3D Gait Analysis
More accurate, objective and repeatable than traditional video-based systems - there are reasons why infrared cameras and 3D gait analysis techniques are used in academia, elite sport and specialist orthopaedic hospitals.
The video above shows Olympian Jo Pavey having an assessment at the launch of Run3D Oxford at the Oxford Gait Laboratory, Nuffield Orthopaedic Centre in 2012. Run3D Oxford has since relocated to The Bosworth Clinic.
3D gait analysis is a harmless and non-invasive procedure, which uses infrared cameras to track the exact 3D positions of small reflective markers that are attached to a person as he moves. A customised computational model of the person is generated from the marker positions and used to calculate his joint angles in the sagittal, frontal and transverse planes. Abnormal movement patterns are identified by time-normalising the data and then comparing the person’s joint angles to a normative database.
This approach is unquestionably the gold-standard of biomechanical assessment and the kinematic results are more accurate, reliable and objective than those measured using alternative techniques:
- Lower-limb joint kinematics are measured 200 times per second to capture as much information as possible. For a runner with a stance time of 0.33 seconds, this gives us 66.7 frames of data compared to 16.7 frames for a system operating at 50 frames per second.
- The superiority of 3D motion analysis over other techniques is well documented in the scientific literature, for example Areblad et al. (1990), McClay et al. (1998), McLean et al. (2005) and Cormack et al. (2011).
- Joint angles are calculated using rigorous mathematical protocols and gait abnormalities are identified by comparing a person’s results to a normal population. All subjectivity is removed from the assessment and clinicians can be confident that their treatment and recommendations are based on real data.
Areblad, M., Nigg, B., Ekstrand, K., Olsson, K. and Ekstrom, H. (1990) Three dimensional measurement of rear-foot motion during running. Journal of Biomechanics. 23(9), 933-940.
Cormack, S., Kendall, K. and Ferber, R. (2011) Validation of 2D Measures of Hip and Knee Frontal Plane Biomechanics During Running. Journal of Athletic Training. 46(3), S163.
McClay, I. and Manal, K. (1998) The influence of foot abduction on differences between two-dimensional and three-dimensional rear-foot motion. Foot and Ankle International, 19(1), 26-31.
McLean, S., Walker, K., Myer, G., Hewett, M. and Van den Bogert, A. (2005) Evaluation of a two dimensional analysis method as a screening and evaluation tool for anterior cruciate ligament injury. British Journal of Sports Medicine, 39, 355-362.