Bilimsel Yayınlar
| Makale | Quantification the relationship between FITA scores and EMG skill indexes in archery |
| Yazar | H. Ertan, A.R. Soylu, F. Korkusuz |
| Önsöz | Forearm electromyographic (EMG) data are assumed to be an effective method in estimating performance level in archery. The aim of the current study was to establish archery skill indexes based on EMG data. Elite (n = 7, FITA score = 1303.4 ± 26.2), begin- ner (n = 6, FITA score = 1152 ± 9.0) and non-archers (n = 10, assumed FITA score = 250 0), were involved in the study. EMG activ- ity of Muscle flexor digitorum superficialis and Muscle extensor digitorum were quantified. Two-second periods – 1 s before and 1 s after the fall of the clicker – were used to obtain averaged and rectified EMG data. The averaged and rectified EMG data were fil- tered by averaging finite impulse response filter with 80 ms time window and then normalized with respect to maximum voluntary contraction. To estimate FITA scores from EMG data, the following skill indexes that based on mean area under some parts of processed EMG waveforms was offered for archery. These were the pre-clicker archery skill index (PreCASI), post-clicker archery skill index (PostCASI), archery skill index (ASI) and post-clicker archery skill index 2 (PostCASI2).The correlations between rank of FITA scores and natural logarithms of archery skill indexes were significant for log(PreCASI): r = .0.66, p < 0.0008; for log(PostCASI): r = .0.70, p < 0.0003; for log(ASI): r = .0.74, p < 0.0001; log(PostCASI2): r = .0.63, p < 0.002. It is concluded that EMG skill indexes may be useful for: (a) assessing shooting techniques, (b) evaluation of archers. progress and (c) selection of talented archers. |
| Makale | Activation patterns in forearm muscles during archery shooting |
| Yazar | H. Ertan, B. Kentel, S.T. Tümer, F. Korkusuz |
| Önsöz | A contraction and relaxation strategy with regard to forearm muscles during the release of the bowstring has often been observed during archery, but has not well been described. The purpose of this study was to analyze this strategy in archers with different levels of expertise; elite, beginner and non-archers. Electromyography (EMG) activity of the M. flexor digitorum superficialis and the M. extensor digitorum were recorded at a sampling frequency of 500 Hz, together with a pulse synchronized with the clicker snap, for twelve shots by each subject. Raw EMG records, 1-s before and after the clicker pulse, were rectified, integrated and normalized. The data was then averaged for successive shots of each subject and later for each group. All subjects including non-archers developed an active contraction of the M. extensor digitorum and a gradual relaxation of the M. flexor digitorum superficialis with the fall of the clicker. In elite archers release started about 100 ms after the fall of the clicker, whereas in beginners and non-archers release started after about 200 and 300 ms, respectively. Non-archers displayed a preparation phase involving extensive extensor activity before the release of the bowstring, which was not observed in elite and beginner archers. In conclusion, archers released the bowstring by active contraction of the forearm extensors, whereas a clear relaxation of the forearm flexors affecting the release movement was not observed. |
| Makale | Bow – arrow interaction in archery |
| Yazar | B.W. KOOI |
| Önsöz | A mathematical model of the flight of the arrow during its discharge from a bow was proposed by Pekalski (1990). His description of the model was incomplete. In this paper, I give a full description of the model. Furthermore, I propose some improvements that make his model more consistent with reality. One achievement is the modelling of contact of the arrow and grip; the pressure button is modelled as a unilateral elastic support. The acceleration force acting upon the arrow during the launch is predicted by an advanced mathematical model of bow dynamics. There is a satisfactory conformity of the simulation and experimental results. The new model predicts that the arrow leaves the pressure button before it leaves the string, as reported previously. The ability to model arrow dynamics can be used to improve the adjustment of the bow-arrow system for optimal performance. |
| Makale | Injury Patterns among Turkish Archers |
| Yazar | H. Ertan, M. Tüzün |
| Önsöz | A poster presentation summarizing injury patterns. |
| Makale | Okçulukta Endislerin Kullanılması: Bir Derleme Çalışması |
| Yazar | H. Ertan |
| Önsöz | Okçuluk, ortaya konulan tüm hareketlerin sabit bir sıra izlediği ve başarının tekrar edilebilir hareket örüntülerinin sergilenmesine bağlı olduğu bireysel bir spor branşıdır. Ok atma hareketinin analiz edildiği çalışmalarda, dünya çapında okçularda yapılan Elektromiyografik (EMG) analizlerde (T.K. ve R.M.) elde edilen verilere göre deltoid kasının biceps kasından fazla çalıştığı gözlenmiştir (Nishizono, 1987). Carlsöö (1975) yaptığı çalışmasında ok atışı sırasında deltoid kasının ok atma hareketinin oluşmasında (çekiş, nişan alma ve bırakış) önemli rol oynadışını ortaya koymuştur (Hennessy & Parker, 1990). Yayın gerilmesi sırasında sağ ve sol omuzda kas ve kemik yapılara düşen yük miktarı yapılan hareketin ekonomik olmasını etkileyen önemli faktörlerden birisidir. Sağ kolla kiriş geriye dopru çekilirken sol kol ile de yay ileri dopru itilmektedir. Bu çalışmada, bir ok atışı sırasında kaslara (M) ve eklem yapısına (J) düşen yük miktarı kabaca hesaplanmaya çalışılmıştır. Kas kuvveti-yük ve eklem yapısı-yük arasındaki açısal fark arttıkça kaslara düşen yük miktarının arttığı, aksi durumda ise bu miktarın düştüğü gözlenmiştir. Okçuluk sporu için de vücut endislerinin belirlenmesi ve bu spor branşı için de uygun fiziksel özellikleri taşıyan sporcuların ortaya çıkarılması gerektiği düşünülmektedir. |
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