Adding instability to strength training may not build more leg strength in older adults, but it may help them feel steadier on their feet. A systematic review and meta-analysis in the American Journal of Physical Medicine & Rehabilitation compared unstable and stable resistance training in older adults, and found the two approaches diverge in an interesting way.
Why this comparison matters. Falls are a leading cause of injury and lost independence in later life, and strength training is a proven countermeasure. A newer idea is unstable resistance training, performing exercises on wobble boards, foam pads, or balance devices, on the theory that challenging balance while building strength might do more for real-world stability. This review set out to test whether that theory holds up.
What the study did. The researchers searched five databases through July 2025 for randomized controlled trials directly comparing unstable resistance training with conventional stable resistance training in older adults. They pooled results separately for short-term programs (10 to 12 weeks) and longer ones (24 weeks), looking at lower-limb strength, mobility (including the Timed Up and Go test and gait speed), and fear of falling. Seven trials, reported across eight articles, were included.
Strength and mobility: little difference short-term. After short-term training, unstable resistance training showed no significant advantage over stable training for lower-limb strength or mobility. In fact, for one measure, the Five-Times Sit-to-Stand test, stable training showed a non-significant trend toward better performance. So for pure strength gains, adding instability did not clearly help.
Where instability pulled ahead. The unstable approach did stand out on two fronts. It significantly reduced fear of falling after short-term training, and it significantly improved Timed Up and Go performance, a common test of mobility and fall risk, after longer-term (24-week) training compared with stable training. In other words, its benefits showed up in confidence and functional mobility rather than raw strength.
Why that distinction is useful. Fear of falling is not just a feeling; it independently predicts activity avoidance, deconditioning, and future falls. A training style that eases it, even without extra strength, could meaningfully support older adults' willingness to stay active and independent.
How to read this. The evidence base is small, just seven trials, and the benefits for mobility emerged mainly with longer training, so patience matters. Unstable training also carries a balance challenge that should be appropriately supervised and progressed, particularly for frailer individuals. The authors frame the findings as suggestive rather than definitive.
Practical takeaway. The foundational message stands: regular resistance training benefits older adults regardless of style. For those specifically worried about falling or looking to improve functional mobility, adding a carefully supervised element of balance challenge may offer something extra, while conventional stable training remains perfectly effective for building strength.
Bottom line. In older adults, unstable resistance training did not outperform stable training for building leg strength, but it did reduce fear of falling and, over 24 weeks, improved functional mobility, suggesting a role for balance-challenging exercise as a complement to, not a replacement for, standard strength work.