Browsing by Author "Bosch, Andrew"

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    A comparison of the pacing profiles adopted by male runners in the Comrades Marathon up run
    (2024) Manchip, Genine; Bosch, Andrew
    Introduction Ultramarathon running is gaining popularity worldwide. Due to the difficulty in completing an ultramarathon, knowledge of the most effective pacing to adopt in an ultramarathon race would be invaluable to coaches and runners, as well as of academic interest, since this information is already well established for the standard marathon. The Comrades Marathon is a globally recognised ultramarathon that takes place in South African annually. Its history and difficult undulating route attracts runners of all abilities, from around the world. Adopting the most effective pacing strategy to complete the Comrades Marathon would optimise the performance of a runner and thereby lead to each being more likely to achieve their specific goal. Aims and Objectives The aim of this study was to analyse the race results of three years of the Comrades Marathon “up” runs, namely 2015, 2017 and 2019 and to compare the pacing profiles of the fastest through to the slowest male runners in the field. The objectives of this study were 1.) To analyse the race results of the Comrades Marathon “up” run to identify the pacing profiles adopted by the fastest male runners, through to the slower runners; 2.) To compare the pacing profile of the top 10 male runners in each year, relative to their most recent standard marathon pace. Methods The study utilised a retrospective design. The study sample included the Comrades Marathon race results over three years of consecutive “up” runs. Only male runners, irrespective of age, were included in the study. If runners featured in more than one race, only their fastest finish time was included in the sample for statistical analysis. Runners were excluded from the study if there were split (intermediate) times missing or if their data was incomplete in some way. In the second part of the study, runners in the top 10 were excluded if their most recent standard marathon time could not be established. Results A total of 22 199 male runners were included for data analysis. The data was divided into quartiles, based on finishing time. This resulted in four groups, separated by 1.67-hour intervals. The first group contained the smallest number of participants (n=503) which was only 2.3% of the field and the last quartile (group) contained the most runners at 50.3% of the field (n= 11181). There was a significant difference between groups one, two, and four in the pacing profile when speed through the race segments was normalised to the speed at which the first segment was run. This was also the case when speed through each segment was normalised to mean race pace (of the entire race). All four groups showed a parabolic pacing profile; specifically a reverse “J“-shaped, when race pace was normalised to both mean race speed and to speed of the first segment. Analysis of the elite runners (top 10) for each year, showed that these runners started at an average of 88% of their marathon pace and averaged 80-90% of their marathon pace throughout the race. The elite runners showed a positive pacing profile with moderate effect. Conclusion This study showed that there is no significant difference between the pacing profiles of the faster male runners versus slower male runners. Runners adopted a reverse “J”-shaped pacing profile when their pace at different points in the race was compared relative to their mean race pace, or when each segment was compared to the pace in the first segment of the race. This finding is similar to previous studies that found that the most efficient pacing profile in recreational ultramarathon and marathon runners is a parabolic shaped profile. The elite runners' Comrades Marathon started the race at an average of 88% of their marathon pace and maintained an average pace of 80-90% of their standard marathon pace, throughout the race.
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    Does the use of upper leg compression garments aid performance and reduce post-race Delayed Onset Muscle Soreness (DOMS)?
    (2021) Kabongo, Ken; Bosch, Andrew
    Introduction: Despite the lack of scientific knowledge on the physiological and biomechanical effects of wearing compression garments, there has been an increase in the use of these garments in endurance running. The purpose of this study was to compare the performance, pain and thigh circumference changes in endurance runners using upper leg compression garments while competing against runners who did not use compression garments in the same marathon race. Methods: A randomised controlled intervention study was conducted in endurance runners (n=18) participating in the 2019 Winelands Marathon (42.2km). The compression garment group (n=10) participated in the race wearing upper leg compression garments while the control group (n=8) did not. Participants in the compression garment group only wore the compression garments during the marathon. Various outcome measures of perceived exercise-induced muscle damage (EIMD) and running performance were assessed three days before, immediately post-race and two days post-race. Three days prior to the race, mid-thigh circumference measurements were performed. Immediately post-race, mid-thigh circumference measurements, Visual Analogue Scale (VAS) pain ratings and Likert scale for determination of muscle soreness were assessed and race performance times were recorded. Two days post-race, mid-thigh circumference measurements, VAS pain rating and Likert scale for determination of muscle soreness were repeated. Results: VAS pain ratings for hamstring (compression garment 2.50 vs control group 4.00) (p=0.04), knee flexion (compression garment 2.50 vs control group 5.00) (p=0.02) and hip extension (compression garment 2.50 vs control group 4.00) (p=0.04) had a statistically significant difference between the compression garment and control group immediately post-race. VAS pain ratings for hamstring (compression garment 0.00 vs control group 1.00) (p=0.04), knee flexion (compression garment 1.00 vs control group 2.00) (p=0.02) and hip extension (compression garment 1.00 vs control group 2.50) (p=0.04) had a statistically significant difference between the compression garment and control group two days post-race. There were no statistically significant differences in any other outcome measures (i.e. Likert scale for determination of muscle soreness, mid-thigh circumference and race performance) between the compression garment and control group. Conclusion: The use of upper leg compression garments is a recovery ergogenic aid which improves VAS pain ratings post-race. The results suggest that upper leg compression garments have a protective effect on the hamstring muscle in runners in the recovery phase. However, since a runner would be in a recovery phase after a marathon, a minor difference would be of little practical advantage since, importantly, there was no statistically significant differences in race performance and thigh circumference measures.
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    The Effect of Sodium Alginate and Pectin Added to a Carbohydrate Beverage on Endurance Performance, Substrate Oxidation and Blood Glucose Concentration: A Systematic Review and Meta-analysis
    (2022-06-21) Sutehall, Shaun; Muniz-Pardos, Borja; Bosch, Andrew; Pitsiladis, Yannis
    Introduction Scientific and public interest in the potential ergogenic effects of sodium alginate added to a carbohydrate (CHO) beverage has increased in the last ~ 5 years. Despite an extensive use of this technology by elite athletes and recent research into the potential effects, there has been no meta-analysis to objectively elucidate the effects of adding sodium alginate to a CHO beverage on parameters relevant to exercise performance and to highlight gaps in the literature. Methods Three literature databases were systematically searched for studies investigating the effects of sodium alginate added to CHO beverage during prolonged, endurance exercise in healthy athletes. For the systematic review, the PROSPERO guidelines were followed, and risk assessment was made using the Cochrane collaboration’s tool for assessing the risk of bias. Additionally, a random-effects meta-analysis model was used to determine the standardised mean difference between a CHO beverage containing sodium alginate and an isocaloric control for performance, whole-body CHO oxidation and blood glucose concentration. Results Ten studies were reviewed systematically, of which seven were included within the meta-analysis. For each variable, there was homogeneity between studies for performance (n = 5 studies; I2 = 0%), CHO oxidation (n = 7 studies; I2 = 0%) and blood glucose concentration (n = 7 studies; I2 = 0%). When compared with an isocaloric control, the meta-analysis demonstrated that there is no difference in performance (Z = 0.54, p = 0.59), CHO oxidation (Z = 0.34, p = 0.71) and blood glucose concentration (Z = 0.44, p = 0.66) when ingesting a CHO beverage containing sodium alginate. The systematic review revealed that several of the included studies did not use sufficient exercise intensity to elicit significant gastrointestinal disturbances or demonstrate any ergogenic benefit of CHO ingestion. Risk of bias was generally low across the included studies. Conclusions This systematic review and meta-analysis demonstrate that the current literature indicates no benefit of adding sodium alginate to a CHO beverage during exercise. Further research is required, however, before firm conclusions are drawn considering the range of exercise intensities, feeding rates and the apparent lack of benefit of CHO reported in the current literature investigating sodium alginate.
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    Ergogenic aids used by ultra-marathon runners
    (2015) Gwilliams, Michael; Burgess, Theresa; Lambert, Michael; Bosch, Andrew
    Background: Athletes of all levels and abilities utilise ergogenic aids to enhance sporting performance. However, the extent of ergogenic aid use within the ultra-marathon running community in unknown and there is little available literature documenting characteristics of use among ultra-marathon runners. Aims and Objectives: The aim of this study is to describe the use of ergogenic aids in ultra-marathon runners. The specific objectives of the study were to: a) To obtain information on the use of ergogenic aids in ultra- marathon runners, with regard to the type of ergogenic aids used, and the pattern of use during training and competition; b) To determine ultra- marathon runner’s perceived benefits of the ergogenic aids; c) To determine the factors influencing the intake strategies of ergogenic aids; d) To explore the factors that may predict the use of ergogenic aids, such as age, gender level of competitiveness, training and competition history. Methods: This study had a descriptive correlational study design. Participants included male and female ultra- marathon runners between 25 and 65 years of age. Participants who did not give informed consent and who failed to meet the defined classifications of being an ultra-marathon runner and medical screening criteria were excluded from the study. Participants were recruited through electronic correspondence, running clubs and running-specific media platforms. A self-developed questionnaire was designed to obtain information on ergogenic aid use in ultra-marathon runners during training and competition, as well as to determine the runners’ pattern of use and their perceived effect of ergogenic aids. The questionnaire was available in English and Afrikaans, and explored both legal and illegal ergogenic aid use. A panel of experts reviewed and validated the questionnaire. The online questionnaire was anonymous; with all referring uniform resource locators (URLs) and internet protocol (IP) addresses of respondents hidden to ensure anonymity. Results: The final sample was comprised of 266 respondents (n=179 males; n=87 females). The mean age of participants was 44 ± 10. The mean number of ergogenic aids used per participant was 5 ± 2. Dietary practice (47%) was the most common ergogenic intervention, followed by supplementary aids (45%), and pharmacological aids (18%). No participants reported the use of illegal/banned ergogenic aids. The highest self-reported ergogenic aid used was s ports drinks (n = 213; 80%) followed by vitamins (n = 181; 68 %) and carbo-loading (n = 165; 62%). Participants tended to use ergogenic aid s predominantly during competition and less so during training. Seventy-nine percent of participants believe d that their chosen ergogenic aid improve d their performance, while 9% did not think their performance was improved, and 9% were uncertain. The most frequently perceived benefits of ergogenic aids were ‘delayed fatigue’ and ‘providing an energy boost ’. Self-experimentation /personal experience, fellow runners and books/magazines were the highest ranked factors influencing intake strategies of the participants chosen aids. Runners who had more than ten years of ultra-marathon running experience were approximately 50% more likely to consume sports drinks. Females were about two and a half times more likely to utilize vitamins as an ergogenic aid. However, evidence from the general population suggests that females have a significantly higher daily intake of vitamins compared to males; therefore this finding might simply reflect daily supplement use and not be specific to ultra-marathon runners. The use of vitamins was also dependant on the number of ultra-marathons performed; participants completing more than five ultra-marathons were almost twice as likely to use vitamins as those completing less than five ultra-marathons. Recreational runners were approximately one third less likely to undertake the dietary practice of carbo-loading than competitive runners. The number of marathons and the number of ultra-marathons completed conversely affected the use of increased protein. This study was unable to identify any descriptive, race or training characteristics that influenced the use of caffeine, medication, gels or electrolytes as ergogenic aids. Conclusion: The findings of this study demonstrated that the prevalence of use of legal ergogenic aids is high and often used simultaneously. This study was unable to identify the prevalence of use of illegal ergogenic aids. However, the inappropriate and potentially unsafe use for many legal ergogenic aids was identified. Participants also reported false performance beliefs, potentially indicating poor knowledge or understanding of the effects of ergogenic aids. A major challenge is the strong influence of personal experience and information from fellow runners on the choice of ergogenic aids. Runners are accessing information through social networking, interactions and possibly social media, rather than scientific resources. Educational initiatives, with a focus on peer-led education, are essential to encourage the safe and effective use of ergogenic aids. This study highlights the importance of collective responsibility of the running community, including regulators, administrators, health care professionals, coaching and support staff, and journalists and authors of books and magazines to ensure that runners are informed about the safe and correct use of legal ergogenic aids.
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    Establishing the physiological, anthropometric and training characteristics, and pacing patterns of runners racing in a tropical ultra-marathon
    (2024) Tan, Loong Seng Philip; Bosch, Andrew
    Background: The popularity of ultra-marathons has rapidly increased in recent years, especially in Southeast Asia, with more recreational runners entering the field. The physiological, anthropometric, and training characteristics of runners participating in these ultra-marathons run in high temperature and humidity, along with their pacing have not been documented. Knowing these parameters and their relationship with performance in this group of participants are important for prescribing appropriate training to maximise performance and minimise the risk of injury, especially heat injury, as well as choosing the optimal pacing strategy for races. Aim: The first aim of the thesis was to compare and determine the differences in the physiological, anthropometric, and training characteristics of the finishers (FIN) and nonfinishers (N-FIN) in a tropical ultra-marathon. The second aim was to establish and compare the pacing patterns of fast and slow FIN in the same race. Two studies were conducted to achieve these aims. Methods: For the first study, two groups of participants of the 161-km category of the race (FIN; N=12 and N-FIN; N=14) completed a series of anthropometric and physiological measurements over two separate sessions at least three weeks prior to the race. Training sessions starting from six weeks prior to the race were recorded. Sum of 7 skinfolds, arm and calf girths, VO2max and peak treadmill speed (PTS) were taken during session 1 while the lactate threshold (LT) and running economy (RE) were assessed during session 2. For the second study, FIN of the 161-km (N=47) and 101-km (N=120) categories of the race were divided into thirds (Group A-C) by merit of finishing time. Altogether, 17 and 11 split times were recorded for the 161-km and 101-km finishers, respectively, and used to calculate the mean running speed for each distance segment. Running speed for the first segment was normalised to 100, with all subsequent splits adjusted accordingly. Running speed during the last 5 km was calculated against the mean race pace to establish the existence of an “end spurt”. Main findings: For the first study, effect size (ES) calculations showed moderate and clear differences in the lactate concentration at LT1 (ES = 0.88; P = 0.05), velocity at LT2 (ES = 0.70; P = 0.07), longest run attempted (ES = 0.73; P = 0.07) and number of cross-training hours (ES = 0.73; P = 0.06) between the FIN and N-FIN. For the second study, a reverse J-shaped pacing profile was demonstrated in all groups for both distance categories. Only 38% of the finishers executed an end spurt. In the 101-km category, in comparison to group B and C, group A maintained a significantly more even pace (P = 0.013 and 0.001, respectively) and completed the race at a significantly higher percent of initial starting speed (P = 0.001 and 0.001, respectively). Descriptive data also revealed that the top five finishers displayed a “herdbehaviour” by staying close to the lead runner in the initial portion of the race. Conclusion: Findings from the studies conducted suggest that from a physiological perspective, the ability to finish a 161-km ultra-marathon in a hot and humid climate might be differentiated by metabolic attributes via LT measurements. For training, runners should not neglect the importance of the long runs and should incorporate cross-training to provide additional stimuli to the body while allowing the running muscles to recover from. Finally, to avoid a significant decline in running speed during the later parts of the race, recreational ultrarunners should adopt a conservative sustainable starting speed. Less competitive runners should set realistic performance goals while competitive runners with a specific time goal should consider running in packs of similar pace.
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    An evaluation of gastrocnemius muscle structure and function in endurance runners and low physical activity individuals
    (2013) Buchholtz, Kim; Burgess, Theresa; Lambert, Mike; Bosch, Andrew
    Distance running has become increasingly popular in recreational runners. The gastrocnemius is the main muscle used for propulsion in running, and may be at risk for injury due to its morphology. In previous studies, changes in the morphology and architecture of the gastrocnemius muscle have been evident following training, but it is unclear whether these changes are related to training or youth. Previous studies of runners have shown a decrease in gastrocnemius and soleus flexibility, as well as changes in the fascicle length and pennation angle. Gastrocnemius volume has not been compared in low physical activity and active participants. Physiological cross sectional area, based on volume and fascicle length measurements may also provide valuable information about the muscle’s ability to produce force. Ultrasound may be a useful tool in assessing potential training adaptations in the morphology and architecture of the gastrocnemius muscle. The aim of this cross-sectional descriptive study was to assess the differences in architecture and function of the gastrocnemius in endurance runners compared to low physical activity participants. (a) To assess differences in calf function and flexibility between endurance runners and low physical activity individuals, and between male and female participants; (b) To determine differences in gastrocnemius muscle architecture and composition between endurance runners versus low physical activity individuals, and between males and females; and (c) To determine whether there are any relationships between training factors and the structure and function of the gastrocnemius muscle. Thirty participants between 20 and 45 years old were recruited for this study and allocated to groups based on their level of physical activity. The low physical activity group (n = 14) were not participating in any regular physical activity, while the endurance running group (n = 16) were running a minimum of 40 km.wk-1, and had participated in at least one full marathon (42.2 km) in the previous six months. All participants completed informed consent, a physical activity and training questionnaire, and a Physical Activity Readiness Questionnaire (PAR-Q) at the first session. The first session also included body composition measurements; ultrasound imaging to measure gastrocnemius length, thickness, fascicle length, pennation angle and volume; and familiarisation with all physical tests. Physical tests were conducted in the second session, including gastrocnemius and soleus flexibility, calf raise endurance and vertical jump height to assess the function of the components of the triceps surae. There were no significant differences between low physical activity and running groups for gastrocnemius thickness, fascicle length, pennation angle and gastrocnemius length. Gastrocnemius volume (p = 0.02) and physiological cross sectional area (p = 0.01) were significantly greater in the running group compared to the low physical activity group. There were no significant differences between low physical activity and running groups in flexibility or vertical jump height, although male participants had significantly decreased gastrocnemius muscle flexibility (p = 0.046) and significantly greater vertical jump heights (p = 0.01) than females. Calf raise endurance was significantly greater in the running group than in the low physical activity group (p = 0.03). Endurance running leads to specific adaptations in participants in both structure and function. While ultrasound appears to be a reliable measure for assessing architectural components of the gastrocnemius muscle in both active and inactive populations, further cadaver studies may provide valuable information on muscle architecture.
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    How do pacing strategies differ in elite versus nonelite female Two Oceans Ultra marathon runners
    (2024) Mouton, Chanel; Bosch, Andrew
    Background: Ultramarathon running is becoming an increasingly popular sport with millions of runners participating annually in events hosted all around the world. Pacing is considered as one of the key determinants of ultramarathon running success. Optimal pacing allows a runner to selectively manage their running speed throughout the race, to prevent premature fatigue, as they aim to achieve their desired outcomes. Although previous pacing studies provide a strong scientific foundation for research on Olympic and Championship endurance running, less is known about pacing patterns during mass-participation events – especially when focusing on female running performance. Previous research found that faster, older, and female runners achieve superior outcomes in marathon running due to their ability to maintain even pacing during competition. In a race with a challenging geographical profile, such as the Two Oceans Ultramarathon, it is unrealistic to adopt an even pacing profile throughout the entire race. This prompted us to investigate the effect of elevation on the pacing patterns adopted by elite and progressively slower female runners who successfully completed the 56- kilometre road race. Aim: The aim of this study was to determine, analyse and compare the pacing profiles adopted by elite and non-elite female runners during the Two Oceans Ultramarathon from 2007 to 2018. Specific objectives: 1) To describe the pacing profiles displayed by the elite female runners. 2) To describe the pacing profiles displayed by the successively slower categories of female runners. 3) To compare how pacing profiles might differ between the elite and slower category runners. 4) To establish how the different categories of female runners adapted their pace in response to the flat and hilly sections of the race and compare how it varied between runners of different ability. Methods: A retrospective, descriptive study was conducted to investigate the pacing patterns of female runners who successfully completed the Two Oceans Ultramarathon from 2007 to 2018. Race results from 9 682 eligible runners were obtained from a publicly accessible archive (www.twooceansmarathon.org). Participants were categorised into seven distinct groups based on their overall finish time. Split times recorded at 28km, 42km, 50km and at the finish (56km) were used to calculate the segmental splits and overall mean race pace for each runner included in the study. The segmental race pace for progressively slower groups were analysed to establish how each group a) paced over the first half of the race; b) changed their pace in response to the elevation over the second half of the race; c) might differ in their pacing profile depending on their running ability. Results: All seven groups of runners slowed down during the race before speeding up toward the finish, thereby adopting an initial positive pacing pattern followed by negative pacing towards the end of the race. The analysis of segmental split and overall finish times showed that the fastest finishers started the race within 4% of their overall mean race pace (103.97%; 95% confidence interval = 102.74 lower level, 105.20 upper level) whereas the slowest finishers had the fastest start, running 8% faster than their mean race pace (107.98%; 95% CI = 107.83 - 108.14). This unrealistic early race pace forced the lesser runners to slow down, resulting in finishing speeds of 8% slower than their starting speed (92.42%; 95% CI = 92.22 - 92.62). In contrast, the strongest group finished within 4% of their starting speed (96.11; 95% CI = 94.52 - 97.71) by adopting a more sustainable early race pace. The fastest finishers were the youngest (33.6 ± 5.1; years ± SD) and the slowest finishers were the oldest (39.5 ± 8.7). The average finishing time was 06:04:52 ± 00:38:11 (hr:min:sec ± SD). Only 0.5% of runners finished in less than four hours (49 of 9 682 participants), whereas 56.4% of the runners (5 406 of 9 682 participants) required six hours or more to finish the race. Conclusion: The results of this study suggest that runners should adopt a patient, sustainable starting speed. Elite runners with a specific time-objective may benefit from a faster pace over the flat first half of the race, making up for time lost over the challenging second half of the race. Slower runners, whose primary goal is to finish the event, should aim for a more conservative approach, equal to their running ability. These recommendations allow for the even distribution of energy resources throughout the race, preventing premature fatigue and improving race outcomes. The findings in this study provide valuable insights into effective pacing strategies for ultrarunners, contributing to our understanding of optimising performance in endurance running events.
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    Investigation of the impact of compression garments on endurance running performance and exercise induced muscle damage in the lower leg
    (2018) Geldenhuys, Alda Grethe; Bosch, Andrew; Swart, Jeroen
    Introduction: Compression garments utilisation is very popular among runners despite the relative lack of consensus in the literature regarding a beneficial impact. Methods: A randomised controlled experimental study was conducted in healthy, uninjured endurance runners (n=41) participating in the Old Mutual Two Oceans 56km race. The experimental group (n=20) trained for six weeks and participated in the race wearing below knee compression garments while the control group (n=21) did not. Participants were tested on four occasions for various markers of exercise induced muscle damage (EIMD) and running performance. Six weeks prior to the race, ultrasound scans of the medial gastrocnemius, mid-calf and figure-of-8 ankle circumference baseline measurements were performed. Shortly prior to the race, these measurements were repeated in addition to a countermovement jump (CMJ) test. Immediately following the race, circumference measurements and CMJ testing were repeated in addition to pain ratings on the visual analogue scale (VAS). Race performance times were also obtained. Two days following the race, the ultrasound scans, circumference measurements and VAS pain ratings were repeated. Results: Ankle circumferences measurements increased significantly less (p=0.01, Cohen's d=0.9) in the experimental group from immediately after the race until two days post-race compared to the control group. There were no further statistically significant changes over time in any other objective outcome measure (i.e. mean mid-calf circumference, medial gastrocnemius mean muscle thickness and mean pennation angle, mean CMJ height and estimated peak power output nor in race performance) between the experimental and control groups. Selected pain ratings were statistically significantly worse in the experimental group. Muscle thickness and pennation angles were significantly greater in the control group compared to the experimental group two days following the race. Conclusion: There were limited indications of a beneficial impact of compression garments with minor improvements in ankle circumference measurements, but no further significant effects related to EIMD were detected. Furthermore, no ergogenic impact was detected. Based on the results of the study, there is limited evidence to support the continued utilisation of commercially available below knee compression garments during running.
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    Medical complications during a community-based mass participation endurance running event – an investigation of the epidemiology and risk factors associated with medical complications, with recommendations for risk mitigation
    (2021) Schwabe, Karen; Schwellnus, Martin; Derman, Wayne; Bosch, Andrew
    Background: The epidemiology and risk factors associated with medical complications, including life-threatening complications during distance running events has not been well described. The aims of this research were to document the incidence of medical complications (study 1), determine risk factors associated with medical complications (studies 2 and 3), and develop and apply a pre-race medical screening tool to determine the prevalence of chronic disease in race entrants, using a risk stratification model (study 4). Design: Prospective studies Setting: Two Oceans Marathon races (2008-2011) (studies 1-3) and race entrants (2012) Participants: Studies 1-3: 65 865 race starters; 21.1 km (n =39 511), 56 km runners (n=26 354). Study 4: 15 778 race entrants Methods: Study 1: In all 4 years, race day medical complications were recorded and subdivided by severity (serious life-threatening/death), organ system and final diagnosis. Studies 2 and 3: Independent risk factors associated with all medical complications, severity and organ system involvement were determined in 21.1 and 56km runners, using multivariate modeling. Study 4: A pre-race medical screening tool was developed, based on international pre-exercise medical screening guidelines, and administered to all race entrants (2012). The prevalence (%) of runners with four risk categories was determined. Results: The incidence (per 1000 race starters) of all and serious/life-threatening medical complications was 8.27 and 0.56 respectively (study 1). Risk factors associated with medical complications were less experience (56km), slower running pace (56 km) and older females (21.1 km) (studies 2 and 3). 16.8% runners were identified as those that should undergo medical evaluation for suspected cardiac disease with 3.4% reporting existing CVD (very high risk) and 13.4% reporting multiple CVD risk factors (high risk) (study 4). Conclusion: The incidence of all and serious/life-threatening medical complications in the 21.1km and 56km race is 1/121 and 1/1786 race starters respectively. Race experience, running pace and sex are risk factors for medical complications. 16.8% runners have underlying suspected cardiovascular disease. These data formed the basis for the implementation of a pre-race medical screening and risk stratification. The research lays the foundation for a future educational intervention programme to reduce the risk of medical complications in distance running and other endurance events.
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    Metabolic and hormonal responses to altered carbohydrate availability and its effect on fatigue development
    (2005) Claassen, Amanda; Lambert, Vicki; Bosch, Andrew
    The main aims of the series of studies comprising this thesis were to investigate the effect of altered endogenous carbohydrate (CHO) availability, achieved primarily by pre-exercise dietary manipulation and antecedent exercise exposure, on interindividual variability in metabolic and hormonal responses to dynamic, steady-state exercise. Further, this thesis examined the impact of altered blood glucose availability on fatigue development during prolonged exercise. In this regard, it was hypothesized that endogenous CHO availability and the associated metabolic sequelae would impact on effort perception during exercise and fatigue development.
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    Racing patterns of elite and non-elite male Two Oceans marathon runners
    (2025) Kruger, Viljee; Bosch, Andrew
    Introduction: Limited information exists about the pacing patterns of elite and non-elite runners competing in the 56km Two Oceans Marathon. Objective: The main aim of the study was to establish and compare similarities and differences in pacing patterns between elite and non-elite male runners in the Two Oceans Marathon. Methods: Data was analysed from the Two Oceans Marathon database of finishers. Male participants across 10 races from 2007 – 2019 formed the sample group (N=25 315). The sample group was ordered fastest to slowest and subsequently divided into 8 groups (A-H) by merit of finishing times. Four timing segments (1-4) were recorded and used to calculate pace (in km/h) in each segment and mean race pace of each finisher. A Generalised Linear Mixed Effects Model (GLMM) analysis was used to examine the patterns of average pace change between groups. Results: A reduction in average pace was observed across all groups for the first three segments, with an increase in average pace for the final segment (p<0.0001). Pairwise comparison of change in pace between mean race pace across all four segments demonstrated that elite runners start the race more conservatively when compared to non- elite runners (p<0.0001). Conclusion: The findings demonstrated a parabolic type pacing pattern where elite runners demonstrated less pace variation, while non-elite runners displayed more pace variation. Non- elite runners completed the first half of the race substantially faster relative to their overall race pace. Results suggest that to achieve an optimal pacing pattern, non-elite runners should consider adopting a more realistic starting pace.
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    The reliability of 10 km treadmill time trial performance and the effect of different high intensity interval training strategies on 10 km running performance and associated physiological parameters
    (2015) Kirkman, Mark Courtney; Bosch, Andrew; Lambert, Michael I
    The reliability and validity of a performance test is important in research to detect meaningful performance differences following an intervention. In accordance with this, the aim of the first study of this thesis was to investigate the reliability and validity of a self-paced 10 km treadmill time trial. This performance measure was then used in the main section of this thesis. This comprised a large training intervention study aimed to answer specific questions following three different high intensity interval training programmes. In particular, changes in 10 km running performance were investigated with respect to various physiological parameters, both immediately following the training intervention, as well as during a subsequent three-week taper period. Methods In the first study, a group of well-trained male runners (n = 8) completed four 10 km treadmill time trials and two 10 km track time trials. Comparisons in performance time were made between the 10 km treadmill time trials to determine the typical percent error between these trials. Additionally, comparisons were made between the track and treadmill time trials. In the second study, well-trained male runners(n = 32) were randomly assigned to one of four groups; a control group, a 400 m interval group, a 1600 m interval group and a mixed (400 m and 1600 m) interval group. The intensity of the intervals was based on the participants' current 10 km time trial time. The high intensity training interventions consisted of eight interval sessions (twice per week) over a four-week period followed by a three-week singlestep30% reduction in total training volume (while maintaining training frequency and some intensity) in all groups.
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    The effect of supplementary Elliptical training protocols on running performance in trained runners
    (2024) Malan, Anna; Bosch, Andrew
    Recent studies at the University of Cape Town found comparable physiological and metabolic responses between the elliptical trainer, stepper, and treadmill, and a decrease in muscular effort of lower extremity muscles when exercising at similar intensities on the elliptical trainer and stepper in comparison to treadmill running. It was therefore suggested that the elliptical trainer and stepper could be useful substitutes for running when periods of reduced running load are required, such as during rehabilitation from an injury, or as a means to increase running load without the risk for increased injury. It remains unknown whether the elliptical trainer can be used to improve running performance, and thereby maintain cardiovascular fitness, if added to a running training programme. Thus, the purpose of this study is to investigate whether supplementing existing running training with elliptical training enhances running performance in trained runners. The study was conducted at the Sport Science Institute of South Africa (SSISA). Thirteen trained runners were recruited (male/female: N=11/2, age: 32.8 ± 8.3) to complete PRE and POST assessments of peak treadmill running speed (PTRS), 8-km time trial, and body composition, with assessments of PTRS, 8-km time trial, RPE, and HRmax. Between PRE and POST assessments, participants took part in an 8-week intervention of either additional running, or the same additional training load on the elliptical trainer. Results indicate a significant difference between PRE and POST PTRS as runners increased their peak running speed following the training intervention by 0.4km/h [18.5 ± 1.5 and 18.9 ± 1.5 PRE and POST, respectively] for all participants combined. However, no difference was found between the elliptical training and running training groups. Eightkm time trial, RPE, and HRmax were unchanged. These findings support expectations that the elliptical trainer can be used as a useful modality to both increase running performance and maintain fitness levels when unable to run.
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    The use of Ergogenic aids in cyclists
    (2014) Hansen, Ashleigh; Burgess, Theresa; Lambert, Mike; Bosch, Andrew
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    Torpedo Swimrun Cape Town: understanding athletes, evaluation of race rules and assessing predictors of performance of a novel sport
    (2020) Geromont, Christina; Bosch, Andrew
    Aims: The first aim was to describe the characteristics and demands of the Torpedo SwimRun Cape 2019 race. The second aim was to determine predictors of race performance, by using entry, result and questionnaire data. Objectives: The first objective was to explore distributions of age (y), sex, 1km pool swimming time (mm:ss), 5km road running time (mm:ss), competency level (Likert scale), estimated race finishing time (hh:mm), training habits (min/week and sessions/week), background sport (type), equipment used (type), wave selection (athletes select if they want to start in a slow, medium or fast wave)(type), total and segment race times (mm:ss) and questionnaire scores of race participants. The second objective was to analyze segment and race result times, 5km run times, 1km swim times and ocean knowledge questionnaire results. Results: In total, there were 99 participants (288 athletes took part in the race) of which 36% were female and 64% were male. Each team in the Torpedo SwimRun Cape must consist of two athletes. Of the athletes, 53% were entered in male teams, 30% in mixed teams (a male and a female per team) and 17% entered in female teams. The median age was 41 years with an interquartile range (IQR) of 19 years. The mean race time was 174:15 mm:ss (± 29:51 mm:ss). Athletes trained on average 7 sessions/week (IQR 7 sessions/week), and 435 min/week (IQR 345 min/week). The median ocean knowledge score (OKQ) was 9 (IQR 4). Athletes' self-reported current 5km road running time was on average 25:00 mm:ss (IQR 07:41 mm:ss) and their current 1km pool swimming time was 18:00 mm:ss (IQR 07:02 mm:ss). Total race time was significantly associated with current 5km road running time ( = 0.488, p = 0.001), current 1km pool swimming time ( = 0.607, p = 0.001) and OKQ score ( = -0.349, p = 0.003). These three variables were also used to predict total race time. The over-all linear regression model was found to be significant (R2 = 0.514, p = 0.001). Conclusion: The athletes that participated in the Torpedo SwimRun Cape 2019 display a large variance in their training habits, particularly their training loads. It was found that the performance in this SwimRun race was not only dependent on how trained athletes were, but 4 also their ocean knowledge. Ocean knowledge is a learned skill and not necessarily attained by swimming in the ocean more (training open-water swimming was not associated with OKQ score). The OKQ questionnaire showed that better scores were associated with faster total racing time. The model used to predict performance accounted for approximately half of the variation seen in total race time. There is a clear need to further understand how performance is affected in SwimRun races. Repeat studies should be done to investigate different training strategies (also taking an athlete's team partner into account), the effect of various environmental exposures and how different equipment influence racing.
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    The use of recovery modalities by endurance runners
    (2015) Lemke, Hanette; Burgess, Theresa; Lambert, Michael I; Bosch, Andrew
    Background: Overtraining and exercise-induced muscle injuries are common in endurance runners. A well-planned recovery protocol is crucial to limit fatigue and prevent injuries. There are multiple modalities available to aid the recovery process and facilitate optimal performance. However, there is limited information regarding the prevalence and pattern of use of recovery modalities in endurance runners, as well as the factors that may influence runners' decisions to use different recovery modalities. This information is important for the promotion of safe and effective use of recovery modalities and to identify potential educational requirements for athletes using recovery modalities. Aim and objectives: The aim of this study was to describe the use of different recovery modalities and regimes by endurance runners following training and races. The specific objectives of the study were: (a) to obtain information on recovery modalities used by endurance runners, such as the type of modalities, frequency of use, an d use during training and races; (b) to determine the factors that influence endurance runners when selecting recovery modalities; (c) to determine the knowledge endurance runners have of the perceived effectiveness of recovery modalities; (d) to explore associations between the use of recovery modalities in endurance runners and socio-demographic factors, such as, gender, age, body mass index, monthly income, level of education and training and competition history. Methods: This study had a descriptive correlation design. Adult runners who ha d been running for at least six months in the 12-month period preceding the study, and who were training a minimum of 30 km.wk -1 were included in this study. Participants who failed to provide informed consent or did not complete the mandatory sections of the questionnaire were excluded from the study. Participants were recruited at races and by contacting South African running clubs. Participants were required to complete a self-developed questionnaire that included demographic information, training and racing history, and the self-reported use of recovery modalities. The questionnaire was validated by a panel of experts. It was available in both hard copy and electronic format. Results: The study sample consisted of 433 participants (m ales 64%; females 36%), who were mostly well-educated with a tertiary degree or diploma. More than 80% of participants were predominantly road runners. Participants in this study reported using the twelve recovery modalities regularly, with passive recovery (90%), active recovery (76%) and stretches (67%) being the most commonly used modalities. Participants used a mean of 6 ± 2 different recovery modalities. All recovery modalities were commonly used during training and races, while cryotherapy, anti-inflammatory medication, contrast therapy, heat and massage were more commonly used after injury or for the management of pain. A protein supplement was used by 60% of participants, compared to 37% of participants' who reported using carbohydrate supplements. Between 10 % and 19% of participants did not know the proposed mechanism of action of different recovery modalities. Personal experience and information from fellow runners were the two main resources that influenced participants' use of different recovery modalities. Approximately 90% of participants reported that passive recovery and massage were effective recovery modalities, while over 30% of participants thought carbohydrates, compression, vitamins and minerals were less effective in assisting recovery from training and competition. Demographic factors such as gender, age, level of education and monthly income predicted the use of carbohydrates, protein, massage, anti-inflammatory medication, active recovery and compression. Training factors associated with more experience (for example number of marathons) predicted the use of vitamins and minerals, anti-inflammatory medication, active recovery and compression. The presence of a current injury predicted the use of cryotherapy, heat and contrast therapy. Conclusion In conclusion, this study showed there is widespread use of recovery modalities among endurance runners, despite the lack of evidence for their efficacy. Unsafe and inappropriate practices were identified, which may compromise performance, but may also place endurance runners at risk of serious adverse events during both training and competition. A major challenge is the strong influence of personal experience and information from fellow runners on the choice of recovery modalities. Educational initiatives, with a focus on peer-led education, are essential to encourage the safe and effective use of recovery modalities.
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    Which resistance training method best improves running economy in elite marathon runners: a 16-week randomised controlled study
    (2025) Behardien, Muhammed; Bosch, Andrew
    Background: Concurrent training combines resistance and endurance exercises in a single program and has been linked to improvements in running economy (RE), running muscle power factors, and time trial performance. However, the mechanisms underpinning these improvements remain unclear. This study compared concurrent heavy-weight training (HWT) and reactive-strength (RST) to determine which leads to better running performance improvements and to investigate the underlying mechanisms and adaptation time-course. Methodology: This blocked, randomised controlled study tested participants (HWT = 8, RST = 8) three times over 12 weeks interspersed with two four-week resistance training blocks. Body composition, 1- rep-max (RM) Smith machine back squat, countermovement jump, squat jump, drop jump, running biomechanics, aerobic treadmill test, maximal anaerobic running test (MART), and 5km time trial (5kmTT) were measured. A linear mixed model analysis assessed the group-by-time interaction for each variable. Post-hoc pairwise analyses were run when applicable. Additionally, Pearson's correlation coefficient tested for significant relationships between all variables. Results: Concurrent training does not affect body composition and VO2max running biomechanics and RE. A main effect of time (p < 0.05) was evident for absolute and relative 1RM back squat, modified reactive strength index during the countermovement jump (RSImod), peak treadmill speed, as well as maximum velocity and maximum oxygen demand during the MART. There was a significant group-by-time interaction (p < 0.05) for relative 1RM back squat at mid-testing, CMJpower at post-testing, and the 5kmTT. The RST group improved their 5kmTT by 73.91seconds (95%CI: -130.59 – 17.24); p = 0.02) more than HWT. Only ∆RE measured at participant's training speed (r = 0.54, moderate; p = 0.048), and oxygen demand during the final lap of the MART (r = -0.621, strong; p = 0.02) significantly correlated with ∆5kmTT over the pre- to mid-testing period. Conclusion: Overall, RST was shown to superior to HWT in improving 5kmTT performance, and that concurrent training improvements continue to linearly increase over a 10-week period. Even though this study was not able to explain the mechanisms underpinning these concurrent training elicited running performance improvements, it still yielded valuable results. This study showed that by periodising an easy, low-cost, time-efficient, and low- intensity RST program into an athlete's schedule, one can significantly improve athletes' race finish times by more than a minute. Therefore, these findings provide athletes, coaches, and conditioning professionals with an RST-based concurrent training program that can effectively improve recreational distance running performance.