Extracting electricity with exosuit braking

Exoskeletons and exosuits are wearable devices designed to work alongside
the musculoskeletal system and reduce the effort needed to walk or run.
Exoskeletons can benefit users by reducing the mechanical power and
metabolic energy that they need to move about on the factory floor, in the rehabilitation clinic, on the playing field, and out at the shopping mall (1). Portable exoskeletons can use motors to add mechanical power into movement phases [net-positive exoskeleton power (2, 3)] or use springs to store and later return mechanical energy in a regenerative braking action [net-zero exoskeleton power (4, 5)]. On page 957 of this issue, Shepertycky et al. (6) describe a
wearable assistive device that uses a generator to extract mechanical energy from the walking cycle (net-negative power) and convert it to electricity. At the same time, the walker actually uses less metabolic energy with the exosuit, saving on the cost to operate muscles as “biological brakes.”