Red light running is one of the main contributing factors of crashes in urban areas in Florida and the United States. Nationwide, according to preliminary estimates by the Federal Highway Administration (FHWA) 2001, there were nearly 218,000 red-light running crashes at intersections. These crashes resulted in as many as 181,000 injuries and 880 fatalities, and an economic loss estimated at $14 billion per year nationwide, According to the Community Traffic Safety Team Florida Coalition (A statewide traffic safety group) there were 9,348 crashes involving red-light running in Florida and 127 fatalities in 1999. This research study focused on studying the red light running crashes and violations in the State of Florida. There were three primary objectives for this research. The first primary objective was to analyze the red light running crashes in Florida from 2002 to 2004. The data for this part was collected from the Crash Analysis Reporting System of the Florida Department of Transportation. These crashes are reported as "disregarded traffic signal" as far as the first contributing cause. The analysis focused on the influences of different factors on red light running crashes including the driver (age group, gender, and DUI history) and the environment (time of day, day of week, type of road, and weather). However, not all red light crashes are reported as "disregarded traffic signal". Therefore, representing red light running crashes only through "disregard traffic signal" noted reports would underestimate the extent of red light running effects at a given intersection. Therefore, the second objective was to review the long form crash reports to determine the actual number of crashes related to red light running. The analysis for a random sample of the crashes on the sate roads of Florida on the year 2004 showed that the percentage of crashes related to red light running reported on the database was found to be (3.13%), and the percentage of crashes related to red light running reported in the original crash repot filled by the police officer are much higher than reported(5.63%), which shows the importance of standardizing the format and coding process for the long form crashes conducted by the police officers to help accurately identify the real cause of the crash at the studied location. The third objective was to analyze the violations data given for five intersections and find if there is a correlation between the average rate of violations per hour and the frequency of red light running crashes. The analysis showed that utilizing the limited number of intersections used in the study, it appears that there is no correlation between the average violations per hour and the red light running crashes at the studied locations.

Background: Achilles tendinopathy is a common debilitating running related injury. Achilles tendon loading force has been hypothesized as a contributor to Achilles tendinopathy. Loading force through the Achilles tendon during running is impacted by many factors such as footwear and foot strike pattern. Achilles tendon biomechanical (Achilles tendon cross-sectional area, thickness, echogenicity, stiffness, and T2*) responses to loading forces are variable and measurable in vivo. These responses impact the physiologic function of the tendon. Aims: 1) To evaluate baseline Achilles tendon biomechanical characteristics associated with a runner's habitual foot strike pattern. 2) To evaluate single running bout Achilles tendon biomechanical changes to varied forces in runners while maintaining their habitual foot strike pattern. This will be accomplished using minimalist and cushioned running shoes. Methods: 29 recreational runners were recruited. Runners completed two separate 5.3 km running sessions wearing alternating shoe types (cushioned and minimalist) at a pace of 3.15 m/s. Prior to running each day, participants had 32 retroreflective markers placed upon them for motion analysis collection. Additionally, participants had their Achilles tendon imaged via ultrasound pre and post run. On a separate day 24 of the participants underwent an ultrashort echo time (UTE) MRI imaging session of their Achilles tendon. Results: Achilles tendon stiffness was 20% greater in non-rear foot strike runners when compared with rear foot strike runners (p = 0.0166). Achilles tendon CSA, thickness, echogenicity, and T2* were not different between running groups (p > 0.05). Both foot strike pattern groups experienced significant Achilles tendon CSA and thickness decreases from pre to post run in minimalist and cushioned shoes (p < 0.05). Both running groups in cushioned shoes and the non-heel strike runners in minimalist shoes experienced significant increases in Achilles tendon echogenicity from pre to post run. Only non-rear foot strike runners had a significant increase in Achilles tendon stiffness while running in cushioned shoes (p = 0.03). Conclusions: The Achilles tendons of non-rear foot strike runners were significantly stiffer than those of rear foot strike runners. This Achilles tendon characteristic may be attributable to differences in Achilles tendon loading force while running but needs further research. Both groups of runners experienced multiple single running bout Achilles tendon changes as measured via ultrasound. Although loading forces varied within groups in different shoes and between foot strike pattern groups, all Achilles tendon changes were similar regardless of loading forces from pre to post run.

No / Motion at the midfoot joints can contribute significantly to overall foot motion during gait. However, there is little information regarding the kinematic coupling relationship at the midfoot. The purpose of the present study was to determine whether the coupling relationship at the midfoot and subtalar joints was affected when step width was manipulated during running. Twelve subjects ran over-ground at self-selected speeds using three different step widths (normal, wide, cross-over). Coupling at the midfoot (forefoot relative to rearfoot) and subtalar (rearfoot relative to shank) joints was assessed using cross-correlation techniques. Rearfoot kinematics were significantly different from normal running in cross-over running (P < 0.05) but not in wide running. However, coupling between rearfoot eversion/inversion and shank rotation was consistently high (r > 0.917), regardless of step width. This was also the case for coupling between rearfoot frontal plane motion and forefoot sagittal plane (r < 0.852) and forefoot transverse plane (r > 0.946) motion. There was little evidence of coupling between rearfoot frontal plane motion and forefoot frontal plane motion in any of the conditions. Forefoot frontal plane motion appeared to have little effect on rearfoot frontal plane motion and thus, had no effect on motion at the subtalar joint. The strong coupling of forefoot sagittal and transverse plane motions with rearfoot frontal plane motion suggests that forefoot motion exerts an important influence on subtalar joint kinematics.

Yes / Background: Individuals with lower-limb amputation can use running specific prostheses (RSP) that store and then return elastic energy during stance. However, it is unclear whether varying the stiffness category of the same RSP affects spring-mass behaviour during self-selected, submaximal speed running in individuals with unilateral transtibial amputation. Research question: The current study investigates how varying RSP stiffness affects limb stiffness, running performance, and associated joint kinetics in individuals with a unilateral transtibial amputation. Methods: Kinematic and ground reaction force data were collected from eight males with unilateral transtibial amputation who ran at self-selected submaximal speeds along a 15 m runway in three RSP stiffness conditions; recommended habitual stiffness (HAB) and, following 10-minutes of familiarisation, stiffness categories above (+1) and below (-1) the HAB. Stance-phase centre of mass velocity, contact time, limb stiffness’ and joint/RSP work were computed for each limb across RSP stiffness conditions. Results: With increased RSP stiffness, prosthetic limb stiffness increased, whilst intact limb stiffness decreased slightly (p

Humans generally use two modes of locomotion as adults. At slow speeds we walk, and at fast speeds we run. To perform either gait, we use our muscles. The central questions in this dissertation were: (1) Why do humans run the way they do, and (2) How do the mechanical properties of muscle influence running performance? Optimal control simulations of running were generated using a bipedal forward dynamics model of the human musculoskeletal system. Simulations of running and sprinting were posed as two-point boundary value problems where the muscle excitation signals were optimized to maximize an optimality criterion. In the first study, minimizing the dimensionless muscle activations rather than the cost of transport generated the simulation that most closely agreed without experimental kinetic, kinematic, and electromyographic data from human runners. In the second study, sprinting simulations were generated by maximizing the model’s horizontal speed. Adjustments in the parameters of the muscle force-velocity relationship, in particular the shape parameter, increased the maximum speed, and provided support for previous theories on limitations to maximum human sprinting speed. In the third study, virtual aging of the model’s muscles induced changes in the running biomechanics characteristic of older adults, and increased the stresses and strains of muscles where older runners are more frequently injured than young runners. Strengthening these muscles reduced their loading while still maintaining an economical gait with a relatively low joint contact force at the knee. The studies provide a framework for testing hypotheses on human movement without a strong dependency on experimental data, and provided new evidence on the validity of the simulation approach for studying human running, and on optimality criteria in human running, limitations to maximum sprinting speed, and relationships between aging, muscular properties, and running injuries.

“Excessive” and/or “delayed” subtalar joint (STJ) pronation has been linked to overuse injuries because of its influence on tibial internal rotation (TIR). The transfer of STJ pronation to TIR occurs via the talocrual joint, believed to have limited transverse plane motion. However, studies have shown the talocrural joint to have more transverse plane motion than once believed, therefore it is feasible that the STJ will only influence the motion of the tibia once this motion has been exhausted. Currently, studies evaluating this relationship have focused on peak joint angles and excursion without reference to the amount of motion available at the ankle joint complex (AJC). Therefore the purpose of these studies were to evaluate whether runners with anterior knee pain (AKP) utilize a greater percentage of their available eversion motion (eversion buffer), evaluate the effects of small eversion buffers on coordination, and evaluate the influence of orthotics on those with AKP and with the smallest eversion buffers. This study found healthy and injured runners, for the most part, presented with no significant differences in traditional pronation related variables. The one exception was peak pronation velocity, where injured runners demonstrated faster velocities. On the other hand injured runners had significantly smaller eversion buffers which lead them to change their coordinative pattern earlier during stance. This difference in pattern also caused the intra-individual coupling variability to peak earlier during stance. Orthotics successfully controlled the kinematics of the AJC and increased the eversion buffer of injured runners and in those displaying the smallest buffers. While orthotics successfully influenced the kinematics of the AJC, they did not influence those of the tibia and knee. These changes at the AJC did not have a strong impact on the coordinative patterns of the lower extremity, however demonstrated a trend toward being able to influence the intra-individual coupling variability. In summary, injured runners demonstrated smaller eversion buffers and changed their coordinative pattern earlier during stance. While orthotics successfully increased the eversion buffer, they did not strongly influence coordination variables. Future studies analyzing pronation related variables in injured populations should evaluate them relative to the available motion at the AJC.

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The societal youth problems of violence, racism, poverty, obesity, and depression have impacted a population of youths within the urban district of Worcester, Massachusetts known as Main South. The coach of a track team there, a Catholic woman whose hobbies include marathon running, leisure reading and theological exploration, combines her passions to create a program that transports small groups of youths out of the city for day trips that include fun runs along scenic trails, followed by silent reading, group discussions and shared meals within a home-like setting. Undergirded by a spirit of playfulness, the author notes the transformational benefits of each program element: distance running, leisure reading, hospitality, and time in nature, toward easing youth problems. Also recognizing a spiritual hunger as complicit in youth problems, “Mama Clark’s” Doctor of Ministry project infuses non-denominational spirituality into an otherwise secular program, toward total wellness of youths, body, mind, and spirit. While long-term change could not be immediately shown, initial responses from participants indicated positive outcomes. Referencing theology, the author suggests that seeds sown can begin to bridge the gap between the problems of youths and a “kingdom” ideal of happy, healthy, and delightful young people, playing on the face of the earth.

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