The Effect of Erector Spinae Muscle Fatigue on the Sensation of Trunk, Hip, and Knee Position among the Male Karate Athletes

Proprioception (PP) and balance play a significant role in improving performance and preventing acute and chronic sport injuries. Muscle fatigue can be one of the factors that may interfere with signaling sensory input to the brain, and disturb the balance. The effect of muscle fatigue on this sensation has hardly been studied. The aim of this study was to investigate the effect of erector spinae muscle fatigue on the sensation (PP) of trunk, hip and knee among the male Karate athletes.

10 male karate athletes participating in Iranian national league matches were recruited in this study. Absolute error of active angles reconstruction (the trunk in 45 degrees of flexion, the hip in 30 degrees of abduction and flexion in open kinetic chain, and the knee in 30 and 60 degrees of flexion in closed kinetic chain) was measured by filming and analyzed, using AutoCAD software in pretest and posttest. Sorensen test was used as fatigue protocol.

The t test showed that erector spinea muscle fatigue had a significant effect on trunk flexion in 45 degrees (P = 0.046), and dominant (P = 0.001), and non-dominant (P = 0.001) hip joint in 30 degrees of abduction; but did not have any significant effect on positioning sensation of dominant (P = 0.434) and non-dominant (P = 0.703) hip flexion in 30 degrees, dominant (P = 0.148) and non-dominant (P = 0.204) knee flexion in 30 degrees, and dominant (P = 0.417) and non-dominant (P = 0.439) knee flexion in 60 degrees.

According to the obtained results, erector spinae muscle fatigue in Karate athletes is likely to cause disruption in their trunk and hip position sensations, which can be the probable cause of lower-limbs injury and instability, particularly in the hips. Erector spinae muscle fatigue, however, may have no significant effect on knee position sensation or the injury potential of this joint