Browsing by Author "Schwellnus, Martin"

Now showing 1 - 20 of 33
  • Thumbnail Image
    Item
    Open Access
    Achilles tendon ultrasound findings in triathletes before and after the ironman triathlon
    (2006) Schwabe, Karen; Schwellnus, Martin
    The aim of this prospective cohort study therefoew was to assess the morphological and blood flow changes in the Achille tendons of triathletes competing in the 2006 South African Ironman Triathlon.
  • Thumbnail Image
    Item
    Open Access
    Anabolic-androgenic steroids : knowledge, attitudes, ethical dilemmas and review for primary care physicians
    (2002) Ebrahim, F A; Lambert, Mike; Schwellnus, Martin
    Includes bibliographical references.
  • Thumbnail Image
    Item
    Open Access
    The application of clinical gait analysis to running injuries
    (2005) Arendse, Regan Emile; Schwellnus, Martin; Gibson, Alan St Clair
    Clinical evaluation of the injured runner requires identification and correction of the multiple factors commonly implicated in running injury. Effective management of running injuries requires that the concerned health professional identify all implicated factors. In this regard it is essential that the relationship between running style and injury he determined, because if there is an association between the gait analysis variables descriptive of running style and injury, these would be important in the management of the injured runner. The Gait Analysis Laboratory at the Sports Science institute of South Africa and the University of Cape Town with its three-dimensional Vicon 370 motion analysis system and Advanced Medical Technology industry® strain gauge force platform is appropriate for collecting data to study running style. These data include the movement patterns and estimated mechanical power and work required to effect the observed movement of the ankle and knee. The forces applied by the supporting surfaces on the runners were collected. The data captured with the Workstation® programme (Oxford Metric, Oxford, England), was processed with GaitLab® (Kiboho Publishers, Cape Town, South Africa), collated in Excel ® (Microsoft Corporation, Redmond, USA) and statistically analysed (StatSoft, Inc. (2000). STATISTICA for Windows [Computer program manual]. Tulsa, OK, USA). In this thesis a series of studies are presented with the aim of determining the relevance of running style to the assessment of the injured runner and the conventional treatment methods used to treat common running injuries.
  • Thumbnail Image
    Item
    Open Access
    A comparison between the effects of hamstring static stretching and active warm-up on range of motion and performance
    (2006) Beukes, Phillo; Schwellnus, Martin; Lambert, Mike
    Includes bibliographical references.
  • Thumbnail Image
    Item
    Open Access
    A comparison of two treatment protocols in the management of exercise-associated postural hypotension (EAPH) : a randomised clinical trial
    (2007) Anley, Cameron; Schwellnus, Martin; Noakes, Tim; Collins, Malcolm
    The aim of this study was to compare which of the two commonly used treatment protocols for Exercise Associated Postural Hypotension (EAPH) (Trendelenburg with oral fluids ad libitum or intravenous fluids) result in quicker recovery and earlier discharge from the medical facility.
  • Thumbnail Image
    Item
    Open Access
    Early management of the iliotibial band friction syndrome (ITBFS) in distance runners
    (2003) Gunter, Petrus; Schwellnus, Martin
    Includes bibliographical references.
  • Thumbnail Image
    Item
    Open Access
    The end of season electroencephalographic and neuropsychological status of a team of secondary school rugby players : a comparison between very mild traumatic brain injury and a sedentary control group
    (2004) Dijkstra, Hendrick Paulus; Schwellnus, Martin
    Although the incidence and consequences of mild traumatic brain injury (MTBI) in secondary school rugby has been well documented, little is known about the incidence and consequences of repetitive sub concussive injuries - the so called very mild traumatic brain injuries (vMTBI). The aim of this study was to compare the end of season neuropsychological and electroencephalographic (EEG) status as well as the academic performance of players in a secondary school rugby team who, during the course of the season sustained only repetitive vMTBI to those players who sustained MTBI and a sedentary control group.
  • Thumbnail Image
    Item
    Open Access
    The epidemiology and risk associated with lower back pain in cyclists
    (2009) Marsden, Mandy; Schwellnus, Martin
    Aims of this thesis: the research reported in this thesis consists of a literature review and two research parts. In the first research part, a descriptive cross-sectional survey was conducted, to investigate 1) the epidemiology and 2) the nature of LBP in cyclists, and 3) possible risk factors associated with LBP in cyclists. In the second research part, a case control study was conducted, to investigate the association between LBP in cyclists and 1) flexibility and 2) anthropometric measurements, and 3) bicycle set-up parameters.
  • Thumbnail Image
    Item
    Open Access
    Epidemiology and risk factors for illness in athletes participating in sport tournaments or competitions - a specific focus on Rugby Union
    (2015) Kourie, Alan; Schwellnus, Martin
    Background: Illness in athletes is an inevitable part of participation in sports, and can significantly interfere with training, during tournaments or at competition time. The incidence of illness in sports varies in different sporting codes and across different tournaments and competitions. The Super Rugby competition is a particularly demanding 16-week tournament among countries in the Southern Hemisphere, and is associated with a high incidence of illness. In this tournament, 15 rugby union teams compete and play international level matches every week, which involves travel across numerous time zones and therefore may be associated with a higher incidence of illness in players. Objective: The main objectives of this dissertation were to 1) review the epidemiology and risk factors for illness in athletes participating in tournaments or competitions, and 2) determine which intrinsic risk factors predispose players to illness during the 2010 Super Rugby tournament. Methods: This dissertation consisted of two main phases. In phase I, a systematic review of the literature was undertaken, using evidence-based criteria, to determine which risk factors predispose athletes to illness during tournaments. In phase II, a prospective cohort research study was undertaken, involving 239 players from South Africa and New Zealand, over the 16-week duration of the 2010 Super 14 Rugby Union tournament. For phase II, a pre-season medical questionnaire was administered to determine baseline medical data. Collection of data then took place each day of the competition, beginning 7 days before the first game the team played, and ending when each team played their final game. Each team physician completed a daily "medical illness log" for every player. Booklets were supplied that contained daily illness report forms. Results: The main findings of the review (phase I) were good evidence (level I and II) indicating that 1) international travel, and the duration of a tournament are extrinsic risk factors for illness in athletes, and 2) that prolonged and high intensity training, older age, and nutritional deficiencies are intrinsic risk factors for illness in athletes. The main findings of the prospective cohort study (phase II) were that an increased number of training days in the 2 weeks before the tournament was an independent risk factor for any illness, respiratory system illness, and digestive system illness; the % time spent on endurance training in the 15 weeks before the tournament was an additional independent risk factor associated with respiratory system illness; the use of anti-inflammatory medication was an independent risk factor associated with respiratory system illness. Summary and conclusion: In summary, novel intrinsic risk factors for illness in rugby players participating in the Super Rugby tournament were training more days/hours per week in the 2 weeks before the tournament, as well as endurance-type training 15 weeks before the tournament. These data can form the basis of planning preventative strategies to reduce the risk of illness in the Super Rugby tournament.
  • Thumbnail Image
    Item
    Open Access
    Exercise-associated muscle cramping (EAMC) in Ironman triathletes
    (2006) Drew, Nichola; Schwellnus, Martin; Collins, Malcolm
    Exercise-associated muscle cramping (EAMC) is a common condition of spontaneous, painful skeletal muscle spasms that occur in exercising muscles during exercise or in the immediate post-exercise period. There is a high prevalence in endurance athletes, including ultra-distance triathletes. The exact cause for this condition has not been defined but various hypotheses have been proposed. Over the last decade the ""fatigue hypothesis"" has received most of the support in the scientific literature. Evidence from animal experiments, clinical studies on endurance athletes and situational information, suggest that neuromuscular fatigue may precede the increased neuromuscular excitability leading to EAMC. The objective of this research study was to identify factors associated with EAMC in endurance triathletes in an attempt to further elucidate the aetiology. Triathletes competing in the 2006 South African lronman triathlon were recruited as subjects in a prospective cohort study. A total of 44 triathletes made up the cramping group and 166 the non-cramping group. A detailed questionnaire, including information on training, personal best performances and a cramping history was completed by both groups of triathletes. Full clinical data was also collected from both groups. This included pre-and post race body weights, and pre- and post-race serum electrolyte concentrations. The main findings of the study were that the two independent risk factors for EAMC in these triathletes were a faster overall race time (and cycling time), and a past history of cramping (in the last 10 races). Results showed that EAMC was correlated with faster overall and cycle section times. The athletes who had experienced cramps in this event not only achieved taster race times but also predicted faster times, despite similarly matched preparation and performance histories as those who did not cramp. A higher intensity of racing would thus be required by these athletes, predisposing them to premature fatigue. The results thus agree with the ""fatigue hypothesis"" as an aetiological mechanism for EAMC. This study also showed no correlation between EAMC and changes in hydration status or changes in serum electrolyte concentration. This study thus adds to the evidence against disturbances in hydration and electrolyte balance as causes for cramping in exercise and further focuses attention on neuromuscular fatigue as a possible primary factor.
  • Thumbnail Image
    Item
    Open Access
    Extracellular matrix gene sequence variant analyses and Achilles tendinopathy
    (2013) Saunders, Colleen Jayne; September, Alison; Schwellnus, Martin; Collins, Malcolm
    The primary aim of this thesis was to identify additional genetic elements predisposing individuals to risk of AT using a candidate gene, case-control genetic association approach, and to propose the biological mechanisms underlying this genetic risk. Candidate genes (COMP, THBS2, COL27A1, TNC, COL3A1, COL5A2 and COL5A3) were selected based on their chromosomal location and/or the biological function of their encoded proteins within the extracellular matrix (ECM) of the tendon.
  • Thumbnail Image
    Item
    Open Access
    Gastrointestinal tract (GIT) symptons in Ironman triathletes : a study relating GIT symptons to changes in splanchnic blood flow
    (2008) Wright, Helen; Schwellnus, Martin; Collins, Malcolm
    Gastrointestinal tract (GIT) symptoms commonly affect endurance athletes such as those competing in the Ironman Triathlon. Although a number of risk factors and the pathophysiological mechanisms for the development of GIT symptoms during exercise have been proposed, scientific evidence in support of these factors and mechanisms is limited. Altered blood flow to the GIT during exercise have been suggested as a possible mechanism for the pathophysiology of GIT symptoms. However, changes in blood flow in the superioir mesentric artery (SMA) and the coeliac artery in athletes presenting with GIT symptoms during exercise have not previously been investigated.
  • Thumbnail Image
    Item
    Open Access
    Genetic risk factors for anterior cruciate ligament ruptures
    (2009) Posthumus, Michael; Collins, Malcolm; Schwellnus, Martin
    The primary aim of this thesis was to identify candidate genes that may be associated with ACL ruptures, and then use a genetic association approach following a case-control study design to identify specific sequence variants (single nucleotide polymorphisms, SNPs) within these candidate genes which may predispose individuals to ACL ruptures. Candidate genes (COL1A1, COL5A1 and COL12A1) were selected based on the biological function of their encoded proteins (type I, type V and type XII collagen respectively) within the basic structural and functional unit of ligaments, namely the collagen microfibril.
  • Thumbnail Image
    Item
    Open Access
    Injury in elite rugby players during the Super 15 Rugby tournament
    (2014) Thomson, Alan; Schwellnus, Martin
    Professional rugby union is a contact sport with a high risk of injury. The Super Rugby competition is a particularly demanding 16-week Southern Hemisphere tournament. In this tournament, 15 teams compete and play international level matches every week, which may be associated with an even higher risk of injuries. The main objectives of this dissertation were 1) to review the epidemiology and risk factors of injuries in professional rugby union, with specific reference to the Super Rugby tournament (Part 1), and 2) to document the incidence and nature of time-loss injuries during the 2012 Super Rugby tournament (Part 2). Part 1: In this component of the dissertation, a comprehensive review of injuries during Super Rugby was undertaken. A search revealed only 3 studies that have been conducted during this competition. Therefore additional data were included from other studies on Rugby Union, where appropriate. Part 2: This component of the dissertation consists of a prospective cohort study that was conducted during the 2012 Super Rugby tournament, in which teams from Australia, New Zealand and South Africa participated. Participants consisted of 152 players from five South African teams. Team physicians collected daily injury data through a secure, webbased electronic platform. Data included the size of the squad, the type of day, main player position, whether it was a training or match injury, hours of play (training and matches), the time of the match injury, the mechanism of the injury, the main anatomical location of the injury, the specific anatomical structure of the injury, the type of injury, and the severity of the injury (days lost).
  • No Thumbnail Available
    Item
    Metadata only
    Intrinsic and extrinsic factors associated with change in range of motion (ROM) after a single stretch session and repeated loading following an endurance run
    (2011) Miller, Caron-Jayne; Collins, Malcolm; Schwellnus, Martin
    Static stretching is commonly performed by athletes and clinicians on the assumption that it increases joint range of motion (ROM). However, observations from our laboratory indicate that there is an apparent inter-individual variance in the change in ROM in response to static stretching. Furthermore, prolonged repetitive loading has also been shown to affect ROM of a joint or series of joints. In particular, runners have a significantly decreased hamstring ROM. The aim of this study was to investigate the factors which are associated with a change in ROM in response to 1) a static stretch session and 2) prolonged repetitive loading. The findings showed that there is a variable response in the change in ROM following both a SSS intervention and in response to participation in a 42.2 or 56 km road race. More specifically, about 10% of the participants had a reduction in ROM after the SSS while the majority of participants had a reduced ROM after completing the marathon or ultra marathon.
  • Thumbnail Image
    Item
    Open Access
    Intrinsic and extrinsic factors associated with range of motion (ROM) with an emphasis on a novel genetic factor
    (2010) Brown, James Craig; Collins, Malcolm; Schwellnus, Martin
    Introduction: Although there are numerous health benefits associated with participating in regular physical activity, there is also an increased risk of sustaining injuries, in particular musculoskeletal soft tissue injuries. Both an increased and decreased joint range of motion (ROM) has been reported as one of the intrinsic risk factors for these injuries. Similarly to injury, the ROM trait has also been associated with various extrinsic and intrinsic factors. Extrinsic factors that are associated with ROM include level and type of sports participation and temperature. Intrinsic factors include age, gender, limb dominance, weight/BMI, height, prior injury, flexibility training, ethnicity and genotype. It has been reported that ROM is a largely (47-70%) heritable trait in both pathological and apparently healthy populations. Mutations within the COL5A1 gene cause classic Ehlers-Danlos Syndrome (EDS) which present with, among other clinical signs, generalised joint hypermobility. Furthermore, a COL5A1 gene sequence variant, the BstUI Restriction Fragment Length Polymorphism (RFLP), has previously been shown to be associated with ROM measurements in a cohort containing individuals with a history of Achilles tendon injuries. Objectives: The aim of this study was, therefore, to investigate the association between the COL5A1 BstUI (C/T) and DpnII (C/T) RFLPs, as well as non-genetic intrinsic and extrinsic factors, and ROM measurements in an apparently healthy and physically active population. 15 Methods: The sit and reach (SR), passive straight leg raise (SLR) and shoulder internal (ShIR) and external rotation (ShER) assessments were performed on 325 (204 males, 121 females) white, apparently healthy and physically active subjects. Subjects were genotyped for the BstUI (SNP rs12722) and DpnII (SNP rs13946) RFLPs within the 3-untranslated region (UTR) of the COL5A1 gene. Level and type of sport participation, age, gender, limb dominance, height, weight, BMI, waist circumference, prior injury and flexibility training were also recorded to investigate possible associations with ROM. Results: There was a significant interaction between age and COL5A1 BstUI genotype with SR ROM. Subjects with a CC genotype were 'protected' against the commonly reported age-related decline in SR ROM. This divergence in response to aging resulted in a significant difference in the mean SR ROM between the BstUI RFLP genotype groups of the 'old' ('¥35 years) (TT=225 ± 96 mm, TC=245 ± 100 mm, CC=321 ± 108 mm, N=96, p=0.017), but not the 'young' (<35 years) (N=197, p=0.626) subjects. While the DpnII RFLP displayed a similar pattern of divergence in SR ROM with aging, this interaction was not significant. Nevertheless, the SR means were significantly different between DpnII genotypes in the 'old' group when the TT and TC genotypes (T allele) were combined and compared against the CC genotype (T allele=244 ± 98 mm, CC genotype=332 ± 15 mm, N=93, p=0.032). Furthermore, flexibility training (stretching) was associated with increased ROM only in the BstUI TT genotype, suggesting a genotype-specific response. Of all the intrinsic and extrinsic factors 16 investigated in this cohort, only gender and genotype (either BstUI or DpnII RFLPs) were shown to contribute to SR ROM variance through multivariate analysis. Some inconsistent associations with intrinsic and extrinsic factors were observed with the SLR and shoulder ROM assessments, although small sample size and poor reliability of these measures made the results difficult to interpret with confidence. Conclusion: The significant interaction of COL5A1 BstUI RFLP genotype with age explains the differences in SR ROM measurements observed in older, but not younger, apparently healthy and physically active individuals. A similar, non-significant pattern in the DpnII RFLP resulted in significantly different SR ROM for the T allele in comparison to the CC genotype. Besides genotype, gender also an contributed significantly to SR ROM variance in the 'old' cohort. Genetic sequence variants, in conjunction with commonly listed non-genetic intrinsic and extrinsic factors, need to be considered in order to understand the observed variance in ROM in apparently healthy and physically active populations. Keywords: COL5A1 genotype, range of motion (ROM), apparently healthy and physically active population, intrinsic and extrinsic factors, age, flexibility training.
  • Thumbnail Image
    Item
    Open Access
    Intrinsic risk factors associated with patellofemoral pain syndrome
    (2003) Prowse, Tracy; Gray, Janine; Schwellnus, Martin
  • Thumbnail Image
    Item
    Open Access
    An investigation of potential kinematic factors associated with patellofemoral pain syndrome during running
    (2013) Allan, Christopher; Burgess, Theresa; Schwellnus, Martin; Karpul, David
    Patellofemoral pain syndrome (PFPS) is a common clinical condition affecting physically active individuals. It is characterised by pain behind or around the patella during loading of the lower limb. It is recognised that there are multiple factors that contribute to PFPS; however these factors are not well understood. There is equivocal evidence for differences in lower limb kinematics in participants with PFPS, particularly during the running gait cycle. The aim of this study was to investigate lower extremity kinematics during running in individuals with a history of PFPS compared to those without symptoms. Specific objectives: (a) To describe lower extremity kinematics during running for individuals with PFPS. (b) To determine whether there are differences in pelvis, hip, knee and ankle kinematics during running in participants with and without PFPS. (c) To determine whether there were any kinematic variables at the pelvis, hip and knee joint during stance phase of running that may be associated with an increased risk of developing PFPS. Methods: This study had a descriptive cross-sectional study design. Thirty one physically active individuals, who participated in at least two hours of physical activity per week for at least three months prior to testing, were recruited for the study. Fifteen participants presented with PFPS, and 16 participants without PFPS formed the control group. Participants were also required to have a Q-angle within the normal range for males (8.2º-14.2º) and females (11.4º-20.3º) respectively. Participants in the PFPS group were required to have a history of unilateral anterior or retro-patellar pain of non-traumatic origin that did not exceed a six-month period prior to testing. The participants’ PFPS also needed to be elicited during one or more symptom provocation tests, namely: resisted terminal knee extension, stair descent, or a unilateral partial squat. The PFPS participants had to be able to run without pain for a minimum period of 10 minutes, which allowed the running test to be completed without reproducing symptoms of PFPS. All participants gave written informed consent before taking part in the study. Participants were familiarised with all testing procedures. Participants completed medical and training questionnaires, and body composition measurements were performed. Sixteen retro-reflective markers were placed on anatomical landmarks of the lower limbs according to the modified Helen Hayes marker set. Participants were then required to perform a running test, which consisted of 10 sets of running at a self-selected speed on a 10 m pathway. Kinematic data of the pelvis, hip, knee and ankle were recorded by an eight-camera motion analysis system during each repetition of the test. The specific data extracted included range of motion at heel strike and toe off, peak range of motion during swing phase and stance phase. In addition, the range of motion travelled during stance and swing phases and the percentage of stance phase a participant took to reach the peak range of motion during stance phase were calculated.
  • Thumbnail Image
    Item
    Open Access
    Jet lag and environmental conditions that may influence exercise performance during the 2010 FIFA World Cup in South Africa
    (2010) Schwellnus, Martin; Derman, Elton
    The 2010 FIFA World Cup will be held in South Africa in June/July 2010. This is the largest international sports event ever to be held in this country. At this time 32 international football teams, with their management and supporters, will travel to South Africa. These players and visitors will be exposed to changes in time zones (those travelling from continents in the East and West) as well as different environmental conditions. In particular, for the players, the achievement of peak sporting performance during this event is most important. It is well established that, in order to achieve peak exercise performance, many variables need to be optimised. These variables include physical and mental training, rest, nutrition, team dynamics and tactics. However, adjustments to differences in time zones as well as environmental factors on and around the playing field can also have a significant impact on exercise performance. In this review, the potential effects of “jet lag”, as well as several important environmental conditions, on exercise performance will be discussed. The climatic, atmospheric and weather conditions that are likely to be prevalent in each of the South African host cities at the time of the 2010 FIFA World Cup will be reviewed. Finally, practical recommendations to deal with the effects of jet lag, as well as guidelines to optimise performance under different environmental conditions that are expected during the 2010 FIFA World Cup, will be provided.
  • Thumbnail Image
    Item
    Open Access
    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.