Short- and Long-Term Effects on Physical Fitness in Older Adults: Results from an 8-Week Exercise Program Repeated in Two Consecutive Years

<b>Introduction</b>: Information on the long-term maintenance of short-term exercise fitness gains measured by field-based tests is scarce in older adults. This study aimed to investigate short- and long-term changes in various physical fitness parameters after an 8-week exercise program. <b>Methods</b>: In this longitudinal study, a total of 265 participants (62% women; mean age 71.4 ± 4.7 years) completed a field-based test battery of 12 fitness tests (22 parameters) at 2 pre-tests and 1 post-test following an 8-week exercise program (2 sessions/week, combining aerobic and strength activities) in 2 consecutive years. The tests assessed muscle endurance, muscle strength, cardiorespiratory fitness, and motor fitness. <b>Results</b>: Significant short-term improvements were observed, e.g., in isometric trunk flexion and extension endurance (21-37%) for both sexes in both years. Lower-body muscular endurance improved in the first year (9-12%) for both sexes, while cardiorespiratory fitness (6-min walk test) improved only for men in both years (3%). No changes were seen in submaximal cycle test heart rates or any balance tests in any year. Most fitness parameters did not significantly decrease during the 9-month inter-intervention period, with a few exceptions in trunk strength and walking distance. <b>Conclusions</b>: This study demonstrates physical fitness improvements in older adults following short-term exercise interventions and that some of these improvements were maintained long term, whereas a few of these physical fitness test improvements decreased significantly over 9 months in older adults.