Choosing a rotation sequence

9.5.4. Choosing a rotation sequence#

After reading this section, the normal reaction is to be confused about which sequence of rotations to choose to express specific joint angles. This is a very interesting topic that may never settle completely, but a good starting point is to consult the 2002 and 2005 recommendations of the International Society of Biomechanics:

  • Wu, G., Siegler, S., Allard, P., Kirtley, C., Leardini, A., Rosenbaum, D., Whittle, M., D’Lima, D.D., Cristofolini, L., Witte, H., Schmid, O., Stokes, I., 2002. ISB recommendation on definitions of joint coordinate system of various joints for the reporting of human joint motion—part I: ankle, hip, and spine. Journal of Biomechanics 35, 543–548. https://doi.org/10.1016/S0021-9290(01)00222-6

  • Wu, G., Van Der Helm, F.C.T., Veeger, H.E.J.D., Makhsous, M., Van Roy, P., Anglin, C., Nagels, J., Karduna, A.R., McQuade, K., Wang, X., Werner, F.W., Buchholz, B., Others, 2005. ISB recommendation on definitions of joint coordinate systems of various joints for the reporting of human joint motion - Part II: shoulder, elbow, wrist and hand. Journal of Biomechanics 38, 981–992. https://doi.org/10.1016/j.jbiomech.2004.05.042

These papers propose standard ways to:

  1. define most body segments’ local coordinate systems based on bony landmarks;

  2. define rotation sequences from a proximal segment to a distal segment to express joint angles.

Later in section Calculating joint angles from a kinematic acquisition, we will use the different Kinetics Toolkit’s functions introduced in this section to calculate joint angles from skin markers by following these recommendations.

In any case, and as a main message for this section, we insist on the importance of communicating how angles were calculated in any scientific communication, since these angles are often much variable between different conventions.