Physical activity, body composition and handgrip strength among South African adults : the PURE study

Abstract

There is a consistent and progressive trend concerning a decrease in handgrip strength and physical activity with increased age that have significant implications for public health. It has been revealed that poor muscle strength is associated with lower levels of physical activity that can increase the likelihood of falls resulting in injuries. Handgrip strength is a marker of muscle quality. Regular participation in physical activity is, therefore, a useful intervention to improve handgrip strength and lower other health risk factors associated with increased age in an attempt to prolong the life. However, there are limited studies in South Africa (especially in the North West) that investigated physical activity, body composition and handgrip strength among young and middle adults. Two manuscripts were prepared from this study. In 2015, a cross-study of 910 participants (men=198; women=490) between the ages of 35-70 years formed part of a multidisciplinary Prospective Urban and Rural Epidemiological (PURE) in the North West of South Africa. Physical activity information was gathered by the use of a self-reported international physical activity questionnaire-short form. Handgrip strength was measured by a hand-held model (T.K.K.54010 Takei) dynamometer; while anthropometric indicators of height, body mass, and waist circumference were measured using the standard procedures described by the International Society for the Advancement of Kinanthropometry. The first article focuses on physical activity and handgrip strength in relation to body mass index among adults in the North West. The result showed that 29% and 22% of the men and women were underweight, respectively; while 22% of the women were overweight and 26% of the men were reported as obese (p<0.001). The men were more physically active, taller and underweight compared to the women in all age groups. The women reported high mean values for triceps, subscapular and waist circumference compared to the men. Regardless of age and gender, the underweight and normal weight groups reported higher physical activity levels and handgrip strength compared to the overweight and obese groups. The handgrip strength according to age groups was significantly (p<0.05) better men compared to women (p<0.05) 42-49 age group: men 34.81 ± 11.13 kg versus women 26.29 ± 7.72 kg; 50-59 age group: men 34.05 ± 9.19 kg versus women 25.12 ± 6.67 kg; 60-70 age group: men 30.28 ± 8.69 kg versus women 23.27 ± 6.44 kg. The overweight and obese men performed poor during the minute spent in moderate-vigorous physical activity per week. The second article focuses on the relationship between physical activity, body composition, and handgrip strength among adults in the North West. About 60% of the participants reported sufficient physical activity per week. Seventeen percent (17%) of the men and 27% of the women were physically inactive per week. The handgrip strength performance significantly (p<0.05) differed according to age. In general, the handgrip strength of the participants in the study was poor when compared to the available handgrip strength norms. The participants younger than 50 years outperformed the older groups with men being stronger than the women are. The men and women who were sufficiently active per week significantly (p<0.05) performed better than the other groups. A positive correlation was found between handgrip strength and body mass index. A negative correlation was found between moderate to vigorous physical activity (r= -0.12; p=0.001) and age. Handgrip strength in both the men (r= -0.23; p= 0.001) and women (r= -0.18; p<0.001) correlated negatively with age. Given the health implications of the current findings, strategic interventions aiming at the reduction of obesity and physical inactivity are needed. As such, the study recommends an urgent strategic physical intervention in older men and women to improve their quality of life