Professor John Challis

Honorary Fellow
Photograph of Professor John Challis.

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John Challis received a PhD in Biomechanics, in 1991, from Loughborough University. He is now Professor of Kinesiology and Graduate Program Director in the Department of Kinesiology at Penn State University, USA.

Research

Principal Areas of Interest

Measurement and modeling of the complex parameters associated with a direct dynamics model of the human musculo-skeletal system, with the aim of examining the role, function, and co-ordination of muscle in vivo.

Investigation of human impacts, with emphasis on quantifying the effect of the "wobbling" mass on joint loads.

Development of improved measurement protocols (three-dimensional photogrammetry, determination of segment position and orientation, data smoothing and differentiation).

Investigation of procedures for determining body segment inertial parameters.

Biography

Staff Publications

Selected publications

Winter, S. L. & Challis, J.H. (2010) The expression of the skeletal muscle force-length relationship in vivo: a simulation study. Journal of Theoretical Biology, 262, 634-643.

Winter, S. L. and Challis, J. H. (2010) The force-length curves of the human rectus femoris and gastrocnemius muscles in vivo. Journal of Applied Biomechanics, 26, 45-51.

Challis, J. H., Murdoch, C., and Winter, S. L. (2008) Mechanical properties of the human heel pad: a comparison between populations. Journal of Applied Biomechanics, 24,  377-381.

Muri, J., Winter, S.L., and Challis, J.H. (2008) Changes in segmental inertial properties with age. Journal of Biomechanics 41, 1809-1812.

Winter, S.L., and Challis, J.H. (2008) Reconstruction of the human gastrocnemius force-length curve in vivo: Part 1, model based validation of method. Journal of Applied Biomechanics 24, 197-206.

Winter, S.L., and Challis, J.H. (2008) Reconstruction of the human gastrocnemius force-length curve in vivo: Part 2, experimental results. Journal of Applied Biomechanics 24, 207-214.

Infantalino, B, W., Gales, D.J., Winter, S.L., and Challis, J.H. (2007) The validity of ultrasound estimation of muscle volumes. Journal of Applied Biomechanics 23, 213-217.

Challis. J.H., and Pain, M.T.G. (2008)  Soft tissue motion influences skeletal loads during impacts.  Exercise and Sports Science Reviews  36, 71-75.

Domire, Z.J., and Challis, J.H. (2007)  The influence of an elastic tendon on the force producing capabilities of a muscle during dynamic movements.  Computer Methods in Biomechanics & Biomedical Engineering  10, 337-341.