Browsing by Author "Lambert, Mike"
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- ItemOpen AccessA description of the profiles of U18 rugby players who attended the Craven Week tournament between 2002-2012(2018) Durandt, Justin; Lambert, MikeRugby union has rich tradition in South Africa with the national team having won the Rugby World Cup in 1995 and 2007. The major rugby nations South Africa competes against have clearly defined rugby talent identification (TID) and development (TDE) pathways. These pathways are not as well described in South Africa where the South African Rugby Union (SARU) has adopted a model of identifying talent at an early age through competition. For example, national competitions occur at U13 (Craven Week), U16 (Grant Khomo Week) and U18 (Craven Week and Academy Week) levels. Previous research on talent identification has highlighted the pitfalls of early talent identification. In particular different rates of maturation can influence the manifestation of talent. In a collision sport such as rugby the early maturers have a distinct advantage. An added complexity in the South African context is the need to provide an appropriate development environment within which transformation can take place. At all levels in South African professional rugby, white players dominate team selection. One of the reasons suggested for this dominance is the physical size of white players compared to their black and mixed race (coloured) counterparts. Rugby is a contact sport and physical size is associated with success, so the need to quantify physical difference between racial groups at a junior level over time is important. The first objective of the thesis was to examine the profiles of U18 Craven Week rugby players to gain insight into the development pathway from U13 to U18. A second aim was to understand factors influencing transformation by measuring the physical profiles of the various racial groups over time. The thesis consists of two studies. The specific objective of the first study was quantify how many players in the 2005 U13 Craven Week (n=349) participated in the subsequent U16 Grant Khomo and U18 Craven Week. The study showed that 31.5% of the players who played in the U13 Craven Week, were selected to play at U16 Grant Khomo Week and 24.1% were selected for the U18 Craven Week tournaments. Another interpretation is that 76% of the players selected for the U13 tournament did not play at the U18 Craven Week tournament. The objective of the second study was to determine whether there are differences in body mass, stature and body mass index (BMI) between racial groups in U18 Craven Week players. Another objective was to determine whether these measurements changed between 2002-2012. Self-reported body mass and stature were obtained from U18 players (n=4007) who attended the national tournament during this period. BMI was calculated for each player. The body mass, stature and BMI of these players in South Africa were significantly different between racial groups. For example, white players were 9.8 kg heavier than black players, who were 2.3 kg heavier than coloured players (p<0.0001). The body mass of all groups increased from 2002-2012 (p < 0.0001). White players were 7.0 cm taller than black players, who were 0.5 cm taller than coloured players (p < 0.0001). The stature of players did not change significantly during the study period. The average BMI of white players was 0.9 kg.m⁻² greater than black players who were on average 0.7 kg.m⁻² greater than coloured players (p<0.0001). The BMI of all groups changed similarly over the study period. To conclude, these results question the effectiveness of the u13 tournament in identifying talent and providing an effective development pathway to U18 Craven Week. The SARU also needs to be aware of the ongoing disparities in size between the racial groups playing rugby at an U18 level in South Africa. These size differences may have implications for transforming the game and making it representative of the South African population.
- ItemOpen AccessAccuracy of prediction of edurance running performance : relationship to training history, muscle pain and relative perception of effort(2014) Nunes, Dawn; Burgess, Theresa; Lambert, MikeBackground: Endurance running performance is a complex interaction between training factors, exercise-induced muscle damage, and fatigue. The accuracy of prediction of running performance allows for the consideration of the effects of teleoanticipatory factors such as pacing and prior experience on performance. However, previous studies have not adequately considered the role of predicting performance outcomes before competition, and the potential influence of self-regulated pacing and prior experience on running performance. Aim: The aim of this descriptive analytical correlational study was to determine potential factors associated with the accuracy of prediction of running performance during a marathon race. Specific objectives: (a) To determine whether there were differences in training history, pacing, muscle pain and the relative perception of effort (RPE) in three identified groups that accurately predicted race time, performed faster than the predicted time, or performed slower than the predicted time; and (b) to determine if demographic characteristics, training and competition history, self-identified pacing strategy, muscle pain and the relative perception of effort (RPE) were associated with the accuracy of predicting performance during the marathon. Methods: Sixty-three healthy male and female runners were recruited through a short message service (SMS), word of mouth and at the 2013 Mandela Day marathon registration. Participants were included if they were over the age of 20 years, and were taking part in the marathon race. Participants were required to complete the marathon within the seven-hour cut-off time. Participants who had any lower limb musculoskeletal injury, medical condition or surgical intervention that prevented training for seven consecutive days in the three-month period prior to the race were excluded from the study. Participants who reported any flu-like symptoms during the two weeks preceding the race were also excluded from the study. In addition, participants with any missing race RPE or pain scores were excluded. Participants were allocated to one of three groups depending on their accuracy in predicting their final race time. A margin of two percentage points was considered as a meaningful difference in time. If the participants’ actual race time was accurate within two percentage points of their predicted race time, it was considered accurate, and those participants formed the accurate group (n = 16). Participants on either side of the two percentage points formed the fast (n = 21) and slow (n = 26) groups respectively. All participants completed an informed consent form and a medical and training questionnaire at a familiarisation session before to the race. Participants were also familiarised with the tests and procedures for collecting data during the race. During the marathon, muscle pain and relative perception of effort (RPE) were recorded at 0 km, 10 km, 21.1 km, 30 km, and 42.2 km. A short compliance questionnaire was completed when participants finished the marathon. Official race times were obtained from the Championchip® website. Muscle pain was recorded for seven days after the marathon. Participants were also asked to report when they resumed running training after the race. Results Participants in the slow group were significantly younger (p < 0.05), had faster 10 km PB times (p < 0.01), and trained at a faster pace (p < 0.01) compared to participants in the accurate and fast groups. Participants in the slow group had faster actual (p < 0.05) and predicted (p < 0.01) marathon times (p < 0.01) compared to participants in the accurate and fast groups. There was a significant positive relationship between actual and predicted marathon times (r = 0.71, p < 0.01). There were no significant differences between groups in muscle pain and RPE during the race; however there were significant main effects of time for pain (p < 0.01) and RPE (p < 0.01) during the race. Muscle pain and RPE were significantly increased at 21 km, 30 km, and 42.2 km, compared to pre-race values. There were no significant differences in post-race pain between groups, but there was a significant main effect of time (p < 0.01) as muscle pain was significantly elevated for three days after the race. This study was also unable to identify any significant demographic, training and competition history, or race factors associated with the accuracy of prediction of marathon performance. Conclusion: Linear increases in muscle pain and RPE were observed during the race in all groups. This study was unable to identify specific factors associated with the accuracy of prediction of running performance during a marathon race. However, it is possible that the slow marathon times and the low relative exercise intensity in all groups may have limited the effects of muscle pain and RPE on self-regulated pacing and performance. Future studies should have more stringent inclusion criteria to ensure runners are competing at moderate to high relative exercise intensities. In addition, future studies should carefully consider route profiles to ensure that the race profile does not potentially confound the accuracy of prediction of performance by limiting actual marathon times.
- ItemOpen AccessAccuracy of the prediction of Ironman performance : relationship to training history, muscle pain and relative perception of effort during, and recovery after the race(2010) Spijkerman, Ronel; Lambert, Mike; Burgess, TheresaWith regards to swimming, cycling and running, several studies have investigated the physiological and genetic contribution of performance in athletes, different training programs and athletes' adaptation to these programs. Other studies have investigated levels of pain and relative perception of effort (RPE) and the athlete's ability to recover after endurance races... The aim of this thesis is to review the literture which discusses the background to the questions outlined above (Chapter 2), followed by a study which attempts to answer these questions (Chapter 3). The aim of the study was to establish whether the training methods in preparation for the Ironman were related to subjective pain and perception of effort during the race, and the recovery time after the race. The study was designed to establish whether there were differences in these variables between triathletes who predicted their finishing time accurately compared to those triathletes wo under-or over-predicted their performance.
- ItemOpen AccessAnabolic-androgenic steroids : knowledge, attitudes, ethical dilemmas and review for primary care physicians(2002) Ebrahim, F A; Lambert, Mike; Schwellnus, MartinIncludes bibliographical references.
- ItemOpen AccessBest medical care practices in sport: investigating the barriers to the implementation in the developing countries. Uganda as a case study(2020) Lubega, Samuelsaul; Lambert, MikeThe dissertation consists of four separate studies that have focused on different aspects of the relationship between the management of sports related injuries and utilisation of best practices before sports, during sports and after sports-related injuries. Background: Participation in sports has an associated risk of injury which is defined by the type of sport and level of participation. Any injury affects the athletes‘ health status. To mitigate this risk, international sporting organizations provide guidelines, and mandates the proper evaluation and care for athletes before, during and after training or participation in competition. Despite the availability of guidelines describing best medical care practices for managing athletes, inappropriate management practices are reported globally. The barriers to best medical practice vary. While these barriers have been investigated in a variety of sports in developed countries, similar investigations have not been extensively conducted in developing countries, where the demands are different. Therefore, the overall aim of this thesis was to explore barriers to best medical practices in a variety of sports in Uganda. Methodology: The research was conducted as four studies. The first study used a descriptive case study approach. The data were collected on a sample of injured athletes (n=75) from four sports in Uganda (football/soccer, athletics, basketball and rugby) to describe the medical care practices of the sports resource providers. The current prevention, emergency care, intermediate treatment, rehabilitation services and return-to-sports strategies were all documented in a period of six months. The gaps in best practices were observed, and further investigated in the next three studies. Firstly, a validated questionnaire was used to establish the level of knowledge and practices of various components/themes of athletes‘ well-being and best practices among the stakeholders. Secondly, the current standards of the sports arenas and medical and high-performance facilities were examined using a validated checklist. The last study was a semi-structured interview which assessed the available national health care policies to support sports best practice strategies in Uganda Findings: The overall results of the first study showed there was a significant lack of compliance to best medical care practices in all the phases of athletes‘ health care. The barriers to best practice were confirmed as: (i) the lack of adequate knowledge and awareness on various best practice strategies, (ii) the sports and health facilities were below the required standards and, (iii) there were no national health sports care policies to support and facilitate the implementation of best practices in Uganda. Conclusion: (i) A holistic approach may be required to address the best medical care practice barriers in Uganda to improve on the health and safety of athletes. (ii) The knowledge of stakeholders should be improved and awareness created about best medical practices in sports in Uganda. (iii) There is a critical need to develop a national sports health care policy. (iv) The facilities for sports and health care of athletes urgently need improvement and supported.
- ItemOpen AccessBody composition and physical performance characteristics of elite senior and U19 South African rugby union players(2000) Scales, Nicola; Derman, Wayne; Lambert, MikeBibliography: leaves 126-134.
- ItemOpen AccessBone stress injuries in the lower back of cricket fast bowlers(2003) Millson, Helen; Lambert, Mike
- ItemOpen AccessCardiorespiratory, kinematic, neuromuscular and metabolic characteristics during the recovery period after an ultramarathon race(2009) Burgess, Theresa Lee; Lambert, MikeThe aim of this study was to investigate the effects of exercise-induced muscle damage caused by a 90 km ultramarathon on submaximal oxygen consumption and stride length. The experimental group consisted of 11 male runners (39.7 ± 9.3 years) competing in a 90 km ultramarathon. Ten male runners (41.0 ± 10.8 years) who did not run the 90 km ultramarathon formed the control group. Maximum oxygen consumption and peak treadmill running speed were measured two weeks before the ultramarathon. Daily measurements of muscle pain and plasma creatine kinase (CK) activity were recorded for seven days after the ultramarathon. Muscle pain, plasma CK activity, and blood lactate concentrations were recorded before, and oxygen consumption, respiratory exchange ratio (RER), heart rate, rate of perceived exertion (RPE), and stride length were all measured during a 15-minute submaximal treadmill test seven days before the ultramarathon, and on days 4, 7, 14, 21, and 28 after the ultramarathon. Peak blood lactate concentrations were determined 3 minutes after the completion of each treadmill test. Plasma CK activity and muscle pain remained significantly elevated in the experimental group for two days (p < 0.00002) and four days (p < 0.02) respectively after the ultramarathon. There was a significant increase in the post-submaximal treadmill test blood lactate concentrations, compared to pre-test values for each day (p < 0.00001). Submaximal oxygen consumption was significantly reduced in the experimental group for up to 28 days (p < 0.0004), and stride length was significantly reduced for 14 days (p < 0.05) after the ultramarathon. Furthermore, in the experimental group RER was significantly increased for up to seven days (p < 0.05), and RPE was significantly increased for up to four days (p < 0.04) after the ultramarathon. In conclusion, the decreased submaximal oxygen consumption following the ultramarathon may be interpreted as a positive training adaptation. However, other responses to the ultramarathon were not compatible with improved running performance. Furthermore, symptoms other than pain should be used to define the recovery period after an ultramarathon race.
- ItemOpen AccessA comparison between the effects of hamstring static stretching and active warm-up on range of motion and performance(2006) Beukes, Phillo; Schwellnus, Martin; Lambert, MikeIncludes bibliographical references.
- ItemOpen AccessCritical analysis of techniques for normalising electromyographic data : from laboratory to clinical research(2008) Albertus, Yumna; Lambert, Mike; Derman, Wayne; Tucker, Ross; Noakes, TimMeasurements of muscle activity derived from surface EMG electrodes are variable due to both intrinsic and extrinsic factors. The intrinsic factors are endogenous in nature (features within the body) and include muscle fiber type, muscle fiber diameter and length, the amount of tissue between muscle and electrode, and depth and location of muscle with respect to the placement of electrodes (24). These biological factors vary between subjects and cannot be controlled. The extrinsic factors are experimental variables which are influenced by the researcher and can be controlled to some extent. Examples of extrinsic factors include the location, area, orientation, shape of electrodes and the distance between electrodes (interelectrode distance). In order to measure biological variation in the EMG signal, which is important in studies where surface EMG is used to gain understanding of physiological regulation, it is important to minimise the variation caused by these factors. This is in part achieved through the appropriate method of normalisation. The isometric maximal voluntary contraction (MVC) has been used as a standardmethod of normalisation for both static and dynamic exercises. However, researchers have recently improved the methods of normalisation by developing alternative techniques for the measurement of EMG during dynamic activities. By using the same type of movement for normalisation as during the trial, experimental errors can be reduced. The appropriate method of normalisation is defined as a method that is capable of showing repeatability, reliability (low intra-subject variation) and sensitivity to changes in EMG amplitude that is due to biological change and not the contribution of experimental factors. The aim of this thesis was to critically analyse alternative methods of EMG normalisation during dynamic exercise. The data should provide possible guidelines to researchers who are planning studies involving measurement of EMG activity during cycling, running and in clinical populations. Furthermore, the thesis aimed to illustrate that decisions regarding the most appropriate method of normalisation should be based on the study design, research question (absolute muscle activity or changes in muscle pattern) and the muscles being investigated.
- ItemOpen AccessDifference in the prevalence of lower limb injuries in classical ballet dancers with and without lumbar-pelvic stability(2005) Swart, Michelle; Lambert, MikeThe grace and ease with which a dancer entertains an audience is deceptive with respect to the sweat and tears shed to achieve such elegance of movement. Ballet demands great flexibility and strength. This is showcased as a story told through movement, full of emotion and expressed to music. As a physiotherapist on watches a ballet in absolute awe of the stresses the human body has to endure. What adaptations are necessary within the musculoskeletal system to allow such movement? Do these adaptations lead to injury?
- ItemOpen AccessDifferences in five kilometer time trial performance during the recovery period after an ultramarathon race(2013) Benney, Tamlyn; Burgess, Theresa; Lambert, MikeAthletes require an appropriate balance between training, competition stress and recovery to achieve maximal performance. Previous studies have shown that exercise induced muscle damage has a negative influence on endurance running performance, and that these negative effects may be mediated by an increased perception of effort. There is a lack of evidence regarding the effects of ultramarathon distance races on running performance, and the optimal duration of the recovery period before returning to competitive running. The aim of this study was to determine the changes in running performance during the recovery period after an ultramarathon race. The specific objectives were: (a) to determine differences in running performance between the experimental group (runners participating in the 2011 Comrades Marathon) and a control group (distance runners not taking part in the 2011 Comrades Marathon) during the recovery period after an ultramarathon race; (b) to determine the differences in muscle pain, heart rate and perception of effort during a 5 km time trial between groups and over time before, and during the recovery period after an ultramarathon race; and (c) to determine if there were any relationships between prior experience, training history, and running performance during the recovery period following an ultramarathon race.
- ItemOpen AccessDoes a greater training load increase the risk of injury and illness in ultramarathon runners? A prospective descriptive, longitudinal design(2020) Craddock, Nicole; Burgess, Theresa; Lambert, Mike; Buchholtz, KimBackground: Ultramarathon running has become extremely popular over the years. Despite the numerous health benefits of running, there are also many negative effects of running such as increased risk of musculoskeletal injury and illness. Training loads imposed on an athlete should induce positive physiological adaptations to improve their performance. Monitoring of an athlete's training load has become extremely important in terms of injury prevention. Currently, the relationship between training loads and injury and illness incidence is uncertain. More research is needed in this field to minimise the risk of injury and illness and maximise performance in ultramarathon runners. Aim: To determine if there are any associations between injury and illness incidences and training loads among ultramarathon runners in the 12 week period preceding an ultramarathon event and the four week period after the event. Specific Objectives: - To describe the incidence rate of overall and region-specific running-related injuries in a population of ultramarathon runners in the 16 week period surrounding an ultramarathon event. - To describe the incidence rate of illness and illness-related symptoms in a population of ultramarathon runners in the 16 week period surrounding an ultramarathon event. - To describe the weekly and cumulative training parameters (training volume, training frequency, training intensity, training duration) of the injured and uninjured groups and the ill and healthy groups over the 16 week period. - To describe the weekly and cumulative absolute training load parameters (internal load, external load) of the injured and uninjured groups and the ill and healthy groups over the 16 week period. - To describe the weekly relative training load parameters (ACWR) of the injured and uninjured groups and the ill and healthy groups over the 16 week period. - To determine whether there are any significant differences between the injured and uninjured groups and the ill and healthy groups with regard to: a) mean training parameters; b) mean internal training load; and c) mean external training load, over the 16 week period. - To identify any significant associations between: a) absolute training load (internal training load; external training load) and injury and illness incidence; and b) relative training load and injury and illness incidence over the 16 week period. Methods: A prospective, descriptive, longitudinal study design was conducted in runners who were training for the 2019 Two Oceans Ultramarathon. One hundred and nineteen participants were recruited for this study and tracked over a period of 16 weeks (12 weeks leading up to the Two Oceans Ultramarathon event and for four weeks afterwards). Data was collected once a week via an online logbook. Training parameters measured included weekly average running distance, average duration, average frequency and average session RPE. Injury data included injury counts, the structure injured, the main anatomical location and time-loss from injury. Illness data included illness counts, the main illness-related symptoms and time-loss from illness. Results: The overall injury incidence proportion was 31%. The week after the ultramarathon race had the highest injury proportion of 7%. The overall injury incidence was 5 per 1000 training hours. The average time-loss due to injury was three training sessions missed. The overall illness incidence proportion was 66%. The week after the ultramarathon race also had the highest illness proportion of 22%. The overall illness incidence was 16 per 1000 training days. The average time-loss due to illness was three training sessions. A moderate significant negative association was found between external training load and injury (r=-0.56; p=0.025). No associations were found between internal training load and injury; or between internal and external training load and illness respectively. A significant relationship was found for external training load and injury incidence in weeks 5 to 8 for participants who ran less than 30km per week. A significant relationship was found for external training load and illness incidence in weeks 5 to 8, 9 to 12 and 13 to 16 for participants who ran less than 30km per week. A significant relationship was found between the ACWR of >1.5 and injury incidence in weeks 1 to 4, 5 to 8 and 13 to 16. A significant relationship was found between the ACWR of <0.5 and illness incidence in weeks 13 to 16. Conclusion: In conclusion a lower training load could potentially predispose to running-related injuries or the development of illness. Specifically, a weekly mileage of less than 30km per week may increase the risk of sustaining an injury or illness when training for an Ultramarathon event. An ACWR greater than 1.5 may increase the risk of injury in the subsequent week of training and an ACWR less than 0.5 may increase the risk of illness in the following week. Non-gradual changes to a weekly training load, whether increases or decreases, could increase the risk of incurring a running-related injury or illness. Maintaining an ACWR between 0.5 and 1.5 appears to be optimal in minimising the risk of sustaining a running-related injury or illness. We therefore recommend the use of both absolute and relative workloads in the monitoring of an athlete's training load with the aim of minimising injury and illness risk and maximising performance in ultramarathon runners.
- ItemOpen AccessThe effect of chronic exposure to endurance exercise on the skeletal muscle of distance runners(2007) Rae, Dale Elizabeth; Collins, Malcolm; Lambert, MikeIt is likely that masters runners may experience an intolerance to exercise primarily due to the age-related changes in their bodies, and specifically of those systems and organs most utilised during running. A more disturbing phenomenon, however, is that of younger runners becoming exercise intolerant. One study described exercise intolerance in athletes who were only 40 +/- 10 years old. The muscle of these athletes had greater levels of markers of structural pathology and showed evidence of having undergone more regeneration compared to age- and mileage-matched apparently healthy athletes. The authors attributed their intolerance to exercise to their large volumes of endurance training and racing which compromised their skeletal muscle. Therefore, the objective of this thesis was to examine the effects of chronic exposure to endurance running on the athlete, with particular emphasis on skeletal muscle.
- ItemOpen AccessThe effect of high intensity training on the angle-torque relationship of the quadriceps and hamstring muscles in a group of well-trained cyclists(2008) Rösemann, Christel; Lambert, MikeIncludes abstract. Includes bibliographical references (leaves 69-74).
- ItemOpen AccessThe effect of simultaneous application of contrast temperature therapy and intermittent compression on recovery following exercise induced muscle damage(2011) Holroyd, Wayne; Burgess, Theresa; Lambert, MikeObjective: To determine the effects of the simultaneous application of contrast temperature therapy with intermittent compression as a recovery strategy for the quadriceps muscle following exercise induced muscle damage in moderately active adult males.
- ItemOpen AccessThe effects of endurance training on neuromuscular characteristics in masters runners(2003) Sharwood, Karen Ann; Lambert, MikeBibliography: leaves 243-298.
- ItemOpen AccessEstablishing associations for the evaluation of mobility screen (EMS) in an adult South African population(2018) Brink, Marthinus Lotz; Lambert, Mike; Burgess, TheresaBackground: Muscle, joint and bone injuries affect mobility and stability, which in turn limits physical activity. Screening tests such as the Functional Movement Screen (FMS) are used to assess an individual’s mobility and stability to determine whether any movement dysfunctions exist. Screening tests aim to establish an individual’s injury risk with the goal of guiding an intervention program. The Evaluation of Mobility Screen (EMS) is a screening test that has been developed at the Sports Science Institute of South Africa. The EMS has been adapted from the FMS by exchanging the Rotatory Stability test for the Seated Rotation test. The current use of screening tools is limited because of the lack of normative data sets that represent the diversity of age, gender and physical activity levels in the general population. Most current published data represent athletes or younger populations. By establishing the relationship between screening outcomes and variables such as age, gender and physical activity level, the effectiveness of screening tests may be improved. Aim: To describe associations between EMS scores for males and females across different age groups and levels of physical activity. Objective: To evaluate and compare differences in EMS scores relating to age, gender and physical activity levels. Methods: This was a quantitative study, with a descriptive, correlational design. The sample consisted of 135 males and 127 females between the ages of 18 and 60. The EMS data were collected at the HighPerformance Centre, in the Sports Science Institute of South Africa, Cape Town. Results: There was no difference between the total scores of males and females (median = 17). The two youngest groups (20-30 and 31-40 years) scored the highest (median = 17), while the oldest group (51-60 years) scored the lowest (median = 15). Gender had a significant effect (p < 0.05) on five subtests (Single Leg Hurdle, Shoulder Mobility, Asymmetric Leg Raise, Stability Push Up and Seated Rotation). Age had a significant effect (p < 0.05) on three subtests (Overhead Squat, Single Leg, Hurdle Split Squat). Physical activity level had a significant effect (p < 0.05) with two subtests (Single leg Hurdle and Stability Push Up). Conclusion: Gender, Age and Physical Activity are associated with changes in EMS scores. EMS total scores declined as age increased. While the total scores remain similar between genders, there were clear variations within the different subtests. The oldest participants (51-60 year) scored the lowest throughout all subtests. Males scored higher in the strength components, while females scored higher in the flexibility components. Physical activity levels did not have a clear pattern as expected but still demonstrated association with two subtests. The results add to the sentiment that the focus should move away from the composite scoring system, and towards analyzing individual subtest scores. Future studies should also investigate if subtest scores can be improved by targeted intervention programs.
- ItemOpen AccessAn evaluation of gastrocnemius muscle structure and function in endurance runners and low physical activity individuals(2013) Buchholtz, Kim; Burgess, Theresa; Lambert, Mike; Bosch, AndrewDistance 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.
- ItemOpen AccessFactors assciated with success in South African Rugby Union(2013) Parker, Ziyaad-Ahmad; Lambert, MikeRugby Union is a popular sporting code in South Africa and the national team (Springboks) has won two World Cups (1995 and 2007). As the pool of players to select the Springboks from has diminished in recent times, it is important for the South African Rugby Union (SARU) to identify and develop young, talented individuals to strengthen the pool of available players. Several talent identification and development programmes have been implemented by SARU with limited success and many of them are not offered anymore.