Purpose (1) To determine the effects of a 9-month resistance training intervention on quality of life, sense of coherence, and depressive symptoms in older adults, and (2) to compare effects between different training frequencies.

Methods Men and women aged 65–75 (N = 106) were randomized to four groups according to training frequency: training groups RT1 (n = 26), RT2 (n = 27), and RT3 (n = 28) and non-training control group (n = 25). All training groups attended supervised resistance training twice a week for 3 months. For the following 6 months, they continued training with different frequencies (1, 2 or 3 times per week). Psychological functioning was measured by quality of life (WHOQOL-Bref), sense of coherence (Antonovsky’s SOC-13), and depressive symptoms (Beck’s Depression Inventory II). Measurements were conducted at baseline and 3 and 9 months after baseline. The effects of the intervention were analyzed using generalized estimating equations (GEE).

Results After 3 months, there was an intervention effect on environmental quality of life (group × time p = .048). Between 3 and 9 months, environmental quality of life decreased among RT1 compared to RT2 and RT3 (group × time p = .025). Between baseline and 9 months, environmental quality of life increased in RT2 compared to all other groups (group × time p = .011). Sense of coherence increased in RT2 compared to the control group and RT3 (group × time p = .032).

Conclusion Resistance training is beneficial for environmental quality of life and sense of coherence. Attending resistance training twice a week seems to be the most advantageous for these aspects of psychological functioning.