Matching Items (7)

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FOOT STRIKE AND INJURY RATES IN ENDURANCE RUNNERS: A RETROSPECTIVE STUDY- REVISITED

Description

Although the sport and exercise of running has a great amount of benefits to anyone's health, there is a chance of injury that can occur. There are many variables that

Although the sport and exercise of running has a great amount of benefits to anyone's health, there is a chance of injury that can occur. There are many variables that can contribute to running injury. However, because of the vast amount of footsteps a frequent runner takes during their average run, foot strike pattern is a significant factor to be investigated in running injury research. This study hypothesized that due to biomechanical factors, runners that exhibited a rear foot striking pattern would display a greater incidence of chronic lower extremity injury in comparison to forefoot striking counterparts. This hypothesis would support previous studies conducted on the topic. Student-athletes in the Arizona State University- Men's and Women's Track & Field program, specifically those who compete in distance events, were given self reporting surveys to provide injury history and had their foot strike patterns analyzed through video recordings. The survey and analysis of foot strike patterns resulted in data that mostly followed the hypothesized pattern of mid-foot and forefoot striking runners displaying a lower average frequency of injury in comparison to rear foot strikers. The differences in these averages across all injury categories was found to be statistically significant. One category that displayed the most supportive results was in the average frequency of mild injury. This lead to the proposed idea that while foot strike patterns may not be the best predictor of moderate and severe injuries, they may play a greater role in the origin of mild injury. Such injuries can be the gateway to more serious injury (moderate and severe) that are more likely to have their cause in other sources such as genetics or body composition for example. This study did support the idea that foot strike pattern can be the main predictor in incidence of running injuries, but also displayed that it is one of many major factors that contribute to injuries in runners.

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Date Created
  • 2014-05

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The Rhythm of Running: An Analysis of Preferred Running Tempo

Description

The action of running is difficult to measure, but well worth it to receive valuable information about one of our most basic evolutionary functions. In the context of modern day,

The action of running is difficult to measure, but well worth it to receive valuable information about one of our most basic evolutionary functions. In the context of modern day, recreational runners typically listen to music while running, and so the purpose of this experiment is to analyze the influence of music on running from a more dynamical approach. The first experiment was a running task involving running without a metronome and running with one while setting one's own preferred running tempo. The second experiment sought to manipulate the participant's preferred running tempo by having them listen to the metronome set at their preferred tempo, 20% above their preferred tempo, or 20% below. The purpose of this study is to analyze whether or not rhythmic perturbations different to one's preferred running tempo would interfere with one's preferred running tempo and cause a change in the variability of one's running patterns as well as a change in one's running performance along the measures of step rate, stride length, and stride pace. The evidence suggests that participants naturally entrained to the metronome tempo which influenced them to run faster or slower as a function of metronome tempo. However, this change was also accompanied by a shift in the variability of one's step rate and stride length.

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Created

Date Created
  • 2017-05

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Robotic augmentation of human locomotion for high speed running

Description

Human running requires extensive training and conditioning for an individual to maintain high speeds (greater than 10mph) for an extended duration of time. Studies have shown that running at

Human running requires extensive training and conditioning for an individual to maintain high speeds (greater than 10mph) for an extended duration of time. Studies have shown that running at peak speeds generates a high metabolic cost due to the use of large muscle groups in the legs associated with the human gait cycle. Applying supplemental external and internal forces to the human body during the gait cycle has been shown to decrease the metabolic cost for walking, allowing individuals to carry additional weight and walk further distances. Significant research has been conducted to reduce the metabolic cost of walking, however, there are few if any documented studies that focus specifically on reducing the metabolic cost associated with high speed running. Three mechanical systems were designed to work in concert with the human user to decrease metabolic cost and increase the range and speeds at which a human can run.

The methods of design require a focus on mathematical modeling, simulations, and metabolic cost. Mathematical modeling and simulations are used to aid in the design process of robotic systems and metabolic testing is regarded as the final analysis process to determine the true effectiveness of robotic prototypes. Metabolic data, (VO2) is the volumetric consumption of oxygen, per minute, per unit mass (ml/min/kg). Metabolic testing consists of analyzing the oxygen consumption of a test subject while performing a task naturally and then comparing that data with analyzed oxygen consumption of the same task while using an assistive device.

Three devices were designed and tested to augment high speed running. The first device, AirLegs V1, is a mostly aluminum exoskeleton with two pneumatic linear actuators connecting from the lower back directly to the user's thighs, allowing the device to induce a torque on the leg by pushing and pulling on the user's thigh during running. The device also makes use of two smaller pneumatic linear actuators which drive cables connecting to small lever arms at the back of the heel, inducing a torque at the ankles. Device two, AirLegs V2, is also pneumatically powered but is considered to be a soft suit version of the first device. It uses cables to interface the forces created by actuators located vertically on the user's back. These cables then connect to the back of the user's knees resulting in greater flexibility and range of motion of the legs. Device three, a Jet Pack, produces an external force against the user's torso to propel a user forward and upward making it easier to run. Third party testing, pilot demonstrations and timed trials have demonstrated that all three of the devices effectively reduce the metabolic cost of running below that of natural running with no device.

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Created

Date Created
  • 2014

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Behavioral strategies for stable maneuvers during locomotion

Description

Humans moving in the environment must frequently change walking speed and direction to negotiate obstacles and maintain balance. Maneuverability and stability requirements account for a significant part of daily life.

Humans moving in the environment must frequently change walking speed and direction to negotiate obstacles and maintain balance. Maneuverability and stability requirements account for a significant part of daily life. While constant-average-velocity (CAV) human locomotion in walking and running has been studied extensively unsteady locomotion has received far less attention. Although some studies have described the biomechanics and neurophysiology of maneuvers, the underlying mechanisms that humans employ to control unsteady running are still not clear. My dissertation research investigated some of the biomechanical and behavioral strategies used for stable unsteady locomotion. First, I studied the behavioral level control of human sagittal plane running. I tested whether humans could control running using strategies consistent with simple and independent control laws that have been successfully used to control monopod robots. I found that humans use strategies that are consistent with the distributed feedback control strategies used by bouncing robots. Humans changed leg force rather than stance duration to control center of mass (COM) height. Humans adjusted foot placement relative to a "neutral point" to change running speed increment between consecutive flight phases, i.e. a "pogo-stick" rather than a "unicycle" strategy was adopted to change running speed. Body pitch angle was correlated by hip moments if a proportional-derivative relationship with time lags corresponding to pre-programmed reaction (87 ± 19 ms) was assumed. To better understand the mechanisms of performing successful maneuvers, I studied the functions of joints in the lower extremities to control COM speed and height. I found that during stance, the hip functioned as a power generator to change speed. The ankle switched between roles as a damper and torsional spring to contributing both to speed and elevation changes. The knee facilitated both speed and elevation control by absorbing mechanical energy, although its contribution was less than hip or ankle. Finally, I studied human turning in the horizontal plane. I used a morphological perturbation (increased body rotational inertia) to elicit compensational strategies used to control sidestep cutting turns. Humans use changes to initial body angular speed and body pre-rotation to prevent changes in braking forces.

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Created

Date Created
  • 2012

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Serious running: factors that lead to awareness, attraction, attachment and loyalty to long distance running

Description

Commitment to an activity is widely studied in leisure research. Serious Leisure Perspective (SLP) describes characteristics a committed activity participant possesses. The Psychological Continuum Model (PCM) describes the psychological process

Commitment to an activity is widely studied in leisure research. Serious Leisure Perspective (SLP) describes characteristics a committed activity participant possesses. The Psychological Continuum Model (PCM) describes the psychological process a person goes through to become committed to a leisure activity. Awareness, attraction, attachment and loyalty make of the four stages of PCM. Both perspectives have been used to describe committed leisure activity participants and commitment to organized recreational events. Research on leisure activity has yet to determine how the individual becomes loyal. Therefore, the purpose of this study is to determine the process in which recreation activity participates becomes loyal and to identify who can be labels as serious within the PCM Framework. Data was obtained from an online electronic survey distributed to participants of four U.S. marathon and half marathon events. A total of 579 responses were used in the final analysis. Path analysis determined the process in which a runner becomes committed. MANOVA is used to determine difference between leisure groups in the four stages of PCM. Results indicate that activity participants need to go through all four stages of PCM before becoming loyal. As knowledge increases, individuals are more motivated to participate. When the activity satisfies motives and becomes a reflection of their identity, feelings become stronger which results in loyalty. Socialization is instrumental to the progression through the PCM Framework. Additionally, attachment is the "bottleneck" in which all loyal activity participants my pass through. Differences exist between serious leisure groups in the attachment and loyalty stages. Those that are `less serious' are not as committed to the activity as their counterparts.

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Created

Date Created
  • 2014

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Modeling motivation: examining the structural validity of the Sport Motivation Scale-6 among runners

Description

Two models of motivation are prevalent in the literature on sport and exercise participation (Deci & Ryan, 1991; Vallerand, 1997, 2000). Both models are grounded in self-determination theory (Deci &

Two models of motivation are prevalent in the literature on sport and exercise participation (Deci & Ryan, 1991; Vallerand, 1997, 2000). Both models are grounded in self-determination theory (Deci & Ryan, 1985; Ryan & Deci, 2000) and consider the relationship between intrinsic, extrinsic, and amotivation in explaining behavior choice and outcomes. Both models articulate the relationship between need satisfaction (i.e., autonomy, competence, relatedness; Deci & Ryan, 1985, 2000; Ryan & Deci, 2000) and various cognitive, affective, and behavioral outcomes as a function of self-determined motivation. Despite these comprehensive models, inconsistencies remain between the theories and their practical applications. The purpose of my study was to examine alternative theoretical models of intrinsic, extrinsic, and amotivation using the Sport Motivation Scale-6 (SMS-6; Mallett et al., 2007) to more thoroughly study the structure of motivation and the practical utility of using such a scale to measure motivation among runners. Confirmatory factor analysis was used to evaluate eight alternative models. After finding unsatisfactory fit of these models, exploratory factor analysis was conducted post hoc to further examine the measurement structure of motivation. A three-factor structure of general motivation, external accolades, and isolation/solitude explained motivation best, although high cross-loadings of items suggest the structure of this construct still lacks clarity. Future directions to modify item content and re-examine structure as well as limitations of this study are discussed.

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Created

Date Created
  • 2012