The purpose of this series of investigations was to determine how custom foot orthotic intervention influences the lower extremity dynamics and intra-limb coordination in healthy and injured female runners. For the first investigation, dynamic data were collected from 12 healthy female runners (Control group) and 12 female runners with a recent history of overuse knee running injury (Treatment group). Results revealed that the influence of CFO intervention on lower extremity appears to occur with short-term intervention. The intervention produced a similar response in both groups. The knee kinematics were not influenced by the intervention however there were changes observed in knee kinetics. For the second investigation, dynamic data were collected during overground running trials in Treatment group from Study One who had completed 6 weeks of orthotic therapy. Data were collected with the subjects running with (CFO condition) and without (Shod condition) foot orthoses in three running shoes with varying midsole composition. Results revealed that the only kinematic variable influenced by running shoe midsole durometer was maximum rearfoot eversion velocity. However, CFO intervention in the footwear led to significant decreases in rearfoot kinematic variables, tibial internal rotation and internal ankle inversion moments. In addition, it was revealed that when a CFO intervention is added to a shoe of lesser density, the dynamics exhibited by the runner are similar to when wearing a shoe of greater density. For the third investigation, kinematic data were collected from 9 healthy female runners (Control group) and 9 female runners with a recent history of overuse knee running injury (Treatment group). Both groups performed a 30-minute treadmill run and relative motion plots were created for the intra-limb couplings. Results revealed that CFO intervention helped to maintain variability during the early stance phase throughout the course of the run in the injured runners. In the Treatment group, the TibTP/CalFP and KnTP/RFFP coordination variability during the early stance phase significantly decreased throughout the course of the 30-minute run for the Shod condition. While wearing the CFO condition the variability went unchanged and better resembled patterns exhibited by the Control group.

No description available.

No description available.

No description available.

Background Cycling is a popular recreational and competitive form of physical activity and method of transport. Cycling is broadly categorised as road cycling or mountain biking, and each form presents unique challenges and has different skill requirements. While cycling, in general, provides many benefits to both physical health and social behaviours, there are legitimate concerns about injuries related to both road and mountain cycling. Most of the available research presents the injury incidence in commuter or road cycling, with an apparent lack of evidence in mountain biking. The van Mechelen model of injury prevention outlines four stages in injury prevention research; the first stage investigates the extent of the injury and provides the basis on which the remaining stages depend. Based on the van Mechelen conceptual model, the broad aim of this thesis was to investigate acute injury epidemiology in mountain biking and the factors affecting bicycle control and falling. Investigations We performed a systematic review of the incidence of injury in mountain biking. Acute injury incidence ranged from 4% to 71% in cross-country mountain bike races. The causal indicators of bicycle control may include balance, agility and visual perception. In a pilot study, we developed novel tests to assess static bicycle balance and bicycle agility as measures of bicycle control. In the following study, we developed additional dynamic bicycle balance with four increasingly difficult levels. In this study, twenty-nine participants attended three days of repeated testing for reliability assessments of these tests. Participants also completed an outdoor downhill run. Performance in the balance tests were compared to performance in the outdoor downhill test to assess their ecological validity. All tests were assessed for reliability using typical error of measurement, standardised typical error, intraclass correlation coefficients, limits of agreement, effect sizes and repeated measures ANOVA's (with post hoc testing) analyses. The novel bicycle balance and agility were significantly associated with the performance in the outdoor downhill run (r=-0.51 to 0.78; p=0.01 to 0.0001). Cognitive and physical fatigue are factors that may contribute to loss of control of the bicycle. In our final study, we aimed to assess the effect of these factors on the performance in the novel tests. Rate of perceived exertion was significantly increased for all tests following physical fatigue (Cliff's d effect size= 0.27-0.40; p=0.001 to 0.037), but balance and agility performance were not affected. Cognitive fatigue had no effect on balance and agility performance. The fatigue induced in these protocols was insufficient to change performance in the bicycle-specific balance and agility tests. This indicates that either the fatigue protocols did not sufficiently replicate the fatigue experienced in mountain biking or that the tests are too blunt to be affected by the magnitude of fatigue in these protocols. Conclusion The overall incidence of injury in mountain biking is difficult to determine due to different injury definitions in the research. However, the available data clearly indicates an area of concern in sports and exercise medicine. We developed novel tests to assess the skill components of balance and agility on a mountain bike. The novel bicycle-specific tests are robust assessments of mountain biking performance and can be applied in clinical and research environments to determine bicycle control. Cognitive and physical fatigue did not affect performance on these novel tests. Based on the overall findings of our studies, we recommend that further research is conducted on the epidemiology of mountain biking injuries. The effect of fatigue on the novel tests needs to be investigated further using a combination of physical and cognitive fatigue.

No description available.

No description available.

No description available.

No description available.

Thesis (M.H.S.A.)--University of Michigan, 1980.