Wobbly surfaces may train something different than strength
A brand-new meta-analysis compared unstable resistance training—squats and lower-extremity exercises using foam pads, balance boards and similar surfaces—with conventional stable resistance training in older adults.
After 10–12 weeks, unstable training provided no significant advantage in leg strength, gait speed or Timed Up and Go performance.
But it did significantly improve fear of falling relative to stable training.
And when training continued for 24 weeks, unstable training finally produced a meaningful advantage in Timed Up and Go performance.
The clinical lesson
We sometimes lump everything together as “balance training.”
But these results suggest two separate adaptations:
Capacity: Can the legs generate enough force?
Confidence/control under uncertainty: Can the person tolerate being slightly destabilized without panicking or overcorrecting?
A BOSU probably isn't magically making the quadriceps stronger.
It may instead be giving the nervous system hundreds of repetitions saying:
“I can be slightly off balance and recover.”
That is a much more interesting justification for unstable training.