Sex Differences in Electromechanical Delay during a Punch Movement1

—This study assessed how sex of participant is related to electromechanical delay during a karate punch. Ten male (M age = 25.00 yr., SD = 3.02; M height = 174.9 cm, SD = 6.3; M weight = 71.13 kg, SD = 9.35) and 8 female (M age = 27.4 yr., SD = 6.0; M height = 161.4 cm, SD = 5.1; M weight = 59.09 kg, SD = 7.00) karate athletes performed 10 ballistic punches to a target as hard as possible. Kinematic analysis and surface electromyographic (EMG) activity of the upper-limb muscles were recorded. Men had a significantly shorter electromechanical delay in the anterior portion of the deltoid, showing a larger effectiveness in the transfer of the contractile force for the beginning of movement. Agonist and antagonist relationships show intermuscular coordination differences between the sexes. Results revealed the existence of a different neuromuscular coordination pattern of motor control between men and women, although a similar kinematic pattern was expected due to karate practice.