Brian P. Self

A biomechanical analysis of a medial unloading brace for osteoarthritis in the knee.

OBJECTIVES The goals of the study were to measure the force applied to the lateral side of the knee by a valgus loading brace designed for patients with medial compartment osteoarthritis (OA) and to compare the varus moment at the knee during level gait with and without the brace. METHODS Five subjects diagnosed with medial compartment OA were fitted with a custom Monarch valgus loading knee brace. A 3-dimensional videobased motion analysis system and force plate information were used to calculate forces and moments at the knee. An instrumented condylar bladder was used to determine the force applied to the knee by the brace. The varus moments for the braced and unbraced trials were compared during gait at 15%, 20%, 25%, and 30% of stance. RESULTS The Monarch brace significantly reduced the varus moment at 20% and 25% of stance. The valgus force measured with the custom condylar bladder remained fairly constant throughout the first 80% of the stance phase. CONCLUSIONS The reduced various moment observed for the braced condition demonstrates the biomechanical function of the brace in 5 subjects and may contribute to a reduction of pain for patients with medial compartment OA.

Unusual Attitude Recoveries With a Spatial Disorientation Icon

Twenty-two participants (12 with prior flying experience and 12 without), performed a series of trials in a low fidelity flight simulator in which they attempted to recover from a series of unusual attitudes. Two display variables were examined: (1) the attitude display was either a traditional head-up display (HUD) with an inside-out motion and pitch ladder, or an Arc-Segmented Attitude Reference (ASAR) display; and (2) a command icon that pointed to the appropriate airplane rotation for recovery direction in pitch and roll was either present or absent. The results revealed that the icon speeded the initial correction and reduced the number of roll reversal errors, while the traditional HUD decreased the total time to recovery. Experienced pilots were more disrupted by the ASAR display than were novices.

Ankle Biomechanics During Impact Landings on Uneven Surfaces

Inversion sprains of the lateral ligaments of the ankle are one of the most common of all sporting injuries. While the strains in the anterior talofibular (ATFL) and calcaneofibular (CFL) ligaments have been measured in quasi-static conditions, the dynamic strains during an actual traumatic event have not been determined. The present investigation determined the strains and strain rates in the ATFL and CFL during an in vitro inversion sprain. The ATFL tended to have higher strain and strain rate values than the CFL, which may explain why it is more often injured than the CFL.

Head Accelerations During Soccer Heading

There is a continuing debate on if heading can cause neurocognitive defects in soccer players. Some studies suggest that repeated sub-concussive impacts may lead to neurocognitive deficits, while others dispute these claims. Any deficits in function would certainly be tied to the characteristics of the ball-head impact, yet the head accelerations of soccer heading have not been fully determined. Furthermore, no researchers to date have examined both head accelerations and neurocognitive function in the same study. The current research examines the potential for head injury suffered by a collegiate soccer player during headers similar to what they would experience in practice. Primary data collection used two three-axis accelerometers and an angular rate sensor coupled to a small remote data collection system, as well as video tapes of the headers to examine incoming and outgoing ball velocities. These accelerations were converted to Head Injury Criteria (HIC) values, which more accurately reflect the potential for injury. Six trials of two heading types were examined during testing. The first simulates heading a goal kick traveling at 16 m/s back in the direction from which it came. The second type involves redirecting a 12 m/s ball 90 degrees from its inflight path, which simulates heading a corner kick or cross towards the goal. Average accelerations were 29.26 and 32.64 Gs for the corner and straight on headers, respectively, and the maximum HIC value for all of the players was 133.3. None of the results from the neurocognitive tests indicated any detrimental effects on the participants.

Work In Progress: Building an Evaluative Research Foundation for Just-in-Time Teaching

Just-in-time teaching (JiTT) involves problem-solving assignments completed by students shortly before class. Responses to thought-provoking questions are used to organize discussions around student understanding. Like many innovations, JiTTs implementation has rapidly outpaced: a) theoretical specification of the strategy; b) systematic evaluation of its efficacy; and c) efforts to validate principles for optimal use. An approach was taken that may serve as an exemplar for other innovations that are growing faster than their theory base. Initially, a Web-based survey and literature review were performed to organize available evidence on JiTTs effectiveness. Two virtual conferences were held to identify important research questions. Then, educational research mentors advised JiTT practitioners on establishing research agendas at an assessment workshop. This effort demonstrates a valuable example of how an emerging community can mobilize itself to treat questions of that innovations theory, validation and design with the same rigor that it brings to the scientific disciplines that the community represents