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This was a descriptive observational study in which a convenient sample of seventy (n = 70) participants (28 males and 42 females) aged 65 years and older were recruited. Participants were recruited from a commercial gym and from a community-based physical activity intervention program. The Community Health Intervention Programmes (CHIPS) aims to promote physical activity and healthier lifestyles for older adults in marginalized communities in Cape Town [20]. More than a third (39.3%) of Cape Town’s total population lives below the poverty line. Low income households range from no income to earning just over R4166 (304.5$ / 230.3£) per a month. Middle income range from R4166 –R33741.75 (2.462$ / 1.865.2£) per a month and high income above R33741.75 (2.462$ / 1.865.2£) per a month. In addition, 20.8% of the population in the city of Cape Town is unemployed. Our participants were recruited from the Cape flats (Hanover Park and Lotus River) as well as the Southern suburbs (Diep River and Newlands). Half (51.1%) of the individuals living in the Cape flats fall within the low income bracket, 39% within the middle income bracket and 9.9% within the high income bracket. In the Southern suburbs, 30.5% of individuals fall within the low income bracket, 40% within the middle income bracket and 29.6% within the high income bracket. As a result, our participants were older adults who were likely to be physically active and from both high and low socio-economic areas. Inclusion criteria were that participants had to be older than 65 years, community dwelling and living independently. Those participants who were identified as being at a high risk for coronary artery disease, according to the American College of Sports Medicine criteria [21], required consent from a medical doctor prior to being allowed to complete the test battery. The exclusion criteria included being previously diagnosed with a stroke, myocardial infarction or uncontrolled disease such as hypertension or diabetes. In addition, those with limited mobility were excluded. Three individuals were excluded as they required the use of assistive walking devices and two individuals due to previously being diagnosed with a mild stroke. Ethical approval for this research study was obtained from the Research and Ethics Committee of the Faculty of Health Sciences, from the University of Cape Town. Written consent was obtained from each participant before the commencement of the study.
Demographic and health status questionnaire: An interviewer-administered questionnaire was administered to obtain information about the participant’s age, occupation, self-perceived health status and highest educational achievement. Participants were also asked to report any previous disease diagnosed by a medical doctor and the associated treatment and medication received.
DiPietro and colleagues developed and validated the Yale Physical Activity Survey (YPAS) for older adults [22] which was later validated in a South African population [23]. The first part of the questionnaire assesses physical activity in five domains, namely; household, yard work, care-giving, exercise and recreational energy expenditure, representing total habitual physical activity. The time spent in each activity was summed to calculate the total physical activity time for the week. Each activity was assigned an intensity code (kcal) as described by DiPietro [22], and subsequently multiplied by the time spent to calculate kcal/week. Each individual’s weekly energy expenditure was calculated for each of the activity domains and then summed to estimate total weekly expenditure.
Height was measured to the nearest centimeter using a wall- mounted tape measure (Detecto). Body mass was measured using a calibrated electric scale (UWB BW-150) and recorded to the nearest 0.5kg. Body mass index (kg/m2) was calculated as body mass (kg) divided by height (m) squared [21]. Waist circumference was recorded at the level of the umbilicus and hip circumference was measured at the largest diameter below the umbilicus or maximum circumference over the buttocks. Waist-to-hip ratio was calculated as waist divided by hip circumference [24]. A Harpenden caliper (Holtain) was used to measure skinfold thickness at four sites, namely; sub-scapular, supra-iliac, triceps and biceps. The Durnin and Womersley (1969) equation was used to calculate percentage body fat [25].
This test measures upper body muscle strength and endurance [9]. Participants were seated in a chair with back support for posture and given a small dumbbell (2kg’s for females and 4kg’s for males). They were instructed to repeat as many bicep curls as possible in 30 seconds [9].
The participants walked around a 70m indoor track for 6 minutes. Two chairs were placed on the track, one at the start and the other at the 35m mark, in case participants needed to rest during the 6-minute walk. Participants were requested to walk for as long and fast as possible and advised that they could sit and rest if needed. The total distance covered was recorded in metres [26].
Static balance was assessed by asking the participant to stand for as long as possible (a maximum of 30 seconds) in the tandem and semi tandem positions, with the left and then right foot in front [27]. The tandem stance was performed by standing with the right foot in front of the left, with the toe of the left foot touching the heel of the right foot, and vice versa with the left foot leading. The time that the stance was maintained without taking a step or losing balance was recorded.
The participants were asked to walk 10 meters along a strip of tape using the tandem gait. Tandem gait involves walking heel to toe. When the left foot is in front, the right heel will move forward touching the left toe and when the right foot is in front, the left heel will move forward touching the right toe [28]. The time taken to walk the first 6 steps [27] as well as the time taken to complete 10 meters was recorded.
Timed Up and Go test: This test is a measure of mobility, balance and agility. Participants started in a seated position with hands across their chest on a standard chair with no arm rests, then stood up, walked 3 meters, turned around and walked back to the chair and sat down. The time taken to complete the Task was recorded [29].
This test is a measure of lower body strength. Participants were seated on a standard chair without armrests, with their hands folded across the chest. They were then instructed to rise from the chair into a standing position and sit down again. They repeated this process for 30 seconds without using their arms for assistance. The time taken to complete 5 repetitions was recorded, as well as the total number of sit-to-stands completed in 30 seconds [30].
Grip strength was determined using a hand held dynamometer (Takei Physical Fitness Test: Grip-D, T.K.K. 5401) and measured in kilograms (kg) of isometric force. Participants were required to squeeze the hand held dynamometer inner and outer grips towards each other as hard as possible without bending the elbow, while remaining seated [31]. Two attempts each for the right and left arms were recorded.
Participants were asked to stand next to a wall and reach as far forward as possible along a wall mounted yardstick (150cm vertically from the ground) without moving, taking a step or lifting their heels [32]. Participants were not allowed to use the wall for support while reaching forward. Each participant was given two familiarization trials and then three performance trials. The mean value (in centimeters) of the last three functional reach trials was recorded.
The six–item cognitive impairment test (6CIT): The six–item cognitive impairment test (6CIT) was developed in the United Kingdom to assess cognitive function in older adults by measuring orientation, concentration and short–term memory [33]. This tool was modified for the use in South African older adults [34] and has been validated against the Bristol Activities of Daily Living Scale [35]. The first three questions assess orientation in time, by asking the participant to recall the current month and year. The latter three questions assess memory and concentration. The number of errors made for each question were scored and weighted. The scores range from 0 to 28, where a score from 0 to 7 indicates normal cognitive function, 8 to 9 indicating mild cognitive impairment and 10 to 28 indicating significant cognitive impairment.
The modified Stroop Task is a computer-based assessment where cues (2cm in height) appear in the centre of a computer monitor [36]. The cues consisted of 4 text words (red, blue, green and yellow) which appeared every 3.2 seconds on a black background and were displayed for 600ms after which a black screen was displayed for 2600ms constituting the response period. The 4 words were presented in 5 different colour inks: red, blue, green, yellow and grey. The words were either presented in grey ink or in a colour ink incongruent with the meaning of the word: e.g. blue word presented in a red colour, or yellow word presented in a green colour, but never a green word presented in a green colour or red word presented in a red colour, etc. The participants were then asked to respond as quickly and as accurately as possible by pressing one of the four response buttons to indicate either the ink colour of the word (if the text was written in either red, blue, green or yellow ink), or the word itself (if the word was written in grey ink). The Stroop Task measures three executive functions: 1) Shifting between tasks; 2) Updating and monitoring of working memory representation and; 3) Inhibition of dominant or pre-potent responses [37]. The objective of the Stroop Task in this study was to determine the balance between speed and accuracy, which is also known as the speed accuracy trade off [38]. Previous studies have shown that when subjects concentrate more on responding as fast as possible, their number of mistakes increases, thereby sacrificing accuracy for speed [38]. The first Stroop Task administered was regarded as a familiarization trial. The outcome variables such as the number of correct responses, mistakes, missed responses and average reaction times of responses. The average reaction time from the second Stroop Task was used in the data analysis.
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