The thesis is based on the randomized, controlled KAAMU exercise intervention study of the UKK Institute, Tampere, Finland. The purpose of the study was to evaluate the effects of two exercise programs and their combination on multiple risk factors for falls and fall-related fractures in home-dwelling older women. The feasibility of the exercise programs and maintenance of the training effects after cessation of the exercise intervention were also assessed.

One hundred and forty-nine women aged 70 to 78 years were randomly assigned to the four groups: 1) a resistance training group (RES), 2) a balance-jumping training group (BAL), 3) a combination group doing resistance and balance-jumping training (COMB), and 4) a control group (CON). The supervised training was three times a week for 12 months.

Measurements were conducted at baseline, immediately after the intervention (12 months) and one year after the end of the intervention (24 months).

Training compliance with the programs was found to be good. No severe adverse events were reported and no differences in the numbers of monthly reported health problems were found between exercisers and controls.

After the end of the intervention at 12 months, isometric lower limb extension force was 13-14% higher in the RES and COMB groups (p=.001), and the dynamic balance 6-8% better in the BAL and COMB (p<.001) groups than in the CON group. In addition, a 10% treatment effect was found in self-rated physical functioning between the COMB and the CON groups (p=.047). Further, the per protocol analysis indicated that the tibial shaft bone strength index (BSI) decreased 2% less in the COMB than in the CON group (p=.032).

At 24 months, about half of the exercise-induced gains in dynamic balance and the tibial shaft BSI were seen in the COMB compared to CON (p=.005 and .065 respectively). The other beneficial effects had been lost. In conclusion, high-to-moderate intensity resistance and balance-jumping training were safe and feasible exercise modalities for relatively healthy older women. Twelve-month resistance and balance-jumping training, especially in combination, prevented functional decline by improving muscle performance and dynamic balance as well as self-rated physical functioning. A positive effect found in the structure of the loaded tibia suggested that training could also prevent bone fragility. Some exercise-induced benefits were partially maintained one year after the cessation of the exercise intervention. However, to maintain the gains achieved, especially in muscle force and self-rated physical functioning, continued training seemed necessary.