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- South African Journal of Sports Medicine
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- Volume 24, Issue 2, 2012
South African Journal of Sports Medicine - Volume 24, Issue 2, 2012
Volumes & issues
Volume 24, Issue 2, 2012
Author Mike LambertSource: South African Journal of Sports Medicine 24 (2012)More Less
Methods of communicating new information have undergone a rapid change. Twenty years ago it was important to go to conferences to remain at the cutting edge of a discipline or specialty. New information was presented at conferences, often months or years before it appeared in print. Experts in the field were invited to present exhaustive overviews on a topic. Other researchers presented their research findings in either oral or poster presentations. A prerequisite was that the data had not been presented or published before. In this era it was tantamount to professional suicide if you missed a major conference. Conferences stimulated new ideas and ensured that as a scientist or practitioner, one stayed abreast of the trends and new findings in a field.
Impact of race pace on development of hyponatraemia in full- and half-marathoners : original researchSource: South African Journal of Sports Medicine 24, pp 36 –42 (2012)More Less
Objective. Prior studies of full-marathon participants have demonstrated a higher incidence of hyponatraemia in runners with completion times of 4 hours or more. Our primary aim was to determine if slower pace is associated with increased prevalence of hyponatraemia. Secondly, we evaluated the prevalence of hyponatraemia in full-marathoners v. half-marathoners.
Methods. This observational, cross-sectional study comprised consenting runners in the 26.2 With Donna, The National Marathon to Finish Breast Cancer, in Jacksonville Beach, Florida, February 2008. On race day, participants completed a questionnaire, provided finger-stick blood samples, and were weighed both pre- and post-race.
Results. A significant negative association was found between pace and post-race sodium level (p<0.001). A negative correlation was found between finishing time and post-race sodium level (p<0.001). The prevalence of post-race hyponatraemia was 4% (4/106) among half-marathoners and 13% (12/89) among full-marathoners (P=0.02). An inverse correlation was found between sodium change and weight change, significant in full-marathoners (r=-0.55, p<0.001) but not half-marathoners (r=-0.23, p=0.042).
Conclusions. Slower race pace and longer finishing times were associated with lower post-race sodium levels. Full-marathoners had a significantly higher prevalence of hyponatraemia. The development of hyponatraemia was associated with weight gain. Our data indicate that the relationship between post-race sodium concentration and pace differs according to the distance of the event. We can extrapolate from this data that longer race distance with increased availability of fluid stations combined with a slower pace may increase the risk of developing exercise-induced hyponatraemia.
Criterion validity and test-retest reliability of a physical activity questionnaire in South African primary school-aged children : original researchSource: South African Journal of Sports Medicine 24, pp 43 –48 (2012)More Less
Objective. We sought to determine the validity, reliability and ranking ability of an interviewer-administered physical activity questionnaire (PAQ), measuring physical activity (PA) and inactivity history over a 1-week and 1-year period in South African primary school-aged children.
Methods. Criterion validity of the PAQ was tested against PA movement counts as measured with an Actical accelerometer in 30 children. Agreement between the two instruments was measured with a weighted Kappa statistic. Test-retest reliability of the past week and past year PAQ was also tested.
Results. A positive, significant (r=0.53, p=0.004) relationship was found between total time spent being physically active as measured by the Actical and PAQ. A similar relationship was found for time spent doing sedentary (r=0.63, p<0.001) and vigorous activities (r=0.47, p<0.001), but not for activities of a moderate intensity (r=0.001, p=0.88). The ability of the PAQ to correctly categorise children into activity levels was moderate (κ=0.41, p<0.001). The PAQ was found to be reliable and reproducible with significant (p<0.001) intraclass correlation coefficients for both the past week and past year administrations.
Conclusion. The interviewer-administered PAQ is a useful assessment tool in this population of children, as evidenced by its good correlation with Actical measurements. The best application of the questionnaire lies in its ability to qualitatively rank subjects according to activity level.
The incidence and severity of injuries at the 2011 South African Rugby Union (SARU) Youth Week tournaments : original researchSource: South African Journal of Sports Medicine 24, pp 49 –54 (2012)More Less
Background. Rugby Union, compared with other popular team sports, presents an above-average risk of injury to players that may increase with age and level of play. Elite schoolboy rugby players have been competing at the South African Rugby Union (SARU) Youth tournaments at the under-13 (CW13), under-16 (GK16) and under-18 (AW18 and CW18) tournaments annually since 1964. The injury epidemiology of these tournaments has yet to be established.
Objectives. To determine the injury incidence densities (IIDs) and severity of SARU Youth Week tournament injuries, if the IID increases with age, and the types of injuries at the different age group levels, in 2011.
Methods. All match-related injuries presenting to the Tournament Doctor during these tournaments were recorded and classified for severity and type, using the injury collection Consensus Statement for Rugby. Injury incidence per 1 000 match hours and 95% confidence intervals were calculated using overall player exposure time.
Results. Match-related IIDs for 'all' (combined: 47.9 injuries/1 000 match hours) and time-loss injuries (combined: 23.1 injuries/1 000 match hours) were not significantly different by age group, despite a strong tendency to indicate differences. The absolute number of injuries per match increased with age. In general, there was a higher proportion of concussions at the GK16, AW18, and CW18 compared with the CW13 tournament(s).
Conclusions. Time-loss IIDs at SARU Youth Weeks are similar to other elite junior rugby data. The absolute number and type/classification of injuries per match may be more informative than IIDs alone for medical planning purposes.
Low 25(OH) vitamin D concentrations in international UK track and field athletes : original researchSource: South African Journal of Sports Medicine 24, pp 55 –59 (2012)More Less
Objective. While it is recognised that vitamin D deficiency is common in the general population, there have been no studies in elite athletes in the UK. This observational study aimed to assess the 25 hydroxy-vitamin D (25(OH)D) status of elite athletes on the Great Britain track and field team.
Methods. A cross-sectional observational study was performed by analysing blood results from elite athletes on the British athletics team (N=63; mean ± standard deviation (SD) age 24.9±4.2 years). Athletes on the elite programme were offered blood tests through the winter and summer of 2009 and were eligible for inclusion in the study.
Results. Nineteen per cent (n=12) of athletes in the current study can be classified as 25(OH)D deficient (<20 mcg/l), while a further 29% (n=18) can be classified as having insufficient serum 25(OH)D levels (20 - 30 mcg/l). Female sex (insufficent and deficient OH(D) prevalence 58%, n=18) and dark skin (prevalence 65%, n=20) were found to be independent predictors of serum 25(OH)D levels of <30 mcg/l.
Conclusion. This study reveals a notable prevalence of low serum 25(OH)D levels in elite athletes and subsequent management of deficient athletes is likely to be of importance for athlete health. The impact of these results on athletic performance remains to be determined, and clinical trials to assess performance, particularly muscular performance, following correction of 25(OH)D status in deficient athletes are required.
Whole body vibration improves body mass, flexibility and strength in previously sedentary adults : original researchSource: South African Journal of Sports Medicine 24, pp 60 –64 (2012)More Less
Objectives. This study aimed to determine the effectiveness of whole body vibration (WBV) training for promoting health-related physical fitness in sedentary adults.
Design. A non-randomised sampling technique was used with an equivalent match-pair comparison group, pre- and post-test design. Volunteers were gathered through a combination of accidental and snowball sampling and divided into either the experimental (n=32) or control group (n=30). Dependent variables included body mass, hamstring flexibility as measured by the sit-and-reach test, upper-body strength as measured by a grip strength dynamometer, abdominal and upper-body muscular endurance as measured by 1-minute timed sit-up and push-up tests, respectively. The standardised YMCA fitness battery was used as the evaluation protocol. The WBV experimental group participated in a progressive 3 times/week training programme for a maximum duration of 30 minutes/session for 12 consecutive weeks. The control group remained sedentary.
Results. Significant improvements in all five of the selected dependent parameters were measured.
Conclusion. WBV training 3 times weekly for 30 minutes/session provides an effective method of exercise intervention for health promotion in sedentary adults over a 12-week period.
Popliteal artery entrapment syndrome misdiagnosed as chronic exertional compartment syndrome in a young male athlete : role of dynamic ultrasound : case reportSource: South African Journal of Sports Medicine 24, pp 65 –66 (2012)More Less
Popliteal artery entrapment syndrome (PAES) is an uncommon cause of exercise-induced pain in the lower extremity of young athletes. However, it might explain the symptoms of those athletes who do not respond to treatment for the more common overuse syndromes. We present a case of a young professional male athlete who was diagnosed with bilateral chronic exertional compartment syndrome (CECS), for which he was operated on twice. His symptoms persisted for 5 years before PAES was diagnosed with dynamic ultrasound, and after bilateral surgical release a few months apart, he was completely symptom-free except for some discomfort in the fasciotomy scars.
Author David KarpulSource: South African Journal of Sports Medicine 24, pp 67 –68 (2012)More Less
Fifteen regional rugby union teams compete for the Super Rugby title - five each from Australia, South Africa and New Zealand. In 2011, significant changes were made to the tournament format and these were continued in 2012. The new changes created an inherent bias, favouring teams that are strong relative to their conference, regardless of their overall strength. It is shown using logic and numerical results from simulations that teams that are weaker are able to unfairly progress to higher positions on the competition log at the end of the 'regular' season. The bias arises as a result of teams playing more matches against teams within their conference than other teams within the competition, and therefore the final log position represents a team's strength relative to their own conference more than their overall strength. In the face of this evidence the tournament format should be altered to re-align with the primary goal of determining the best team in the competition. Should the tournament organisers choose not to change the tournament format, it would not be unreasonable for them to face criticism for failing to implement measures to ensure fairness to each team within the competition.
South African Sports Medicine Association position statement on exercise in pregnancy : position statementSource: South African Journal of Sports Medicine 24, pp 69 –71 (2012)More Less
There are many concerns about exercise during pregnancy, with medical advice historically dissuading women from continuing or initiating regular exercise programmes. However, research has shown that high levels of exercise are not associated with an increased incidence of negative events.
Currently, many women of childbearing age wish to continue with their exercise programmes during pregnancy. Appropriate guidance and exercise counselling by the attending care provider can fulfil this need. This position statement aims to assist pregnant women and their care providers in assessing the merits and benefits of improving and maintaining fitness during this period.