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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

The effect of protective knee braces on agility and muscle performance

Polascik, Michael A. 08 September 2012 (has links)
Thirty-two Virginia Tech varsity football players served as subjects to examine the effect of protective knee braces on agility and selected isokinetic strength, power, and endurance measures. Each subject performed the Semo agility test in each of three experimental conditions: braced with the Anderson knee stabler (B,An); braced with the Arco knee guard (Bâ Ar); and unbraced (Un). The order of agility tests was randomized. The subjects were than administered a Cybex knee extension/flexion test at 60 deg/sec and 300 deg/sec. Each subject performed the Cybex tests in each of the three experimental conditions (B-An, B-Ar, and Un). The order of Cybex tests was randomized. The test protocol consisted of three maximal repetitions at 60 deg/sec and 40 maximal repetitions at 300 deg/sec. The following isokinetic variables were recorded: (1) peak torque/body weight ratio of the quadriceps and hamstrings at 60 deg/sec and 300 deg/sec; (2) average range of motion for knee extension/flexion at 60 deg/sec and 300 deg/sec; (3) average power, torque acceleration energy, and endurance ratio of the quadriceps and hamstrings at 300 deg/sec. Repeated measures analysis of variance revealed no significant difference (p > .05) in agility test scores between the three experimental conditions. Repeated measures analysis of variance also revealed no significant difference (p > .05) in the isokinetic responses of subjects as they were tested within the three experimental conditions. The investigator concluded that protective knee braces had no effect on agility, isokinetic strength, power, and endurance. / Master of Science
42

Seismic Retrofit of Reinforced Concrete Frame Buildings with Tension Only Braces

Khosravi, Sadegh 13 October 2021 (has links)
Reinforced concrete buildings built prior to the enactment of modern seismic codes are often seismically deficient. These buildings may have inadequate strength and ductility to withstand strong earthquakes. Conventional retrofit techniques for such frame buildings involve adding reinforced concrete shear walls or structural bracing systems to the existing bays. These techniques can be intrusive and result in lengthy down times and expensive structural interventions. An alternative to conventional techniques is the use of high-strength prestressing strands or cables, diagonally placed as tension elements. This technique was researched and used in a limited manner after the 1985 Mexico City Earthquake. It has since been further investigated at the University of Ottawa through experimental and analytical research (Shalouf and Saatcioglu (2006), Carrière (2008), Molaei (2014)). While the use of steel strands as tension bracing elements proves to be an effective technique, the resulting stiffening effects on the frames lead to increased seismic force demands and higher based shear, as well as increased axial forces on the attached columns, potentially generating net tension, foundation uplift and excessive compression. Relatively low elongation characteristics of high-strength cables and slack caused by yielding strands and associated pinching of hysteresis curves reduce potential energy dissipation capacity. The current research aims to improve the previously observed deficiencies of the system. One of the improvements involve the use of shape memory alloys (SMA) in the middle of the cables, which reduce/eliminate residual deformations upon yielding and associated pinching of the hysteresis curves. SMA allows energy dissipation in the system while forcing the structure to recover from its inelastic deformations because of the flag-shape hysteretic characteristics of the material. The feasibility of the cable-SMA assembly as tension brace elements is illustrated through dynamic analyses of selected prototype buildings. The other improvement is the development of progressively engaging, initially loose multiple strands as tension cables. These cables are placed loosely to engage in seismic resistance at pre-determined drift levels, thereby eliminating premature increase in seismic force demands until their participation is required as the frame capacity is reached. Tests of a large-scale reinforced concrete frame, designed following the requirements of the 1965 National Building Code of Canada NRC (1965) as representative of existing older frame buildings in Canada, are conducted under simulated seismic loading to assess the effectiveness of the proposed system. The verification of the concept is extended analytically to prototype buildings and the effectiveness of the system is demonstrated for mid-rise and low-rise frame buildings.
43

The clinical effectiveness of therapeutic exercises alone and in combination with orthotic bracing in the treatment of lateral epicondylalgia

Flanders, Megan January 2012 (has links)
Dissertation submitted in partial compliance with the requirements for the Master’s Degree in Technology: Chiropractic, Durban University of Technology, 2012. / Lateral epicondylalgia (L.E) is a common diagnosis in elbow pathology. The aetiology is poorly understood but it is generally accepted to be as a result of repetitive microtrauma, affecting the proximal end of the extensor carpi radialis brevis tendon. Elbow bracing and exercise modification are often utilised by sufferers in order to reduce symptoms. In addition, there have been multiple treatment regimes used in practice to treat L.E, but none has stood out as being more effective than another. Thus, the aim of this study was to investigate the relative clinical effectiveness of therapeutic exercises alone and in combination with orthotic bracing, in terms of subjective and objective clinical findings. Methods This stratified, quantitative, prospective clinical trial consisted of two equal groups (n=15) diagnosed with L.E. Group One consisted of a strengthening and stretching programme alone, and Group Two consisted of a combination of the same programme and an orthotic brace. The participants performed the programme daily at home for six weeks, and the brace was worn throughout the day for six weeks. Each participant was assessed before, during and after the programme, in terms of subjective and objective clinical data which was then statistically analysed using SPSS version 18. Repeated measures ANOVA testing was also used to compare the outcomes between the groups over the time points. Results Both groups showed significant statistical improvement in terms of all the outcome measures. The groups also showed a clinically significant improvement for all the outcome measures except pressure pain threshold where Group Two showed clinically significant improvement over Group One. v Conclusion The results show that there was negligible benefit when combining an orthotic brace with therapeutic exercises as opposed to performing the therapeutic exercises alone.
44

Concurrent Whitening and Orthodontic Treatment

Gladwell, Jason Thomas 01 January 2007 (has links)
The aim was to evaluate whether a whitening system, when used during the final stages of orthodontics, would yield results comparable to whitening alone. Patients were assigned to either the control (n=20) or experimental (n=26) groups. At T1, patients were given a ten day supply of Trèswhite™ by Opalescence®, instructions on use, and initial shade determination was made and photographs were taken. At T2 and T3, shade determination was accomplished and updated photographs were taken. Whitening of the teeth occurred in both groups on average, but significantly more whitening was experienced in the experimental group (p < 0.004). An average of 87% of teeth whitened during orthodontic treatment compared to 97% of control teeth (p < 0.01) were judged to be uniform in appearance. In conclusion, the data do not contraindicate the concurrent accomplishment of teeth whitening during orthodontic treatment.
45

A comparison of the protective characteristics of selected ankle braces

Comer, Shawn January 1992 (has links)
The purpose of this study was to compare the protective characteristics of four different ankle braces and one form of ankle taping. An inversion and plantar flexion platform was used to induce ankle movements. The subjects used in this study consisted of 10 volunteer male students. The subjects had no sprains five months prior to testing. All subjects were tested in the same size 10 shoes, high tops and low tops. A Certified Athletic Trainer applied all ankle braces and ankle tapings. A closed basketweave with heel locks, adherent spray, and pre-wrap was used for all taping conditions.After the application of the ankle braces or taping, each subject performed two tests on the inversion and plantar flexion platform. A random order was used among the subjects. An ankle inversion platform was modified to induce 30 degrees of inversion and 35 degrees of plantar flexion simultaneously. The subjects will be filmed using a Locam 16mm at 200 frame/second. All subjects were filmed from the posterior plane with markings on the posterior aspect of the lower leg to help analyze the movement at the subtalar joint. A Calcomp 9100 series digitizer that was interfaced with a VAX computer was used to analyze the data and calculate the amount of angular displacement at the subtalar joint. An ANOVA with repeated measures was used to determine significant differences between support techniques. University procedures for the protection of human subjects was followed. ANOVA procedures indicated no significant difference in angular displacement between braces. A statistical analysis indicated that low top shoes provided significantly more support than high top shoes in braced ankles. / School of Physical Education
46

Prophylactic ankle stabilizers and their effect on lower extremity landing mechanics during drop jump landings to fatigue

Clanton, Tameka A. January 2009 (has links)
The impact forces at landing are predominately absorbed by the hip, knee and ankle joints. Fatigue has been shown to increase the amount of work performed by the ankle and to reduce the work performed by the knee during landings. The purpose of this study was to assess the kinematic lower extremity motion and kinetic patterns during landings to fatigue, with and without ankle brace usage. Nine recreationally active males (n = 7) and females (n = 2) performed repetitive drop jumps to fatigue for an un-braced and braced condition. Kinematic and kinetic variables were assessed during the first 100 ms after ground impact. Due to the high skill level of the participants, none of the individuals reached a fatigued state. No significant main effect of fatigue was demonstrated on ankle work (p= 0.260). There was no significant main effect due to fatigue on the hip (p= 1.000), knee (p= 1.000) or ankle (p= 0.636) relative work contributions. Fatigue caused a shift toward a more erect landing position at initial ground contact (IGC). No significant main effect of the brace on hip (p= 0.437), knee (p= 0.283) or ankle (p= 0.314) angles was observed at IGC angles. The use of Ankle Stabilizing Orthosis® (ASO) ankle braces caused a shift toward greater knee contribution in a fatigued state. Plantar flexion angles were decreased the most during the braced un-fatigued condition. There was an inverse relationship between knee and hip angles as compared to ankle angles at IGC. When the hip and knee joint displayed less flexion at IGC, the ankle balanced the positions out by landing in more plantar flexion. / School of Physical Education, Sport, and Exercise Science
47

The normal and ACL deficient knee : an in-vivo three dimensional kinematic and electromyographic analysis /

Ramsey, Dan K., January 1900 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 5 uppsatser. - På omsl. felaktigt: Karolinska University Press.
48

Anterior cruciate ligament injury : factors affecting selection of treatment and intermediate outcome /

Swirtun, Linda R. , January 2006 (has links)
Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 4 uppsatser.
49

Ankle bracing alters knee and ankle kinematics but not ground reaction forces during a jump-landing

Strickland, Lindsay J. January 2005 (has links)
Thesis (M.A.)--University of North Carolina at Chapel Hill, 2005. / Includes bibliographical references (leaves 109-114). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.
50

Ankle bracing alters knee and ankle kinematics but not ground reaction forces during a jump-landing

Strickland, Lindsay J. January 2005 (has links)
Thesis (M.A.)--University of North Carolina at Chapel Hill, 2005. / Includes bibliographical references (leaves 109-114).

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