Biomechanical optimization models are often used to estimate muscular and intervertebral disc forces during physical exertions. The purpose of this study was to determine whether an optimization-based biomechanical model predicts torso muscular activity of males and females equally well. The Minimum Intensity Compression (MIC) model, which has been extensively applied in industrial ergonomic task analysis, was used to estimate muscle forces for 3D moments. Participants (6 M, 6 F) performed 18 isometric exertions resisting 3D L3/L4 moments while electromyographic (EMG) activity was recorded for 8 muscles. Overall, model force estimates correlated better with male EMG activity (R 2 = 0.43) than with female EMG activity (R 2 = 0.33). Model force estimates of 4 muscles (LRA, RRA, REO, and RES) correlated better with male EMG activity than with female EMG. We conclude that trunk muscle forces estimated by current biomechanical modeling do not correlate equally well to male and female EMG activity. Future research needs to address validation or improvement of biomechanical trunk models for females.
Mark L. McMulkin, Jeffrey C. Woldstad and Richard E. Hughes
Marcelo Peduzzi de Castro, Daniel Cury Ribeiro, Felipe de Camargo Forte, Joelly Mahnic de Toledo, Roberto Costa Krug and Jefferson Fagundes Loss
The aim of this study was to compare shoulder muscle force and moment production during external rotation performed in the transverse and sagittal planes. An optimization model was used for estimating shoulder muscle force production of infraspinatus, teres minor, supraspinatus, anterior deltoid, middle deltoid and posterior deltoid muscles. The model uses as input data the external rotation moment, muscle moment arm magnitude, muscle physiologic cross-sectional area and muscle specific tension. The external rotation moment data were gathered from eight subjects in transverse and six subjects in sagittal plane using an isokinetic dynamometer. In the sagittal plane, all studied muscles presented larger estimated force in comparison with the transverse plane. The infraspinatus, teres minor, supraspinatus and posterior deltoid muscles presented larger moment in sagittal when compared with transverse plane. When prescribing shoulder rehabilitation exercises, therapists should bear in mind the described changes in muscle force production.
Yanxin Zhang, David G. Lloyd, Amity C. Campbell and Jacqueline A. Alderson
The purpose of this study was to quantify the effect of soft tissue artifact during three-dimensional motion capture and assess the effectiveness of an optimization method to reduce this effect. Four subjects were captured performing upper-arm internal-external rotation with retro-reflective marker sets attached to their upper extremities. A mechanical arm, with the same marker set attached, replicated the tasks human subjects performed. Artificial sinusoidal noise was then added to the recorded mechanical arm data to simulate soft tissue artifact. All data were processed by an optimization model. The result from both human and mechanical arm kinematic data demonstrates that soft tissue artifact can be reduced by an optimization model, although this error cannot be successfully eliminated. The soft tissue artifact from human subjects and the simulated soft tissue artifact from artificial sinusoidal noise were demonstrated to be considerably different. It was therefore concluded that the kinematic noise caused by skin movement artifact during upper-arm internal-external rotation does not follow a sinusoidal pattern and cannot be effectively eliminated by an optimization model.
David L. Carey, Justin Crow, Kok-Leong Ong, Peter Blanch, Meg E. Morris, Ben J. Dascombe and Kay M. Crossley
plans for performance improvement. 13 No study has explored optimization models that incorporate training guidelines for injury prevention based on cumulative loads and workload ratios in team-sport athletes. This study aimed to determine the extent to which current training-load guidelines (for
Bianca Miarka, Katarzyna Sterkowicz-Przybycien and David H. Fukuda
exception of subsequent penalties incurred by the opponent. PNN to Classify T-T Indicators in Female and Male Judo Athletes During Competition Table 3 presents the PNN classification results for each of the combat/pause phase models and for an additional optimized model consisting of 13 T-T indicators
Christopher M. Saliba, Allison L. Clouthier, Scott C.E. Brandon, Michael J. Rainbow and Kevin J. Deluzio
osteoarthritis and control subjects (Figure 2A ). Although only tested with osteoarthritis, our method is robust to shape features and could be extended to populations with other pathologies. One limitation of our method is that it is derived from a static optimization model that does not explicitly capture
Brad Donohue, Yulia Gavrilova, Marina Galante, Elena Gavrilova, Travis Loughran, Jesse Scott, Graig Chow, Christopher P. Plant and Daniel N. Allen
.1080/02791072.2000.10400225 Gavrilova , Y. , & Donohue , B. ( in press ). Mental health interventions in athletes: A call for optimization models sensitive to sport culture . Journal of Sport Behavior . Gavrilova , Y. , Donohue , B. , & Galante , M. ( 2017 ). Mental health and sport performance programming in athletes who