Research Publications (Health Sciences)
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Item Steps that count : pedometer-measured physical activity, self-reported physical activity and current guidelines- how do they relate?(South African Sports Medicine Association, 2014) Pillay, Julian David; Kolbe-Alexander, Tracy L.; Proper, Karin I.; Tomaz, Simone A.; Van Mechelen, Willem; Lambert, Estelle V.Background. The association between self-perceived and actual physical activity, with particular reference to physical activity guidelines, may be an important factor in determining the extent of uptake of and compliance with physical activity. Objectives. To examine the association between self-perceived and actual physical activity in relation to physical activity guidelines, with reference to volume, intensity and duration of steps/day, and to establish the level of agreement between pedometer-measured and selfreported ambulatory physical activity, in relation to current guidelines. Methods. A convenience sample of adults (N=312; mean (standard deviation) age 37 (9) years), wore a pedometer (minimum 3 consecutive days) and completed a questionnaire that included information on physical activity patterns. Analyses of covariance, adjusted for age and gender, compared volume- and intensity-based steps according to meeting/not meeting guidelines (self-reported). The extent of agreement between self-reported and pedometer-measured physical activity was also determined. Results. Average (SD) steps/day were 6 574 (3 541). Of a total of 312 participants’ self-reported data, those meeting guidelines (n=63) accumulated significantly more steps/day than those not meeting guidelines (8 753 (4 251) v. 6 022 (3 114) total steps/day and 1 772 (2 020) v. 421 (1 140) aerobic steps/day, respectively; p<0.0001). More than half of the group who self-reported meeting the guidelines did not meet guidelines as per pedometer data. Conclusion. The use of pedometers as an alternative and/or adjunct to self-reported measures is an area for consideration. Steps/day recommendations that consider intensity-based steps may provide significant effects in improving fitness and health.Item Steps that count! : a feasibility study of a pedometer-based, health-promotion intervention in an employed, South African population(South African Sports Medicine Association, 2014) Pillay, Julian David; Kolbe-Alexander, Tracy L.; Proper, Karin I.; Van Mechelen, Willem; Lambert, Estelle V.Background. The emergence of the pedometer as a useful motivational aid for increasing physical activity (PA) has supported its use in PA interventions. Objectives. To examine the feasibility of a 10-week pedometer-based intervention complemented by regular motivational messages, to increase ambulatory PA; and to determine the minimum sample size required for a randomised, controlled trial (RCT). Methods. Participants, sourced by convenience sampling of employees from an academic institution, were randomly assigned to either an intervention group (IG) (n=11) or control group (CG) (n=11), following baseline health measurements and blinded pedometer wear (week 1). Participants in the IG subsequently wore an unblinded pedometer (10 weeks) to self-monitor daily steps. Individualised messages using pedometer data (IG) and general motivational messages (IG and CG) were provided bi-weekly. Blinded pedometer wear (IG and CG) and a feedback questionnaire (IG) were completed at week 12. Pedometer data were compared between the IG and CG at week 12. Results. Participants’ perceptions of the intervention supported the benefit of the pedometer as a useful motivational aid and a reminder to increase steps per day. Occupational sitting time and inability to incorporate PA into daily routine emerged as the main barrier to adherence. Steps per day increased more in the IG (mean ± standard deviation (SD) 996±1 748) than in the CG (mean±SD 97±750). Modest improvements were noted in all clinical measures (IG). Conclusion. Based on the improvement of 1 000 steps/day (IG), a minimum of 85 participants in the IG and CG, respectively, is required for a future RCT (80% power; p<0.05). We recommend a minimum of 150 participants in each group to account for loss to follow-up and to allow for subgroup analyses.Item The association between daily steps and health, and the mediating role of body composition : a pedometer-based, cross-sectional study in an employed South African population(Biomed Central, 2015) Pillay, Julian David; Van der Ploeg, Hidde P.; Kolbe-Alexander, Tracy L.; Proper, Karin I.; Van Stralen, Maartje; Tomaz, Simone A.; van Mechelen, Willem; Lambert, Estelle V.Background: Walking is recognized as an easily accessible mode of physical activity and is therefore supported as a strategy to promote health and well-being. To complement walking, pedometers have been identified as a useful tool for monitoring ambulatory physical activity, typically measuring total steps/day. There is, however, little information concerning dose-response for health outcomes in relation to intensity or duration of sustained steps. We aimed to examine this relationship, along with factors that mediate it, among employed adults. Methods: A convenience sample, recruited from work-site health risk screening (N = 312, 37 ± 9 yrs), wore a pedometer for at least three consecutive days. Steps were classified as “aerobic” (≥100 steps/minute and ≥10 consecutive minutes) or “non-aerobic” (<100 steps/minute and/or <10 consecutive minutes). The data were sub-grouped according to intensity-based categories i.e. “no aerobic activity”, “low aerobic activity” (1-20 minutes/day of aerobic activity) and “high aerobic activity” (≥21 minutes/day of aerobic activity), with the latter used as a proxy for current PA guidelines (150-minutes of moderate-intensity PA per week). Health outcomes included blood pressure, body mass index, percentage body fat, waist circumference, blood cholesterol and blood glucose. Analysis of covariance, adjusting for age, gender and total steps/day were used to compare groups according to volume and intensity-based steps categories. A further analysis compared the mediation effect of body fat estimates (percentage body fat, body mass index and waist circumference) on the association between steps and health outcomes, independently. Results: Average steps/day were 6,574 ± 3,541; total steps/day were inversely associated with most health outcomes in the expected direction (p < 0.05). The “no aerobic activity” group was significantly different from the “low aerobic activity” and “high aerobic activity” in percentage body fat and diastolic blood pressure only (P < 0.05). Percentage body fat emerged as the strongest mediator of the relationship between steps and outcomes, while body mass index showed the least mediation effect. Conclusion: The study provides a presentation of cross-sectional pedometer data that relate to a combination of intensity and volume-based steps/day and its relationship to current guidelines. The integration of volume, intensity and duration of ambulatory physical activity in pedometer-based messages is of emerging relevance.Item Calories and steps! How many days of walking/hiking in the Himalayas does ONE Christmas lunch translate to?(Health & Medical Publishing Group, 2015) Pillay, Julian David; Brown, W.Background. The festive season is a time when people are at risk of overeating and weight gain. An active break during this time can help maintain energy balance. Objectives. To determine steps taken during a walk/hike to Everest Base Camp and back and compare estimated activity-related energy expenditure to a typical Christmas lunch. Methods. Five adults (39-70 years) completed an 11-day walk/hike. Pedometer-measured steps were recorded at two cadences: ‘aerobic’ (>100 steps/minute for 10 consecutive minutes) or ‘slower’ steps. Activity-related energy expenditure was estimated using generic values for walking uphill/downhill at each cadence. Energy intake of a typical Christmas lunch was estimated. Results. Participants accumulated a total of 143 770 steps, or 13 070 (SD 8 272) steps/day, 20% of which were ‘aerobic’. Total walk-related energy expenditure was estimated at 22 816 kcals, or 1 901 (SD 580) kcals/day. Conclusion. Estimated energy intake in one Christmas lunch equates to 1.7 days of walking/hiking.Item Meta-analyses of the effects of habitual running on indices of health in physically inactive adults(Springerlink, 2015) Junior, Luiz Carlos Hespanhol; Pillay, Julian David; van Mechelen, Willem; Verhagen, EvertAbstract Background In order to implement running to promote physical activity, it is essential to quantify the extent to which running improves health. Objective The aim was to summarise the literature on the effects of endurance running on biomedical indices of health in physically inactive adults. Data Sources Electronic searches were conducted in October 2014 on PubMed, Embase, CINAHL, SPORTDiscus, PEDro, the Cochrane Library and LILACS, with no limits of date and language of publication. Study Selection Randomised controlled trials (with a minimum of 8 weeks of running training) that included physically inactive but healthy adults (18–65 years) were selected. The studies needed to compare intervention (i.e.endurance running) and control (i.e. no intervention) groups. Study Appraisal and Synthesis Methods Two authors evaluated study eligibility, extracted data, and assessed risk of bias; a third author resolved any uncertainties. Random-effects meta-analyses were performed to summarise the estimates for length of training and sex. A dose-response analysis was performed with random-effects meta-regres-sion in order to investigate the relationship between run-ning characteristics and effect sizes. Results After screening 22,380 records, 49 articles were included, of which 35 were used to combine data on ten biomedical indices of health. On average the running programs were composed of 3.7 ± 0.9 sessions/week, 2.3 ± 1.0 h/week, 14.4 ± 5.4 km/week, at 60–90 % of the maximum heart rate, and lasted 21.5 ± 16.8 weeks. After 1 year of training, running was effective in reducing body mass by 3.3 kg [95 % confidence interval (CI) 4.1–2.5], body fat by 2.7 % (95 % CI 5.1–0.2), resting heart rate by 6.7 min-1 (95 % CI 10.3–3.0) and triglycerides by 16.9 mg dl-1 (95 % CI 28.1–5.6). Also, running significantly increased maximal oxygen uptake (VO2max) by 7.1 ml min-1 kg-1 (95 % CI 5.0–9.1) and high-density lipoprotein (HDL) cholesterol by 3.3 mg dl-1 (95 % CI 1.2–5.4). No significant effect was found for lean body mass, body mass index, total cholesterol and low-density lipoprotein cholesterol after 1 year of training. In the dose-response analysis, larger effect sizes were found for longer length of training. Limitations It was only possible to combine the data of ten out the 161 outcome measures identified. Lack of information on training characteristics precluded a multi-variate model in the dose-response analysis. Conclusions Endurance running was effective in provid-ing substantial beneficial effects on body mass, body fat,resting heart rate, VO2max, triglycerides and HDL choles-terol in physically inactive adults. The longer the length of training, the larger the achieved health benefits. Clinicians and health authorities can use this information to advise individuals to run, and to support policies towards invest-ing in running programs.Item Meta-analyses of the effects of habitual running in indices of health of physically inactive adults(Springer Verlag, 2015-07-15) Luz Junior, Mauricio Antonio; Van Mechelen, Willem; Pillay, Julian DavidBACKGROUND: In order to implement running to promote physical activity, it is essential to quantify the extent to which running improves health. OBJECTIVE: The aim was to summarise the literature on the effects of endurance running on biomedical indices of health in physically inactive adults. DATA SOURCES: Electronic searches were conducted in October 2014 on PubMed, Embase, CINAHL, SPORTDiscus, PEDro, the Cochrane Library and LILACS, with no limits of date and language of publication. STUDY SELECTION: Randomised controlled trials (with a minimum of 8 weeks of running training) that included physically inactive but healthy adults (18-65 years) were selected. The studies needed to compare intervention (i.e. endurance running) and control (i.e., no intervention) groups. STUDY APPRAISAL AND SYNTHESIS METHODS: Two authors evaluated study eligibility, extracted data, and assessed risk of bias; a third author resolved any uncertainties. Random-effects meta-analyses were performed to summarise the estimates for length of training and sex. A dose-response analysis was performed with random-effects meta-regression in order to investigate the relationship between running characteristics and effect sizes. RESULTS: After screening 22,380 records, 49 articles were included, of which 35 were used to combine data on ten biomedical indices of health. On average the running programs were composed of 3.7 ± 0.9 sessions/week, 2.3 ± 1.0 h/week, 14.4 ± 5.4 km/week, at 60-90% of the maximum heart rate, and lasted 21.5 ± 16.8 weeks. After 1 year of training, running was effective in reducing body mass by 3.3 kg [95% confidence interval (CI) 4.1-2.5], body fat by 2.7% (95% CI 5.1-0.2), resting heart rate by 6.7 min(-1) (95% CI 10.3-3.0) and triglycerides by 16.9 mg dl(-1) (95% CI 28.1-5.6). Also, running significantly increased maximal oxygen uptake (VO2max) by 7.1 ml min(-1) kg(-1) (95% CI 5.0-9.1) and high-density lipoprotein (HDL) cholesterol by 3.3 mg dl(-1) (95% CI 1.2-5.4). No significant effect was found for lean body mass, body mass index, total cholesterol and low-density lipoprotein cholesterol after 1 year of training. In the dose-response analysis, larger effect sizes were found for longer length of training. LIMITATIONS: It was only possible to combine the data of ten out the 161 outcome measures identified. Lack of information on training characteristics precluded a multivariate model in the dose-response analysis. CONCLUSIONS: Endurance running was effective in providing substantial beneficial effects on body mass, body fat, resting heart rate, VO2max, triglycerides and HDL cholesterol in physically inactive adults. The longer the length of training, the larger the achieved health benefits. Clinicians and health authorities can use this information to advise individuals to run, and to support policies towards investing in running programs.Item Steps That Count: The association between the number and intensity of steps accumulated and fitness and health measures(Human Kinetics Journals, 2014-01) Pillay, Julian David; van Mechelen, Willem; Lambert, Estelle V.; Kolbe-Alexander, Tracy L.Background: Pedometer-based recommendations for accumulating steps/d largely focus on volume, with less emphasis on intensity and fitness/health outcomes. We aim to examine this relationship. Methods: A convenience sample (N = 70, 35 men, 32 ± 8yrs) wore a pedometer (4 days). The pedometer classified steps as “aerobic” (≥ 60 steps/minute, minimum duration of 1 minute) or “non-aerobic” (< 60 steps/minute and/or < 1 minute). Estimated maximal oxygen uptake (VO2max), derived from a 12-minute submaximal step-test, and health outcomes: blood pressure (BP), body mass index (BMI), percentage body fat (%BF), and waist circumference (WC) were correlated with pedometer data. Participants were grouped according to number and intensity of steps: LOW (< 5000 steps/d), HIGH-LOW (≥ 5000 steps/d, no aerobic steps), HIGH-HIGH (≥ 5000 steps/d, including some aerobic steps). Analyses of covariance, adjusting for age, gender, and total steps/d were used to compare groups. Results: Average steps/d was 6520 ± 2306. Total steps/d and total time spent accumulating “aerobic” steps (minutes/day) were inversely associated with %BF, BMI, WC, and systolic BP (P < .05). After adjusting for gender and total steps/d, %BF was different between all 3 groups, VO2max was different between the LOW and HIGH-HIGH groups, WC was lower in the HIGH-HIGH versus the other 2 groups (P < .03, respectively). Conclusion: Intensity seems an important factor to consider in steps/d cut-points.Item Steps that count! : The development of a pedometer-based health promotion intervention in an employed, health insured South African population(BioMed Central, 2012-10-17) Pillay, Julian David; Kolbe-Alexander, Tracy; Mechelen, Willem; Lambert, Estelle V.Physical activity (PA) has been identified as a central component in the promotion of health. PA programs can provide a low cost intervention opportunity, encouraging PA behavioral change while worksites have been shown to be an appropriate setting for implementing such health promotion programs. Along with these trends, there has been an emergence of the use of pedometers as a self-monitoring and motivational aid for PA. This study determines the effectiveness of a worksite health promotion program comprising of a 10-week, pedometer-based intervention (“Steps that Count!”), and individualized emailbased feedback to effect PA behavioral change.Methods The study is a randomized controlled trial in a worksite setting, using pedometers and individualized email-based feedback to increase steps per day (steps/d). Participant selection will be based on attendance at a corporate wellness event and information obtained, following the completion of a Health Risk Appraisal (HRA), in keeping with inclusion criteria for the study. All participants will, at week 1 (pre-intervention), be provided with a blinded pedometer to assess baseline levels of PA. Participants will be provided with feedback on pedometer data and identify strategies to improve daily PA towards current PA recommendations. Participants will thereafter be randomly assigned to the intervention group (INT) or control group (CTL). The INT will subsequently wear an un-blinded pedometer for 10 consecutive weeks. Individualized feedback messages based on average steps per day, derived from pedometer data (INT) and general supportive/motivational messages (INT+CTL), will be provided via bi-weekly e-mails; blinded pedometer-wear will be conducted at week 12 (post-intervention: INT+CTL). Discussion The purpose of this paper is to outline the rationale behind, and the development of, an intervention aimed at improving ambulatory PA through pedometer use, combined with regular, individualized, email-based feedback. Pedometer-measured PA and individualized feedback may be a practical and easily applied intervention.Item Are point-of-decision prompts in a sports science and medicine centre effective in changing the prevalence of stair usage? : a preliminary study(2009) Pillay, Julian David; Kolbe-Alexander, Tracy; Achmat, Masturah; Carstens, Madelaine; Lambert, Estelle V.Objective. To determine the impact of a signed intervention on promoting stair versus lift usage in a health and fitness facility. Design. A 3-week observational study in which a simple timeseries design of collecting data before, during and after the introduction of an intervention was used. Setting. The Sports Science Institute of South Africa (SSISA): a 5-storey building with a centrally located lift lobby and internal stairwell. Method. Observers were placed unobtrusively on the ground floor, with good visibility of lift/stairwell, to observe ascending movement of students, staff, tenants, visitors and patients 4 hours/day (07h00 - 09h00, 16h00 - 18h00), 4 days/week for 3 weeks. During week 2, motivational signs were displayed on the wall next to the lift and stairs and on the floor leading to the stairwell. In week 3, signage was removed. Factors considered in predicting stair use were gender, phase of intervention, and whether persons were staff/students or visitors. Results. A total of 4 256 person-counts were recorded. Prevalence of stair use increased from 43% before the intervention to 53% during the intervention to 50% after the intervention. Odds of using the stairs during the intervention increased by 45% (odds ratio (OR) 1.45, 95% confidence interval (CI) 1.25 - 1.68) (p<0.00001), were 41% higher for staff/students compared with visitors (p<0.00001) and were 55% greater for women (p<0.00001). These effects did not change significantly after the intervention and stair use remained modestly higher than before the intervention. Conclusion. Signed intervention produced significant increases in stair usage during and after the intervention. These findings support the effectiveness of point-of-decision prompts for changing behaviour, and highlight potential factors influencing the impact of such messages.