Masters Degrees (Exercise, Sport and Lifestyle Medicine)

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Browsing Masters Degrees (Exercise, Sport and Lifestyle Medicine) by browse.metadata.advisor "De Waal, Simon Jake"

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    Acute kinetic and kinematic differences between minimalist sandal, shod and barefoot running in habitually shod male recreational trail runners
    (Stellenbosch : Stellenbosch University, 2021-03) Swart, Matthew; De Waal, Simon Jake; Venter, Ranel; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Sport Science.
    ENGLISH ABSTRACT: Please refer to full text for abstract.
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    Analyzing gait parameters in trail runners using wireless trunk accelerometry during real-world and treadmill incline running
    (Stellenbosch : Stellenbosch University, 2020-12) Bergh, Oloff Charles Wessel; Venter, Ranel; De Waal, Simon Jake; Faculty of Medicine and Health Sciences. Dept. of Sport Science.
    ENGLISH ABSTRACT: Few studies have explored dynamic stability when running over complex or challenging surfaces, and no studies have investigated how trail terrain could affect components of dynamic stability. The aim of this study was to measure the acute changes in dynamic stability when running at incline, between treadmill and trail surfaces. Twelve recreational trail runners (age 25.2 ±2.6 years; mass 78.8 ±5.9 kg; height 183.6 ±7.1 cm) participated and completed all aspects of testing. They ran at 10 km.h-1with an eight-degree incline, over both treadmill and trail surfaces. Each participant had a single Noraxon®myoMotion Research PRO inertial measurement unit (IMU) attached to their third lumbar vertebrae region, capable of collecting wireless acceleration data. Linear acceleration data was captured up to 200 Hz and ± 16 g at the trunk region in three-dimensions, namely the vertical (VT), anterior-posterior (AP) and mediolateral (ML). Data was streamed to the Noraxon®myo RESEARCH software. Thereafter, the data was filtered using a zero-lag 4thorder low-pass Butterworth filter with a cut-off frequency of 50 Hz. Filtered acceleration data was imported into MATLAB R2020a (Version 9.6), with a custom written code performing an autocorrelation procedure of each participant over both treadmill and trail surfaces. The autocorrelations provided information regarding the step and stride regularity, as well as the symmetry of the individual over the two terrains, based on the three-dimensional accelerations at the trunk. Furthermore, mean step and stride times, as well as their coefficients of variations (CV) were calculated from the filtered data. Results were reported in the article (Chapter Four) and indicated that step and stride regularity was decreased (p< 0.01) in all three-dimensions when running over the more complex trail surface, compared to the steady treadmill surface. The AP and ML directions indicated a greater degree of diminution compared to the VT and is evident in the symmetry values. Symmetry decreased over the trail surface for both the AP (z= -3.06, p< 0.01) and ML (p< 0.01) directions, but not in the VT (z= -1.65, p= 0.10) direction. Additionally, there was no change in mean step (p= 0.45) and stride (p= 0.33) times, but a significant increase was observed for both step CV (p< 0.01) and stride CV (p< 0.01) when running on the trail surface. The first null hypothesis was rejected, as the coefficients of variation for both step and stride times indicated a significant difference when comparing the treadmill and trail surfaces. The second null hypothesis was rejected, as the trail surface did indicate a general decrease in dynamic stability components compared to the treadmill. In conclusion the trail demonstrated a higher degree of step and stride variability, and low symmetry, primarily due to the inconsistent nature of the trail surface. Future studies could investigate the role of cognition during trail running, by examining the decision-making process while traversing complex terrain such as the trail environment. Furthermore, future studies in the field of sports biomechanics could aim to incorporate a greater degree of software technology, such as adopting a more algorithmic approach to analysing data.
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    Comparison of kinematic, and gait-spatio-temporal factors in ultra-trail runners with zero-drop versus regular-drop shoes
    (2023-03 ) Henning, Robert; De Waal, Simon Jake; Lamberts, Robert P.; Venter, Ranel; Stellenbosch University. Faculty of Medical Health Sciences. Dept. of Exercise, Sport and Lifestyle Medication.
    ENGLISH ABSTRACT: Few studies have explored zero-drop (ZD) shoes, with no studies investigating these shoes in trail- and ultra-trail running. The aim of this study was to investigate the difference in relative oxygen uptake related and gait-spatiotemporal variables in a homogenous group of ultra-trail runners wearing ZD shoes versus those wearing regular-drop (RD) shoes. Twenty-nine recreational ultra-trail runners participated in this study: 15 habitually RD runners (age 36 ± 8.9 years; mass 70.48 ± 11.85 kg; height 174.14 ± 7.85 cm), and 14 habitually ZD runners (age 32 ± 9.31 years; mass 75.53 ± 32.99 kg; height 174.5 ± 8.23 cm). Participants ran a VO2 max protocol to determine maximal fitness, as well as to determine treadmill speed at VO2 max (vVO2 max). Thereafter, participants ran a protocol at 70% and 85% of their vVO2 max to determine relative oxygen uptake, gait spatio-temporal variables, ankle kinematics at ground contact and foot strike pattern. All physiological measures were determined by breath-by-breath analysis (COSMED, Rome, Italy), and gait-spatiotemporal measurements were done via the Optogait system (Microgate, Bolzano, Italy) and video interpretation (Kinovea, Belgium). ZD runners displayed a significantly greater VO2 max and VO2 at anaerobic threshold (AT) (p < 0.05). There was no significant difference between ZD and RD runners for all the gait-spatiotemporal variables at both 70% and 85% vVO2 max. However, a large effect size for ankle angle was observed for both 70% (d=1.24) and 85% (d=1.11) speeds, indicating that ZD runners (86.54 ± 3.12o) were more dorsiflexed than RD runners (85.81 ± 4.15o) at ground contact. Furthermore, RD runners increased stride length significantly between 70% (202.46 ± 35.14 cm) and 85% (213.36 ± 41.83cm) vVO2 max, while ZD increased cadence significantly (96.83 ± 12.59 to 106.65 ± 20.88 steps.min). The first null hypothesis was rejected, as the VO2 max in the ZD group was significantly higher than the RD group. The second null hypothesis was accepted, as there were no significant differences between the ZD and RD groups for physiological fitness variables at both 70% and 85% vVO2 max. The third null hypothesis was partially rejected, as no significant difference in any of the gait-spatiotemporal variables between ZD and RD ultra-trail runners were observed, barring the distribution in foot strike pattern at 70% vVO2 max, where the ZD (n = 9) runners displayed a significantly higher distribution of MF/FF striking pattern compared to the RD (n = 1) runners. No studies have shown differences in physiological fitness and gait-spatiotemporal variables between ZD and RD ultra-trail runners. These results help runners understand how shoe drop-height affects relative oxygen uptake related variables to make informed choices in shoe selection, namely that runners wearing ZD shoes tend to strike the ground with a MF/FF pattern, as well as to expand the current body of literature regarding trail running. Further studies could investigate the effects of ZD shoes on physiological and gait-spatiotemporal variables in a much larger sample, which should provide a more accurate description of these effects.
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    Quantitative analysis of in-match penalty kicks from 2009/10 to 2018/19 in the English Premier League
    (2020-12) Horn, Michael; Kraak, Wilbur Julio; De Waal, Simon Jake; Stellenbosch University. Faculty of Medicine and Health Sciences. Sport Science.
    ENGLISH ABSTRACT: Football association (hereafter referred to as soccer), which is played across several playing levels and ages, is regarded as the most popular sport globally and has been subject to the highest number of scientific studies in relation to any other sport. Currently there is an excess of well-documented studies highlighting many aspects related to soccer. However, studies on quantitative measures on in-match penalty kicks and the influence of factors on penalty kick outcomes are scarce or only briefly touched on in the literature. The importance that successful or unsuccessful in-match penalty kicks could have towards the outcome of a match, or potentially a competition, is essential and requires close assessment through performance analysis. The aim of this study was to conduct a video-based performance analysis of in-match penalty kicks during the English Premier League (EPL) seasons from 2009/10 to 2018/19 in order to identify the relationships between selected technical and match classification Key Performance Indicators (KPIs) and in-match penalty kick outcomes and direction. The thesis was presented in five main parts, namely the Introduction (Chapter One), Literature review (Chapter Two), Methodology (Chapter Three), Research article titled, In-match penalty kick analysis of the 2009/10 to 2018/19 English Premier League competition (Chapter Four) and Summary, conclusion, limitations and future research (Chapter Five). The Senate of Stellenbosch University approved the article format theses and dissertations. The Faculty of Medicine and Health Sciences at Stellenbosch University stipulates one article as a requirement for a Master of Science thesis. The research article of the current study was presented in accordance with the guidelines outlined by the respective journal. In-match penalty kicks (N=952) in the EPL between the 2009/10 to 2018/19 seasons were analysed by means of video analysis to identify the relationship between selected technical and match classification KPIs and in-match penalty kick outcomes. The KPIs included footedness of the penalty kick taker, match score line at the time of the penalty kick, match status (winning/losing/drawing at time of the penalty kick), match period (time in match), match location (home/away) and in-match penalty kick directions. The results indicated that of the KPIs analysed only in-match penalty kick direction, particularly in relation to the top vertical zone significantly related to penalty kick outcomes (p<0.01). Grid area frequencies for K3 (278) and F3 (235) were the highest of the in-match penalty kick directions and had the lowest success rates (K3 – 79.2%, F3 – 77.3% together with M3 – 74.3%). Optimal grid areas for penalty kick directions were identified (K1 –97.7%, M1 – 100%, F1 – 100% and M2 – 94.3%), which indicated a greater probability of success in relation to the other areas of penalty kick directions. Other KPIs, such as match location, match status, score line and footedness did not present a significant influence on penalty kick outcomes or direction. Penalty kick takers may possibly have a perception bias in relation to the perceived miss factor indicating that they would rather go low and in the bottom corners and be saved by the goalkeeper than aim for a higher penalty kick direction in the goal and miss the goal all together. The practical implications of training in-match penalty kicks for an optimal strategy in relation to penalty kick directions could assist coaches, players and goalkeepers in optimising the in-match penalty kicks for the desired outcome. Future studies should consider using the goalkeeper’s movement direction prior to a penalty kick to save it and the penalty kick taker’s run up speed, speed of shot, stutter vs non-stutter as part to the penalty kick outcome and direction analysis. Future research should include penalty kicks that were not placed on target as part of the direction analysis, either by allocating them into the nearest grid area to the missed kick, or possibly by using ‘missed zones’ around the goal to track and analyse missed penalty kicks, and therefore, cater for the ‘miss factor’. Based on the current study’s findings and that of previous studies, penalty kick takers should be encouraged to direct their penalty kicks to the upper areas of the goal in order to achieve optimal penalty kick outcomes.
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    The site, type and incidence of injuries in South African trail runners
    (Stellenbosch : Stellenbosch University, 2022-12) Van Wyk, Harry; De Waal, Simon Jake; Grobler, Lara; Stellenbosch University. Faculty of Medical and Health Sciences. Dept. of Exercise, Sport and Lifestyle Medication
    ENGLISH ABSTRACT: There is an abundance of literature pertaining to injury epidemiology and running related injury (RRI) in road running. Comparatively, there is a scarcity of literature pertaining to trail running injury epidemiology, especially within South Africa. The aim of this study was to prospectively determine the site, type, incidence and severity of running related injuries in a cohort of South African trail runners. Forty-nine (n = 49) South African trail runners (29 men and 20 women) aged 18-60 years were included in the study. Participants performed more than 50% of their training volume on trails. Participants entered at different time periods and were observed for 16 weeks between August 2021 and February 2022. Participants completed a pre-observational period survey. Injury surveillance surveys were administered via SunSurveys every two weeks. The modified Oslo Sports Trauma Research Centre questionnaire for overuse injuries (OSTRC-O) (0.96; 0.91) was used to collect training and RRI data. A descriptive analysis was performed to present baseline and follow-up data. A Shapiro-Wilk test was used for normality. Means, standard deviations, 95% confidence intervals (CI) (𝑋 ± 2 SD), and percentages were reported. Injury prevalence and incidence per 1000 h were calculated for both sexes. Independent samples t-tests, Welches tests, and Mann-Whitney U tests were used to measure differences between sex. Cohen’s d effect sizes were calculated to evaluate the magnitude of reported effects between sexes. Pearson’s Chi-Squared test was used to evaluate associations between sex and running related characteristics. For all tests, statistical significance was set to p < 0.05. 71% of trail runners sustained a RRI during the observational period. Most of these (78%) injuries were overuse in nature. The most prevalent site for overuse RRI was the foot (49%), then the knee (24%), hip (17%), and lower back (10%). The ankle (32%) was the most prevalent acute RRI, followed by the knee (23%) and foot (14%). Ankle ligament sprains were the most common acute injury. A mean injury severity score of 47 was reported based on the OSTRC-O scale. An overall injury incidence of 22.2 RRIs per 1000 h was reported. Women reported a higher mean prevalence of all RRIs 25.2%, (95% CI: 11.9-38.6), with men reporting a mean prevalence of 19.1% (95% CI: 14.3-23.9). Women reported a statistically significant higher mean overuse RRI prevalence of 21.1% (95% CI: 7.2-34.9%) than men, 17.6% (95% CI:11.4-23.7%) (p = 0.33; d = 0.50) and a medium effect size. Trail running in the current study presents with a high injury incidence in comparison to most mainstream sporting codes as well as other prospective, epidemiological studies on road and trail running. Most injuries in this study occurred in the lower limb and were low to moderate in severity. Trail runners are fourfold more likely to incur an overuse injury than an acute injury. As such, precautionary measures should be taken to reduce injury likelihood, particularly in the lower limb.