The kinematic and kinetic characteristics of arm movement during four activities of daily living: lifting a weight, driving a steering wheel, opening/closing a door and cutting were investigated in this study by using a human movement analysis system comprising a 6 camera Vicon motion analysis system, a 6 component strain-gauged transducer, a specially designed and instrumented steering wheel simulation system, a door and a cutting plate. The most important achievements of this study are: (1) Implementation of the residual analysis technique into a computer program to filter the noisy kinematic data at an autoselected cut-off frequency for each data sequence. (2) The development of a new method of representing the velocity and acceleration of points of interest using the phase plane presentation. It was found that driving is the most complicated activity investigated in this study according to the range of arm movement. From the kinetic results, it was found that the order of difficulty of the four activities can be arranged as cutting, door opening/closing, lifting, and driving according to the magnitude of the maximum resultant total shoulder moment. The difficulty of the lifting activity increased with the weight to be lifted and the height of lifting. It was also found that the major component of the shoulder moment is the flexion/extension moment for most of the activities except driving, therefore it is concluded that having sufficient shoulder flexion/extension strength is most important for conducting most upper limb activities of daily living. In addition, the results of this study provide information for improving the understanding of the biomechanics of the upper limb activities and for clinical reference.

The purpose of this study was to establish an influence on static and dynamic postural control in sitting for voluntary arm movement for children with diplegic cerebral palsy. The investigation was fulfilled with control and experimental groups. The control group included ten healthy children and the experimental group included ten children with cerebral palsy. The age of the children was from 10 to 13 years. Subjects had to perform the same task with a single arm for four times. Every time the demands of postural control were increasing – the distance between objects and outward stability was changing. Task performing time was measured and visual estimation of the quality of postural control was done. The study showed that children with cerebral palsy performed the task slower than healthy ones (P < 0.05). The task performance time in the experimental group increased depending on growing distance between objects (p <0.05) and increased depending on decreasing outward stability (p < 0.05). The task’s time in the control group increased only when the distance was increasing between objects (p < 0.05), though when outward stability was decreasing the task’s performance time decreased (p < 0.05). A connection between task’s performance speed in standard conditions and task’s performance speed when the distance between objects was increased (r = 0.8), outward stability was decreased (r = 0.79), the distance between objects was increased and outward stability was decreased (r = 0... [to full text]

Human functional laterality, typically involving a right-sided preference in most sensory-motor activities, is still a poorly understood issue. This is perhaps particularly true in terms of what underlying mechanisms that may govern lateral biases, as well as the developmental origins and course of events. The present thesis aims at investigating functional asymmetries in the upper and lower body movements of young human infants. In Study I, the presence of side biases in the stepping and placing responses and head turning in healthy fullterm newborns were explored. No evident lateral bias for the leg responses in terms of the first foot moved or direction of head turning was found. However, a lateral bias was revealed for onset latency in relation to the first foot moved in both stepping and placing. Asymmetries in head turning did not correspond to asymmetries in leg movements. In Study II, functional asymmetries in the stepping response of newborn infants were investigated in more detail by means of 3-D kinematic movement registration. Evident side differences were found in relation to smoother movement trajectories of the right leg by means of less movement segmentation compared to the left leg. Side differences were also found in relation to intralimb coordination in terms of stronger ankle-knee couplings and smaller phase shifts in the right leg than the left. In Study III, using the same movement registration technique, the kinematics of left and right arm movements during goal-directed reaching in infants were prospectively studied over the ages 6, 9, 12, and 36 months. Main findings included side differences and developmental trends related to the segmentation of the reaching movements and the reaching trajectory, as well as the distribution of arm-hand-use frequency. The results from Study I and II are discussed in relation to underlying neural mechanisms for lateral biases in leg movements and the important role of a thorough methodology in investigating newborn responses. Findings from Study III are discussed in terms of what they imply about the developmental origins for hand preference. An emphasis is also put on developmental differences between fullterm and preterm infants. Overall, the studies of the present thesis show that an increased understanding of subtle expressions of early functional asymmetries in the upper and lower body movements of young infants may be gained by means of refined measurements. Furthermore, such knowledge may provide an insight into the underlying neural mechanisms subserving asymmetries in the movements of young infants. The present studies also add new information to the current understanding of the development of human lateralized functions, in particular the findings derived from the longitudinal data. Apart from theoretical implications, the present thesis also involves a discussion with regard to the clinical relevance of investigating functional asymmetries in the movements of young infants.