roller blades

Roller blades used by skying - which is not very natural for human being: long training, troubles with braking, you have to wear hard shoes, they are bulky to keep them all the time, not universal in size and so on.

My offer is to use natural step movement instead of the side sliding one.    On the picture below the bigger than usual roller blades wheels1 (not necessary but it makes ride smoother) geared up to expandable base 2 (it allow wheels tray further apart for stability) and step pedals 3. The rider just slip his shue 5 into small boot clasp 4. Since the the roller moves only forward the stiff plastic shoe in not necessary

When the man makes a step, the pedals bend and propel the wheels

For brakes the foot in angle starting braking process  which is asymmetric to increase the space between  legs and stabilize  the riders posture.