Increased Liveliness of Trunk Muscle Responses in Elite Kayakers and Canoeists

Abstract

Trunk stability functions play an important role in sport and everyday movements. The aim of this study was to analyze trunk strength, trunk muscles onset of activity, and rate of electromyographic rise (RER) in the case of self-inflicted and unexpected trunk loading. Thirty-two healthy young adults (16 elite kayakers/canoeists and 16 non-athletes) were measured with a multi-purpose diagnostic machine. Trunk strength was assessed in standing position. Trunk muscles onset of activity and RER were assessed through unexpected loading over the hands and rapid shoulder flexion, respectively. In comparison with non-athletes, kayakers/canoeists did not significantly differ in trunk strength and showed lower trunk extension/flexion strength ratio (p = 0.008). In general, trunk muscles onset of activity did not significantly differ between the groups. On the contrary, kayakers/canoeists showed higher RER mean values in all the observed muscles (p < 0.041), except in multifidus muscle during self-inflicted movements. Similarly, higher RER variability was observed in the majority of the observed muscles among kayakers/canoeists. Higher RER among kayakers/canoeists could represent a protective mechanism that ensures spine stability and prevents low back pain.

Effect of different isometric trunk extension intensities on the muscle stiffness of the lumbar and lower limbs

“…After pre-experimentation, three contraction intensities of 0%, 30%, and 60% MVIC were selected in this study to explore the optimal intensity for effective ES activation. Trunk flexion produces greater lumbar extension forces than the neutral trunk position, but this is primarily a force produced by the hip extensors with less force being generated by the lumbar muscles ( CHOLEWICKI and VANVLIET, 2002 ; Kocjan and Sarabon, 2014 ) also found that the lumbar back muscles contributed most to spinal stability in neutral isometric extension exercises compared to flexion tests. In combination with our previous experiment ( Zhang et al, 2023 ), lumbar extension strength in the trunk hyperextension position was not as strong as in the trunk neutral position, and therefore we chose to perform IPTE in the trunk neutral position to assess lumbar extensor strength.…”