The purpose of this prospective study was to analyze the value of health-related fitness (HRF) tests in predicting the occurrence of mobility difficulties among high-functioning older adults. In addition, the study described six-year changes in HRF test performance and associations between test performance and physical activity. The safety and feasibility of the tests were also considered. The study was based on the Kainuu Study on Living Habits and Health, which is a longitudinal cohort study conducted by the UKK Institute for Health Promotion Research. The study started as a postal questionnaire survey in 1980. In 1996 and 2002 the assessment of HRF targeted at persons aged 55 years and older was included into the study. The sample of the present study consisted of 55 to 79-year-old men and women who participated in the assessment of HRF in 1996. The assessment included seven field-based tests that were considered to represent the most important fitness factors for mobility function. Balance was assessed by one-leg stand and backwards walk, functional muscle strength of the lower extremities by one-leg squat, trunk extensor muscle strength by dynamic back extension, flexibility by trunk side-bending and walking ability by 6.1-m walking speed and 1-km walking time. Additionally, body mass index was used as a relative indicator of body composition. Mobility difficulties and participants’ level of physical activity were assessed by self-reported questionnaires. Participants were regarded as having mobility difficulties if they reported at least some difficulties in walking 2 km or climbing several flights of stairs without a rest.

During six-year follow-up the study sample was selected to younger, healthier and physically more active individuals who performed the baseline HRF assessment better than those who were lost to follow-up. Over six years performance in HRF tests deteriorated, especially among the older age groups and among women. Deteriorations were greatest in the 6.1-m walk, backwards walk and trunk side-bending tests. Poor performance in the HRF tests, non-vigorous physical activity and overweight in terms of high body mass index were all independent predictors of new mobility difficulties. The least active people with the poorest HRF test performance or with overweight had the highest risk of mobility difficulties. Backwards walk, dynamic back extension, one-leg squat and 1-km walk were the most powerful predictors. Optimal cut-off values predicting mobility difficulties were successfully identified for these tests.

The results suggest that the proposed HRF tests are valid, safe and feasible tools to assess mobility function among high-functioning older adults. The tests can be used to identify those at increased risk of declining mobility. The test results can also be utilized in physical activity counseling in order to target activity at those components of fitness that are not adequate for good mobility.