As an avid reader of Science fiction I always thought, secret of speedy walking is to defy gravity. Later when I read “walk is nothing but a series of fall supported by leg” it struck me as joke, and later I was dumb by the profound implication and simplicity of the statement.
When we walk, we raise our body against gravity and let ourselves fall in front. We repeat the process to move forward. This is process adopted by all non-wheeled movement. Gravity and friction thus helps us in moving forward. Less gravity will make us more energetic but not nacessrily move faster. The secret in moving faster is to control our motions to use less energy.
Birds also uses the same princlple in flying. Bird flaps its wing to go up and then spreads it to move forward in a controlled fall. Fish looks to be a odd one out, as fish in water is actually weightless. But the study shows the movement of fish is possible as displacement of water. It creates a swirl in water by its tail and pushes the swirl back to move forward. Water pressure, thus gravity is required to create the swirl.
It looks very strange that for movement we are bound and at the same time empowered by gravity. Perhaps it is similar with other things also. The same thing that looks to be a hinderance at first sight actually enables us to perform. Maybe such discovery is awaiting for some learned soul to take a fresh look.