| Preparation activities are an essential and important part of physical education,sports training and sports fitness.The post-activation enhancement effect is the effect of load activation by athletes during the preparation activity phase,which in turn causes rapid strength enhancement in the short time of the organism.The starting phase of dragon boat short distance events is an important part of the race performance,and the explosive power of the upper limbs during the paddle pulling is a physical quality that needs to be given high attention.Therefore,the purpose of this paper is to investigate the effect of post-activation enhancement effect induced by different loads and intervals on the explosive strength of the upper limbs,and to provide a basis for reasonable load intervals for college dragon boat athletes to test their exercise preparation before the competition.In this paper,we used literature method,experimental method and mathematical statistics to study the activation of 50%1RM,70%1RM and 90%1RM of weighted prone pulling on 10 dragon boat athletes from Minzu University of China,and monitored at four interval time points of 4th,8th,12th and 16th minutes after the intervention using surface EMG apparatus and explosive strength apparatus,respectively,to measure the effect of different index scores at different loads and interval times.The experimental results were as follows.(1)The peak power,peak velocity,and muscle integral EMG values at the 4th minute of 50%1RM weighted bench pull activation showed a small increase compared to the previous measurement.The deltoid integral EMG was the largest,the trapezius was the second largest,and the latissimus dorsi was the lowest,with the right side having higher values than the left.The three subsequent indicators at 8,12 and 16 minutes all showed a small decrease compared to the previous measurement.(2)The effective interval of 70%1RM weighted bench pull activation that could produce post-activation enhancement effect was 8-12 minutes,and the peak power,peak velocity,and muscle integral EMG values in this time period were significantly improved compared with the previous test,with the best performance in the 8th minute.There was a decrease in the 4th and 16th minutes,specifically peak velocity at 4 minutes was slightly lower than the pre-test.(3)The 90%1RM weighted pulling activation improved from 8-16 minutes,mainly because the peak power,peak velocity,and muscle integral EMG values were significantly higher in this time period,with the best performance in the 12th minute.However,there was a tendency to decrease in the 4th minute,as evidenced by the decrease in the three indexes compared to the pre-test,the 8th,12th and 16th minutes.(4)The higher the activation load,the better the enhancement effect on the body,but the fatigue caused will also be deeper,and the time to show the enhancement effect will be delayed accordingly.The 90%1RM activation showed a greater increase in performance than the 50%1RM and 70%1RM,but the best performance was delayed until the 12th-16th minutes.Conclusions:50%1RM prone pull activation showed a slight increase in peak power and peak speed at minute 4 compared to the pre-test,but no significant effect,with subsequent interval enhancement effects gradually decreasing;70%1RM load activation,at minutes 8-12,showed significant peak power and peak speed activation effects,with the best effect at minute 8;90%1RM load activation,at minutes 8-16 The peak power and peak velocity activation effects were higher in the 8th-16th minutes,with the best effect in the 12th minute.The three load activations showed the greatest activation of the deltoid,followed by the trapezius,and the lowest activation of the latissimus dorsi.70-90%1RM load activation had a relatively better effect on the enhancement of the explosive power of the upper limb,but it also caused deeper fatigue and delayed the time to show the enhancement effect. |
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