Figure 5.
Pooled data for CMEP and Mmax with maintained muscle ischemia. Data from brachioradialis (left panels) and biceps brachii (right panels) before, during, and after a 2 min sustained MVC (0-120 sec; n = 8 subjects) with the period of maintained muscle ischemia represented by the dashed box labeled CUFF. In both panels the solid bar indicates the duration of the sustained maximal effort. A, Panels show the mean area (±SEM) of the responses to stimulation of the corticospinal tracts (CMEP, open circles) and the brachial plexus (Mmax, filled circles) expressed as a proportion of the mean initial maximal M wave (% initial Mmax). B, Panels show the mean of the CMEP area normalized to the Mmax recorded at close to the same time (% ongoing Mmax). During the 2 min sustained MVC the CMEP decreases and still recovers by the first recovery contraction to control size despite the maintained period of muscle ischemia. The broken horizontal lines indicate the mean area of CMEPs during brief control contractions. *CMEPs grouped over the last 40 sec of sustained MVC were reduced compared with those in the control period, in the first 40 sec of sustained MVC and in the first 90 sec of recovery (p < 0.05).