Academic literature on the topic 'Kicking (Football) Physiological aspects'

Perception relates not only to the optical information from the environment but also to the perceiver's performance on a given task. We present evidence that the perceived height and width of an American-football field goal post relates to the perceiver's kicking performance. Participants who made more successful kicks perceived the field goal posts to be farther apart and perceived the crossbar to be closer to the ground compared with participants who made fewer kicks. Interestingly, the current results show perceptual effects related to performance only after kicking the football but not before kicking. We also found that the types of performance errors influenced specific aspects of perception. The more kicks that were missed left or right of the target, the narrower the field goal posts looked. The more kicks that were missed short of the target, the taller the field goal crossbar looked. These results demonstrate that performance is a factor in size perception.

The topic of the research is part of the sphere of interest of the specialists in the field, dealing with one of the most important aspects within the training process of footballers aged 10-12 years. The importance of this study is represented by the use of specially selected software for the purpose of optimizing biomechanics in the game of football. The objectives of the research are aimed at optimizing the biomechanics of kicking the ball at the age of 10-12 years by means of three basic procedures. Within the research were used the method of studying the specialized literature, the method of pedagogical experiment, the method of graphic representation, the statistical method – mathematics. Within the pedagogical experiment method, a series of tests were applied specially designed for the investigation of the components of proprioception, which have a basic role in optimizing the biomechanics of hitting the ball in the game of football. Following the analysis and interpretation of the results, it was found the validity of the research hypothesis through the progress made by the research subjects at the final testing compared to the initial one. The conclusions of the research recommend the validated experimental model within the method of training of children aged 10-12 years for the optimization of the biomechanics of kicking the ball.

This study aimed to analyze the kinematical characteristics values of accurate penalty-kicking for Turkish football players in goalkeeper confrontation. Fifteen male Turkish Regional Amateur League players (Age: 21.08± 1.56 years old) was scanned, by two video cameras synchronous in two-dimensional (2D), placed at optical axes X&Y. the best three tries of penalty kicking performance were analyzed by video analysis Dartfish 9.0 software. Standard statistical methods were used for the calculation of mean±sd, Pearson test for the correlations between all variables. A value of p-value ≤ 0.05 was considered a threshold of statistical significance. The results were shown in the ball contact phase that the distance pivot foot & ball factor has a statistically significant effect in producing accuracy (p-value=.001), and the interaction between two main factors namely the trunk and inclination body angles has a statistically significant effect with a p-value≤.05 in producing accuracy too. In addition, in the followthrough phase, we can see too the statistically significant effect in p-value≤.005 of the trunk angle, and in pvalue≤.05 of the thighs angle in producing accuracy. As a conclusion, it can be conveyed that the distance between the support leg and the ball is very decisive for the kinematic profile formed such as contraction of the abdominal muscles (trunk angle), the amortization process (the pivot leg angle), shot power (angle and length of the shot leg swing trajectory), where these aspects are significantly affected to the shot power, ball velocity and the level of accuracy.

Football is the most important and popular sport in the world, being influenced by several aspects and generating a billion dollar financial income. The constant scientific advancement of the modality allows a rapid evolution of football, being important to constantly review aspects of its dynamics and, consequently, its laws. The aim of this work is to analyze and argue, based on several aspects, e.g., evolution of the modality, physiological aspects, incidence of injuries, relationship with the media and economic aspects, etc., if there is a need to increase substitutions in modern professional football matches. In order to achieve this objective, a wide bibliographic research on the most important aspects of football was used.. As demonstrated throughout the text, according to the constant changes that have occurred in various aspects related to football over the years, there is a need for changes in the regulations to meet the need and provide a greater evolution of the modality. In this way, we believe that the increase in the number of substitutions can be very beneficial for football in general, mainly to make the modality more dynamic and attractive to the spectators.

Context: The nature of Australian rules football (Australian football) predisposes both unique and common injuries compared with those sustained in other football codes. The game involves a combination of tackling, kicking, high-speed running (more than other football codes), and jumping. Two decades of injury surveillance has identified common injuries at the professional level (Australian Football League [AFL]). Objective: To provide an overview of injuries in Australian rules football, including injury rates, patterns, and mechanisms across all levels of play. Study Design: A narrative review of AFL injuries, football injury epidemiology, and biomechanical and physiological attributes of relevant injuries. Results: The overall injury incidence in the 2015 season was 41.7 injuries per club per season, with a prevalence of 156.2 missed games per club per season. Lower limb injuries are most prevalent, with hamstring strains accounting for 19.1 missed games per club per season. Hamstring strains relate to the volume of high-speed running required in addition to at times having to collect the ball while running in a position of hip flexion and knee extension. Anterior cruciate ligament injuries are also prevalent and can result from contact and noncontact incidents. In the upper limb, shoulder sprains and dislocations account for 11.5 missed games per club per season and largely resulted from tackling and contact. Concussion is less common in AFL than other tackling sports but remains an important injury, which has notably become more prevalent in recent years, theorized to be due to a more conservative approach to management. Although there are less injury surveillance data for non-AFL players (women, community-level, children), many of these injuries appear to also be common across all levels of play. Clinical Relevance: An understanding of injury profiles and mechanisms in Australian football is crucial in identifying methods to reduce injury risk and prepare players for the demands of the game.

The goal: comparative analysis of psycho-physiological fitness of football players and differently skilled football referees. Research materials and methods. We studied indicators of psychomotor status, the level of development of speed and volitional qualities, subject-activity and communicative aspects of temperament of 15 football players aged 19-21, with the experience of sport training from 10 to 13 years, and 25 football referees of the first rank aged 25-32, with the experience of refereeing from 5 to 9 years. We compared the outcomes to identify the trend of convergence of the level of studied indicators. Research results and discussion. The study has demonstrated that about 50% of all subjects have a medium-weak type of nervous system, but there are referees with a strong type (16%). We have revealed that football players and referees have no significant difference in the period of implementation of the audio-motor reaction. Visio-motor reaction of football players is 16.44 ± 0.45 msec, which is faster than the reaction of referees by 10.6% (p <0.05). Repeated sprint ability of referees and players was not significantly different, average indicator at 40 m intervals was 5.63 sec. for referees and 5.25 sec. for players. Football referees demonstrate a very high work pace - 10.3 ± 0.32 c.u., life pace, activity, high rhythm of operations. Emotional background of players at work and in social communication was 6.0±0,59 c.u. and of 6.80 c.u. respectively, and it was twice higher than the indicators of referees (p< 0.001). Vitality indicators were the same for both groups. Conclusion. Modern football requires that a referee should obtain a new, higher level of physical and psychological training. Most of the quantitative indicators of the studied parameters of players and referees did not have significant difference, while the moral-volitional and emotional components differed significantly.

It is a very common phenomenon to have ankle injuries during sports. Therefore, the detection of ankle injuries has become a concern theme of scholars. It is of great significance to realize the ankle apparent strain measurement quickly in colleges and universities. In this paper, a data mining algorithm-based approach to measuring the apparent strain of the ankle joint in football sports is proposed. This paper first analyzes and integrates the research results of scholars and then expounds from the two aspects of data mining and ankle apparent strain measurement. The method is introduced in detail, and the principle of apparent strain measurement is explained by the formula. The feasibility and robustness of the research scheme are then demonstrated through specific experimental data. The data showed that there was a difference between the boy group and the girl group in the time of jumping, kicking, and reaching the ground (significant level P = 0.026 ).

Marma is very important topic of Ayurveda, it is also related with trauma and its effect on body. As mentioned in Sushrut Samhita, excruciating pain is produced when there is any injury at the site of Rujakar Marma. In routine any type of pain affects daily activities which is mostly found in sports. Trauma is important aspect of sport medicine as it could hamper whole carrier of sport person. Ayurveda being a complete science of health care can contribute in this field also. Principles, treatment modalities, diet & drugs of Ayurveda can play very useful & im- portant role in this field. In Football game, very rigorous activities are involved which causes direct effect on joints, ligaments, muscles of their extremities. Physical interaction between players can cause contusion, severe pain etc. which affect the player’s game. So, it is necessary to study the Marma sharir through aspects of sports medicine. Also, there is need to protect the Marma sites from trauma to avoid future problems. In present study we are trying to establish relation between science of Marma especially the RujakarMarma & sports medicine. For this we se- lected football game. In this game, chances of injury on Rujakar Marma are more prone. So, the detailed knowledge of Rujakar Marma is useful in prevention of injury in football players. Study shows the commonest site of injury to be ankle joint with inflammation followed by sprain due to kicking. Also, the highly affected marma is Ru- jakar Marma specially Gulpha Marma along with vedana, shopha, stabhdapadata. Keywords: Marma, Rujakar Marma, football, Gulpha Marma, sprain

ABSTRACT All aspects of development are very important in a person's life where the development of cognition, affection and psychomotor is well developed in accordance with its development, these three aspects can be said to be good and successful if the three aspects develop well. Like wise with the psychomotor aspect where between gross motor and fine motor are also balanced. Motoric is the development of coordinated body movement control between nerves, brain, and spinal cord (spinal cord or spinal cord). Child's gross motorization can be optimized by improving his motor movement coordination skills through physical activity in the form of coordination of body movements. Like throwing, catching, kicking, running, melopat, and maintaining balance. The condition of a Down Syndrome child who experiences weakness in the ability to think will affect in all aspects of his life. Down syndrome children have problems in cognitive abilities, effective and self-care abilities. This results in them needing special education. Basically, the educational goals that children with Down Syndrome want to achieve are not different from those of education in general. Because Down Syndrome children themselves are born in the midst of society. Keywords: football sports, gross motoric, down syndrome

Abstract Introduction: Sport for people with disabilities has interested scientists for a long time. However, there is a scarcity of research on the subject of amputee football – football adapted to individuals after amputations. The aim of the study was to describe this sport and to review research carried out in this field so far. When looking for investigations on amputee football, the available computer databases (Academic Search Complete, SPORTdiscus, MEDLINE, Health Source, Master-FILE Premier) were searched comprehensively. The following key words were used to identify proper articles: amputee football, football + amputations, crutch football. Also, the following article inclusion criteria were applied: (A) original scientific paper, (B) available full text of paper, (C) paper published in a peer-reviewed journal, (D) paper published in the English language. Eleven articles that met the criteria were selected for the analysis. Description of amputee football: The description of amputee football included the history of the sport in the world and in Poland, rules of the game and players’ classification. Amputee football in research: The articles selected for the review were divided into three categories: 1) psychological and social aspects, 2) anthropomotorics and nutrition, 3) endurance, physical capacity and speed abilities. . Summary: The majority of studies carried out so far have focused on general characteristics of amputee football players and the effects of this sport on the functioning of individuals after amputations. Future studies ought to involve injury-related aspects as well as training effectiveness on the basis of physiological parameters.

Playing professional football is a high risk occupation. Injury rates among professional footballers are higher than those commonly found in other industries. Several Scandinavian studies have begun to document the long-term physical health problems, such as osteoarthritis (OA), that can beset ex-professional footballers. However, the experiences of ex-professional footballers playing and living in the United Kingdom (UK) have not received similar academic attention. Furthermore, no studies have investigated the impact that OA has on the quality of life of former players anywhere in the world. This thesis aimed to rectify a widespread and serious health problem among a cohort that has largely been neglected to date. In Phase I, 284 ex-professional footballers responded to a postal survey which aimed to establish the prevalence of injury and OA. In Phase II, 12 semi-structured interviews were conducted with ex-professional footballers from Phase I who had developed OA. The aim was to gain an in-depth understanding of how the condition impacted on their lives and how they coped. In Phase II, 101 ex-professional footballers, who were not involved in Phases I and II, responded to a cross-sectional postal survey, which investigated the relationships between pain, pain coping and psychological distress within the context of a stress and coping model. Career injury and surgery were common among respondents in Phase I and nearly half (49%) had subsequently developed OA in at least one joint. Pain was the most common problem for all respondents irrespective of OA diagnosis. Lack of mobility and work disability were other problems reported by respondents. Interviewees in Phase II described how they were encouraged to 'play hurt' during their career and to accept, minimise or ignore the threat of pain, injury and OA. It was some of these attributes which enabled respondents to 'live hurt' in the presence of chronic pain and disability in later life. In Phase II it was shown that psychological distress was not a serious problem for many respondents. However, several coping strategies (denial, emotional venting and upward comparison) were positively associated with pain and psychological distress, particularly for those participants in greater pain. Although OA and chronic pain are prevalent among ex-professional footballers in the UK, its impact upon psychological distress was not as great as reported in some other studies of persons which chronic disease and pain. Increased psychological distress was linked to greater pain and the use of several coping strategies (e.g. denial, emotional venting and upward comparison). However, given the cross-sectional design, it remains to be clarified whether coping predicts psychological distress or whether an increase in psychological distress precipitates more coping. Suggestions are proposed for a psychosocial intervention which would have an impact on pain coping and psychological distress among ex-professional footballers.

Previous research investigating the effects of resistance training (RT) on fatigue has used protocols unrelated to the practices of team sport athletes. The purpose of this investigation was to examine the response pattern of specific performance and physiological measures following an acute bout of high-intensity lower body RT in Australian Rules Football (ARF) players over a five day recovery pcriod. Thirty-live resistance trained ARF players were divided into intervention (n = 18) and control groups (n = 17) with groups being matched for age (mean ± standard deviation. intervention = 17.7 ± 0.7: control = 17.7 ± 0.6 .y ears). Weight (intervention == 76.6 ± 8.2: control = 77 .7 ± 7.6 kg). heiight (intervention == 180.7 ± 7.1: control = 181.2 1: 5.7 cm), I RM back squat (intervention = 120.7 ± I 1.3: control = 114.2 ±: 13.3 kg), and IRM power clean (intervention == 67.8 ± 6.7: control == 64.9 ± 9.2 kg) measures. Intervention subjects performed a high intensity lower body RT session following determination of baseline (pre-test) performance and physiological variables. Performance test variables consisted of strength (peak force during an isometric mid thigh pull [IMPT]) power (peak power and vertical jump height of counter movement jump [CMJ ] and squat jump [SJ]), speed (10 metre sprint time), agility (Australian Football League [AFL], specific agility test time), and subjective levels ofrecovery as determined from the total quality recovery (TQR) perceived scale.

To enhance understanding of recovery and preparation in rugby union, the aim of this thesis was to examine the impact of competition on key parameters and investigate factors which may influence the recovery process from competition and training. The findings of study one demonstrate that movement patterns and thus the physiological demands of match-play vary considerably between different positional groups. Additionally, study two demonstrates that the movement characteristics which determine the extent of muscle damage post-match are position specific, and that movement characteristics may be used to prospectively tailor individual recovery and manage subsequent training. Recovery patterns may also be influenced by factors not associated with match-play such as sleep, which has important physiological and psychological restorative effects. The findings of study three suggest that sleep patterns may vary considerably within a squad with many players presenting evidence of sleep disruption, particularly post-match which may be detrimental to recovery. Recovery following exercise may also be modulated by the application of post-exercise recovery strategies such as cold water immersion. However, study four demonstrates that cold water immersion may impede adaptation to strength training in rugby union players. When no recovery intervention was administered during a five week pre-season period, isometric mid-thigh pull peak force and relative peak force significantly increased by 5.4 +/- 4.7 and 5.8 +/- 5.4% respectively. However when individuals were immersed in cold water post-training there were no significant changes in strength during the training period. These findings may have great implications for strength training, particularly during periods of physical development. The findings of the thesis have furthered understanding of the characteristics of performance and identified several factors which influence recovery from training and competition. This in turn may be used to inform best practice procedures in attempt to 'optimise' preparation and recovery in rugby union.

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

Prolonged and intense exercise is known to modulate and suppress certain aspects of the immunoendocrine system. Such effects are thought to be largely mediated by the release of stress hormones and regulatory cytokines which originate from a variety of stress related paradigms in sport. These include acute physical exertion, chronic and repetitive exercise as well as other psychological and psychosocial aspects of training and competing in an elite environment. It may be of particular interest to study the effects of regular competition and training on immunoendocrine markers in rugby union players. At the professional level, rugby is an intense and physically demanding game where a significant amount of tissue trauma occurs as a result of the many game collisions. The aims of the studies outlined in this thesis were to determine the effects of acute, repeated and chronic exercise exposure on immunoendocrine markers and illness incidence in professional rugby union. Additional case studies were also undertaken to supplement main study findings. The first part of the thesis documented the effects of acute and repeated exercise on immunoendocrine markers in a cohort of international rugby union players. Data in study 1 showed that large disturbances in immunoendocine and hormone levels occur in players (n = 10) following game play. The magnitude of this response appeared dependent on game physicality (number of rucks/mauls, tackles) and the number of collisions players received during match play. Findings also showed suppression in host immunity, and in particular, innate immune function (neutrophil degranulation) which was not resolved 38 h (-29%) into the recovery period. In study 2, bloods were taken from players (n = 8) across a 21-day international rugby series. Data revealed that players entered the international camp with residual muscle damage (creatine kinase; CK) and inflammation (hs-CRP) following previous club involvement in European cup rugby. Further increases in stress related markers (cortisol, IL-6, CK, CRP) were not evident throughout the players time at the international training base. Conversely, a progressive increase in anabolic-catabolic balance (T/C ratio) was observed across time. In comparison to values on camp-entry (day 1), increases in T/C ratio were evident on day-5 (9.8%), day-7 (13%), day-19 (35%) and day-21 (45%) (P < 0.05). This data is suggestive of improved physiological recovery and was commensurate with team fitness goals (reduced volume + maintenance of training intensity) for that time. Findings suggest that monitoring of player club activities and training load preceding international duty is pertinent if they are required to represent their country inside 7 days. The second part of the thesis evaluated the stress induced effects of chronic rugby exposure in professional club players. Questionnaire data analysed from study 3 showed that players (n = 65) perceived current season length as being ‘too long’ (55%), ‘poorly structured’ (56%) and that game demands are increasing with time (52%). Furthermore, the majority of players (80%) felt that time ‘away’ from rugby was not sufficiently long enough and were in favour of a mid-season break (2 wks in duration). Investigation into the effects of chronic exercise on illness incidence, immunological and psychological state was carried out in a squad of club players (n = 30) over a competitive season (n = 48 wks) in studies 4-6. Findings revealed that specific periods in a rugby season resulted in disturbances to hormonal and immune status. These periods occurred following breaks in club game fixtures [November international and Six-nations period: February/early March], times of increased training intensity and increased ratio of conditioning/rugby activity. Peaks in number of upper respiratory illnesses (URIs) and disturbances in psychometric variables also occurred during these time periods. In 23% of all URIs, players reported that the presence of the illness either reduced activity (14.4%) or felt the need to go to bed (8.6%). Positional differences in variables were also observed. A higher incidence of URIs (3.4 vs 4.3) and lower concentrations of resting immune markers [salivary lysozyme: s-Lys (-31%); immunoglobulin A: s-IgA (-27%)] was observed in ‘backs’ (vs forwards) over the season. Higher mid-season cortisol levels was also observed in backs (P < 0.05) while conversely, greater concentrations of plasma CK and CRP were found in forwards throughout the season. These findings indicate positional specific differences in response to exercise load and point to the role of group specific recovery at certain times during the season. Data from study 6 showed that the number of training related complaints decreased across the season, findings which closely resembled corresponding decreases in plasma CRP values. This data is suggestive of a ‘repeated-bout’ effect or ‘contact adaptation’ in rugby union. Finally, comparison of methods used in the recording of illness data revealed that players were more honest when disclosing the existence of banal infections to a web-based training diary and under-reported infections to medical staff.

Sprinting speed is a highly valued physical ability in rugby. There is little research examining sprinting biomechanics in rugby players and it is unclear the extent that sprinting speed and sprint momentum can even be improved in highly trained rugby players and how different speed and strength training methods might help improve it. This thesis consists of 6 studies that examine the sprinting biomechanics of elite rugby players, how strength and power training might improve sprinting speed and the potential for elite rugby players to make further improvement in their sprinting speed and sprint momentum. Key biomechanical factors were that as a player transitions from a standing start to maximal velocity; they do so without an appreciable change in stride rate but with a substantial increase in stride length. Stride rate remains the same because ground contact time and flight time are inversely proportional with each other as they accelerate from a standing start to maximal velocity. Faster players were found to have lower ground contact times and longer stride lengths for both acceleration and maximal velocity. Sprinting with a rugby ball in one hand did not seem to negatively affect international players in either acceleration phases or maximal velocity phases. Mass was found to have a negative relationship with acceleration and maximal sprinting velocity. Sprint momentum, on the other hand, was found to have a strong positive relationship with body mass. Body mass and height were found to be higher in successful teams at the 2007 and 2011 Rugby World Cups when compared with less successful teams. Senior international players were found to have much greater sprint momentum and body mass, but not sprinting speed, when compared to junior players. Collectively, all of these results point out that sprint momentum is a highly important physical quality. Sprinting speed is an important outcome of training programs but improving sprint momentum by increasing body mass is probably more important. The senior and junior athletes that were tracked for two years were able to effectively improve their sprinting speed and sprint momentum over a two year period which suggests that these are trainable qualities. Strength and power were found to be important discriminators between fast and slow players. Faster players showed greater results in power clean, front squat, broad jump and triple broad jump. The relationships between these exercises and acceleration were similar for both the slow and fast groups but these exercises had much stronger correlations with maximal sprinting velocity in the slow group then with the fast group. The differences in these relationships seemed to be explained by ground contact time. The group of highly trained players that were tracked over a one year period did not show positive improvement in sprinting speed from increasing the different strength qualities. An 8 day hypergravity condition for international players was ineffective in producing profound changes in sprinting speed. These results suggest that sprinting speed is a trainable quality but there is a limited capacity for strength training to improve it once these qualities have been reasonably well developed in an elite population.

Thesis (M Sport Sc)--Stellenbosch University, 2011.
ENGLISH ABSTRACT: This study investigated the optimal training load required for peak-power production in two types of exercises, namely an Olympic-type and a ballistic exercise. The hang clean and the squat jump were selected to represent these two types of exercise. It was ascertained whether a change in strength levels and training status will have an effect on the optimal loads for peak-power production of rugby players. In addition, the influence that different playing positions have on power production was also investigated. Fifty-nine under-21 male rugby players (Mean Age 19.3yrs; SD ± 0.7yr) from two rugby academies, performed a maximal-strength test in the hang clean and squat, followed by a power test in the hang clean and squat jump with loads ranging from 30 to 90% of maximal strength (1RM). Testing was conducted in the pre-season phase and repeated during the inseason phase. Peak power for the hang clean was achieved at 90% 1RM in the pre-season and at 80% 1RM during the in-season. Peak power for the squat jump was achieved at 90% 1RM in the pre-season. However, this location of the optimal loading was not significantly higher than that of the other loadings (60, 70 and 80% 1RM). During the in-season, peak power for the squat jump was reached at 90% 1RM. Here again, the optimal-loading location was not significantly higher than that of the other loadings (50, 60, 70 and 80% 1RM). It was concluded that the optimal load for power production is 90% 1RM for the hang clean and 60-90% for the squat jump. It was found that an improvement in strength levels of the subjects affected both peak-power production and the optimal load in both exercises. During the in-season peak power in the hang clean was reached at 80% 1RM, and at 50% 1RM for the squat jump. There were no significant differences in the performances of subjects from different playing positions (forwards versus backline players). In the hang clean, peak-power production seems to be reliant on increased strength and results in peak-power output at high loads. The squat jump, on the other hand, is more reliant on velocity due to its ballistic nature and is possibly better suited to developing power at lighter loadings. Because it produces peak power at a lower percentage load than the hang clean, the squat jump could be more effective in power development for players who are inexperienced in power training. Long-term exercise periodisation in power training can therefore be employed progressively from simpler exercises (e.g., squat jump) using only the legs, to more complex exercises (e.g., Olympic-lifting) that involve the whole body. This study confirmed that the specific requirements of different sport codes should be considered meticulously before selecting and prescribing exercises and loads for power-training programmes.
AFRIKAANSE OPSOMMING: Die hooffokus van hierdie studie was op die optimale oefenlading wat vereis word vir die produsering van piek-profkrag tydens die uitvoering van twee tipes oefening, naamlik ’n Olimpiese- en ’n ballistiese oefening. Die hang clean en die squat jump is geselekteer om bogenoemde twee tipes oefening te verteenwoordig. Daar is bepaal of ’n verbetering van die krag-vlakke en oefenstatus van rugbyspelers ’n invloed het op die optimale ladings vir piek-plofkrag ontwikkeling. Verder is die moontlike rol van verskillende speelposisies ondersoek. Nege-en-vyftig onder-21 mans-rugbyspelers (M-ouderdom 19.3jr; SD ± 0.7jr) vanuit twee rugbyakademies het ’n maksimale-krag toets in die hang clean en squat uitgevoer. Dit is opgevolg deur ’n plofkrag-toets in die hang clean en squat jump met ladings wat gewissel het van tussen 30 en 90% van maksimale werkverrigting (1RM). Toetsing het plaasgevind in die voor-seisoen fase en is herhaal tydens die daaropvolgende speelseisoen. Piek-plofkrag vir die hang clean is bereik tydens ’n oefenlading van 90% 1RM in die voor-seisoen en by 80% 1RM later in die speelseisoen. Piek-plofkrag vir die squat jump is behaal by 90% 1RM in die voor-seisoen fase. Hierdie optimale lading-lokasie was egter nie beduidend hoër as by die ander ladings van 60, 70 en 80% 1RM nie. Tydens die speelseisoen is piek-plofkrag bereik in die squat jump by 90% 1RM. Die optimale lading-lokasie was weereens nie beduidend hoër as by die ander ladings van 50, 60, 70 en 80% 1RM nie. Daar is tot die gevolgtrekking gekom dat die optimale oefenlading vir die ontwikkeling van piek-plofkrag vir die hang clean 90% 1RM is, en 60% vir die squat jump. Daar is ook gevind dat ’n verbetering in kragvlakke van die toetslinge, beide piek-plofkrag-produksie en die optimale oefenbelading in albei oefeninge beïnvloed. Tydens die speelseisoen is piek-plofkrag behaal in die hang clean by 80% 1RM, en by 50% 1RM in die squat jump. Geen beduidende verskille in werkverrigting is gevind tussen toetslinge uit verskillende speelposisies (voorspelers versus agterlyn-spelers) nie. Dit blyk dat in die hang clean, die produksie van plofkrag beïnvloed word deur ’n verbetering in krag en dat dit tot hoër optimale ladings vir piek-plofkrag produksie lei. Die squat jump, in teenstelling, is meer afhanklik van snelheid en is moontlik beter geskik vir die produsering van plofkrag teen ligter oefenladings. Omdat die squat jump piek-plofkrag genereer teen laer ladings as die hang clean, kan dit meer effektief wees vir spelers met gebrekkige ervaring in krag-oefening. Lang-termyn oefen-periodisering in plofkrag-oefening kan gevolglik progressief aangewend word vanaf eenvoudiger oefeninge (bv. squat jump), waar slegs die bene gebruik word, tot meer komplekse oefeninge (bv. Olimpiese-gewigoptel) waar die hele liggaam betrek word. Hierdie studie bevestig dat die spesifieke vereistes van verskillende sportkodes deeglik oorweeg moet word alvorens oefeninge en ladings geselekteer en voorgeskryf word vir plofkrag-programme.

Thesis (MSc)--University of Stellenbosch, 2007.
ENGLISH ABSTRACT: The human body has developed an integrated antioxidant defence system to protect against free radical damage. Acute exercise may result in the increased generation of free radicals, including reactive oxygen species, and this may overwhelm antioxidant defence systems resulting in oxidative stress. However, it has been shown that individuals who undergo regular exercise training may have improved antioxidant capacity when compared to sedentary controls. Results from research regarding the association between antioxidant capacity and exercise training are however not conclusive and further investigation is required. Therefore, the aim of this study was to investigate the association between the total plasma antioxidant status and selected plasma indicators of antioxidant status and the MnSOD Ala-9Val (-28C®T) polymorphism in trained male athletes (rugby players) and sedentary male students while controlling for dietary intake of the major antioxidants using a validated dietary assessment method. In order to address the potential confounding effect of dietary antioxidant intake on antioxidant status in the main study, a FFQ that measures vitamin C, vitamin E, carotenoid and flavonoid intake was developed. The reproducibility was assessed by the repeat administration of the FFQ (n = 38), while the va lidity was assessed using a 28-day closeended dietary record and repeated plasma vitamin C values (n = 18). Several statistical tests were conducted to compare the values obtained from the FFQ with values obtained from the various reference methods. While results from Bland-Altman plots suggested that the reproducibility and validity of FFQ was not completely satisfactory, similar mean values, moderate to strong correlation coefficients, and a high percentage of individuals classified correctly according to quartiles of intake indicated satisfactory reproducibility and validity of the FFQ in assessing antioxidant intake. Furthermore, moderate to strong validity coefficients obtained from the method of triads also indicated satisfactory validity for the FFQ. The main study involved a cross-sectional study that compared plasma vitamin C and carotenoid levels as well as total plasma antioxidant status in trained rugby players (n = 76) and sedentary male subjects (n = 39) with different MnSOD genotypes, while controlling for dietary antioxidant intake. Rugby players had significantly higher plasma vitamin C and carotenoid levels compared to sedentary students, which indicated more satisfactory plasma antioxidant status. This was also reflected in the tendency for total plasma antioxidant status (ORAC assay) to be higher in rugby players than sedentary students. MnSOD genotype did not influence plasma vitamin C and carotenoid levels or plasma total antioxidant status, with or without control for dietary antioxidant intake. Dietary vitamin C, vitamin E, carotenoid an flavonoid intake (from foods + supplements) was similar for rugby players and sedentary students and was adequate for both groups. Thus the association between antioxidant status and MnSOD genotype in rugby players and sedentary students seemed not to be influenced by dietary antioxidant intake. In conclusion therefore, rugby players undergoing regular exercise training had a more satisfactory antioxidant status compared to sedentary students. Based on this conclusion, the widespread use of antioxidant supplements by athletes is questioned.
AFRIKAANSE OPSOMMING: Die menslike liggaam beskik oor ‘n geintegreerde antioksidantmeganisme om dit teen vryradikaalskade te beskerm. Akute oefening kan bydra tot ‘n verhoogde produksie van vry radikale, insluitend reaktiewe suurstofspesies, wat kan veroorsaak dat die antioksidantbeskermingsmeganisme oorlaai word, wat dan kan aanleiding gee tot die ontstaan van oksidatiewe stress. Dit is aangetoon dat persone wat gereeld oefening doen verbeterde antioksidantkapasiteit toon in vergelyking met persone wat geen oefening doen nie. Die resultate van navorsingstudies wat die verband tussen antioksidantkapasiteit en oefening ondersoek is egter teenstrydig en verdere navorsing op hierdie gebied is essensieël om uitsluitsel te kry oor kontensieuse vraagstukke. Die doel van hierdie studie was dus om ondersoek in te stel na die verband tussen plasma antioksidant status, die MnSOD Ala-9Val (-28C T) polimorfisme en geselekteerde plasma antioksidantmerkers in geoefende manlike atlete (rugby spelers) en ‘n onaktiewe manlike kontrolegroep terwyl gekontroleer word vir die dieetinname van die vernaamste antioksidante. Om vir die potensiële invloed van dieetantioksidantinname op die antioksidantstatus van proefpersone in die hoofstudie te kontroleer, is ‘n voedsel frekwensievraelys wat vitamien C-, vitamien E-, karotenoïed- en flavinoïedinname meet, ontwikkel. Die herhaalbaarheid (betroubaarheid) van die vraelys is getoets deur herhaalde voltooiing daarvan deur ‘n toetsgroep (n=38), terwyl die geldighied getoets is deur gebruik te maak van ‘n 28-dag geslote dieetrekord en herhaalde plasma vitamien C bepalings as verwysingswaardes (n=18). Verskeie statistiese toetse is uitgevoer om die frekwensievraelys waardes met die verskillende verwysingswaardes te vergelyk. Alhoewel die Bland -Altman grafieke nie dui op bevredigende herhaalbaarheid en geldigheid van die voedselfrekwensie vraelys nie, dui gelyke gemiddelde waardes, matig tot sterk en betekenisvolle korrelasiekoeffisiënte en ‘n hoë persentasie individue korrek geklassifiseer volgens kwartiele van inname, wel op bevredigende herhaalbaarheid en geldigheid. Matige tot sterk geldigheidskoeffisiënte is ook verkry met die toepassing van “The method of Triads”, wat verdere steun bied vir bevredigende geldigheid. In die hoofstudie is plasma vitamien C, karotenoïedvlakke en totale plasma antioksidantstatus in manlike rugby spelers (n=76) vergelyk met dié van onaktiewe manlike kontroles (n=39). Vergelykings tussen MnSOD genotipes binne die aktiwiteitsgroepe is ook getref. Al genoemde analises is gekontroleer vir dieet antioksidantinname. Resultate dui daarop dat die plasma vitamien C en karotenoïedvlakke van rugby spelers betekenisvol hoër was as dié van die kontrolegroep, wat dui op ‘n meer bevredigende antioksidantstatus. Hierdie resultaat is ook weerspieël in die feit dat totale plasma antioksidantstatus (ORAC) in die rugby spelers oog geneig was om hoër te wees as dié van die kontrole groep. Dit het ook geblyk dat MnSOD genotipe nie ‘n effek gehad het op plasma vitamien C-, karotenoïed- of totale antioksidantstatus nie, met of sonder kontrole vir dieet antioksidantinname. Die dieet vitamien C-, vitamien E-, karotenoïed- en flavinoïedinname (vanaf voedsel en supplemente) was dieselfde vir rugby spelers en kontrole en was toereikend vir beide groepe. Dit blyk dus dat dat die verband tussen antioksidantstatus en MnSOD genotipe in die twee groepe nie beinvloed is deur antioksidantinname nie. Ten slotte kan die gevolgtrekking gemaak word dat manlike rugby spelers ‘n meer bevredigende antioksidant status het as onaktiwe manlike kontroles. Op grond van hierdie gevolgtrekking word die algemene gebruik van antioksidant supplemente deur atlete bevraagteken.

Thesis (MScPhysio)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: Introduction: Groin injuries are among the top six injuries in contact sports and may lead to career ending chronic pain. Research on the role of knee kinematics in developing chronic groin pain in sport is scarce. Objective: The purpose of this study was to determine if there are differences in knee kinematics during a single-leg drop-landing in sports participants with chronic groin pain compared to asymptomatic controls. Methodology: A descriptive study was conducted. Twenty active sports’ participants were recruited from soccer and rugby clubs situated around the Cape Peninsula area, Western Cape, South Africa. The three-dimensional (3D) knee kinematics of ten cases with chronic groin pain and ten asymptomatic controls was analysed. Knee kinematics was analysed in the FNB-3D Vicon Laboratory at Stellenbosch University, using an eight camera Vicon system. A positive adductor squeeze test was used as a diagnostic test to include cases with chronic groin pain. Each participant performed six single-leg drop landings. The main outcome measure was 3D knee kinematics at initial foot contact and at the lowest vertical position of the drop landing. The following sub-groups were analysed: seven unilateral groin pain cases compared to their seven matched controls; three bilateral groin pain cases where their most painful leg and least painful leg were compared to their matched controls, respectively. Descriptive statistical techniques were used for all outcome measures; means and standard deviations (SD) were calculated, followed by a Student’s t-test to determine significant differences between the cases and controls. For all outcomes with p-values equal to or below 0.05, the effect size was calculated using the Cohen’s D. Results: The findings of this study indicated a significant difference (p=0.0001) between cases with unilateral groin pain having less knee internal rotation compared to the controls at the lowest vertical position of the drop landing in the transverse plane. Significantly less internal rotation (p<0.0001), was also noted in the cases with bilateral groin pain (in the most painful leg and the less painful leg), although this was noted at foot contact. Cases with bilateral groin pain also had significantly (p<0.001) more knee varus (adduction) during the landing phase. Conclusion: Differences in knee kinematics between sports participants with chronic groin pain and asymptomatic controls were found. These findings imply that the knee joint should be included during assessment and rehabilitation of individuals suffering with chronic groin pain. Due to the cross-sectional study design of the current study, it cannot be stated for certain whether the knee kinematics noted in the groin pain group are causative or as a result of groin pain. Future prospective studies are thus recommended; these studies should focus on the effect of contralateral knee kinematics on the hip adductors and may include exploration of the muscular components during a single-leg drop landing.
AFRIKAANSE OPSOMMING: Inleiding: Lies beserings is een van die top ses beserings in kontak sport en kan lei tot chroniese lies pyn en selfs die be-eindigging van ‘n sportloopbaan. Navorsing oor die rol van knie kinematika in die ontwikkeling van chroniese liesbeserings in sport is skaars. Doelwit: Die doel van hierdie studie was om te bepaal of daar verskille in die knie kinematika is tydens 'n enkel been val landing in sport deelnemers met chroniese lies pyn in vergelyking met gesonde kontroles. Metode: 'n Beskrywende studie was uitgevoer. Twintig aktiewe sport deelnemers is gewerf van rugby en sokker sportklubs geleë rondom die Kaapse Skiereiland, Wes-Kaap, Suid-Afrika. Die 3D knie kinematika van tien gevalle met chroniese lies pyn en tien asimptomatiese bypassende kontroles is ontleed. Knie kinematika was ontleed in die FNB-3D Vicon Laboratorium by die Universiteit van Stellenbosch, met behulp van 'n agt-kamera Vicon stelsel. 'n Positiewe Adduktor druk toets was gebruik as 'n diagnostiese toets om gevalle met chroniese lies pyn in te sluit. Om die knie kinematika te analiseer, het elke deelnemer ses enkel been val landings uitgevoer . Die belangrikste uitkomsmeting was 3D knie kinematika by die aanvanklike voet kontak en by die laagste vertikale posisie van die enkel-been val landing. Die volgende sub-groepe was ontleed: sewe unilaterale lies pyn gevalle in vergelyking met hul sewe bypassende kontroles; drie bilaterale lies pyn gevalle waar hul mees pynlike been, sowel as minder pynlike been onderskeidelik vergelyk was met hul bypassende kontroles. Beskrywende statistiese tegnieke was gebruik vir alle uitkoms maatreëls; gemiddeldes en standaardafwykings (SA) was bereken, gevolg deur 'n Studente’s t-toets om beduidende verskille tussen die gevalle en kontroles te bepaal. Vir al die uitkomste met p-waardes gelyk of onder 0.05, is die effekgrootte bereken deur die Cohen’s D. Resultate: Die bevindings van hierdie studie dui op 'n beduidende verskil (p=0,0001) tussen gevalle met unilaterale lies pyn met minder interne knie rotasie in vergelyking met die kontroles by die laagste vertikale posisie van die val landing in die dwars vlak. Aansienlik minder interne rotasie (p<0,0001), is ook opgemerk in gevalle met bilaterale lies pyn (in die mees pynlike been en die minder pynlik been), alhoewel tydens voet kontak. Gevalle met bilaterale lies pyn het ook betekenisvol (p <0.001) meer knie varus (adduksie) tydens die landingsfase gehad. Gevolgtrekking: Verskille bestaan in die knie kinematika tussen sport deelnemers met chroniese liesbesering pyn en gesonde kontroles. Hierdie bevindinge impliseer dat die knie behoort ingesluit te word tydens die assessering en rehabilitasie van individue met chroniese lies pyn. As gevolg van die deursnee-studie ontwerp van hierdie studie, kan dit nie bevestig word of die knie kinematika die oorsaak van die chroniese pyn is nie. Toekomstige voornemende studies word dus aanbeveel, hierdie studies moet fokus op die effek van die kinematika van die kontralaterale knie op die heup adduktore en kan moontlik die ondersoek van die spier kinetika tydens hierdie aktiwiteit insluit.