Thesis (M.Tech.: Chiropractic) -Dept. of Chiropractic, Technikon Natal, 2002 1 v. (various pagings) / The purpose of this study was to evaluate the effect of wearing a scuba diving cylinder on static lumbar spine posture, in terms of clinical objective findings, namely radiographic changes in the lumbar lordosis, lumbosacral angle, lumbosacral disc angle, and the lumbar gravity line, during upright standing on land.

Les mouvements volontaires sont accompagnés par des ajustements posturaux anticipateurs (APAs). Leur rôle consiste à prévenir et à compenser de possibles perturbations du corps provoquées par l'exécution du mouvement. Des études antérieures ont montré que la coordination posture / mouvement est modifiée selon que le mouvement est exécuté le plus rapidement possible en réponse à un signal externe (réactif :TRS), ou que le mouvement est auto-initié (prédictif :AI). L'objectif de ce travail est d'examiner le mode de coordination posture / mouvement impliqué dans une situation d'anticipation-coïncidence (AC) lors de l'exécution de mouvements simples et complexes, et ensuite, comparer ce mode aux modes TRS et AI. Trois études expérimentales ont été menées pour vérifier si : (1) les modes de coordination, obtenus sur des gestes simples, s'étendent à des mouvements complexes ; (2) le mode de coordination en AC dépend des caractéristiques temporelles du mobile utilisé dans la tâche ; (3) les commandes impliquant les APAs et le mouvement focal sont associées ou dissociées en fonctions des contraintes temporelles TRS et AC. Ainsi, nous avons démontré que : (1) les stratégies de coordination posture / mouvement s'appliquent sur les mouvements complexes ; (2) la prédictibilité du moment de déclenchement dans la condition AC rapproche celle-ci de la situation AI ; (3) les différences de coordination entre les conditions réactive (TRS) et prédictives (AC, AI) sont liées à des différences dans les mécanismes de préparation consistant à dissocier les commandes posturales et focales en situation prédictive et à associer ces commandes dans la situation réactive. Les implications théoriques qui émergent de ces résultats sont discutées.

The game of rugby union has evolved over the years into a professional sport in which an increased incidence of injury is evident. This also applies to the shoulder joint. It appears that certain risk factors are associated with shoulder pathology among rugby players as well as among the general population. In a competitive sporting environment where high stress loads are placed upon the body and joints, this association may be even more pronounced. Despite the fact that numerous studies have investigated the various factors that potentially play a role in the occurrence of shoulder injuries among sports participants generally, similar studies involving rugby union players in particular are limited. Previous studies have investigated and profiled rugby players with regards to posture, shoulder isokinetic muscle strength and electromyographic patterns, but no study has yet investigated the relationship between these factors and the role they may play in the risk of being injured. It would be beneficial to have a better understanding of the interplay between these factors and to identify the most likely factors to predict and/or prevent shoulder injuries in rugby players. With this information at hand, it might be possible to identify players who are at risk of shoulder injuries in order that they may potentially benefit from effective “pre-habilitation” protocols. The aim of this study was to determine what the relationship between thoracic posture, isokinetic shoulder strength and scapulae muscle activation patterns in injured and uninjured rugby players was, and to determine which of these variables might predict shoulder injuries. Methods Ninety-one (91) uninjured semi-professional rugby union players’ shoulder joint range of motion differences (ROM) were manually tested with the hand-behind-the-neck and hand- behind-the-back method. The profiling and classification of the thoracic posture was performed using the New York Posture Test. Scapular muscle activation patterns were determined by means of electromyography (EMG) measuring the activation of the upper and lower trapezius, serratus anterior and infrapinatus muscles. The isokinetic muscle strength of the rotator cuff muscles was determined at 60°/sec (Kin-Com 500H) measuring concentric and eccentric forces during internal and external rotation. Results Some participants presented with non-ideal or unsatisfactory shoulder internal rotators (59%) and external rotators (85%) bilateral ROM differences. Of all the participants, 68% presented with an abnormal shoulder position in the lateral view, and the sequence of muscle activation of the scapula stabiliser muscles was found to be: serratus anterior; lower trapezius; infraspinatus and then upper trapezius. The isokinetic antagonist/agonist strength ratio for shoulder rotation during concentric muscle contraction was 64% for the non-dominant and 54% for the dominant shoulder. The corresponding ratios for the eccentric muscle contraction of the non-dominant and dominant shoulders were 67% and 61% respectively. The median muscle onset times of the backline players’ non-dominant infraspinatus muscles were 35.90 ms for ideal, 95.20 ms for non-ideal, and 93.90 ms for the unsatisfactory external rotators’ range of motion (ROM) differences. The median firing orders of the forwards’ dominant lower trapezius muscle was 3 for ideal, 1 for non-ideal, and 2 for unsatisfactory external rotators’ ROM differences. Among the forward shoulder group and the normal shoulder position group of the forwards respectively, the median muscle onset time of their non-dominant infraspinatus muscle was 113 milliseconds (ms) and 42 ms. Their non- dominant serratus anterior muscles’ median onset time was 78.85 ms among the players with a rounded back, and 31.90 ms among the players with a normal thoracic curvature. The backline players displayed a median non-dominant serratus anterior onset time of 47.45 ms (in the uneven shoulder group) versus 32.75 ms (in the even shoulder group). The median firing order of the backline players’ non-dominant infraspinatus muscle was third in the normally curved back group. Among the players with an abnormally rounded back, however, the median firing order changed to second. The median external rotation/internal rotation isokinetic strength ratio of the forward players was 63% (forward shoulders), versus 56.50% (normal shoulder position). This was for their non-dominant shoulders. Certain isokinetic shoulder strength ratios displayed statistically significant correlations with scapular muscle activation patterns but they were not clinically significant. Players who had sustained shoulder injuries during the season differed significantly from those who had not sustained injuries with regards to the following baseline measurements: age (the injured were older), height (the injured were taller) and non-dominant/dominant concentric external rotation ratio (the injured had a higher ratio). Among the backline players baseline differences occurred within age (the injured were older), weight (the injured were heavier), height (the injured were taller) and the body mass index (BMI) (the injured had a higher BMI). The variables that displayed statistically significant predictive values towards future injury were age (1.34 times increase for each year older), insufficient shoulder external rotator ROM differences (16.15 times increase if an unsatisfactory ROM difference occurs), uneven shoulders (4.43 times increase if shoulders were abnormally uneven) and the non- dominant/dominant concentric external rotation strength ratio (a 1.42 times increase for every 10% that the ratio increases). Conclusion Profiling of the group of players revealed that their non-ideal or unsatisfactory flexibility of shoulder external rotators, their forward shoulders in the lateral view, and their weakness of the shoulder external rotators did not result in abnormal scapular muscle activation patterns. Positive relationships were found between certain postural abnormalities (forward shoulders, a rounded back and uneven shoulders) and the delay of muscle onset times of infraspinatus and serratus anterior, as well as the firing order of infraspinatus. Forward shoulders increased antagonist/agonist isokinetic shoulder rotation strength ratios. Non-ideal or unsatisfactory flexibility of shoulder external rotators displayed positive relationships with altered infraspinatus muscle onset times and an altered lower trapezius muscle firing order. No clinically significant correlations were found between isokinetic shoulder strength ratios and scapulae muscle activation patterns. It appears that posture (uneven shoulders), has a higher predictive ability than shoulder strength imbalance (non-dominant/dominant concentric external rotation ratio) regarding future shoulder injury. However, age and especially external rotator ROM deficiency proved to be strong predictors of future shoulder injury in semi-professional rugby players. / Thesis (PhD (Human Movement Science))--North-West University, Potchefstroom Campus, 2013.

The game of rugby union has evolved over the years into a professional sport in which an increased incidence of injury is evident. This also applies to the shoulder joint. It appears that certain risk factors are associated with shoulder pathology among rugby players as well as among the general population. In a competitive sporting environment where high stress loads are placed upon the body and joints, this association may be even more pronounced. Despite the fact that numerous studies have investigated the various factors that potentially play a role in the occurrence of shoulder injuries among sports participants generally, similar studies involving rugby union players in particular are limited. Previous studies have investigated and profiled rugby players with regards to posture, shoulder isokinetic muscle strength and electromyographic patterns, but no study has yet investigated the relationship between these factors and the role they may play in the risk of being injured. It would be beneficial to have a better understanding of the interplay between these factors and to identify the most likely factors to predict and/or prevent shoulder injuries in rugby players. With this information at hand, it might be possible to identify players who are at risk of shoulder injuries in order that they may potentially benefit from effective “pre-habilitation” protocols. The aim of this study was to determine what the relationship between thoracic posture, isokinetic shoulder strength and scapulae muscle activation patterns in injured and uninjured rugby players was, and to determine which of these variables might predict shoulder injuries. Methods Ninety-one (91) uninjured semi-professional rugby union players’ shoulder joint range of motion differences (ROM) were manually tested with the hand-behind-the-neck and hand- behind-the-back method. The profiling and classification of the thoracic posture was performed using the New York Posture Test. Scapular muscle activation patterns were determined by means of electromyography (EMG) measuring the activation of the upper and lower trapezius, serratus anterior and infrapinatus muscles. The isokinetic muscle strength of the rotator cuff muscles was determined at 60°/sec (Kin-Com 500H) measuring concentric and eccentric forces during internal and external rotation. Results Some participants presented with non-ideal or unsatisfactory shoulder internal rotators (59%) and external rotators (85%) bilateral ROM differences. Of all the participants, 68% presented with an abnormal shoulder position in the lateral view, and the sequence of muscle activation of the scapula stabiliser muscles was found to be: serratus anterior; lower trapezius; infraspinatus and then upper trapezius. The isokinetic antagonist/agonist strength ratio for shoulder rotation during concentric muscle contraction was 64% for the non-dominant and 54% for the dominant shoulder. The corresponding ratios for the eccentric muscle contraction of the non-dominant and dominant shoulders were 67% and 61% respectively. The median muscle onset times of the backline players’ non-dominant infraspinatus muscles were 35.90 ms for ideal, 95.20 ms for non-ideal, and 93.90 ms for the unsatisfactory external rotators’ range of motion (ROM) differences. The median firing orders of the forwards’ dominant lower trapezius muscle was 3 for ideal, 1 for non-ideal, and 2 for unsatisfactory external rotators’ ROM differences. Among the forward shoulder group and the normal shoulder position group of the forwards respectively, the median muscle onset time of their non-dominant infraspinatus muscle was 113 milliseconds (ms) and 42 ms. Their non- dominant serratus anterior muscles’ median onset time was 78.85 ms among the players with a rounded back, and 31.90 ms among the players with a normal thoracic curvature. The backline players displayed a median non-dominant serratus anterior onset time of 47.45 ms (in the uneven shoulder group) versus 32.75 ms (in the even shoulder group). The median firing order of the backline players’ non-dominant infraspinatus muscle was third in the normally curved back group. Among the players with an abnormally rounded back, however, the median firing order changed to second. The median external rotation/internal rotation isokinetic strength ratio of the forward players was 63% (forward shoulders), versus 56.50% (normal shoulder position). This was for their non-dominant shoulders. Certain isokinetic shoulder strength ratios displayed statistically significant correlations with scapular muscle activation patterns but they were not clinically significant. Players who had sustained shoulder injuries during the season differed significantly from those who had not sustained injuries with regards to the following baseline measurements: age (the injured were older), height (the injured were taller) and non-dominant/dominant concentric external rotation ratio (the injured had a higher ratio). Among the backline players baseline differences occurred within age (the injured were older), weight (the injured were heavier), height (the injured were taller) and the body mass index (BMI) (the injured had a higher BMI). The variables that displayed statistically significant predictive values towards future injury were age (1.34 times increase for each year older), insufficient shoulder external rotator ROM differences (16.15 times increase if an unsatisfactory ROM difference occurs), uneven shoulders (4.43 times increase if shoulders were abnormally uneven) and the non- dominant/dominant concentric external rotation strength ratio (a 1.42 times increase for every 10% that the ratio increases). Conclusion Profiling of the group of players revealed that their non-ideal or unsatisfactory flexibility of shoulder external rotators, their forward shoulders in the lateral view, and their weakness of the shoulder external rotators did not result in abnormal scapular muscle activation patterns. Positive relationships were found between certain postural abnormalities (forward shoulders, a rounded back and uneven shoulders) and the delay of muscle onset times of infraspinatus and serratus anterior, as well as the firing order of infraspinatus. Forward shoulders increased antagonist/agonist isokinetic shoulder rotation strength ratios. Non-ideal or unsatisfactory flexibility of shoulder external rotators displayed positive relationships with altered infraspinatus muscle onset times and an altered lower trapezius muscle firing order. No clinically significant correlations were found between isokinetic shoulder strength ratios and scapulae muscle activation patterns. It appears that posture (uneven shoulders), has a higher predictive ability than shoulder strength imbalance (non-dominant/dominant concentric external rotation ratio) regarding future shoulder injury. However, age and especially external rotator ROM deficiency proved to be strong predictors of future shoulder injury in semi-professional rugby players. / Thesis (PhD (Human Movement Science))--North-West University, Potchefstroom Campus, 2013.

Nursing staff have an elevated risk of developing musculoskeletal disorders, in particular in the lower back area. Statistics produced by leading industrial nations show that back problems are the world’s number one work-related health problem, and that healthcare workers suffer from a greater occurrence of such problems than workers in other professions. In this context, many studies have examined manual patient handling activities, which was thought to be the main cause of musculoskeletal disorders of the lower back. But nurses have many other types of work to perform and several reviews have concluded that approaches which only focus on manual patient handling activities do not sufficiently reduce back problems in nursing professions. Other risk factors for musculoskeletal disorders of the lower back discussed in the literature included repeated bending and the high proportion of static trunk postures. The main aim of this doctoral thesis was therefore to examine the influence of stressful trunk postures on the physical workload of nursing staff in hospitals and nursing homes. It focuses on the type, number and extent of stressful postures and on identifying activities that encourage their occurrence. We used our findings to derive strategies for reducing stressful postures in nursing, and examined whether nursing staff regard such a reduction as actually relieving their physical workload. A secondary aim was to consider the older people potentially in need of care. The background to this is that, due to steadily rising costs, many older people are unable to afford care in a nursing home, and additionally that the forecast severe shortage of nursing staff in future gives reason to look for solutions that can reduce the demand for nursing staff. Among older people who still look after themselves, we therefore examined which stressful postures they adopt when carrying out domestic tasks such as cooking and washing laundry. From the results, we provided some examples of a better design of the domestic environment, which reduces stressful postures, when performing these tasks and helps older people to be able to look after themselves in their own homes for longer. / <p>QC 20140324</p>

Master of Applied Science (Occupational Therapy) / Background: Handwriting is an important activity which is commonly affected after a stroke. Handwriting research has predominantly involved children. In adults, the focus of handwriting research has been identifying forgery, doctors’ handwriting legibility and the kinematics of writing strokes. There are no known studies which provide information on unimpaired adult handwriting in real situations to guide stroke rehabilitation therapists. Aim: This study aims to describe the handwriting practices of 30 unimpaired adults aged 65 years and over to inform adult handwriting rehabilitation. Methods: This study used a cross-sectional observational design. Three data collection methods were used: self-report questionnaire, handwriting samples collected using a digital pen and a handwriting log. Following ethical approval, 30 older adults were recruited using snowball sampling. Data were analysed using descriptive statistics. Results: The median age of participants was 72 years. Three-quarters of participants scored less than 4 for legibility on a 4-point scale. A tripod pen grip was used by 97% of the sample. Variations in handwriting were evident in letter size, slant and spacing. Participants wrote very little, an average of three times per day (SD = 1.5) and a median of 18 words per occasion. Most handwriting (85%) involved self-generated, not copied or transcribed text. Participants stood whilst writing for 17% of handwriting occasions. The most common reasons for handwriting were taking notes (23%) and completing puzzles (22%). Discussion: Legibility in older adults may not depend exclusively on the handwriting script that a beginning writer was taught at school, but may be due to other factors, as a person ages. A comprehensive adult handwriting assessment and retraining program should consist of relevant handwriting activities, involve self-generated text and few words. Conclusion: Findings will contribute to the ongoing development of an ecologically valid adult handwriting assessment and help inform stroke rehabilitation practice.

Obstructive sleep apnoea (OSA) is a common condition characterized by recurrent complete and partial upper airway obstruction. OSA sufferers have been shown to have a significantly smaller upper airway lumen compared to non-OSA sufferers. However, non-anatomical factors of sleep stage, arousability and neuromechanical responses to airway occlusion and chemosensitivity are likely to play a significant part in influencing OSA severity across the night. An exploration of these non-anatomical factors forms the basis for the experiments in this thesis. In the first experimental chapter presented in this thesis, a detailed retrospective epoch by epoch analysis of nocturnal polysomnography in 253 patients referred to a clinical sleep service was performed to examine differences in sleep apnoea severity and arousal indices across the different stages of sleep, while controlling for posture. Both patients with and without OSA demonstrated significant reductions in respiratory and arousal event frequencies from stage 1 to 4 with intermediate frequencies in REM sleep. Lateral posture was also associated with significant improvements in OSA and arousal frequencies, with an effect size comparable to that of sleep stage. The majority of patients showed significant reductions in OSA severity during slow wave sleep. In non-REM sleep, there was a strong correlation between OSA severity and arousal frequency. These results confirm in a large group of patients, a strong sleep stage dependence of both OSA and arousal frequencies. The second study in this thesis explores the development of a CO2 stabilising or ‘clamp’ device to enable the provision of positive airway pressure, and by proportional rebreathing, the maintenance of relatively constant end-tidal CO2 despite significant hyperventilation. Healthy volunteers performed brief periods of significant voluntary hyperventilation at 2 levels of CPAP with the rebreathing function off and with active CO2 clamping in randomized order. Compared to CPAP alone, the device substantially attenuated hypocapnia associated with hyperventilation. The third study of the thesis was designed to investigate if increasing and stabilizing end-tidal CO2 could improve obstructive breathing patterns during sleep. 10 patients with severe OSA underwent rapid CPAP dialdown from therapeutic to a sub-therapeutic level to experimentally induce acute, partial upper airway obstruction over 2 minute periods repeated throughout the night. The CO2 clamp device developed and validated in Study 2 was used to determine whether during periods of partial upper airway obstruction with severe flow limitation, (1) increased end-tidal CO2 resulted in improved airflow and ventilation and (2) clamping end-tidal CO2 lessened post-arousal ventilatory undershoot. Three conditions were studied in random order: no clamping of CO2, clamping of end-tidal CO2 3-4 mmHg above eucapnic levels during the pre-dialdown baseline period only, and clamping of CO2 above eucapnia during both baseline and dialdown periods. Elevated CO2 in the baseline period alone or in the baseline and dialdown periods together resulted in significantly higher peak inspiratory flows and ventilation compared to the no clamp condition. Breath-by-breath analysis immediately pre- and post-arousal showed higher end-tidal CO2 despite hyperventilation immediately post-arousal and attenuation of ventilatory undershoot in CO2 versus non-CO2 clamped conditions. These results support that modulation of ventilatory drive by changes in pre- and post-arousal CO2 are likely to importantly influence upper airway and ventilatory stability in OSA. The fourth study was designed to explore several possible pathophysiological mechanisms whereby obstructive sleep apnoea is improved in stages 3 & 4 (slow wave) versus stage 2 sleep. 10 patients with severe OSA who demonstrated significant reductions in OSA frequency during slow wave sleep on diagnostic investigation were studied. Patients underwent rapid dialdowns from therapeutic CPAP to 3 different pre-determined sub-therapeutic pressures to induce partial airway obstruction and complete airway occlusions in a randomised sequence during the night in both stage 2 and slow wave sleep. Partial airway obstructions and complete occlusions were maintained until arousal occurred or until 2 minutes had elapsed, whichever came first. After airway occlusions, time to arousal, peak pre-arousal negative epiglottic pressure and the rate of ventilatory drive augmentation were significantly greater, suggesting a higher arousal threshold and ventilatory responsiveness to respiratory stimuli during slow wave compared to stage 2 sleep. Post dialdowns, the likelihood of arousal was lower with less severe dialdowns and in slow wave compared to stage 2 sleep. Respiratory drive measured by epiglottic pressure progressively increased post-dialdown, but did not translate into increases in peak flow or ventilation pre-arousal and was not different between sleep stages. These data suggest that while arousal time and propensity following respiratory challenge are altered by sleep depth, there is little evidence to support that upper airway and ventilatory compensation responses to respiratory load are fundamentally improved in slow wave compared to stage 2 sleep. In summary, sleep stage, arousal threshold and chemical drive appear to strongly influence upper airway and ventilatory stability in OSA and are suggestive of important non-anatomical pathogenic mechanisms in OSA.

During pregnancy the female body must accommodate the enlarging gravid uterus and increased mass. Therefore the maternal musculoskeletal system is required to adapt in both morphology and functional workload. After childbirth there is a rapid change in both mass and dimensions, requiring further adaptations. The objectives of the study were to investigate seated and standing upper body posture, the kinematics of seated and standing trunk motion, and the three dimensional kinematics and kinetics during rising to stand from a chair, as pregnancy progressed and in the early post-birth period. Nine maternal subjects (aged 28 to 40 years) were tested at less than 16 weeks, 24 weeks, 30 weeks, 38 weeks gestation and at 8 weeks postbirth. The subjects, fitted with 37 retroreflective markers, were filmed during upright sitting, quiet standing, and four trials each of maximum seated and standing trunk forward flexion, side to side flexion and during maximum seated axial rotation. Three trials each of constrained and free rising to stand from a height adjustable stool and with each foot placed on a forceplate were also recorded. An eight-camera motion analysis system was used to record movements of the body segments and synchronised force plate variables in three dimensions. Motion of the ankle, knee and hip joints, pelvic, thoracic and head segments and the thoracolumbar and cervicothoracic spines and shoulder joints were investigated. Twelve nulliparous subjects (aged 21 to 35 years) were used as controls to provide standard descriptive data and to investigate the consistency of the selected biomechanical variables with repeated testing. A repeated measures ANOVA was used to investigate the possibility of linear and quadratic trends showing systematic changes within the maternal group, over the four test sessions during pregnancy for each variable. Two tailed Student t-tests were used to compare the maternal postbirth variable results with the control group. There was no significant effect of pregnancy on the upper body posture during upright sitting and quiet standing. Postbirth, the pelvic segment had a smaller anterior orientation and the thoracolumbar spine was less extended, indicating a flatter spinal curve. The maternal subjects were similar to the control subjects in early pregnancy and postbirth for trunk segment motions during seated and standing forward flexion and side to side flexion and seated axial rotation. Strategies, such as increasing the width of the base of support and reducing obstruction to movements from other body parts, were used in late pregnancy in attempts to minimise the effects of increased trunk mass and circumference. For seated and standing side to side flexion, the strategies were successful and no significant decreases in range of motion were seen. For seated and standing forward flexion and seated axial rotation, motion of the thoracic segment and the thoracolumbar spine were significantly reduced, although movement of the pelvis was less affected. In early pregnancy and postbirth the kinematics and kinetics of the lower limbs and upper body segment kinematics during constrained and free rising were generally similar to the control subjects. As pregnancy progressed there were increases in mass and dimensions of body segments. The effect of increased mass was seen in increased ground reaction forces and sagittal plane lower limb joint external moments. An increased base of support width was found in association with an increased lateral ground reaction force and ankle inversion moment from each foot, which would move the body centre of mass medially. There was little change in the three dimensional kinematics of the thoracolumbar and cervicothoracic spine, although the contribution of the upper body segments differed for each rise condition. There were also few significant changes in the displacement of the ankle, knee and hip, and the angular velocity of ankle and knee joints. The maternal subjects were thus able to flex the upper body forward, raise the body and maintain stability as pregnancy progressed, regardless of whether the rise to stand was performed in a natural manner or under constrained conditions. The overall results show that, contrary to expectations as pregnancy progressed, maternal subjects minimised propulsion rather than increasing it to overcome the increased mass and possibly limited trunk flexion. A fear of postural instability may have made the subjects more cautious and as they were able to adequately flex the trunk forward, propulsion was minimised in favour of maintaining upright terminal balance.

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 5 uppsatser.