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- Volume 19, Issue 5, 2007
South African Journal of Sports Medicine - Volume 19, Issue 5, 2007
Volumes & issues
Volume 19, Issue 5, 2007
Author Mike LambertSource: South African Journal of Sports Medicine 19 (2007)More Less
This is the last edition of the South African Journal of Sports Medicine for 2007. Four editions of the journal have been published in 2007, with 21 articles (original research, opinions and letters). Over 50% of these articles are unique to the South African context.
COPD : is there evidence to support a role for resistance training in improving measurable health-related quality of life in pulmonary rehabilitation? : commentarySource: South African Journal of Sports Medicine 19, pp 108 –113 (2007)More Less
Chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality. As such, the disease places a significant burden on health care services. Although the pathogenesis of COPD is complex, progressive airflow limitation and a chronic inflammatory response are two hallmark characteristics of the disease. In addition, systemic manifestations such as peripheral muscle dysfunction have recently received considerable attention in the literature. Pulmonary rehabilitation is an evidence-based multidisciplinary intervention that has been shown to produce clinically relevant outcomes. One important component of rehabilitation is exercise. With the majority of COPD patients presenting with muscle weakness and exercise intolerance, the inclusion of resistance training into a pulmonary rehabilitation programme would seem appropriate. Compared with other exercise / training modalities only a small number of studies have investigated the effects of resistance training in COPD patients. Although further research is required to identify the optimal mode, intensity and frequency, it appears that resistance training may prove to be a valuable intervention for COPD patients enrolled in pulmonary rehabilitation programmes.
Author T. MannSource: South African Journal of Sports Medicine 19, pp 114 –116 (2007)More Less
Background. Lactate or, as it was customarily known, 'lactic acid' was one of the first molecules to attract the attention of early exercise scientists, mainly because blood lactate concentration could be measured and was shown to increase with increasing exercise intensity. This connection resulted in lactate being associated with numerous other events associated with high-intensity exercise including muscle cramps, fatigue, acidosis and post-exercise muscle soreness. Nobel prize-winning research by AV Hill and Otto Meyerhof provided a rational explanation linking lactate to anaerobiosis and acidosis, which resulted in this relationship being widely accepted as fact. It was only following isotopic tracer studies of George Brooks and others that the true role of lactate during rest and exercise was revealed.
Conclusions. Lactate is now acknowledged as an important intermediate of carbohydrate metabolism, taken up from the blood by tissues such as skeletal and cardiac muscle as a substrate for oxidation. Furthermore, lactate formation consumes a proton, thereby buffering against muscle acidosis. For this reason, lactate production forms an essential aid to endurance performance rather than a hindrance.
Validity and reliability of a physical activity / inactivity questionnaire in South African primary schoolgirls : original research articleSource: South African Journal of Sports Medicine 19, pp 117 –124 (2007)More Less
Objective. We sought to determine the validity and reliability of a self-report physical activity questionnaire (PAQ) measuring physical activity / inactivity in South African schoolgirls of different ethnic origins.
Methods. Construct validity of the PAQ was tested against physical activity energy expenditure estimated from an ACTIVITYGRAM and inactivity from reported television programme viewing in 332 girls (ages 9 - 12 yrs, grades 4 - 5). Body composition (WHO BMI percentiles and percentage body fat) was used as an indirect measure of validity for the PAQ. Test-retest reliability of the PAQ was assessed in a convenience sample of 14 girls.
Results. Weak but significant associations were found between the body composition and PAQ-derived total energy expenditure (r=-0.18; p< 0.05 for percentage body fat; r=-0.17; p< 0.01 for WHO BMI percentiles) and inactivity (r=0.35; p< 0.001 for percentage body fat; r=0.23; p< 0.001 for WHO BMI percentiles). Positive associations were found between moderate and vigorous energy expenditure by PAQ and the same intensity activities by ACTIVITYGRAM (r=0.19; p< 0.001 and r=0.26; p< 0.001, respectively). Further, the television viewing time reported by PAQ was significantly positively related to the number of programmes noted from the television programme list. Only total energy expended while partaking in structured school sports showed good test-retest reliability (r=0.80; p< 0.05).
Conclusions. Our results showed that the PAQ may provide some reasonable insights into levels of physical inactivity and activity in South African primary schoolgirls. However, additional studies are required using objective measures of physical activity, such as pedometry or accelerometry,to better understand the utility of the PAQ for children.
Nature and proportion of total injuries at the Stellenbosch Rugby Football club : a comparison of the years 1973 - 1975 with 2003 - 2005 : original research articleSource: South African Journal of Sports Medicine 19, pp 125 –128 (2007)More Less
Objective. The purpose of this study was to compare the nature and proportion of total injuries occurring at Stellenbosch Rugby Football Club in Stellenbosch, South Africa, between the years 1973 - 1975 and 2003 - 2005.
Design. Retrospective, descriptive study.
Main outcome measures. Injured rugby players from the Stellenbosch Rugby Football Club from the different time periods were included in the study. Results from the 1973 - 1975 time period were obtained from two previously published articles (Roy, 1974; Van Heerden, 1976), while data from the 2003 - 2005 time period were available through the Stellenbosch University Rugby Injury Database.
Results. An increase in the proportion of head and facial injuries from 1973 - 1975 (21%) to 2003 - 2005 (42%) was found as well as a doubling in the proportion of concussions between the two time periods (12% - 23%). There was an overall decrease in total injuries between the two time periods.
Conclusion. The findings highlight the high and increased proportion of head and facial injuries in the game of rugby at the Stellenbosch Rugby Football Club. This is a matter that should be further investigated.
A review of cricket injuries and the effectiveness of strategies to prevent cricket injuries at all levels : original research articleAuthor R.A. StretchSource: South African Journal of Sports Medicine 19, pp 129 –132 (2007)More Less
Objective. This review evaluates the scientific research on cricket injuries, including long-term injury surveillance studies, the consensus statement paper for injury surveillance, specific counter-measures to reduce the risk of cricket injuries and finally identifies areas of future concern.
Results. The literature shows that three major cricket-playing countries, Australia, England and South Africa, have collected long-term injury data. While these sets of data show definite trends, it was not always possible to make direct comparisons between data collected in various countries. As a result a consensus statement paper with regards to definitions and methods to calculate injury rates, incidence and prevalence was developed. The first study using this newly accepted injury surveillance method showed injury patterns in West Indies domestic and national cricket teams. There have been three primary studies carried out with regards to interventions aimed at reducing the risk of injury to fast bowlers. These included a coaching interventions programme, the use of a bowling aid in an attempt to modify bowling technique and a study that evaluated the recommended bowling workloads in young cricketers. The implications of the changes to the laws relating to the bowling action and the increased usage of the sliding stop in fielding are reviewed.
Conclusion. From the review it is evident that there is a need to continue with injury surveillance, as well as a need to continue with and increase the number of studies that evaluate the efficacy of intervention strategies in order to reduce the risk of injury to cricketers.