Influence of Handrim Wheelchair Propulsion Training in Adolescent Wheelchair Users, A Pilot Study

This paper overviews the importance for sports biomechanics of movement variability, which has been studied for some time by cognitive and ecological motor skills specialists but, until quite recently, had somewhat been overlooked by sports biomechanists. The paper considers biomechanics research reporting inter- and intra-individual movement variability in javelin and discus throwing, basketball shooting, and locomotion. The overview does not claim to be comprehensive and we exclude such issues as the theoretical background to movement and coordination variability and their measurement. We overview evidence, both theoretical and empirical, of inter-individual movement variability in seeking to achieve the same task goal, in contrast to the concept of "optimal" movement patterns. Furthermore, even elite athletes cannot reproduce identical movement patterns after many years of training, contradicting the ideas of motor invariance and "representative" trials. We contend that movement variability, far from being solely due to neuromuscular system or measurement "noise"--as sports biomechanists may have previously supposed--is, or could be, functional. Such functionality could allow environmental adaptations, reduce injury risk, and facilitate changes in coordination patterns. We conclude by recommending that sports biomechanists should focus more of their research on movement variability and on important related topics, such as control and coordination of movement, and implications for practice and skill learning.

To compare the prevalence and intensity of shoulder pain experienced during daily functional activities in individuals with tetraplegia and individuals with paraplegia who use manual wheelchairs. Self-report survey. General community. Fifty-five women and 140 men, 92 subjects with tetraplegia and 103 subjects with paraplegia who met inclusion criteria of 3 hours per week of manual wheelchair use and at least 1 year since onset of spinal cord injury. Respondents completed a demographic and medical history questionnaire and the Wheelchair User's Shoulder Pain Index (WUSPI), a measure of pain during typical daily activities. More than two thirds of the sample reported shoulder pain since beginning wheelchair use, with 59% of the subjects with tetraplegia and 42% of the subjects with paraplegia reporting current pain. Performance-corrected WUSPI scores were significantly higher in subjects with tetraplegia than in subjects with paraplegia. Both the prevalence and intensity of shoulder pain was significantly higher in subjects with tetraplegia than in subjects with paraplegia. Efforts to monitor and prevent shoulder pain should continue after rehabilitation.

Intra-individual variability over a short period of time may contain important information about how individuals differ from each other. In this article we begin by discussing diverse indicators for quantifying intra-individual variability and indicate their advantages and disadvantages. Then we propose an alternative method that models inter-individual differences in intra-individual variability by separately considering both the amplitude of fluctuations and temporal dependency in the data. In the proposed model, temporal dependency and amplitude of fluctuations are both included as random effects. Parameter estimation is done with a multiple-step approach using maximum likelihood, or with a recommended 1-step approach using a Bayesian method. The similarities and differences between the proposed method and some existing methods are discussed and investigated using diary study data from older adults. The results from empirical data analysis revealed that temporal dependency and amplitude of fluctuations have different predictability of health outcomes and thus should be modeled and considered separately. PsycINFO Database Record (c) 2013 APA, all rights reserved.