Real-time biomechanical biofeedback effects on top-level rifle shooters
ABSTRACT The aim was to examine the effects of training with real-time biomechanical biofeedback on technique and performance of rifle shooters. Top-level shooters were randomly assigned to biofeedback- (n = 5) and control- (n = 4) groups. Bi-weekly training of 20 shots air-rifle for 4 weeks, with pre- and post-tests of 20 shots air-rifle and smallbore, were performed. The biofeedback group received individualized real-time auditory biofeedback on postural- and barrel-stabilities. Results revealed a technique of reducing postural- and barrel-stabilities towards triggering (e.g. barrel speed 8.0 ± 1.2 mm/s at 3.0-1.0 s reducing to 5.4 ± 0.8 mm/s at 0.3-0.1 s). There were no changes pre- to post-tests and no differences between groups in these measures of stability. The biofeedback group showed meaningful improvements in performance measures, whereas the control group showed no improvement (e.g. smallbore shot group diameter change: biofeedback group -2.6 mm; control group 0.1 mm). Biomechanical biofeedback is proposed to have improved performance, possibly through training better decision making, but the actual cause requires further research.
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ABSTRACT: This work presents a system that permits a real-time ergonomic assessment of manual tasks in an industrial environment. First, a biomechanical model of the upper body has been developed by using inertial sensors placed at different locations on the upper body. Based on this model, a computerized RULA ergonomic assessment was implemented to permit a global risk assessment of musculoskeletal disorders in real-time. Furthermore, local scores were calculated per segment, e.g. the neck region, and gave information on the local risks for musculoskeletal disorders. Visual information was fed back to the user by using a see-through head mounted display. Additional visual highlighting and auditory warnings were provided when some predefined thresholds were exceeded. In a user study (N = 12 participants) a group with the RULA feedback was compared to a control group. Results demonstrate that the real-time ergonomic feedback significantly decreased the outcome of both globally as well as locally hazardous RULA values that are associated with increased risk for musculoskeletal disorders. Task execution time did not differ between groups. The real-time ergonomic tool introduced in this study has the potential to considerably reduce the risk of musculoskeletal disorders in industrial settings. Implications for ergonomics in manufacturing and user feedback modalities are further discussed.Applied Ergonomics 06/2013; 44(4):566-574. DOI:10.1016/j.apergo.2012.11.008 · 1.33 Impact Factor
- French Society of Movement Analysis for Children and Adults 2012; 01/2012
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ABSTRACT: The purpose of this study was to develop a novel protocol to be used in assessing performance outcomes in projectile sports. This study also wanted to establish if variability within a movement pattern (throwing) is detrimental to the outcome of that skill and to assess the validity of current methods used to measure performance. Single subject analysis was undertaken as 4 Wilson Trainer TM tennis balls were launched using a Tennis Cube TM launcher at a wall 25 times each. Infra-red light gate technique (wall mounted Optojump TM) in which ball tracking co-ordinates were obtained were compared to traditional movement measure device (3D Motion Analysis Corporation TM) coordinates. Agreement between the 3D landing point X and Y coordinates and the OptojumpTM landing points X and Y coordinates were analysed using the Bland-Altman method. INTRODUCTION: This paper focuses on the development of a novel protocol for assessing performance measurement in target sports. Sports such as archery and rifle shooting are generally scored in a manner where a numeric value is awarded the closer to the centre of the target the projectile hits. Previous research on archery has used the FITA (International Archery Federation) scores to measure performance (Soylu, Ertan & Korkusuz, 2006). By doing so this awards the athlete with a numeric value to quantify success or failure. Research in rifle shooting has used conventional air rifle targets (Mullineaux, Underwood, Shapiro & Hall, 2012) and in basketball researchers have developed scoring methods themselves where numerical values are awarded based on how "clean" a basket is achieved (3 marks) to a complete miss (0 marks).These performance measures although informing the athlete whether they were successful or not return little feedback on how the performance could be enhanced. Ganter, Matyshiok, Partie, Tesch and Edelmann-Nusser (2010) enhanced performance feedback by measuring performance by the FITA scoring system and simultaneously measuring the movement of the bow which showed good correlation and could be used in individual performance evaluation. Lin and Hwang (2005) investigated the length of aiming time in relation to shot points in archery and compared these results not with the FITA but with vertical, horizontal and radial deviation. Studies previous to this had found that there was a positive correlation between increased aiming time and shot points on target along the radial direction and this was confirmed in this study. Mullineaux et al. (2012) also used electronic targets (MEGAlink4k187) which registered shots using 4 microphones on the corners of the target. This gave a precise measurement of the shot location which was relayed back to a screen for the shooter to see. This gives them an arguably more valid performance outcome measure. These are some of the previous ways of assessing performance outcome however this study aims to use new technology to create a highly accurate and reliable new performance measurement instrument. The Optojump TM has proved to be a valid method of measuring vertical jump height and has also been tested against the IR contact mat (Erotest TM) for flight time and contact time (Bosquet, Berryman & Dupay, 2009) where results showed the two machines to be interchangeable. It has also been identified as the "Gold Standard" when comparing and testing other systems (Casartelli, Muller & Maffiuletti, 2010). Knowing Optojump TM is a valid measure will allow us to investigate whether when compared to MAC (Motion Analysis Corporation Ltd., Santa Rosa, California) the Optojump TM can produce accurate, reliable and easily-obtained results for assessing projectile throwing performance.Presented at the 2012 International Society of Biomechanics in Sports Conference; 07/2012