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. Author manuscript; available in PMC: 2014 Feb 1.
Published in final edited form as: Exp Gerontol. 2012 Oct 26;48(2):259–268. doi: 10.1016/j.exger.2012.10.006

Figure 1. Experimental protocol.

Figure 1

A. The top panel shows the order of force and power tasks performed by each subject with the elbow flexor muscles. Three maximal voluntary concentric contractions (MVCC, open arrow) were followed by sets of 3 brief contractions shown in solid bars [maximal voluntary isometric contractions (MVIC), 60% and 80% MVIC] before (baseline), during (at 1 min) and in recovery from the fatiguing contraction. Recovery measures occurred at task failure (TF) and at 1, 5 and 10 min post fatigue (recovery). The fatiguing contraction (20% of MVIC, either dynamic or isometric) is symbolized with the hatched rectangle, and was performed until task failure by each subject. The second and third panel shows with the arrows, when the magnetic stimulation (M-stim) and electrical stimulation (E-Stim) were applied during each contraction. Please note the Figure 1A is not to scale. B–C. Representative data for an old male subject. B. Motor evoked potential (MEP) during MVIC contraction performed before (solid line) and after (dotted line) the dynamic fatiguing contraction. C. Shown are the interference EMG and elbow angle (provided as feedback) for 5 contractions at the start and end of dynamic fatiguing contraction.