Marker placement to describe the wrist movements during activities of daily living in cyclical tasks Alessio Murgia a, * , Peter J. Kyberd a , Paul H. Chappell b , Colin M. Light b a School of Systems Engineering, Department of Cybernetics, University of Reading, Whiteknights, Reading RG6 6AY, UK b Department of Electronics and Computer Science, University of Southampton, Southampton, UK Received 17 July 2003; accepted 26 November 2003 Abstract Objective. To describe the wrist kinematics during movement through free range of motion and activities of daily living using a cyclical task. Design. The wrist angles were initially calculated in a calibration trial and then in two selected activities of daily living (jar opening and carton pouring). Background. Existing studies which describe the wrist movement do not address the specific application of daily activities. Moreover, the data presented from subject to subject may differ simply because of the non-cyclical nature of the upper limbs movements. Methods. The coordinates of external markers attached to bone references on the forearm and dorsal side of the hand were obtained using an optical motion capture system. The wrist angles were derived from free motion trials and successively calculated in four healthy subjects for two specific cyclical daily activities (opening a jar and pouring from a carton). Results. The free motions trial highlighted the interaction between the wrist angles. Both the jar opening and the carton pouring activity showed a repetitive pattern for the three angles within the cycle length. In the jar-opening task, the standard deviation for the whole population was 10.8° for flexion–extension, 5.3° for radial-ulnar deviation and 10.4° for pronation–supination. In the carton-pouring task, the standard deviation for the whole population was 16.0° for flexion–extension, 3.4° for radial-ulnar deviation and 10.7° for pronation–supination. Conclusion. Wrist kinematics in healthy subjects can be successfully described by the rotations about the axes of marker-defined coordinates systems during free range of motion and daily activities using cyclical tasks. Relevance This study explores the kinematics of the wrist during free motion and daily activities. The technique can be used by the clinician to describe the upper limbs joint angles from a functional perspective. Ó 2003 Elsevier Ltd. All rights reserved. Keywords: Upper limbs kinematics; Wrist angles; Euler angles; Activities of daily living 1. Introduction A complete description of the wrist kinematics is particularly useful when observing the wrist when it performs daily activities rather than the use of range of motion (RoM) tests. The reason is that RoM does not always correlate well with the subject’s real hand func- tion (Light et al., 1999; Fowler and Nicol, 2001). The kinematical models presented by Youm et al. (1978), Chao and Morrey (1978) described the move- ment of the wrist and elbow during in vitro tests. The invasive nature of the measurements, requiring bone implanted markers and Roentgen photogrammetry, makes it impossible to validate and difficult to apply the models to real conditions. The advances in motion capture systems and the use of external markers coupled to larger capture volumes and higher resolution make possible the measurement of representative activities, while at the same time reducing the subject’s inconvenience and the invasiveness of the tests. The approach to the study of upper kinematics using an optical motion capture system proposed by Light (2000a) and Rau et al. (2000) shows the importance * Corresponding author. E-mail address: a.murgia@reading.ac.uk (A. Murgia). 0268-0033/$ - see front matter Ó 2003 Elsevier Ltd. All rights reserved. doi:10.1016/j.clinbiomech.2003.11.012 www.elsevier.com/locate/clinbiomech Clinical Biomechanics 19 (2004) 248–254