Fitness testing, exercise intervention and health-related quality of life validation in Setswana speaking community dwelling Potchefstroom adults
Abstract
This study was a series of linked investigations in which we explored self-reported health-related quality of life and fitness tests, as well as exercise preferences and effects among black South African adults. We (1) translated the SF-8 into Setswana, and determined face validity and reliability of this version of the questionnaire, (2 and 3) compared group and individual protocols, as well as metronome and musical accompaniment, for an 8-minute step test to determine cardiorespiratory fitness (CRF), (4) explored people’s most preferred and enjoyed physical activities (PA), and (5) trialled the effects and acceptability of a 4-week exercise intervention for non-communicable diseases (NCDs) risks factors, CRF, and HRQoL among the same population.
All the participants were adults (male and female) aged 35-65 years, drawn from a low resourced area (LRA) of Kenneth Kaunda district in Ikakeng (study 1: n=60, study 2: n=52, study 3: n=52, study 4: n=130). A total of 76 adults participated at the baseline of the fifth objective of which only 54 completed. Study 1: Participants’ completed both the English and Setswana versions of the SF-8 on separate occasions, and the correlation between responses compared using a Spearman’s rank correlation co-efficient. Internal consistency of the Setswana questionnaire was calculated via Cronbach’s alpha. Study two and three gathered information about CRF testing of an eight-minute graded step test of one protocol comparing individual and group, and whether metronome or culturally-specific music accompanied protocol increased the rate of completion. Simple percentages were used to determine the best adaptation while a one-way ANOVA was used to test the significant difference in participants’ maximum oxygen consumption level. Study 4 gathered information on most preferred and enjoyed mode of physical activity and the reliability of the questionnaire was calculated with the Cronbach’s alpha coefficients. Frequency analyses and chi-square tests were performed to determine the most preferred type and time of PA and association between preferred type of PA and demographic variables were performed using regression analyses. Study 5 gathered information on the compliance and acceptability alongside effects of a four-week aerobic physical activity intervention on NCD risk factors, cardiorespiratory fitness, and quality of life. Independent sample t-test was performed to determine the significance of differences of the all variables. The exercise benefits and barriers scale (EBBS) reliability was calculated by Cronbach’s alpha coefficient while mean and standard deviation were computed for each sub-scale of EBBS to allow straight forward comparisons between each sub-scale. ANCOVA with adjustment for pre-test was performed for all repeated variables. Qualitative data were analyzed using AtlasTi7. Normality for all variables was assessed using the Shapiro-Wilk test and the level of significance used was 5% level.
The Setswana SF-8 has good concurrent validity with the spearman correlation coefficients ranged from moderate (ρ= 0.72, p < 0.001) to excellent (ρ = 0.91, p < 0.001) relationship. Cronbach alpha coefficient for first and second measurement was 0.87 and 0.87 for the Setswana-translated SF-8 and for the original English SF-8 was 0.86 and 0.89 conferring to translated and original index a good internal consistency. Most participants (67.7%) completed the step-test individually, and accompanied by metronome. Walking (39.2%) was the most preferred and enjoyed type of physical activity, and most participants (70%) reported that they preferred to exercise in the morning. Four weeks of community exercise was acceptable for most participants (71% compliance, 29% drop out), and produced measurable improvements in NCD risk factors such as body mass (p=0.02), RPE (p=0.03) and MCS (0.003) in men, and body mass (p=0.00), BMI (p=0.003), 2OV•max (p=0.003), RPE (p=0.00), glucose (p=0.04), PCS (p=0.00) and MCS (0.00) in women. The results of the ANCOVA evaluating the change from baseline to end of the exercise intervention shows that there was no statistically significant difference in all the variables between the groups when adjusted for the covariates (pre-test) (p < 0.05). Covariates were height, weight, BMI, WHR, systolic BP, diastolic BP, RHR, glucose, cholesterol, predicted maximum oxygen consumption, RPE, PCS and MCS
In conclusion the SF-8 is brief, reliable, and internally consistent in Setswana when used among community dwelling South Africans. Individual, metronome accompanied step-test protocol appears to be acceptable and robust across culture. We recommend use of the standard protocol to obtain the largest possible completion rates for cardiorespiratory fitness testing. The drop-out rate of nearly 30% is a reality that should be factored in with exercise intervention studies. Although not the main purpose, as little as four weeks of regular exercise may improve the NCD risk profiles. Consideration of PA preference may increase motivation for future exercise intervention programs.
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