It was five years ago that prosthetics took a very literal step forward when Arizona State University's SPARKy foot offered a more natural walk, capturing the inherent kinetic energy that previously needed a big motor to replicate. Belgium's Vrije Universiteit Brussel may well carry the torch for the next wave of artificial limbs. Its second-generation Ankle Mimicking Prosthetic Foot (AMP-Foot 2.0) uses a pai