Dr.Biol., Professor A.B. Trembach1
Postgraduate O.I. Shestakov1
PhD T.V. Ponomareva1
1Kuban State University of Physical Culture, Sports and Tourism, Krasnodar
Keywords: archery, shooting process timing and phasing, biological markers
Background. Purposefulness may be ranked among the key indicators of the discretional highly coordinated movement sequences or sport skills, with the modern archery providing an excellent example of such model sport-specific physical skills. In a few studies for the last few years there were made attempts to phase the shooting sequences in the rifle/ handgun/ bow shooting processes based mostly on the relevant biomechanical and electromyographic (EMG) test rates [1, 2, 5]; and to profile the cortical electric activity in the shooting process on the whole and bow shooting in particular [3, 4, 6]. Accuracy of the focused skills in the shooting sports is known to largely depend on how harmonized the movements are secured by the relevant bodily systems; with the relevant system-level functionality rates and coordination indices being critical for success of the shooting process. Such a systemic research approach makes it possible to objectively profile the key process timing and phasing elements by a variety of biological markers.
Objective of the study was to time, phase and analyze the bow shooting process using the relevant biomechanical, electromyographic (EMG), electroencephalographic (EEG) and autonomic nervous system activity indices.
Methods and structure of the study. Sampled for the study were four 16-19 years-old Russian Masters of Sport duly informed, as required by the Helsinki Declaration, on the goals and mission of the study, with their consent verified in writing. The sample was tested for the shooting accuracy in 18m shooting session, with every archer given two attempts of 30 shots each. The shot execution kinematics was tested by a computerized SportLab Electromyograph System (made in Moscow) to obtain the relevant kinematic data including the joint travel coordinates and speeds on X/ Z axes using 16 movement markers; i.e. to profile the head movement and the both shoulder/ elbow/ radiocarpal/ coxofemoral/ knee/ ankle/ metatarsal joint movements fixed at discretional frequencies of 50HZ and 120Hz.
The SportLab system made it possible to obtain real-time ENG for the key muscles including M. triceps brachii sinister/ dexter, biceps brachii sinister/ dexter, deltoid eis sinister/ dexter, trapezius sinister/ dexter parsascendens. The telemetric electroencephalographic (EEG) data were obtained using Encelophalan-EEGR-19/26 System (made by the Taganrog-based Medicom MTD) in 19 versions of the 10-20 pattern (Fp1; Fpz; Fp2; F3; Fz; F4; FC3; FCz; T3; C3; Cz; C4; T4; T5; P3; Pz; P4; T6; O1; Oz; O2). The test data were complemented by two electrooculograms (EOG), pneumograms, ECG and physical activity rating data. An optical-mechanical sensor of our own design fixed the clicker trigger moment to have synchronized the biomechanical and electrophysiological parameters of the shooting process – and thereby identify and track by the relevant dominant markers the shooting process phases. The EEG data arrays were analyzed using WinEEG software made by the Saint-Petersburg-based Mitsar Co. Generalized topographic maps presenting the EEG spectra were obtained in the active quiescent eyes-closed sitting positions; eyes-open sitting/ standing positions; and the shooting positions. Significant differences of the data arrays were found using the standard single-factor dispersion analytical toolkit provided by Statistika10 data processing software.
Study findings and discussion. Given on Figure 1 hereunder are the setup, preparation and execution periods and phases of the bow shooting process as identified and profiled by the above biomechanical, electromyographic (EMG), electroencephalographic (EEG) and autonomic nervous system activity indices. Each of the phases is critically important as it provides a basis for the next phase of the shooting sequence.
Setup Period I was classified into the following two phases: (1) taking the shooting position; arrow fixing; and preliminary tension of the bow hand with a check pulling of the bowstring; (2) setup finalizing and optimal vertical posture fixing phase focused on due balance. This period is considered critical for success since a sound postural control provides a basis for the further movement sequence. It is the EEG spectral characteristics and radiocarpal joint movement coordinates on Z/ Y axes that dominate in the biomechanical markers of Period I.
Figure 1. Periods I-III including phases 1-7 of the bow shooting process
Periods I-III including phases 1-7 of the shooting process are given on the horizontal axis of Figure 1; and the process parameters are given on the vertical axis as follows: 1,2 – right and left EOG; 3-5 – EEG (Fp1, C3, O1); 6,7 – left/ right radiocarpal joint movement coordinates on axis Z; 8,9 – left/ right radiocarpal joint movement coordinates on axis Y; 10,11 – left/ right radiocarpal joint movement speeds on axis Z; 12,13 - left/ right radiocarpal joint movement speeds on axis Y; 14-21 – EMG data for M. triceps brachii sinister/ dexter, biceps brachii sinister/ dexter, deltoid eis sinister/ dexter, trapezius sinister/ dexter parsascendens; 22 – ECG data; 23 – pneumogram; 24 – physical activity sensor.
Dynamic postural control Period II includes three phases in the shooter-bow system forming and posture adjusting process: phase 3 with the bow hand raised and the bowstring pulled. The phase startup is identified by a peak in the M. deltoideus, triceps and biceps brachii sinister electric activity followed by the radiocarpal joint coordinates moving along the Z axis. Phase 3 is ended up by the right/left radiocarpal joint coordinates reaching the peaks, with their movement speed stopping to grow. Phase 4 is the further bow pulling phase driven by M. triceps brachii dexter. And setting phase 5 was identified by the downfall of the radiocarpal joint coordinate on Z axis associated with a fall in the M. triceps brachii dexter electric activity. The athlete focuses on the postural control with the above muscle being harmonically strained in this period.
Aiming Period III includes two phases with the fine visual-motor adjustments followed by release of the arrow. This final period of the shooting process is dominated by a precise coordination with the visual feedback and fine motor responses to zero in on the target. Phase 6 startup is identified by the EOG, with the kinematic parameters being stabilized and crowned by the clicker trigger moment. Arrow release phase 7 is identified by the drop in electric activity of the M. trapezius pars ascendens, biceps brachii, deltoideis sinister/ dexter, with minor changes in the radiocarpal joint biomechanics. It should be noted that Period III is critical for success of the shot as verified by the sensorimotor and vegetative NS indices, EEG, ECG and pneumograms versus the shooting accuracy rates.
The above biological markers give the means to rate the archer’s functionality in Periods I and III and track their variations versus the shooting accuracy by a variety of tools including the EEG data analysis and variations of the radiocarpal joint coordinates in Period III. These tools make it possible to test the archers’ functionality in the training process and apply the individual data arrays and analyses for the competitive performance forecasts. A comparative analysis of the EEG spectral variations on the topographic maps in Periods I and III versus the shooting accuracy data may be applied to rate the cortical electric activity in a variety of experimental situations and use the biological feedback toolkit to make adjustments when necessary. The radiocarpal joint movement profiles (with the joint coordinates and their variations in the above experimental situations) may be applied to objectively rate how harmonic is the shooter-bow system and shooting process management versus the shooting accuracy. Variations of the RR peaks on the ECG in the aiming period, for example, give the means to analyze the autonomic nervous system responses in this critical period of the shooting process.
Conclusion. The proposed multifactor analysis with an emphasis on the key functional periods and the relevant phases in the bow shooting movement sequence provides an insight into the physiological mechanisms of the targeted sport-specific motor skills and helps objectively rate the training progress and attain certain competitive goals using the above variety of biological markers of the shooting process.
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Archery may be classified with the sport disciplines driven by targeted skillful actions. Movement accuracy is secured by a harmonized sequence of actions with the shooting process phasing and timing being critical for success. Objective of the study was to time, phase and analyze the bow shooting process using the relevant process biomechanical, electromyographic (EMG), electroencephalographic (EEG) and vegetative NS activity indices. Four Russian Masters of Sport were sampled for the standard shooting sequence profiling tests to obtain the following test data: kinematic parameters of the radiocarpal joint movements fixed at discretional frequencies of 50HZ and 120Hz; EMG of 8 core muscles; EEG in 19 points; electro-oculograms; pneumograms; ECG with application of the motor activity sensor; and with WinEEG software applied to process and analyze the EEG data. The movement profiling by the biological markers made it possible to identify the key periods of the shooting process i.e. the setup, preparation and execution periods with their phases. Setup Period I was classified into two phases designed to reach the optimal prime vertical posture. Dynamic postural control Period II includes three phases. And aiming Period III includes two phases followed by a shot. The biological markers to profile the radiocarpal joint travel trajectories versus the EEG data made it possible to analyze the athletes’ functionality rates in Periods I and III and find logics in their variations versus the shooting accuracy rates.