1974 Volume 18 Issue 4 Pages 191-198
Electromyograms were recorded with cords from 9 muscles of upper extremity and shoulder girdle, the serratus anteriors of both side and the tensor fasciae latae, during paddling the kayak chained in the paddling tank. Paddling form was filmed with 16mm or 8mm movie camera in 32 frames a second, and pulling strength developed on tne paddle was recorded with strain gauge attached at the central part of the shaft. These were simultaneously recorded with the electromyograms. Subjects employed in the experiments were 4 candidates for the Canoe Regatta of Mexico Olympics for the skilled subject, 5 unskilled college boys of 3 months experienced in paddling kayak, and 2 beginners of male adults. The loci of the center of blade and the grip point plotted from the movie pictures indicated that the skilled subjects performed more effective catch and paddling even in the latter half stage between middle and finish with more elected paddle than the unskilled subjects and the beginners. The marked discharges of the deltoid posterior portion, the latissimus dorsi, the teres major, and the triceps brachii long head were observed during pulling motion, and the deltoid anterior portion and the pectolaris major clavicular portion, during pushing motion, in the skilled subjects and even in the unskilled subjects. No discharge of the pectolaris major abdominal portion in the skilled subjects and few in the unskilled subjects were observed during pulling motion. This indicates that the direction of pull of the paddle is somewhat outward from the sagittal plane. The marked discharges of the serratus anteriors of both side in the skilled and unskilled subjects showed that the subjects twisted their trunks fully. But the discharge of the serratus anterior appeared far in advance of the one of the posterior deltoid in the skilled subjects. This means that the subjects performed trunk twist far in advance of pulling motion. The discharges of the muscles appeared at about the same time in the most cases of the unskilled subjects. However, after one month training, the discharge of the serratus anterior tended to appear earlier than the posterior deltoid. No discharge of the biceps brachii long head and the triceps brachii lateral head during pulling motion was observed in the skilled subjects, however, fairly large discharges of the muscles, in the unskilled subjects. This indicated that the unskilled subjects uselessly fixed their elbow joints in contrast with the skilled subjects. Only a few discharge of the tensor fasciae latae in the skilled subjects and fairly large discharge in the unskilled subjects, suggested that there was more useless muscle contraction in the lower extremity of the unskilled subjects than the skilled subjects. In the beginners, one of them could not make all of the upper arm extensors participate in pulling motion, and the another, even though he could make them participate in the motion, developed only far small pulling strength on the paddle as compared even with the unskilled subjects.
