Introduction to Sports Biomechanics: Analysing Human Movement ...

INTRODUCTION TO SPORTS BIOMECHANICS
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Digitising The process of specifying or measuring the x- and y-image coordinates of
points on a video frame; more strictly called coordinate digitising.
Genlock A common technique in which the video output of one source, or a specific
reference signal, is used to synchronise other picture sources so that images are
captured simultaneously. Rarely found, currently, on digital video cameras.
Inverse dynamics An analytical approach calculating forces and moments based on the
accelerations of the object, usually computed from measured displacements and
angular orientations from videography or another image-based motion analysis
system.
Longitudinal (study) A correlational research study that involves observations of the
same items over long time periods. Unlike a cross-sectional study, a longitudinal
study tracks the same people and, therefore, the differences observed in those people
are less likely to be the result of cultural differences across generations.
Low-pass filter A filter that passes low frequencies but attenuates (or reduces) frequencies
above the cut-off frequency. In movement analysis, used mainly to remove
high-frequency ‘noise’ from a low-frequency movement signal.
Statics The branch of mechanics in which the system being studied undergoes no
acceleration.
Three-dimensional Occurring in two or three planes; requiring a minimum of three
coordinates to describe, for example x-, y- and z-coordinates. See also twodimensional.
Two-dimensional Occurring within a single plane; requiring a minimum of two
coordinates to describe, for example x- and y-coordinates. See also threedimensional.
Videography The process of capturing images on a videotape or directly to a computer;
also used to include the later analysis of these images. See also cinematography.
FURTHER READING
Bartlett, R.M. (1999) Sports Biomechanics: Reducing Injury and Improving Performance, London:
E & FN Spon. Chapter 4 provides a simple introduction to inverse dynamics without being
too mathematical.
Challis, J.H. (2007) Data processing and error estimation, in C.J. Payton and R.M. Bartlett (eds)
Biomechanical Evaluation of Movement in Sport and Exercise, Abingdon: Routledge. Chapter 8
elaborates on the errors in sports biomechanical data and outlines, with clear examples, the
calculation of uncertainties in derived biomechanical data.
Milner, C. (2007) Motion analysis using on-line systems, in C.J. Payton and R.M. Bartlett (eds)
Biomechanical Evaluation of Movement in Sport and Exercise, Abingdon: Routledge. Chapter
3 provides a lucid and easy-to-follow explanation of some difficult concepts. Highly recommended
if you see research into sports movement as something you might wish to pursue.
Payton, C.J. (2007) Motion analysis using video, in C.J. Payton and R.M. Bartlett (eds) Biomechanical
Evaluation of Movement in Sport and Exercise, Abingdon: Routledge. Chapter 2
contains much useful advice on a video study, including the reporting of such a study, which
you could adopt for the technical report in Study task 6.