Surface electromyographic activity of the erector spinae and multifidus during arm and leg ergometer exercises in young healthy men

Surface electromyographic activities of the erector spinae and multifidus during graded arm- and leg-ergometer exercise were investigated. Fifteen young healthy male participants performed arm- and leg-ergometer exercises at 50W and 100W for 1 min, while monitoring the electrocardiograms of the paraspinal muscles and heart rate, and the root mean squares of the electromyograms were calculated. Time series of contractions of the paraspinal and extremity muscles during both exercises were assessed (n = 7). Both paraspinal muscle activities increased with increased workload in both exercises similarly (P < 0.01, each). Heart rate increased with increased workload, and the increase was greater for arm-ergometer exercise than for leg-ergometer exercise. Each contraction time of trunk and limb muscles suggested that the paraspinal muscles facilitated trunk rotation and prevented excessive lateral bending of the trunk, respectively. The activities of these paraspinal muscles increased with increased workload similarly in both exercises, although heart rate response was different between them.