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- Volume 25, Issue 3, 2013
South African Journal of Sports Medicine - Volume 25, Issue 3, 2013
Volumes & issues
Volume 25, Issue 3, 2013
Author Mike LambertSource: South African Journal of Sports Medicine 25 (2013)More Less
With the increasing ease with which information can be obtained from the internet, it is becoming more important to be able to discern 'good quality' information from 'not-so-good' information. This even applies to scientists who are accustomed to the process of peer review. Information on the internet often breaks from convention where scientists aspire to have their research papers published in high-impact journals. The practice of striving to publish in high-impact journals is based on the assumption that high-quality research papers are associated with high impact factor (IF) journals. However, this assumption is not always fulfilled. This is because the IF of a journal was originally developed by librarians to rank journals; it was not designed as a marker of the quality of the research papers published in the journal.
Intrinsic factors associated with medial tibial stress syndrome in athletes : a large case-control study : original researchSource: South African Journal of Sports Medicine 25, pp 63 –67 (2013)More Less
Background. Medial tibial stress syndrome (MTSS) is the most common lower-leg injury in athletes, and is thought to be caused by bony overload. To prevent MTSS, both pathophysiological and aetiological factors specific to MTSS need to be identified. The intrinsic risk factors that contribute to the development of MTSS are still uncertain.
Objective. To determine the intrinsic risk factors of MTSS by sampling a large population of athletic MTSS patients and controls.
Methods. Athletes with MTSS and control subjects were medically examined in terms of range of motion of the leg joints (hip abduction, adduction, internal and external range of motion; ankle plantar and dorsal flexion; hallux extension and flexion; subtalar inversion and eversion), measures of over-pronation and maximal calf girth.
Results. Ninety-seven subjects agreed to participate in the study: 48 MTSS patients and 49 active controls. The following variables were considered: gender, age, body mass index (BMI), hip abduction, hip adduction, internal and external hip range of rotation, ankle plantar and dorsal flexion, hallux flexion and extension, subtalar inversion and eversion, maximal calf girth, standing foot angle and navicular drop test. In multivariate logistic regression analysis, hip abduction (odds ratio (OR) 0.82; 95% confidence interval (CI) 0.72 - 0.94), ankle plantar flexion (OR 0.73; 95% CI 0.61 - 0.87) and subtalar inversion (OR 1.24; 95% CI 1.10 - 1.41) were significantly associated with MTSS. The Nagelkerke R2 for this model was 0.76, indicating that 76% of the variance in the presence of MTSS could be explained by these variables.
Conclusion. Decreased hip abduction, decreased ankle plantar flexion and an increased subtalar inversion could be considered risk factors for MTSS.
Source: South African Journal of Sports Medicine 25, pp 67 –73 (2013) http://dx.doi.org/10.7196/SAJSM.470More Less
Objective. To evaluate whether three-dimensional (3D) musculoskeletal modelling could be effective in assessing the safety and efficacy of exercising on a seated row resistance-training machine. The focus of the evaluation was on biomechanical and anthropometric considerations of the end user.
Methods. Three anthropometric cases were created; these represented a 5th percentile female as well as a 50th and a 95th percentile male based on body mass index. Two repetitions, with a resistance equal to 50% of the functional strength of one repetition maximum (1RM) for each anthropometric case, were performed.
Results. Results indicate that the default model of the LifeModeler software has important limitations that should be taken into consideration when used to evaluate exercise equipment. Adjustments had to be made to the model to solve the forward dynamics simulations; as a result, no muscle forces or contraction values were obtained. This negatively influenced the value of the results as these parameters are important when analysing an exercise. The seated row resistance-training machine's engineered or manufactured adjustability was sufficient, as it appeared to accommodate the three anthropometric cases adequately during execution of this exercise.
Conclusion. It appears that 3D musculoskeletal modelling can be used to evaluate resistance-training exercises such as the seated row; however, the limitations indicated by this study must be taken into consideration, especially when using the default LifeModeler model.
Source: South African Journal of Sports Medicine 25, pp 74 –76 (2013)More Less
Background. The chronological age of the ordinary Ghanaian has often been difficult to verify as registration at birth is not compulsory. Consequently, an accurate method of age determination is needed in competitive age-restricted sports.
Objective. To evaluate the age of Ghanaian soccer players who are aspiring to play for the national under-17 (U17) team, using the degree of fusion of the distal radius on magentic resonance imaging (MRI) and comparing it with the Fédération Internationale de Football Association (FIFA) MRI grading.
Methods. MRI scans of the left wrists of 86 players aspiring to play for the national U17 football team were recruited for the study during a 'justify your inclusion tournament' organised by the Ghana Football Association between June and August 2012. The study was conducted in a diagnostic centre in Accra using a 0.35T MRI scanner. The images were analysed using the previously published FIFA grading system.
Results. The mean chronological age of the players was 15.4 years (standard deviation ±0.7; range 12 - 17). The study showed that 43.0% of the MRI images were grade 6 (≥17 years) in relation to the degree of fusion of the distal radius, and 93.0% of the grade 6 players were aged 15 - 16 years chronologically. There was no significant correlation between the chronological age and the degree of fusion (r=0.075; p=0.493).
Conclusion. Ghanaian U17 soccer players seem to be more biologically mature than a normative population of the same age category. The lack of correlation between age category and degree of fusion supports the suspicion that most Ghanaian players may not know their true age.
Injury prevention in football : knowledge and behaviour of players and availability of medical care in a Nigerian youth football league : original researchSource: South African Journal of Sports Medicine 25, pp 77 –80 (2013)More Less
Background. Exposure to competitive football is increasing among male youth football players in Nigeria. However, medical support to abate the impact of injuries appears inadequate and there is limited literature to show whether youth football players are knowledgeable about, and practise effective measures for injury prevention in football (IPF).
Objective. To assess the knowledge and behaviour of male youth football players regarding IPF and the availability of medical care for players.
Methods. We conducted a cross-sectional study among all registered first-division players of a male youth football league in Lagos, Nigeria. Using a self-administered questionnaire, we assessed players' knowledge regarding IPF, awareness of the Fédération Internationale de Football Association (FIFA) 11+ injury-prevention programme, injury-prevention behaviour and availability of medical attendants during training and competitive matches.
Results. The mean age of the players was 18.5 years (standard deviation (SD) ±1.7; range 12 - 19). Their overall mean knowledge score regarding IPF was 4.40 (SD ±1.92) from a total score of 9, with the majority falling into the poor (39.1%) and fair (43.9%) knowledge categories. Most (79.3%) players were not aware of the FIFA 11+ programme. Less than half (40.5%) wore shin guards during training sessions, while 52.5% reported wearing shin guards during matches. Less than two-thirds always warmed up or cooled down at training or matches. About three-quarters (73.1%) and over half (52.1%) reported not having medical attendants working with their teams during matches and training, respectively.
Conclusion. There is a clear deficiency in the knowledge and behaviour of injury-prevention measures among Nigerian male youth football players, and adequate medical care is lacking. There is a need for injury-prevention advocacy and implementation of effective interventions to bridge the identified deficiencies in youth football in Nigeria.
Side-to-side asymmetry in absolute and relative muscle thickness of the lateral abdominal wall in cricket pace bowlers : original researchSource: South African Journal of Sports Medicine 25, pp 81 –86 (2013)More Less
Background. The abdominal musculature plays a protective role against lower-back injury. Knowledge of the asymmetry in abdominal wall thickness in healthy, injury-free cricket pace bowlers may provide a useful platform against which pathology could be assessed and the effects of training could be evaluated.
Objective. To compare side-to-side differences in absolute muscle thickness and activity of the abdominal musculature and to compare these measurements at the start, with those at the end of a cricket season among a group of amateur pace bowlers.
Methods. This was a controlled longitudinal prospective study. Rehabilitative ultrasound imaging was used to assess abdominal muscle thickness in 26 right-handed, injury-free cricket pace bowlers at the start and at the end of a cricket season. Thickness measurements were done at rest, during an abdominal drawing-in manoeuvre (ADIM) and the active straight-leg raise (ASLR) on the left (-L) and right (-R).
Results. The absolute thickness of the non-dominant obliquus abdominis internus (OI) was higher than that of the dominant OI at the start (p=0.001; ES=0.87) as well as at the end of the cricket season (p=0.001; ES 1.09). At the start of the season, the percentage change during the ADIM, thus muscle activity, was higher for the non-dominant OI than for the dominant OI (p=0.02; ES=0.51). Absolute thickness of the dominant obliquus abdominis externus (OE) at rest was significantly higher at the end of the season compared with the start of the season (p=0.0001; ES=0.85). During ASLR-R, the activity of the left transversus abdominis (TA) was significantly higher than that of the right TA during ASLR-L (p=0.03) when measured at the end of the season.
Conclusion. This study highlights the possible muscle adaptations in absolute muscle thickness and activity as a consequence of the asymmetrical bowling action.
Source: South African Journal of Sports Medicine 25, pp 87 –92 (2013)More Less
Cricket is played in three formats at elite level: Test, One Day and Twenty20. Fielding is an important component of cricket, as all players are obliged to field. However, there is a paucity of literature on fielding compared with that on batting and bowling. We review the available literature in terms of technical, mental, physiological and physical factors important to fielding, to identify knowledge gaps and better understand the performance requirements of fielding in cricket.