examined the effect of eccentric strength testing on delayed-onset muscle pain. Muscle pain was the primary dependent variable due to its importance in exercise adherence and its failure to correlate with other indices of muscle damage. METHODS Upper-body untrained university students (N = 20, 50% women) performed eccentric strength testing (5 RM) bilaterally. Next, one arm - either dominant or non-dominant - completed 3 sets of 10 eccentric repetitions to induce delayed-onset muscle pain. Then, in a subsequent experimental session, whichever arm previously performed only the 5 RM test, completed the 5 RM test a second time and the 3 sets of 10 eccentric repetitions. Thus, one arm performed two strength tests (2 – 5 RM arm), one arm performed one strength test (1 – 5 RM arm), and both arms performed the muscle pain induction protocol. Bilateral ratings of pain intensity and pain unpleasantness were collected for 48 hrs after both sessions. RESULTS Based on pain ratings of the arm that initially only performed the 5 RM test, the 5 RM test increased pain intensity and unpleasantness across 48 hrs post-exercise, F2, 38 = 11.25, p <.01, ν2 = .37, and, F2, 38 = 11.23, p <.01, □2 <.37. However, comparison of the delayed-onset muscle pain ratings from the arm that completed two strength tests (2 – 5 RM arm) to the arm that completed only one strength test (1 – 5 RM arm) revealed lower pain intensity, ts(19) = 2.89–3.04, ps <.05, d = .67−.58, and pain unpleasantness, ts(19) = 2.60, ps <.05, d = .54−.72, in the arm that completed a previous strength test. CONCLUSION Thus, the eccentric strength testing alone produced low levels of delayed-onset muscle pain. However, a 5 RM eccentric strength test was sufficient to protect against future delayed-onset muscle pain. These results have direct implications for the development and assessment of eccentric strength training protocols. Supported by NIAMS Postdoctoral Fellowship Grant (AR08623-01) to Dr. Erin A Dannecker.