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- Volume 21, Issue 1, 2009
South African Journal of Sports Medicine - Volume 21, Issue 1, 2009
Volumes & issues
Volume 21, Issue 1, 2009
Author Mike LambertSource: South African Journal of Sports Medicine 21 (2009)More Less
We are in the midst of an exponential growth of access to information. In particular, the development of the Internet has been paralleled by the ease of setting up a blog which assumes some status of authority among the readers and contributors. Now anyone who has access to a computer and the Internet can write on a topic and contribute their viewpoint to a discussion.
Incidence of injuries among male soccer players in the first team of the University of the Free state in the coca cola league - 2007 / 2008 season : original research articleSource: South African Journal of Sports Medicine 21, pp 3 –6 (2009)More Less
Objective. To determine the incidence, nature and severity of injuries among male soccer players in the first soccer team of the University of the Free State (UFS) in the Coca Cola League during the 2007 / 2008 season. Informed consent was obtained from the players and the study was approved by the Ethics Committee of the Faculty of Health Sciences, UFS.
Design. A cohort descriptive study was conducted.
Setting. Twenty-three league matches were attended, during which injury information was recorded on game sheets.
Main outcome measures. The injury type and site, the player game time, and the game period during which the injury occurred were recorded. Follow-up questionnaires were completed for injured players.
Results. In 23 matches played, a total of 15 injuries were sustained by 10 players. The incidence of injuries per 1 000 hours game time was 39.5. More injuries occurred at the beginning of the season. Midfield players were most often injured (53%). Most injuries were minor (class 1 severity), and none exceeded class 3 severity. Most injuries occurred in the first or fourth quarter of the game. Knee and ankle injuries were the most common (27% and 47%, respectively), consisting mainly of sprains sustained while being tackled.
Conclusion. The most common soccer injuries incurred were to the lower extremity. The relatively low impact nature of the sport resulted in mild to moderate injuries. The incidence of injuries decreased as the season progressed. The results of this study were consistent with those of similar studies reporting the incidence of soccer injuries.
Impact of a primary school-based nutrition and physical activity intervention on learners in KwaZulu-Natal, South Africa : a pilot study : original research articleSource: South African Journal of Sports Medicine 21, pp 7 –12 (2009)More Less
Background. The opportunity for children to be physically active during school hours is rapidly decreasing in selected schools. This study evaluated the effects of a nutrition and physical activity (NAP) intervention incorporated within the school curriculum.
Study design and methods. A prospective empirical pilot study with an intervention and an assessment of pre- and post-intervention fitness. Learners completed a NAP questionnaire and participated in a battery of fitness tests before and after intervention.
Setting. A purposive sample of four primary schools in KwaZulu-Natal was selected by the provincial Department of Health.
Interventions. The NAP intervention was designed to introduce various methods of physical activity and healthy nutritional habits within the school's existing curriculum. Classroom-based intervention materials were developed to provide cost-effective and, more importantly, a sustainable intervention.
Results. Post-intervention results showed a significant increase (p<0.05) in the average number of sports participated in by each learner during physical education / life orientation periods. Learners were motivated to participate in physical activity including games and sports during break times. A general increase in after-school activities from pre- to post-intervention per learner was noted.
Conclusion. A school-based physical activity and nutrition intervention programme has the potential to increase the physical activity of learners and to a lesser degree their nutritional behaviour.
Monitor placement, sources of variance and reliability of free-living physical activity : a pilot investigation : original research articleSource: South African Journal of Sports Medicine 21, pp 13 –18 (2009)More Less
Objectives. We investigated the effect of monitor placement on the sources of variance and reliability of objectively measured free-living physical activity (PA).
Design. A convenience sample (N=7; 3 females, 4 males) of rural, adult, black South Africans was recruited from the plantation section of a local lumber mill. PA was assessed using two uni-axial accelerometers placed on the right hip (RH) and left hip (LH), over 3 weekdays. PA indices were total counts, average counts, inactivity (0 - 499 counts.min-1), moderate-1 activity (500 - 1 951 counts.min-1) and moderate-2+vigorous activity (≥1 952 counts.min-1).
Results. Accelerometer output did not differ across trials for either hip placement (p>0.2). There were no significant differences between RH-LH for any accelerometer variable (p>0.1) and effect sizes were small (0.02 - 0.15). Monitor position did not contribute any variance to accelerometer variables. Variance due to monitor unit contributed <2% to raw and derived accelerometer variables. Coefficients of variation derived from the standard deviation of RH-LH transformed differences ranged from 2.7% to 10.5%, except for moderate-1 and moderate-2+vigorous variables (16.0 - 72.8%). Intraclass correlation coefficients (ICC, RH-LH) were >0.90, except for moderate-1 time accumulated in bouts ≥10 min (ICC=0.83). Agreement between RH-LH for achieving CDC / ACSM PA guidelines was significant (kappa=0.79, p=0.002)
Conclusions. Firstly there was no statistically significant difference between RH-LH for any accelerometer variable. Secondly, accelerometer units accounted for little of the variance in accelerometer variables. Thirdly, greater variability in monitor placement was apparent for moderate-1 and moderate-2+vigorous variables.
Impact of training status on maximal oxygen uptake criteria attainment during running : original research articleSource: South African Journal of Sports Medicine 21, pp 19 –22 (2009)More Less
Objectives. The aims of this study were to assess whether training status influenced maximal physiological and perceptual responses and whether certain maximal criteria were more sensitive for individuals with different levels of training.
Methods. Males who were either trained (N=8) or untrained (N=9) underwent a maximal treadmill test to assess whether the criteria to indicate VO2 max were training-specific.
Results. VO2 max was significantly higher in the trained (70.0 mlO2. kg-1.min-1) compared with the untrained group (54.5 mlO2. kg-1.min-1). Only 11% of the trained and 56% of the untrained individuals achieved a plateau in the oxygen uptake curve. Peak treadmill running speed was significantly faster and total test time significantly longer in the trained group. In contrast, peak lactate, although maximal for both groups, was significantly higher in the untrained group (13.5 mmol.l-1 compared with 10.3 mmol.l-1). The other responses were not different between the groups. Noteworthy is that none of the subjects achieved all of the criteria indicating a maximal effort. The criteria most achieved in both samples were HRmax, RPEmax and Lamax with the latter being the most attained in the untrained group and RPEmax being mostly attained by the trained group.
Conclusions. The criteria used to indicate attainment of VO2 max may be limited and may differ when comparing a heterogeneous training sample. Although VO2 max was significantly higher in the trained group, responses were different for O2 plateau attainment and Lamax but similar for the other British Association of Sports Sciences criteria. It may be concluded that the physiological variables coinciding with maximal effort may differ in individuals with different levels of training.
Acute and session RPE responses during resistance training : bouts to failure at 60% and 90% of 1RM : original research articleSource: South African Journal of Sports Medicine 21, pp 23 –26 (2009)More Less
Objective. To compare resistance bouts performed to failure at low (60% 1RM) and high (90% 1RM) workloads for acute rate of perceived exertion (RPE) (per exercise), session RPE (S-RPE) (30 min post), HR (per exercise) and total work (per session, and per exercise).
Background. RPE is a convenient method for quantifying intensity in aerobic exercise. However, RPE has recently been extended to exercise modalities dominated by anaerobic pathways such as resistance training (RT).
Method. Subjects (N=12) were assessed using an exercise-specific 1 repetition maximum (1RM) for 6 exercises. On separate days in a counterbalanced order, subjects performed 3 sets of each exercise to volitional failure at a low intensity (LI) and a high intensity (HI) with 2 minutes rest between sets and exercises. At the end of each set, subjects estimated acute RPE for that set using a 10-point numerical scale. Thirty minutes after the end of the exercise session subjects estimated their S-RPE for the entire workout. HR, total work, and acute RPE were compared (HI v. LI) using repeated measures ANOVA.
Results. A paired samples t-test showed LI was significantly higher (p=0.039) than HI for session RPE (LI=8.8±0.8, HI=6.3±1.2) and total work (LI=17461±4419, HI=8659±2256) (p=0.043). Per exercise, total work and acute RPE were significantly greater (p=0.01) for LI for all exercises. Peak HR was significantly higher per exercise during LI for leg press (p=0.041), bench press (p=0.031), lat pull-down (p=0.037) and shoulder press (p=0.046).
Conclusion. In resistance exercise performed to failure, total work influences acute and session RPE more so than percentage 1RM.
Author Catherine E. DraperSource: South African Journal of Sports Medicine 21, pp 27 –28 (2009)More Less
Qualitative research is featuring more frequently in health sciences research, a field in which the 'hard sciences' and statistics have traditionally dominated. For example, within the fields of exercise science and sports medicine, qualitative research methods are included to evaluate intervention programmes. These methods are also being used in studies that require measurement of behavioural perspectives, such as an understanding of individuals' motivations, attitudes, beliefs and perceptions. Qualitative research methods are also becoming increasingly useful in the investigation of contextual factors that impact on physical activity and sporting performance. The purpose of this article is to clarify the role of qualitative research in exercise science and sports medicine and provide the reader with a basic understanding of the basis of qualitative research. Qualitative data collection and analysis, sampling strategies in qualitative research, the role of the qualitative researcher, and issues of scientific rigour regarding qualitative research will be addressed.