- ItemBiomechanical modeling as a practical tool for predicting injury risk related to repetitive muscle lenthening during learning and training of human complex motor skills(SpringerOpen, 2016) Wan, Bingjun; Shan, GongbingPrevious studies have shown that muscle repetitive stress injuries (RSIs) are often related to sport trainings among young participants. As such, understanding the mechanism of RSIs is essential for injury prevention. One potential means would be to identify muscles in risk by applying biomechanical modeling. By capturing 3D movements of four typical youth sports and building the biomechanical models, the current study has identified several risk factors related to the development of RSIs. The causal factors for RSIs are the muscle over-lengthening, the impactlike (speedy increase) eccentric tension in muscles, imbalance between agonists and antagonists, muscle loading frequency and muscle strength. In general, a large range of motion of joints would lead to over-lengthening of certain small muscles; Limb’s acceleration during power generation could cause imbalance between agonists and antagonists; a quick deceleration of limbs during follow-throughs would induce an impact-like eccentric tension to muscles; and even at low speed, frequent muscle over-lengthening would cause a micro-trauma accumulation which could result in RSIs in long term. Based on the results, the following measures can be applied to reduce the risk of RSIs during learning/training in youth participants: (1) stretching training of muscles at risk in order to increase lengthening ability; (2) dynamic warming-up for minimizing possible imbalance between agonists and antagonists; (3) limiting practice times of the frequency and duration of movements requiring strength and/or large range of motion to reducing micro-trauma accumulation; and (4) allowing enough repair time for recovery from micro-traumas induced by training (individual training time). Collectively, the results show that biomechanical modeling is a practical tool for predicting injury risk and provides an effective way to establish an optimization strategy to counteract the factors leading to muscle repetitive stress injuries during motor skill learning and training.
- ItemThe influence of X-factor (trunk rotation) and experience on the quality of the badminton forehand smash(De Gruyter Open, 2016) Zhang, Zhao; Li, Shiming; Wan, Bingjun; Visentin, Peter; Jiang, Qinxian; Dyck, Mary; Li, Hua; Shan, GongbingNo existing studies of badminton technique have used full-body biomechanical modeling based on three dimensional (3D) motion capture to quantify the kinematics of the sport. The purposes of the current study were to: 1) quantitatively describe kinematic characteristics of the forehand smash using a 15-segment, full-body biomechanical model, 2) examine and compare kinematic differences between novice and skilled players with a focus on trunk rotation (the X-factor), and 3) through this comparison, identify principal parameters that contributed to the quality of the skill. Together, these findings have the potential to assist coaches and players in the teaching and learning of the forehand smash. Twenty-four participants were divided into two groups (novice, n = 10 and skilled, n = 14). A 10-camera VICON MX40 motion capture system (200 frames/s) was used to quantify full-body kinematics, racket movement and the flight of the shuttlecock. Results confirmed that skilled players utilized more trunk rotation than novices. In two ways, trunk rotation (the X-factor) was shown to be vital for maximizing the release speed of the shuttlecock – an important measure of the quality of the forehand smash. First, more trunk rotation invoked greater lengthening in the pectoralis major (PM) during the preparation phase of the stroke which helped generate an explosive muscle contraction. Second, larger range of motion (ROM) induced by trunk rotation facilitated a whip-like (proximal to distal) control sequence among the body segments responsible for increasing racket speed. These results suggest that training intended to increase the efficacy of this skill needs to focus on how the X-factor is incorporated into the kinematic chain of the arm and the racket.
- ItemUnraveling mysteries of personal performance style; biomechanics of left-hand position changes (shifting) in violin performance(PeerJ, 2015) Visentin, Peter; Li, Shiming; Tardif, Guillaume; Shan, GongbingInstrumental music performance ranks among the most complex of learned human behaviors, requiring development of highly nuanced powers of sensory and neural discrimination, intricate motor skills, and adaptive abilities in a temporal activity. Teaching, learning and performing on the violin generally occur within musico-cultural parameters most often transmitted through aural traditions that include both verbal instruction and performance modeling. In most parts of the world, violin is taught in a manner virtually indistinguishable from that used 200 years ago. The current study uses methods from movement science to examine the “how” and “what” of left-hand position changes (shifting), a movement skill essential during violin performance. In doing so, it begins a discussion of artistic individualization in terms of anthropometry, the performer-instrument interface, and the strategic use of motor behaviors. Results based on 540 shifting samples, a case series of 6 professional-level violinists, showed that some elements of the skill were individualized in surprising ways while others were explainable by anthropometry, ergonomics and entrainment. Remarkably, results demonstrated each violinist to have developed an individualized pacing for shifts, a feature that should influence timing effects and prove foundational to aesthetic outcomes during performance. Such results underpin the potential for scientific methodologies to unravel mysteries of performance that are associated with a performer’s personal artistic style.
- ItemPerception of safe horizontal reaching distance changes with repetitive occupational loading in novice lifters(Elsevier, 2015) McCubbing, Dustin C.; Shan, Gongbing; Gonzalez, Claudia L. R.; Awosoga, Olu A.; Doan, Jon B.Safe work behaviours rely on accurate perceptions of injury risks, and workers who have a misperception of risk can be injured. Despite the importance of perception-action coupling, little is known about modification of those perceptions with changing physical or cognitive STATE. It is hypothesized that changing values for perceived affordances could evidence these modifications. A better understanding of how worker characteristics (e.g., level of fatigue) affect perceptions of affordance and their corresponding behaviours, may help when developing strategies for ergonomic best practices, particularly in manual material handling (MMH) activities. The aim of this study was to compare safe perceptions of affordance from workers that completed repetitive STATE loading. Seventy-five novice MMH workers (23 male; mean age = 21.43, SD = 3.24) made perceived affordances of their safest horizontal reaching distance (acceptable limit) to complete a model task. STATE loading consisted of physical or cognitive fatigue or a control. The levels of fatigue were assessed at five-minute intervals using Ratings of Perceived Exertion (RPE) values and Multi-Fatigue Inventory (MFI) values, respectively. A significant main effect of TIME indicated a decrease of perceived safest reaching distance observed from baseline through subsequent measurements (p<.001). The magnitude of these changes did not differ significantly between groups, suggesting that general learning more than specific STATE loading may be a major contributor to modification of affordance perceptions. However, it remains important to consider TIME and STATE influences on perceptions for safe occupational handling. Novice workers’ initial perceptions of safe working affordance may put them at risk for soft tissue injury. Physical and cognitive loading similarly affect perceived safe affordances.
- ItemKinematics of the turning kick: measurements obtained in testing well-trained taekwon-do athletes(Archives of Budo, 2015) Wasik, Jacek; Shan, GongbingBackground & Study Aim: The aim of the paper is the influence of selected kinematic factors on the turning kick technique. This issue is practically relevant in the traditional version of taekwon-do, where an effectively performed strike may divulge the winner. Material & Method: Using 3D motion capture technology, six International Taekwon-do Federation athletes were tested. Biomechanical parameters related to range of motion, kick power and kick time were applied in the analyses. The athletes executed the turning kick three times in a way typically applied in a board breaking kick. The quantification focused on the speed changes related to kicking leg extension, the maximum knee and foot velocities in the Cartesian coordinate system and the total time of kick execution. The descriptive statistics (i.e. average values and the standard deviations) and correlation analysis were applied in data analysis. Results: The results have shown that the effect of the kick is mainly represented by component of kick foot velocity in frontal – and lateral-directions. The correlation analyses unveil that the maximal knee speeds reached in frontal – and lateral-directions as well as foot take-off velocity in frontal – and vertical-directions are highly correlated to kick foot effectiveness (r = 0.60 to 0.87). The analysis of velocity development in relation to kick leg extension divulges that the maximal velocity occurs around 80% of a full leg extension. Conclusion: For increasing kick effectiveness, athletes should work on the foot take-off velocity, the dynamics of the knee motion and consider the optimum kick length for kicking power maximization.