Physical activity level, musculoskeletal fitness,balance, strength and power performance in older adults

The link between physical activity and prevention of disease, maintenance of independence, and improved quality of life in older adults is supported by strong evidence. However, there is a lack of data on population levels where physical activity level has been measured objectively in association with self-reported health, musculoskeletal fitness and balance variables in older men and women. Also, little is known about the functional adaptive responses of older adults to power training. Therefore, there is a need of developing adequate assessment tools/tests and investigating different training regimes aiming at muscle strength, power, and function in older age groups. The aims of the thesis were therefore: 1) to describe the level of accelerometer-determined physical activity and to investigate its association to self-reported health in a population of Norwegian older adults (65-85 years) (Paper I), 2) to describe musculoskeletal fitness and balance in Norwegian older men and women and to investigate its association with objectively-assessed physical activity levels, expressed as a daily increments of 1,000 steps (Paper II), 3) to test if the field-based 30-s chair-stand test and a modified field-based version of the progressive isoinertial lifting evaluation (PILE) test were valid tests for assessing relationships between lower extremity strength and power and total lifting strength and power in older adults, and also to investigate the reliability across trials for the laboratory-based tests («chair-stand» and «box-lift» tests) and the reliability across days for the field- and laboratory-based tests (Paper III), and 4) to test the effect of traditional versus functional strength training, both performed at 80% of 1RM at a maximal intended concentric velocity, on muscle strength and power measured functionally and traditionally in older adults compared to nontraining controls (Paper IV)