KINETIC AND KINEMATIC ANALYSIS OF RECURVE ARCHERY SHOOTING TECHNIQUE

The study investigated shooting techniques of the archers with kinetic and kinematic methods. Twenty-seven archers of different skill levels have been involved into the current study to investigate both muscular activation strategies of nine muscles and some kinematic data on drawing hand side. A statistical significant difference (p0.05) in the time-dependent exchange values of the angle of the joints, a difference was detected in the graphical sense. Elite archers use distal muscles less but proximal and axial muscles more, and mid-level and novice archers use distal muscles more to pull the bowstring. This was interpreted to be the most important factor affecting the horizontal oscillation (lateral diflection) of bowstring

Determination Of Electromyography-Based Coordinated Fatigue Levels In Agonist And Antagonist Muscles Of The Thigh During Squat Press Exercise

Background. Simultaneous tiredness of two or more muscles around a joint can be defined as coordinated fatigue (co-fatigue) and might occur between agonist and antagonist muscles, and vary according to the level of sporting activity levels or gender. Objectives. The aim of this study was to determine the levels of coordinated fatigue in agonist and antagonist muscles during squat-press exercise. Methods. Twenty athletes and twenty sedentary subjects participated in the study. Surface electromyography signals of the rectus femoris, vastus lateralis obliquus, biceps femoris and semitendinosus muscles were recorded at the squat press position for 15 seconds during isometric contraction. Measurements were repeated five times and a 2-minute rest period was allowed between repetitions. After erroneous EMG elimination, movement artefacts were removed by using a 20 Hz high-pass Butterworth filter. Then, as a well-recognized fatigue index, the median frequency (MF) of each filtered middle part of the EMG signal (5 to 10 s. of contraction) was calculated, given that it is known that the MF decreases during isometric contractions. Finally, each MF-based co-fatigue index was calculated by dividing the mean RF and VLO median frequencies by the mean ST and BF median frequencies. The cumulative co-fatigue values of “male vs. female” and “sedentary vs. athlete” comparisons were performed by using a two-sided Student t-test with a Bonferroni correction. Results. There was a statistically significant (Bonferroni corrected p-value < 0.05) difference between the mean female (1.57 +/- 0.53) and the mean male (1.23 +/- 0.17) co-fatigue values, while there was no statistically significant difference between the mean co-fatigue values of sedentary (1.51 +/- 0.52) and athlete (1.29 +/- 0.27) subjects. Conclusion. The offered co-fatigue indices might be useful for other sports, physiotherapy and related areas if sufficient scientific proof is accumulated.WoSScopu

Muscular coordination of movements associated with arrow release in archery

The aim of this study was to examine the muscular activation strategy of archers with different levels of expertise. Twenty-seven (27) male archers volunteered to participate in the current study. The activation of nine forearm and shoulder girdle muscles were analysed. Statistically significant differences were observed among the archery groups in the activation of muscles (flexor digitorum superficialis, extensor digitorum communis, deltoids middle, deltoids posterior, trapezius pars ascendens, trapezius pars transversa, and trapezius pars descendens) (p&lt;0.05). The results of this study, indicated that in order to pull the bowstring, the elite archers used distal (forearm) muscles less, but used proximal (shoulder) and axial (trapezius) muscles more, while the mid-level and novice archers used distal muscles more. This differential muscle use was interpreted as the most important factor affecting the horizontal oscillation of the bowstring. To minimise horizontal oscillation, it is suggested that archers carry the weight with their axial and proximal muscles. The findings of the present study could be used as a reference to pave the way for the development of effective archery training, which would include visual or audial feedback methods.Keywords: Archery; Electromyography (EMG); Muscular activation; Shooting

Ele iletilen titreşim ve submaksimal kuvvet üretiminin el-kol sisteminde biodinamik yanıt üzerine etkisinin incelenmesi

TÜBİTAK MAG01.08.200

What Is The Optimal Frequency For Ankle Muscles During Whole-Body Vibration Exercises?

Usage of the whole-body vibration (WBV) is effective in preventing the ankle injuries caused by increasing neuromuscular activity. The aim of this study was to investigate effective frequencies for neuromuscular activity of ankle muscles. A single-group, repeated-measures study design was used. Twenty-three healthy subjects (age 23.91 +/- 3.07, BMI 22.66 +/- 3.39) participated in this study. This study investigated the effects of WBV on the EMG responses of the Tibialis Anterior (TA), Peroneus Longus (PL), Gastrocnemius Medial (GM) and Lateral heads (GL). The muscle activity was measured with an 8-channel EMG Noraxon MiniDTS system (Noraxon, USA, Inc, Scottsdale, AZ) during 0, 20, 40 and 60 Hz of vibration. The Physio Plate (R) vibration platform (Physio Plate (R), Domino S.R.L, San Vendemiano, Italy) was used to deliver mechanical vibration. Compared with no vibration condition; EMG activity of all ankle muscles were significantly increased from at 60 Hz (123 % in TA, 64 % in PL, 53 % in GM, 77 % in GL) (p<0.01). At 40 Hz of vibration frequency, EMG responses of GM and GL was significantly increased (27 % and 53%, respectively) (p<0.01). Only GL was significantly increased of 33 % at 20 Hz (p<0.01). It could be concluded that using higher frequencies at whole-body vibration exercises are more effective than lower frequencies on ankle muscles' EMG activities. During squat exercises on the WBV platform, higher frequencies should be used to increase ankle muscle activation.Wo

Individual Variation Of Bowstring Release In High Level Archery: A Comparative Case Study

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