Strain (bone)

Bone strain is the tiny amount of bending or deformation that happens inside a bone whenever it's loaded, like when you walk, jump, or push against resistance. Scientists sometimes measure it in microstrain, a unit describing how much the bone's length changes under force. Your bones constantly experience small amounts of strain, and this mechanical signal is thought to influence whether bone cells build up, maintain, or lose tissue over time.

Researchers have also looked at how quickly bending happens, called strain rate, in addition to how much bone bends. Some studies using surgically implanted strain gauges (a method that can't be done outside of research settings) suggest that quicker, more varied loading may send a different signal to bone than slow, steady loading. This is an active area of research rather than a settled rule for any one activity.

It's worth knowing that bone strain in living people has only been measured directly through highly invasive research methods, done in a small number of studies. So when you hear specific numbers tied to an exercise or device, those are estimates, not measurements from your own body. No exercise method, supplement, or program can guarantee a specific strain level or promise it will prevent fractures — understanding this helps you stay realistically informed about what's known and what's still uncertain.