The lower body muscle activation of intermediate to experienced kayakers when navigating white water

In white-water kayaking, the legs play a vital part in turning, stabilising and bracing actions. To date, there has been noreported information on neuromuscular activation of the legs in an authentic white-water environment. The aim of thecurrent study was to identify lower body muscle activation, using ‘in-boat’ electromyography (EMG), whilst navigating awhite-water run. Ten experienced male kayakers (age 31.5 ± 12.5 yr, intermediate to advanced experience) completedthree successful runs of an international standard white-water course (grade 3 rapids), targeting right and left sides of thecourse, in a zigzag formation. Surface EMG (sEMG) outputs were generated, bilaterally, for the rectus femoris (RF),vastus lateralis, biceps femoris and gastrocnemius, expressed as a percentage of a dynamic maximal voluntary contraction(dMVC). Only RF showed significantly higher activation than any muscle on the left side of the body, and only on the leftside of the course (P = .004; ETA2 = 0.56). Other results showed no significant difference between muscle activation inthe right and left legs during each run, nor when assessed at either the right or left side of the course (P > .05). Thesefindings indicate that contralateral symmetry in lower limb muscle activation is evident during white-water kayaking. Thissymmetry may provide a stable base to allow more asymmetrical upper body and trunk movements to be fully optimised.Lower body symmetry development should be considered useful in targeted training programmes for white-water kayakers.Keywords: Kayaking; electromyography; white water; bilateral; lower body; bracin