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2000 Publications

THE REPEATED BOUT EFFECT: A CENTRAL OR LOCAL MECHANISM?by Connolly DAJ, Reed B, McHugh MPNicholas Institute of Sports Medicine and Athletic Trauma, New York, NY and Human Performance Laboratory, Department of Physical Education, U. of Vermont, Burlington, VT. - last modified 2013-02-10 00:00
Medicine and Science in Sports and Exercise. 32: S279, 2000.


Individuals undergoing an unaccustomed exercise bout incorporating a high degree of eccentric muscle contractions commonly experience delayed onset muscle soreness. The damage manifests itself via tenderness, loss of strength, swelling, elevated muscle enzyme activity and loss of flexibility.

Following an initial "damage bout," a repeated bout results in reduced symptoms. This protective effect is known as the repeated bout effect (RBE) and can last up to 24 weeks between bouts. The mechanism for this RBE is unclear and both central and local mechanisms have been suggested. In an attempt to test the central hypothesis, six subjects underwent an exercise protocol whereby one leg was exercised eccentrically and following complete recovery; the contralateral leg was exercised in the same manner.

Subjects were required to step on and off a 46-cm step for 20 minutes at a cadence of 15 steps/minute. One leg was used to go up the step (concentric) while the opposite was used to go down (eccentric). Approximately two weeks later and following complete recovery, the protocol was repeated with the concentrically exercise leg now performing the eccentric contraction. Data analyses indicate that muscle damage was induced in both trials on the eccentrically exercise leg as evidenced by a change in tenderness (bout 1 P < 0.05: bout 2 P < 0.01) and pain scores (bout 1 P < 0.0001; bout 2 P < 0.01) over a four day period. No tenderness was evident on the concentrically exercised limbs when compared to baseline (Bout 1: P =0.13, Bout 2: P = .06).

There were no significant differences in pain or tenderness scores between bout 1 and bout 2 (P = 0.84). These preliminary data do not provide evidence for a central mechanism in that an initial bout of eccentric exercise using one limb did not provide protection against damage from a repeated bout with the contralateral limb two weeks later.