Abstract: Objective: To analyze and compare the consistency of muscular exertion in straight arm bow-opening and bent arm bow-opening techniques. Methods: 16 young healthy male compound bow beginners were randomly chosen as subjects to continuously shoot 12 arrows with the two techniques respectively. The sEMG signals of major muscles on both the arms were collected synchronously with Cometa Wireless sEMG Test System. In addition, iEMG's "ratio of standard deviation to average (%)" was used as a derivative indicator. The difference of the averages of the two techniques were investigated with the two-factor repeated measures ANOVA statistical method. Results: (1) In the straight arm bow-opening technique, the Z_10-12 (%) values of both the lateral deltoid and the posterior deltoid on the holding arm were higher than the Z_1-3 (%) value (P<0.05) and there was no significant change in both the Z_10-12 (%) value and the Z_1-3 (%) value of triceps; both the Z_7-9 (%) value and the Z_10-12 (%) values of biceps, posterior deltoid, and lower trapezius on the drawing arm were higher than the Z_1-3 (%) value (P<0.05);(2)In the bent arm bow-opening technique, the Z_10-12 (%) values of triceps, lateral deltoid and posterior deltoid on the holding arm were all higher than the Z_1-3 (%) value (P<0.05); the Z_10-12 (%) values of biceps, posterior deltoid, and lower trapezius on the drawing arm were higher than the Z_1-3 (%) value (P<0.05); (3) In the two open-bow techniques, there was no significant difference in the Q (%) and Z (%) values of major muscles from arrow 1 to arrow 9 (P>0.05); while the Q10-12 (%) value was significantly lower than the Z_10-12 (%) value and the Q_1-12 (%) was also significantly lower than the Z_1-12 (%) value (P<0.05). Conclusion: (1) Consistency of major muscles of the upper arm and trunk was significantly reduced when compound bow beginners shot the last three arrows of the twelve arrows respectively with the straight arm technique and the bent arm technique. The posterior deltoid on the holding arm was the most obvious, followed by the triceps and the lateral deltoid; while the biceps on the bow drawing arm was the most obvious, followed by posterior deltoid and lower trapezius.(2) In the two bow-opening techniques, compound bow beginners' consistency of both the holding arm and the drawing arm in the bent arm technique was higher than that in thebow-opening technique, especially in arrow 10 to 12.

Key words: compound bow, straight arm bow-opening technique, bent arm bow-opening techniquw, consistency, bow-holding arm, bow-drawing arm