Browsing by Author "Schwellnus, Martin P"

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    The effect of upper respiratory tract illness on exercise performance
    (1999) Viljoen, Deon Andre; Schwellnus, Martin P; Coetzee, M
    Two studies were undertaken to investigate the relationship between upper respiratory tract infection (URTI) and exercise performance. The first study documented the incidence of URTI in an athletic population and the second study determined the effect of URTI on exercise performance during the recovery period. Endurance runners (n=29) were used for these studies and the athletes were monitored for 45 months. During this time the subjects ran an average of 40 kilometers/week. In the first study, 22 reports of symptoms (n=22) of URTI occurred during the 45-month period. Of these, 10 subjects (n=10) were ill for less than 3 days. All 10 subjects reported their symptoms directly following an endurance event. The other 12 subjects (n=12) were ill for 5 days and longer and fulfilled the inclusion criteria for illness due to infection. The incidence of symptoms of URTI/1000 hours of training for the group of 29 runners was 1,26. The incidence of symptoms for the 10 athletes not fulfilling the inclusion criteria for illness was 0.58 and the incidence for the 12 athletes fulfilling the inclusion criteria was 0.69. The odds ratio for the athletes (n=22) for developing symptoms of URTI during a year is 1.03 compared to the odds ratio of 2.5 for the general population during the similar period. These results seem to indicate that 45% of athletes (n=10) who reported URTI symptoms directly following strenuous exercise do not have clinical infection. Furthermore, the study indicates that regular, moderate, endurance exercise may afford protection against URTI, when compared to the general population. In the second study, 5 athletes (n=5) of the original 12 subjects with URTI complied with all the test protocols. On recruitment, baseline tests were done for muscle strength, muscle endurance, aerobic endurance and maximal effort to exhaustion. Following the development of the URTI, the above parameters were tested over six days on days 0, 2, 4 and 6. After regaining their pre-illness fitness levels over a three-month period, the subjects were detrained for comparative periods and the above tests repeated on similar days for comparative purposes. iv Parameters for muscle strength and muscle endurance [Work (Joule), Power (Watt), Torque to mass (Nm/kg), and Total power (Watt)] appeared to be unaffected following periods of illness and following comparative periods of detraining.
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    The epidemiology of injuries in professional rugby union in South Africa
    (2001) Holtzhausen, Louis Johannes; Schwellnus, Martin P
    The first aim of this study was therefore to review the available literature on the epidem iology of injuries in professional rugby. The second aim was to collect data on medical profiles, previous injuries, use of protective gear, medication and nutritional supplements in South African professional rugby players. Thirdly, the incidence, nature and circumstances surrounding injuries in a cohort of professional South African rugby players were documented. The data collected was compared with available literature.
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    The epidemiology of injuries in South African high school soccer players
    (1998) Ramathesele, Jonas Ramorwesi; Schwellnus, Martin P
    The aim of the study was to document the epidemiology of injuries sustained by South African high school soccer players. Subjects for the study were selected from all the high schools (n = 10) in Tembisa (Gauteng, South Africa). A cohort of 227 high school soccer players, representing all the players in the Tembisa schools, was followed over one playing season. All practice and match hours were recorded and specific injury report forms were completed by all the coaches. All injured players were then referred to the principal investigator (JR) for detailed examination to document injuries. Factors such as pre-season training, warm-up, stretching, playing surface, environmental factors, and the use of protective equipment were also recorded. In this study, 63% of all the players sustained an injury during the season (seasonal incidence). The overall incidence of injuries was 9.04/1000 hours of play. The incidence in matches was 274 times higher than in practice. More than half (57%) of the injuries were classified as moderate. The highest incidence of injury per player position was in goalkeepers (13.7/1000 hours play). The lower extremity accounted for most injuries (88.8%), principally the ankle (42.4%) and the knee (27.1%). The most common type of injury was a ligamentous sprain (68%), followed by musculotendinous strains (15.8%). There were only two joint dislocations, and no fractures. All the participants in this study played on gravel pitches and on no occasion was a first-aid kit available. The majority of players were not aware of appropriate stretching, warm-up, and strapping techniques to prevent injuries. None of the players engaged in any form of pre-season training. In two of the schools (20%) the soccer coaches had formal training with coaching certification. Although the injury rate in high school soccer players in this study is only slightly higher than that reported · by others, it is clear that scientifically based measures of injury prevention (pre-season training, warm-up, stretching, and strapping) need to be implemented in these schools. In addition, proper sports and first-aid facilities should be provided, and coaches should receive formal continuous training.
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    The epidemiology of injury and risk factors associated with injury in first league field hockey players
    (1998) Ferguson, Kerry Jean; Schwellnus, Martin P; Sole, Gisela
    This study investigated the epidemiology of injury in a population of first league field hockey players during a playing season, establishing the true incidence (injuries/ 1000 hours) of injury, as well as the risk factors associated with field hockey injuries. Both the epidemiology of field hockey injuries, and associated risk factors, have not been well investigated on an international level, and no data on Southern African players have been published. A study population of 222 first league hockey players (males n= 111, females n= 111) from one particular region were followed over the duration of a hockey season (7 months). A preseason player profile questionnaire established player characteristics and training methods. A pre-season fitness assessment recorded the flexibility (sit and reach test), muscle power (standing broad jump), speed (40 m sprint) and endurance capacities (double winder) of all the players. Male players performed significantly better in the muscle power (p=0.0001), speed (p=0.0001) and muscle endurance (p=0.0001) tests compared to female players. However, female players recorded significantly better flexibility results (p=0.012) compared with male players. Player position influenced the results of the pre-season fitness assessment. Attacking players (strikers, midfielders) achieved significantly better results in the muscle power (p=0.0704), speed (p=0.0003) and muscle endurance (p=0.002) tests compared with defending players (defenders, goalkeepers). During the prospective study, an injury report form was completed for players that sustained injuries during the season. An injury was defined as physical damage that resulted in (i) a player being unable to complete the match or practise, (ii) a player missing a subsequent match or practise, or (iii) a player requiring medical attention. An overall incidence of injury of 10/1000 hours was reported for the playing population, with an injury risk of 0.59 injuries per player per season. No other study of hockey injuries has recorded the true incidence of injury. A number of factors were associated with field hockey injuries. The incidence of injury was significantly greater in matches compared to practices (p=0.003). The highest incidence of injury was recorded in the beginning of the season (month 2) (16 injuries/1000 hrs). Strikers reported the highest incidence of injury (11/1000 hrs). In certain instances, the player position could be associated with an injury to a specific anatomical area or mechanism of injury. For example, goalkeepers sustained significantly more upper limb injuries than players in outfield positions (p=0.001), which can be attributed to the nature of their play. The activities of a goalkeeper include diving, and fending off the ball with their hands. The most frequently injured anatomical areas were similar to those reported in other studies of field hockey injuries, namely the fingers (1.6/1000 hrs), knee (1.4/1000 hrs) and ankle (1.4/1000 hrs) joints, and hamstring muscle (0.8/1000 hrs). The type of injuries sustained were predominantly muscle strains (2.4/1000 hrs), ligament sprains (2/1000 hrs) and fractures (1.7/1000 hrs). The most frequent mechanism of injury was tackling (2.3/1000 hrs). There was a significantly higher incidence of injury reported on artificial turf (13/1000 hrs) compared with grass (4/1000 hrs) (p=0.015). Players who discontinued hockey due to injury missed an average of four subsequent matches or practices. There was no significant association between past injury history, pre-season training, stretching methods, equipment usage and pre-season fitness assessments and the incidence or epidemiology of injury in hockey players.
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    Exercise associated muscle cramping : investigating a novel hypothesis
    (2003) Sulzer, Nicole Uschi; Schwellnus, Martin P; St Clair Gibson, Alan
    This thesis on Exercise Associated Muscle Cramping (EAMC) comprised three individual studies. The aims of this series of investigations were firstly to investigate the nature and prevalence of EAMC in a group of lronman triathletes with a past history of EAMC, secondly to compare the serum electrolyte concentrations in cramping and control Ironman triathletes as well as to record the baseline electromyography (EMG) of cramping lronman triathletes during recovery and thirdly to compare the EMG activity of cramping and control runners before, during and after a fatiguing bout of exercise.
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    Incidence, prevalence and aetiology of chronic exercise induced lower back pain in runners
    (1999) Lewis, Grant; Schwellnus, Martin P; Sole, Gisela
    The aim of this study was to determine the prevalence of lower back pain (LBP) in the running population and any initiating or aggravating factors. The aetiology of low back pain in runners was also investigated. A random sample population of 225 roadrunners were interviewed following the completion of six local road races. A further subgroup (n = 52) (LBP group as well as control group) of these runners was evaluated to determine if there were any biomechanical; muscle strength, flexibility and stability measures; as well as any training protocols which were more commonly associated in those runners who complained of LBP. Questionnaires were completed by 225 runners and a detailed clinical evaluation was performed to identify the incidence and aetiology of running-related lower back pain. Attention was focussed on the lumbar-pelvic muscles in terms of their flexibility, strength and coordinating ability as well as static biomechanical measures of the lower limb. LBP in runners was found to be common with an injury risk of 1.42 injuries per 1000 running hours. This running-related LBP seldom forced the athlete to stop running yet did affect running performance. It was associated with any increase in the running load. Hip flexor inflexibility on the left (p = 0.07); short hip adductor muscle length (p = 0.055), hamstring inflexibility (p = 0.09) and iliotibial band inflexibility (p = 0.036) on the right were found to be more common in the LBP group. The abdominal muscles were weaker in the LBP group when assessed in the trunk curl-up test (p = 0.0085) and the stabilising ability (p = 0.032) for this group was judged to be poor. Biomechanically, only a marginal difference was found between those with and without LBP (p = 0.077) with regard to the hindfoot and forefoot postures which were valgus and varus respectively for the lower back pain group. Lumbar intervertebral joints were mostly hypomobile (p = 0.004) in the LBP group. Adherence to a poor training regime (excessive running distances and frequencies) was associated with the LBP group. Attention to correct training patterns and adequate muscle control (strength, coordination and flexibility) is suggested to protect from this running-related LBP. Further research into a comparison of rehabilitation protocols is required to validate these findings.
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    Osteoarthritis and ultra-distance marathon running
    (1999) Leaver, Roy; Schwellnus, Martin P
    Osteoarthritis (OA) is the most common degenerative joint disease. The impact loading on the articular cartilage of the large weight bearing joints (hip, knee, and ankle joints) during distance running might be a potential precipitating factor in OA. The aim of this case-control study was to investigate the relationship between total accumulated running volume and OA in the weightbearing joints. In this study, OA was defined as pain and/or stiffness and/or swelling in the weight-bearing and non-weight-bearing joints (wrists and fingers). The subjects for this study were selected from previous and current runners of the Two Oceans Ultra-marathon (56 km) in Cape Town (South Africa). The database (1356) consisted of all the runners who participated in this race between 1970 and 1983. From this data-base a random group of male runners (n =128) were divided into six 10-year age groups of runners (18 and 79 years). There was a random sample of 25 runners in five of these groups and three in the 70-79 year age group. Runners were age matched with a random sample of past pupils (n=204) of a school who were in their final year between 1923 and 1994. This was the control group. A questionnaire to diagnose OA was designed and validated with a sensitivity of 92% and a specificity of 71 %. The questionnaire was posted to the runners and controls. Incentive prizes were offered to improve the response rate, which was 59%. Completed information was obtained from 76 ultra-distance marathon runners (response rate 59%) and 114 controls (response rate 56%). In the control group there was a group who participated in running. This group was combined with the runners who were then divided into three groups according to their total running volume which was calculated by the following formula; years involved in running x months/year running x 4 x hours/week running. The subjects were thus divided into four groups: 1) controls (non-runners) (n=60), 2) low volume runners (n=43), 3) medium volume runners (n=43), and 4) high volume runners (n=44). Of these, 22 low volume runners, 7 medium runners, and 7 high volume runners stopped running. The prevalence (%) of OA in all groups was compared. The mean age of the control group was significantly higher than the three running groups. The mean height and weight of the medium volume group was significantly higher than the other groups. There was no significant difference in the BMI in each group. The frequency of professional and retired people was significantly higher in the control and each running group. A significantly greater percentage of controls had a history of admission to hospital. There were more controls on long-term medication, compared to runners. A significant number of injuries to the weight-bearing joints (specifically the knee joint) occurred in all groups, due to other sports (p =0.007). There were no significant differences in symptoms suggestive of OA in all groups when not adjusting for age and previous injuries. However, when assessing the odds ratio to determine the risk for OA in the weight-bearing joints, adjusting for age and previous injuries, the low volume group had the highest risk to develop OA (O.R. = 3.2, 95% C.I. = 1.0-10.3); the medium group had the second highest risk (O.R. = 1.7, 95% C.I. = 0.6- 4.8) and the high-volume group (O.R. = 1.1, 95% C.I. = 0.4-3.1) and control groups (O.R. = 1.0) had equally the lowest risk to develop OA. This study confirmed that distance running is unlikely to be a predisposing factor in the development of OA in the weight-bearing joints, even at high running volumes commonly seen in ultra-distance running.
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    Patellofemoral pain in cyclists
    (1999) Van Zyl, Elizabeth; Schwellnus, Martin P
    The aim of this thesis was first to review the current literature that deals with patellofemoral pain in cyclists. The second aim was to investigate the possibility of reducing media-lateral deviation during the down stroke of cycling, by altering the biomechanics of the lower limb and, to observe the effect of this reduction on patellofemoral pain in a clinical trail. This thesis is in the format of two papers that is submitted for publication in sports medicine journals. The first paper is a review of the aetiology, biomechanics, diagnosis and management of patellofemoral pain in cyclists. The second is a research paper, titled: correcting lower limb biomechanics decreases patellofemoral pain (PFP) in cyclists.
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    Risk factors for Achilles tendinopathy in runners - an investigation of selected intrinsic, kinematic, kinetic and muscle activity factors that are associated with Achilles tendinopathy
    (2008) Azevedo, Liane; Schwellnus, Martin P
    The overarching purpose of this study was to investigate the multifactorial aetiology of Achilles tendinopathy. Variables such as training and injury history, lower limb alignment, running biomechanics and movement variability were investigated. This study also aims to understand how different sensory inputs, such as shoe or pain may affect biomechanics. Thirty four uninjured runners (UN) and twenty one runners with Achilles tendinopathy (AT) composed the population sample for this study. Questionnaire and lower limb measurements were used to investigate the multifactorial aetiology of the injury. Selected kinetic, kinematic and muscle activity parameters were employed to analyse the biomechanics aetiology of the injury. Runners performed 10 running trials at a self-selected speed in two running shoes with different hardness. Additionally, the UN runners ran for 10 min on the treadmill while the AT runners ran on the treadmill until they developed pain in the Achilles tendon. The results of the study showed that AT runners have a higher incidence of previous injury, run for more years, have reduced hamstring flexibility, and are heavier and taller than uninjured runners. The study also showed a reduced integrated electromyography activity (IEMG) of tibialis anterior and rectus femoris in the AT group during the running cycle. Stride to stride variability was similar between UN and AT runners but the biomechanics variability between participants were lower for the AT runners. No specific biomechanical adaptations were found between the two different shoe conditions (soft vs. hard). Similarly, biomechanics parameters were not altered at the onset of pain, but the reduced IEMG activity of tibialis anterior and rectus femoris were presented before and during the pain condition. It can, therefore, be concluded that runners with Achilles tendinopathy present reduced muscle activity during running which may be either a novel aetiological factor, or an adaptive response to the injury. The lower variability between runners with AT may indicate that these runners are less able to adjust their biomechanics according to their different functional behaviour or external input signals but this may require further investigation. Finally, it can also be concluded that the sensory inputs such as shoes and pain do not change this muscle activity pattern.
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    The COL5A1 gene and musculoskeletal soft-tissue injuries
    (2010) Posthumus, Michael; September, Alison V; Schwellnus, Martin P; Collins, Malcolm
    Background. It has been shown that there is an association between various genetic variants and Achilles tendon injuries as well as anterior cruciate ligament (ACL) ruptures. Among other variants the BstUI restriction fragment length polymorphism (RFLP) within the COL5A1 gene has been shown to be over-represented in asymptomatic participants when compared with those with chronic Achilles tendinopathy, and in asymptomatic female participants when compared with those with ACL ruptures. The male asymptomatic control participants in the ACL study, which were 10 years younger than previously investigated cohorts, had a distinctly different genotype frequency. Aim. The aim of this study was therefore to determine whether the distribution of the COL5A1 BstUI RFLP in the combined asymptomatic participants without any known history of tendon injuries is age dependent, particularly among males. Results. When the 265 male asymptomatic participants from all studies were pooled and divided into age-group tertiles, there was a significant linear increase in the CC genotype frequency (p=0.032) among the male age groups, with the youngest group having the lowest frequency (CC genotype frequency, 13%) and the oldest group having the highest (CC genotype frequency, 27%) frequency. There was however a similar CC genotype content in all three female (N=231) age groups (CC genotype frequency, 24 - 27%; p=0.795). Conclusion. The practical implication is that the selection of asymptomatic groups is of critical importance when future studies of this nature are designed. Future research investigating this genetic variant as a risk factor for soft-tissue injuries should consider these findings when selecting asymptomatic participants.
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    The effect of "fusafungine" on the incidence of upper respiratory tract symptoms in ultradistance runners
    (1998) Kiessig, Michael; Kiessig, Michael; Schwellnus, Martin P
    Fusafungine is an antibiotic of fungal origin with a potent local anti-inflammatory action (German-Fattal, 1995; German-Fattal, 1996). It is administered locally to the nasal and pharyngeal mucosa by spray. It can be hypothesised that the anti-inflammatory action of fusafungine may decrease the development of mucosa! inflammation in such a manner that the incidence of symptoms of upper respiratory tract infection may be reduced if it is administered before, during and after completion of an ultramarathon. Furthermore, fusafungine could also reduce the risk of secondary bacterial infection. The potential value of fusafungine in reducing the symptoms of upper respiratory tract infections or the development of bacterial upper respiratory infection is the focus of this thesis.