Tag: Li-Shan Chou

Presenter: Howey Richard

Metatarsal stress fractures (MSF) are some of the most common, most debilitating injuries that athletes experience. Most previous studies have focused on calculating the loading rates using the vertical ground reaction force (vGRF), with inconclusive results. The purpose of this study was to compare metatarsal loading rates in runners with retrospective history MSF and runners who have never sustained this kind of injury. This was done with ten runners, five with a history of MSF and five without. Plantar pressure measurements were collected using the FScan VersaTek wireless system. The runner ran on a treadmill at a self-selected speed that approximated their easy training pace. Thirty steps on each foot were recorded. The data was analyzed using the FScan Research software, then run through a custom LabView program that calculated the maximal force (MF), average vertical loading rate (AVLR), and instantaneous vertical loading rate (VILR). There were no differences in any of the dependent variables between the injured and non-injured feet of the MSF subjects and the matching feet of the control subjects. However, three of the five subjects did show significantly higher values for MF, AVLR, and VILR in the injured foot compared to the non-injured foot. Subject 5 also showed a significant difference between feet, but in the opposite way. These individualized responses, in combination with the small sample size, partially explain the lack of significance in the group analysis.

Aging results in declines in many physiological functions, which can negatively affect the performance of everyday activities such as mov- ing from a sitting position to walking. This study was intended to determine how decreases in lower extremity strength can negatively influence elderly performance during Sit-to-Walk, putting them at risk for falling. Forty eight subjects above the age of 70 were recruited to perform the Timed-Up-and-Go (TUG) as well as strength tests targeting hip abductors, knee extensors and ankle dorsiflexors. Lower strength subjects took longer to complete the TUG test. Smaller GRFs were correlated with longer duration of TUG, which indicates a decrease in overall performance and a higher probability of falling as a result of poor muscle strength. This study provides an explanation to how muscle strength correlates with performance in terms of GRF’s and time.

Approximately 136,000 sports related concussions or mild traumatic brain injuries occur in the high school population annually. This study aims to further understand the initial deficits exhibited in the first 72 hours post injury. We hypothesized that the concussed individuals would walk with slower gait velocities and produce slower reaction times when compared to the control subjects during static and dynamic continuous Stroop testing. Motion data was collected using 29 reflective markers and a 10-camera motion analysis setup. The auditory Stroop task consisted of a computer that presented the word, high or low either in high or low pitch. The subject was then asked to declare which pitch the word was presented in, while ignoring the actual word announced. Each trial was present- ed in increments of four continuous presentations. For concussed subjects significant differences were detected in the gait velocity between level walking and walking while performing concurrent auditory Stroop tasks. This may be due to injury to a region of the brain that is susceptible to injury within 72 hours post concussion. We observed that tests that include divided attention and walking may give an indication of cognitive disturbances experienced post concussion. In the future this finding may be used to assist clinicians with the diagnosis of concussion.

The purpose of this study was to investigate how the gait of high school concussed subjects changes from the time of injury to 2 months post-concussion as well as assessing their reaction times to a Stroop reaction task in static and dynamic conditions. During the auditory Stroop task, the participant was required to listen to a computer generated word (“high” or “low”) that was spoken in either a high or low pitch. The goal for the participant was to answer the pitch of the word rather than the actual word produced by the computer. Twelve concussed subjects were identified by an athletic trainer and then matched by age, height, and weight with 12 controls. They performed 3 tasks: single task walking (walking in a straight line as normal as possible), dual task walking (walking in a straight line while performing an auditory Stroop task), and an auditory Stroop task while seated. Temporal distance parameters (stride length, stride width, and gait velocity) were calculated using a 10 camera motion analysis system. It was hypothesized that concussed subjects would prioritize when performing a dual-task; their gait would become more conservative in order to respond to the Stroop task. When the concussion subjects responded to the Stroop task, their gait velocity and stride length decreased and stride width increased in relation to single-task walking trails. This study is significant in that people of ages 15-19 years old are more prone to suffering a concussion than any other age group.

Elderly adults suffer a high incidence of falls during daily activity. It is well documented that dynamic balance and muscle strength deteriorate with age. The goal of this study is to compare total support moment and joint moment distribution of the supporting lower limb during the sit-to-walk transition in groups of young, elderly faller and elderly non-faller subjects (≥ 70 years). Force plate and three-dimensional motion analysis data were collected during several trials of the Timed Up and Go test (TUG) to calculate total support moment and joint moments at the hip, knee, and ankle during sit-to-walk. Significant differences between the groups were found in the amount of ankle joint moment produced at seat-off and swing-off events. There were not significant differences in total support moment, hip, or knee moments at these events. However, there seems to be variation in the patterns of the total support moment graphs between the groups. The variation in the ankle moment between the groups identifies the correlation between the torque produced around the ankle and balance performance. The differences in total support moment patterns found between faller, non-faller, and young groups indicate different strategies used to perform the sit-to-walk motion that may compensate for impaired balance. The relevance of this study is that it provides a correlation found between balance performance and joint moment contribution, which would be useful in creating a fall prevention and balance treatment plan.