You may have seen training shoes with inbuilt LEDs that glow when the wearer takes a step. These generate their power 'onboard'; only a few microwatts, enough for a bit of fun, but
no more. To do something useful like powering a mobile phone requires a few watts of power, and is going to need some clever engineering.
The 'Electric Shoe Company' owned by Trevor Bayliss (the inventor of the clockwork radio) along with Texon International was set up to use a powerful 'Biomechanical Transducer' in a commercially available shoe.
Dr Jim Gilbert a lecturer in engineering at Hull University developed a kind of dynamo for the shoe that converts the kinetic energy from the weight transfer during the stepping action and from the flexion of the foot. Along with piezo-electric materials incorporated into the structure of the shoe, a reasonable amount
of power can be produced. This energy is transferred to a 'storage device' (some kind of battery I presume!) inside the shoe.
This technology was succesfully tested in the Namibian desert by Trevor during a 100km walk, when a telephone call was made to Richard Branson in Great Britain.
As far as I am aware this technology has never gone beyond this prototype and made it to the marketplace. (The website for the company in fact says it has gone out of business..)
However the military in various countries are supposed to be financing similar projects, so such techno-shoes could only be a short step away for the rest of us!