Objectives: To evaluate postural control in individuals with functional ankle instability using static, dynamic, and clinical balance tests. Also, to examine the relationships between the performances in each of these tests. Design: Postural control was evaluated with a single leg balance test, a balance test involving movement, and the star excursion balance test. Participants: A volunteer sample of 19 subjects with functional ankle instability and 19 uninjured control subjects. Main Outcome Measures: Center of pressure sway path length was calculated for the static and dynamic balance tests. Total reach distance was measured for the star excursion balance test. Results: Subjects with functional ankle instability demonstrated a significantly greater center of pressure sway path length in both the static and dynamic balance tests. Conclusions: Functional ankle instability may be associated with reduced postural control as demonstrated by decreased performance in static and dynamic balance tests. / Graduation date: 2003

Thesis (MScPhysio)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Aims: This study aims to ascertain if there are differences in ankle kinematics and ground reaction force in sports participants with chronic groin pain compared to healthy controls. Methods: A cross sectional descriptive study design was used. Twenty participants - 10 cases with chronic groin pain and 10 healthy controls participated. The 10 cases included participants with unilateral pain (n=7) and bilateral pain (n=3). For analysis, the bilateral pain group was divided into the most and less painful side. The study was conducted at the FNB 3D Motion Analysis Laboratory, Stellenbosch University. Sagittal plane kinematics and VGRF was analysed during a single leg drop landing. Results: The group with unilateral groin pain had a higher peak force compared to the matched side of the controls. The bilateral pain groups had less plantarflexion at foot contact (most affected p=<0.001; least affected p=<0.001) and total range of motion (p=<0.05) compared to the control group. The bilaterally injured groin pain groups demonstrated less peak force when compared to controls. Conclusion: This is the first study to indicate alterations in ankle kinematics and VGRF and that these changes are more apparent in sports participants with bilateral pain. Less range of motion during the landing task illustrated by the bilateral pain group suggests less effective force absorption of the distal segments. In the bilateral groups it suggests that force attenuation may have occurred high up the kinetic chain which may place more strain on the groin. Clinically rehabilitation of the athlete with chronic groin pain should include the distal segments of the lower limb. Further research should be conducted in larger groups. / AFRIKAANSE OPSOMMING: Doelstellings: Hierdie studie poog om vas te stel of daar verskille in enkelbeweging en grondvloer-reaksiekrag is in deelnemers van sport met chroniese liespyn in vergelyking met gesonde kontrole deelnemers. Metode: ‘n Deursnee beskrywende studieontwerp is gebruik. Twintig deelnemers, 10 gevalle met chroniese liespyn en 10 gesonde kontrole het deelgeneem. Die 10 gevalle het ingesluit deelnemers met eensydige pyn (n=7) en bilaterale pyn (n=3). Vir die analise, is die bilaterale pyngroep verdeel in die mees en mins geaffekteerde kant. Die studie is gedoen by die FNB3D Beweginsanalise-laboratorium, Universiteit van Stellenbosch. Sagitaal-platvlak kinematiek en vertikale reaksiekrag is geanaliseer gedurende ‘n enkele beenlanding. Resultate: Die groep met eensydige liespyn het ‘n hoër piekkrag gehad in vergelyking met dieselfde kant van die kontrolegroep. Die bilaterale pyngroep het minder plantaarfleksie met voetkontak getoon (mees geaffekteer p=<0.001; minste geaffekteer p=<0.001) en totale beweginsomvang (p=<0.05) in vergelyking met die kontrolegroep. Die bilateraal-liesbeseringsgroep het minder piekkrag getoon in vergelyking met die kontrolegroep. Gevolgtrekking: Hierdie is die eerste studie om veranderings in enkelbeweging en grondreaksiekrag aan te toon, asook dat hierdie veranderinge meer opvallend is in persone wat aan sport deelneem wat bilaterale pyn ondervind. Verminderde beweginsomvang gedurende die landingstaak deur die bilaterale pyngroep suggereer minder effektiewe kragabsorpsie van die distale segmente. In die bilaterale groep suggereer dit dat kragvermindering waarskynlik hoog op die kinematiese ketting voorgekom het wat weer meer stremming op die lies plaas. Kliniese rehabilitasie van die atleet met chroniese pyn behoort die distale segmente van die onderste ledemaat in te sluit. Verdere navorsing behoort in groter groepe uitgevoer te word.

The purpose of this study was to determine the jump landing impact absorption kinematic and kinetic characteristics of the four subject groups: a) male high school athletes, b) female high school seasonal athletes, c) female high school year-round athletes, and d) female college athletes who train year-round. Subjects dropped onto a force platform from a height of 40 centimeters. Variables analyzed were flexibility, strength, Fz, Fy, and Fx force, free moment, range of motion, contact and maximum angles, time to maximum angle, contact and maximum angular velocities, and time to maximum angular velocity. Significant differences among subject groups were determined through use of a factorial analysis of variance and Scheffe' post hoc test.A difference was noted in the landing patterns of males and females. Male subjects exhibited a significantly longer time to first vertical peak force. This longer time may allow for greater initial force attenuation; however, the male athletes had a significantfy greater second peak force. Males also differed significantly from females in anteroposterior and mediolateral force.The differences in method of force attenuation may be due to significantly greater ankle eversion shown by the males and greater knee flexion used by the females. Additionally, the males had significantly greater leg strength, which may have allowed them to increase the time to first peak.The year round female high school athletes were found to use the best biomechanical landing method. They had a greater range of motion in the knee and ankle, and subsequently produced the lowest amount of vertical and anterio-posterior force. / School of Physical Education