Matching Items (11)

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Firefighter Fitness and Injury Prevention

Description

Workplace injuries, especially those caused by overexertion, are a significant issue among firefighters. This investigation filmed 8 firefighters during simulated firefighting tasks. A detailed movement analysis for each task was

Workplace injuries, especially those caused by overexertion, are a significant issue among firefighters. This investigation filmed 8 firefighters during simulated firefighting tasks. A detailed movement analysis for each task was completed and used to infer the prime muscles and injury-prone joints during each task. A comprehensive strength training program was developed from this information to help reduce workplace injuries in firefighters.

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Date Created
  • 2014-05

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Generating Electricity from Kinetic Energy in Gym Equipment

Description

As society's energy crisis continues to become more imminent many industries and niches are seeking a new, sustainable and renewable source of electricity production. Similar to solar, wind and tidal

As society's energy crisis continues to become more imminent many industries and niches are seeking a new, sustainable and renewable source of electricity production. Similar to solar, wind and tidal energy, kinetic energy has the potential to generate electricity as an extremely renewable source of energy generation. While stationary bicycles can generate small amounts of electricity, the idea behind this project was to expand energy generation into the more common weight lifting side of exercising. The method for solving this problem was to find the average amount of power generated per user on a Smith machine and determine how much power was available from an accompanying energy generator. The generator consists of three phases: a copper coil and magnet generator, a full wave bridge rectifying circuit and a rheostat. These three phases working together formed a fully functioning controllable generator. The resulting issue with the kinetic energy generator was that the system was too inefficient to serve as a viable system for electricity generation. The electrical production of the generator only saved about 2 cents per year based on current Arizona electricity rates. In the end it was determined that the project was not a sustainable energy generation system and did not warrant further experimentation.

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Date Created
  • 2014-05

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ASYMMETRIES OF THE LOWER LIMBS AND VERTICAL JUMP LANDING PATTERNS IN DANCERS COMPARED TO NON-DANCERS AND POTENTIAL RISK OF INJURY

Description

Dancers tend to injure the anterior cruciate ligament in their left leg more often than the right. It is unclear whether this trend is due to biased choreography or if

Dancers tend to injure the anterior cruciate ligament in their left leg more often than the right. It is unclear whether this trend is due to biased choreography or if leg dominance and left versus right asymmetries are contributing factors. The purpose of this study was to investigate asymmetries between the left and right leg, in knee abduction during landing, hip external rotation (ER) and internal rotation (IR) strength, and hip ER and IR range of motion in dancers compared to non-dancers. This study aimed to determine whether these asymmetries can be linked to leg dominance, and if this puts one leg at higher risk for ACL injury. Ten dancers and eleven non-dancers performed three maximal effort countermovement vertical jumps off of two feet, as well as three maximal effort single leg jumps on each leg. Knee abduction angles during the landing phase of the jumps were calculated using motion capture data. Maximum isometric hip ER and IR strength was measured at 15, 30, 45, 60, and 90 of knee flexion, and hip ER and IR range of motion was measured at 90 of knee flexion. Contrary to the hypothesis, few significant differences were found between the left and right leg, as well as between dancers and non-dancers. Dancers exhibited significantly greater IR range of motion than non-dancers, and knee abduction angles were greater on the right than left leg during double leg jumps. This opposes the hypothesis that knee abduction angles would be greater in dancers on the left leg. However, significant positive correlations were found
between IR strength and knee abduction angles during single leg jumps on the left leg, suggesting that IR strength may be a contributing factor to knee valgus. Further studies may want to utilize qualitative analyses, more relevant jumping tasks, and a different marker set to elucidate asymmetries of the lower limbs that may truly be present.

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Date Created
  • 2013-05

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The Functional Anatomy of the Hindlimb of the Ringtail (Bassariscus astutus)

Description

The ringtail (Bassariscus astutus), a member of the Procyonidae, is capable of 180 degrees of hindlimb reversal during headfirst descent down a vertical substrate. The goal of this study was

The ringtail (Bassariscus astutus), a member of the Procyonidae, is capable of 180 degrees of hindlimb reversal during headfirst descent down a vertical substrate. The goal of this study was to determine the presence or absence of myological adaptations related to hindlimb reversal in the ringtail. Data for B. astutus are presented, including muscle weights and muscle maps ascertained from the dissection of four hindlimbs. Data from the current study were compared to published accounts of other species capable of hindlimb reversal, including procyonids (raccoon, coati, kinkajou, olingo), a mustelid (marten), palm civet, mongoose, tree squirrel, common tree shrew, and slow loris. Muscle mass data from this study demonstrate that the hip adductors of scansorial mammals are significantly more robust than those of terrestrial mammals, indicating a myological adaptation for climbing, but not necessarily hindlimb reversal. Among hindlimb reversers, the majority exhibit one belly of m. sartorius, the presence of m. extensor digiti I longus, and a fibular origin for m. fibularis longus. These characteristics indicate an emphasis on hip extension, ankle plantarflexion, and pes inversion. However, these characteristics are more likely due to phylogeny than hindlimb reversal because of their presence in closely-related non-reversers. Additional data on families outside of Carnivora may help determine if these myological traits are indeed due to phylogeny. Other myological data, such as moment arms and cross sectional areas, may provide evidence of adaptations for hindlimb reversal.

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Date Created
  • 2014-05

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A Simpler Method To Evaluate The Knee Adduction Moment During Gait Using Plantar Pressure Measurements

Description

Medial compartment knee osteoarthritis (OA) is a disease whose severity has been associated with the peak adduction moment during walking (pKAM). Unfortunately, measuring patients' pKAM to track their therapy progress

Medial compartment knee osteoarthritis (OA) is a disease whose severity has been associated with the peak adduction moment during walking (pKAM). Unfortunately, measuring patients' pKAM to track their therapy progress involves the use of a gait laboratory which is expensive and time intensive. This study aimed to develop and assess a regression method to predict the pKAM using only plantar pressure measurements. This approach could greatly reduce the burden of evaluating pKAM.

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Date Created
  • 2014-05

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The Effect of Resistance Band Training on Power Output

Description

Most athletic or daily activities require the use of force production at a given velocity, in other words, power is needed to complete these activities. There are different methods for

Most athletic or daily activities require the use of force production at a given velocity, in other words, power is needed to complete these activities. There are different methods for how this can be done, but the main two are heavy resistance training and plyometric training (Kawamori and Haff, 2004). However, resistance bands are another option of training that is available at a low cost and equipment needs. Resistance bands can also be used by athletes and elderly alike, but so far the benefits have barely been studied. Two participants were recruited to be followed as a case study. Both were of college age and were currently recreationally active with no health or musculoskeletal problems. Both participants were given a 35 lb. resistance band and instructed to do four different lower extremity exercises (three sets of four repetitions each) that were designed to target the muscles used for jumping. The study ran for five weeks, requiring three workouts per week separated by at least 24 hours. Participants were tested at three points; initial, halfway, and after all 15 workouts had been completed. Tests included measuring for changes in maximal vertical jump height as well as maximal broad jump. Results showed that both participants were able to increase their vertical jump and broad jump measurements from the initial testing day. Participant one had a 22.95% and 39.40% increase in broad jump and vertical jump respectively. Participant two had a 7.84% and 11.72% increase in broad jump and vertical jump respectively. Based on this study, it would appear that the power training program is effective in producing an increase in power based off the measured performance variables. There may be some effect from familiarity with testing protocol but most likely increased were caused by neural adaptation from speed aspect of program, as well as some increase in force production.

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Date Created
  • 2014-05

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Comparing the Efficacy of the Total Stabilizing and Posterior Stabilizing Knee Prostheses in Obese and Pre-Obese Females: A Retrospective Cohort Study

Description

Obesity is a growing issue in the Western world, as well as other international countries. This is leading to increases in complications associated with obesity. One such complication is osteoarthritis

Obesity is a growing issue in the Western world, as well as other international countries. This is leading to increases in complications associated with obesity. One such complication is osteoarthritis (OA) of load bearing joints that requires surgical treatment by total knee arthroplasty (TKA). Obesity is also associated with an increase in surgical complications that may lead to poor TKA outcomes. Additionally, the female gender is also known to be associated with increased rates of severe, clinical OA. This study was designed to determine the comparative efficacy of two knee implants in the obese female population through retrospective chart review and data analysis. The implants differ in their level of constraint, with the total stabilizing (TS) being more constrained than the posterior stabilizing (PS). We hypothesized that the TS implants would be associated with improved functional outcomes in the obese female population. The TS implant was observed to be associated with earlier improvement of both passive and active range of motion. This implant also showed greater improvement from pre-operative condition in stability, rejecting our null hypothesis and supporting our hypothesis.

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Date Created
  • 2015-05

Oscillation and Reaction Board Techniques for Estimating Inertial Properties of a Below-knee Prosthesis

Description

The purpose of this study was two-fold: 1) demonstrate a technique that can be used to directly estimate the inertial properties of a below-knee prosthesis, and 2) contrast the effects

The purpose of this study was two-fold: 1) demonstrate a technique that can be used to directly estimate the inertial properties of a below-knee prosthesis, and 2) contrast the effects of the proposed technique and that of using intact limb inertial properties on joint kinetic estimates during walking in unilateral, transtibial amputees. An oscillation and reaction board system was validated and shown to be reliable when measuring inertial properties of known geometrical solids. When direct measurements of inertial properties of the prosthesis were used in inverse dynamics modeling of the lower extremity compared with inertial estimates based on an intact shank and foot, joint kinetics at the hip and knee were significantly lower during the swing phase of walking. Differences in joint kinetics during stance, however, were smaller than those observed during swing. Therefore, researchers focusing on the swing phase of walking should consider the impact of prosthesis inertia property estimates on study outcomes. For stance, either one of the two inertial models investigated in our study would likely lead to similar outcomes with an inverse dynamics assessment.

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Date Created
  • 2014-05-01

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Using mechanical strain as a vehicle to direct fibroblasts-mediated myoblast differentiation and myotube function

Description

Skeletal muscle injury may occur from repetitive short bursts of biomechanical strain that impair muscle function. Alternatively, variations of biomechanical strain such as those held for long-duration are used by

Skeletal muscle injury may occur from repetitive short bursts of biomechanical strain that impair muscle function. Alternatively, variations of biomechanical strain such as those held for long-duration are used by clinicians to repair muscle and restore its function. Fibroblasts embedded within the unifying connective tissue of skeletal muscle experience these multiple and diverse mechanical stimuli and respond by secreting cytokines. Cytokines direct all stages of muscle regeneration including myoblasts differentiation, fusion to form myotubes, and myotube functionality. To examine how fibroblasts respond to variations in mechanical strain that may affect juxtapose muscle, a myofascial junction was bioengineered that examined the interaction between the two cell types. Fibroblasts were experimentally shown to increase myoblast differentiation, and fibroblast biomechanical strain mediated the extent to which differentiation occurred. Intereleukin-6 is a strain-regulated cytokine secreted by fibroblasts was determined to be necessary for fibroblast-mediated myoblast differentiation. Myotubes differentiated in the presence of strained fibroblasts express greater number of acetylcholine receptors, greater acetylcholine receptor sizes, and modified to be more or less sensitive to acetylcholine-induced contraction. This study provides direct evidence that strained and non-strained fibroblasts can serve as a vehicle to modify myoblast differentiation and myotube functionality. Further understanding the mechanisms regulating these processes may lead to clinical interventions that include strain-activated cellular therapies and bioengineered cell engraftment for mediating the regeneration and function of muscle in vivo.

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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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Date Created
  • 2012