A Dissertation submitted to the Department of Physiology, University of Witwatersrand, Johannesburg in fulfilment of the requirements for the degree of Master of science in Medicine. / The management and prevention of ankle sprains had been a topic of controversy in the sport medical literature to date, with various rehabilitative and preventative protocols having been suggested. In part one of this study, a relatively new rehabilitative device, the Cybex II Dynamometer,was used to determine whether the rehabilitation period of ankle sprain injuries could be reduced in recently injured patients. In part two, the Cybex II Dynamometer was used in conjunction with other training techniques in a preventative trial of first league volleyball players, to see whether the incidence of ankle sprains (which is particularly high in this population group) could be reduced. Although the experimental group was discharged almost 35 percent sooner than the control group in part one, the difference was not found to be statistically significant. In part two the preventative measures resulted in a notable difference in the incidence of injuries (32 percent in the control group compared to 11 percent in the experimental, group). Differences were just not statistically significant (p=O.059). / Andrew Chakane 2018

published_or_final_version / Community Medicine / Master / Master of Public Health

The aim of this study was to describe and compare the gaze behaviour patterns of expert and near expert under 19 level rugby union players during one-on-one defensive play. Gaze characteristics such as the areas of interest visited, the number of fixations, the duration of each fixation, the starting and last fixations; and the order of fixations adopted were used to achieve the aim of the study. In addition, biographical data, including sporting and vision history, were collected. Data of the two groups were described and compared with statistically and practically significant differences been highlighted. Inferential statistics were used and the following significant levels set: p<.05 for t-tests and Chi-sq'ared - tests while Cohen's d (absolute value) ≥0.20 and Cramér‟s V ≥0.10 were used to determine the practical significance for statistically significant results, respectively. An exploratory and quasi-experimental design was used, in which 81 participants (16 – 19 years of age) were sampled for differences between experts' and near experts' visual-search strategies and gaze behaviour patterns when anticipating the direction of deceptive running skills in rugby union, however, only 68 participants had eye tracker data analyzed due to the strict calibration criteria. The expert players correctly anticipated significantly (t-stat = -3.16, p = .002, d = 0.71) more than the near expert players on average (75.76% compared to 66.46%), and therefore, were less susceptible to deceptive running skills. The near expert players were, however, more aware of their fixation location than expert players. Both expert and near expert players fixated considerably more on the knees and hips than any other area of interest, however expert players had fewer, but longer fixations than near expert players per run with 4.29 ± 1.89 fixations (χ2 = 3.90, p = .048, V = 0.24) of 0.420 ± 0.140 seconds (χ2 = 3.97, p = .046, V = 0.24) compared to 5.34 ± 2.39 fixations of 0.350 ± 0.150 seconds. Both the expert and near expert groups fixated more on the lower body than the upper body on average, however, the near expert players fixated significantly more off the body for all correct runs than the expert players (t-stat = 2.17, p = .034, d = 0.53). The expert players start fixating more on the knees at the start of each trial, whereas the near expert players start fixating more on the knees and hips, and considerably off-target. The expert players fixate significantly more on the knees (t-stat = -2.56, p = .013, d = 0.63) at the end of each trial than the near expert players on average, whereas the near expert players fixate more on the hips. The orders of fixation did not yield any discernable patterns between expert and near expert players for correctly anticipated runs. Experts exhibit superior visual-search strategies and gaze behaviour control, presumably using the top-down approach, to successfully anticipate an opponent's intended direction. This information could help coaches teach perceptual tackling skills to enhance motor learning and performance.

Fast bowlers are especially prone to injury as they perform their bowling techniques repetitively at very high intensities. The fast bowling action in the past has been described as a highly explosive activity that produces high levels of stress and strain on the body. The aim of this study was to compile an injury profile of 46 fast bowlers aged 11 to 18, and to identify the associated risk factors for injury during an academy cricket season. A descriptive correlational research design was utilised. Subjects were selected according to age and fast bowling ability. These subjects were observed for one academy cricket season (March to November). Three testing sessions occurred during this time (T1, T2 and T3). Each subject completed two questionnaires: i) bowler history (at T1) and ii) injury history (at T1, T2, and T3). These assisted in grouping the subjects according to their responses into one of three injury classifications (uninjured = S1; injured but able to play = S2; injured and unable to play = S3). Anthropometric and postural data for the entire group of fast bowlers were also collected pre-season (T1). Physical fitness screenings were also conducted during each of the three testing sessions to establish any relationship between the fitness of each fast bowler and the occurrence of injuries. Additional factors assessed during the season were bowling techniques and bowling workload. Statistical significance was indicated by p-values less than .05 (p< .05), while practical significance was indicated by either Cohen’s d-values of 0.2 or better (d>0.2) for tests based on sample means or Cramer’s V for tests based on sample frequencies, the values of which depend on the applicable degrees of freedom. All fitness scores as well as bowling workload figures for each testing session were converted to standard T-scores and these in turn were summated to derive overall fitness and workload T-scores. ‘TT’ indicated the overall average score for the entire season. Changes in performances, bowling workload and injury status were analysed using ANOVA and ANCOVA. A regression analysis was also conducted to analyse the relationship between bowling workload and weeks incapacitated. This study found that hyperextension in the knees had the highest incidence of postural deviation injury (43 percent) followed by winged scapula (39 percent). Only 15 percent of the fast bowlers remained injury-free for the duration of the season, while 35 percent of the subjects were at some stage injured to such an extent that they were unable to play. The incidence of serious injury (S3) showed a statistical and moderate practical (V=0.23, d.f. ≥2) significant increase throughout the data collection period (4 percent at T1 to 30 percent at T3). The most common injury was to the knee (41 percent) followed by those to the lower back (37 percent). These injuries occurred mostly during test periods T2 and T3. The nature of injuries were predominantly strains and "other" which accounted for 39 percent of the injuries overall (TT) and had the highest reported incidence during the period T1 to T3. Sprains followed with an overall incidence of 14 percent. Less frequently reported injuries were tears, fractures, bruises and dislocations. The degree of severity of injuries was defined in terms of the number of weeks a player reported being incapacitated as a result of injury during the academy session. During midand end-season bowlers were on average incapacitated approximately one week out of every five due to injury. The statistics for the duration of the study translate to approximately one week incapacitated out of every seven weeks of play. When comparing the S1/S2 bowlers with the S3 group, the S1/S2 bowlers performed consistently better than the S3 bowlers in all the fitness variables tested. However no significant differences (p>.05) in either flexibility or muscle strength were observed. Of the risk factors analysed, bowling workload presented a statistically significant (p<.0005) increased risk for injury. A strong significant positive relationship (p<.0005, R²=.619) was found between weeks incapacitated and bowling workload, supporting the finding that increased bowling workloads show a linear relationship with the increase in the number of weeks incapacitated from normal play. This study concluded that inadequate fitness, high bowling workload and bowling technique all have a multi-factorial role in predisposing a bowler to increased risk for injury. These variables did not act alone, but have all contributed to recurring injuries. The bowling action alone would not have been detrimental if the workloads were not in excess of the recommended guidelines. Furthermore the workload would not have been as detrimental if the bowlers were well conditioned and uninjured. Management of minor injuries and adequate recovery time, coupled with adequate and relevant fitness preparation would better prepare fast bowlers for the demands of the game.

Background: Clothing and protective gear worn during intermittent exercise has shown to increase physiological and perceptual responses, and negatively impact performance capacities, due to increased heat strain, suggested to hasten the onset of fatigue. However, the mechanisms of fatigue experienced in rugby remain unclear. Objectives: The aim of this study was establish whether clothing and protective gear worn during a simulated rugby protocol impacts players‘ biophysical, physiological, perceptual and performance responses. Methods: 15 registered university and school first XV rugby players with a mean (± SD) age of 20.9 years (± 1.9) volunteered to participate in the study. Testing was performed in a controlled laboratory setting, with temperatures having to be within the range of 16º C-22º C. The mean (± SD) ambient temperature was 17.6º C (± 1.6) for the control condition and 17.3º C (1.5) for the experimental condition. The mean (± SD) relative humidity was 65.2 % (± 9.5) for the control condition and 66.3 % (± 10.0) for the experimental condition. Player‘s performed two protocols of 80-minutes; a control condition (minimal clothing and protective gear) and an experimental condition (full clothing and protective gear). Physiological, perceptual and performance responses were measured at set intervals during the protocol, while biophysical responses were measured pre-, at half-time and post-protocol during a 3-minute EMG treadmill protocol. Results: Muscle activity significantly (p< 0.05) increased with increasing running speeds. There were no significant (p> 0.05) differences for muscle activity between conditions, except for the semitendinosus muscle, which was significantly (p< 0.05) higher during the control condition while running at high speeds. Players‘ heart rates, core temperatures and perceptual responses were significantly (p< 0.05) higher during the experimental condition, compared to the control condition. Performance responses were significantly (p< 0.05) lower during the experimental condition. Conclusion: The main driver of physiological and perceptual responses was the exercise itself. However, the additional clothing and protective gear exacerbated the responses, particularly towards the end stages of the protocol. This negatively impacted players‘ performance. Muscle activity appeared to be unaffected by increased body temperatures. However, core temperatures never reached critically high levels during either condition.

The purpose of this project was to review anterior cruciate ligament (ACL) literature and develop a performance evaluation and injury risk assessment (PIER) for female soccer players. A strategy guide for decreasing injury risk and enhancing performance was developed in hopes to bring awareness to the athletic community about ACL injury for female soccer players.

[Truncated abstract] Anterior cruciate ligament injuries are a major problem in sport. The purpose of this thesis was to investigate the causative factors of ACL injuries and to study the effect of various types of lower-limb training on underlying neuromuscular mechanisms involved in stabilisation and risk of ACL injury. Investigation of the mechanisms was conducted on controlled balance and strength tests as well as in sporting manoeuvres. It was aimed to assess if the neuromuscular changes map over into the performance of sporting manoeuvres and if potential for loading on the ACL and risk of injury was reduced or exacerbated . . . ACL strain can be decreased through reduction in the applied loads and greater knee flexion. Further to this, muscle activation has the ability to reduce loading on the ACL through co-contraction and selective activation patterns. This thesis demonstrated differing neuromuscular adaptations from various training types that map over into the performance of sporting manoeuvres. The research indicated that the Balance-Training was the most favourable in reducing potential for injury risk on the ACL. Alternatively strength training elicited neuromuscular changes that were likely to increase the risk of force on the ACL. The Machine+Balance training resulted in some negative and positive outcomes with the balance training tending to counteract the negative affects of machine weights training resulting in small improvements in muscular support and load reduction. This study provides us with better understanding of the underlying mechanisms from various training types and their potential affect on risk of ACL injury.

No description available.

This thesis uncovers the rational and Romantic assumptions about the relationship between objects and identity that are embedded in occupational therapy, and critiques current practice from that perspective. It is based on an initial assumption that there is in fact a relationship between people's identity and the objects they make, have, use and are associated with. This assumption is explored through an interpretive examination of the fields of literature that are commonly identified as informing occupational therapy, supplemented by selected popular literature. The exploration takes a philosophical approach, guided by notions from philosophical hermeneutics, including pre-understandings, the hermeneutic circle and fusion of horizons. The conclusion reached is that people informed by Western philosophies interpret the identity meanings of objects in both rational and Romantic ways. To inform the study, the nature of rationalism and Romanticism are then explained, and the implications of these philosophical traditions in relation to objects and identity are teased out. This interpretation is guided by a history of ideas methodology, which entails approaching historical texts from a new perspective, in this case the identity meanings of objects. Thus informed, occupational therapy literature, primarily that published in Britain between 1938 and 1962 is examined from the perspective of objects and identity. What is revealed is that rational and Romantic understandings of objects, and of patients' and their own identity are clearly discernible. Such understandings afforded early occupational therapists both ways to organise their growing knowledge of the therapeutic application of crafts and the transformative outcomes of occupational therapy intervention. Gradually however, factors both internal and external to the profession served to undermine therapists' Romanticism. Primary amongst these were World War II, which saw a redeployment of occupational therapists from mental health to physical rehabilitation settings; advances in rehabilitative medicine, which brought a reduction in secondary complications and the adoption of teamwork; and the development of new practice areas including domestic rehabilitation using gadgets to enhance function and pre-vocational rehabilitation. As a result, tensions between rational and Romantic understandings crystallised around two long-standing controversies. These were whether or not craft equipment such as weaving looms should be adapted to serve specific remedial purposes, and whether it was the process of making a crafted object or the quality of the finished product that was more important. In the event, these contested ideologies became largely irrelevant as craftwork was sidelined from mainstream practice. With it, occupational therapists' Romantic vision of transforming people's lives through creative activity also slipped away. Several reasons for this loss of one of the profession's founding philosophies are proposed. They include the substantial absence of the professions' philosophical foundations from its education, and the paucity of theory and research methodologies that might have informed the nature and process of transformative change that earlier occupational therapists had observed and reported. The thesis concludes by arguing for the importance of recovering a balance between rationalism and Romanticism. A call to action is issued, addressing change in educational practice, concerted research effort to identify and articulate transformative processes within occupational therapy, and political action focusing on the inclusion of Romantic perspectives within policy and strategic documents.

published_or_final_version / Anatomy / Doctoral / Doctor of Philosophy