Volume 4, Issue 4 (3-2019)                   J Sport Biomech 2019, 4(4): 66-77 | Back to browse issues page

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Ramezani A, Hosseini M. Study of Shooting Accuracy and Fatigue of Leg Muscles After Eight Weeks of Resistance Training in Shooters Men With a Inflatable Pistol. J Sport Biomech. 2019; 4 (4) :66-77
URL: http://biomechanics.iauh.ac.ir/article-1-163-en.html
1- Department of Exercise Physiology, School of Sport Sciences, Shahid Rajaee Teacher Training University, Tehran, Iran.
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1. Introduction
n many daily activities and some sports, like golf and shooting, standing for a long time with proper posture is essential [1-3]. Ankle muscle fatigue reduces postural control. During a shooting race, some shooters stay in their place until the end of the competition, while others leave the race to hear coach guidance and some sit on their seats to relieve fatigue. Each of these situations may occur several times. This indicates that coaches are not following a specific approach based on the competition’s strategy and shooting tactics, and shooters follow their own rules [1].
Shooters require long-term biopsychological stability to achieve desirable records. During shooting competition with air guns, men can have 60 shots within 105 minutes, while for women, this rate is 40 shots in 75 minutes [2]. Shooting rules do not allow people to shoot in the sitting position; thus, for a shooter, most of the time in a shooting race is spent in standing position. Shooting with a 10-m air pistol is among the shooting competitions where a person must stand for a long time [2]. Checking the fatigue of each lower limb muscle caused by shooting and identifying the most active muscles can be an appropriate guide for trainers in designing training programs. Finding new approaches to reduce fatigue and increase accuracy in the shooting is also necessary.
2. Participants and Methods
This was a quasi-experimental study. The study participants were 20 healthy male shooters practicing in a shooting hall in Yasuj City, Iran. They were selected using a convenience sampling technique. The study subjects performed two different shooting forms (prolonged standing and intermittent standing) before and after an 8-week resistance training course. The shooting accuracy and muscle fatigue were assessed accordingly. 
The training protocol included the following 5 movements performed slowly and in the morning: seated leg curl, standing calf raise on a machine, cable standing leg curl, standing barbell calf raise, and calf raise on a leg press machine without knee bending. Movements started in 3 sets of 10 repetitions with a 1-min rest interval in the first session; they ended with 5 sets of 14 repetitions with a 1-min interval in the last session. They were performed for 8 weeks, 3 sessions per week.
According to a program previously written for DASYLAB software, the raw Electromyography (EMG) signal was recorded every 1 second. A pass filter of 5 to 450 Hz was applied. Then, using the Fast Fourier Transform (FFT) algorithm, the time domain of the signal was converted to the frequency domain. Next, the median frequency was calculated per second and recorded until the end of the test. Consequently, using the MATLAB software, the slope of median frequency was illustrated for each muscle throughout the test. In the intermittent standing protocol, the study subjects sat and rested every 20 minutes. During the resting period, muscle activity and the median frequency values were reduced; thus, resting times were eliminated the intermittent standing protocol by Microsoft Excel V. 2010 software.
3. Results
After the test (resistance training), the frequency (%) of shooting error, as well as the amount of muscle fatigue (slope of muscle activity changes), decreased. As per Table 1, after performing 8 weeks of resistance training, the posttest shooting accuracy significantly differed compared to the pretest accuracy values in different postural forms (F(2, 18)=8.22; P=0.001). These results indicated that after conducting 8 weeks of resistance training, the subjects’ shooting accuracy significantly improved; such an effect was higher in the extended-standing position with no rest. Furthermore, changes in post-training muscle fatigue were significantly different from those of the pretest values in different postural forms (F(2, 18)=0.0024; P=0.001).
4. Discussion
The collected results revealed that conducting 8 weeks of resistance training significantly improved muscle fatigue and shooting accuracy in a prolonged standing position with no rest. This finding is consistent with the those of Janice Tan et al. [1], Abdol Rahim et al. [6], Sartika and Dawal [8], Vuillerme et al. [9], Walesh et al. [10], and Davidson et al. [11]. The conditions that were created for the present study subjects were the standard and routine situations of the shooters. They followed the same shooting protocols as before.
Furthermore, all environmental conditions were the same as their previous training conditions. The only nuisance variable that caused differences in test performance, compared to the subjects’ previous training conditions, was the attachment of electromyographic electrodes to their leg muscles; this might slightly impact the results’ accuracy. However, this does not appear to affect the study’s purpose (comparing two different shooting situations). Factors such as subjects’ psychological and nutritional status during the two test days, as well as the effects of cross talk on the EMG signal, could be considered as other nuisance variables [7, 10]. 
5. Conclusion
Conducting an 8-week resistance training could improve the shooting accuracy with air pistols in young adult shooter men. The intervention also reduced muscle fatigue in these subjects.
Ethical Considerations
Compliance with ethical guidelines
Ethical issues (including plagiarism, informed consent, misconduct, data fabrication and/or fal-sification, double publication and/or submission, redundancy, etc.) have been completely observed by the authors.
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the Shahid Rajaee Teacher Training University, Tehran Research Council (17129).
Authors' contributions
All authors contributed equally in preparing all parts of the research.
Conflicts of interest
The authors declared no conflict of interest.
The writers are grateful to the shooters and their trainers and sports officials in Yasuj City.

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Type of Study: Research | Subject: Special
Received: 2018/09/27 | Accepted: 2019/01/9 | Published: 2019/03/1

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