“However, we quickly realized you cannot use concrete alone to make a flywheel, because concrete doesn’t resist traction from external forces ... the tension, you have issues with glass fiber breaking ...

Forget the drill, forget the hammer: Nab a couple of thin tension rods, and they'll join forces as a shelf ... But you can take the concept vertical to corral stackable items.

Methods Vertical ground-reaction forces of experienced runners (12 male, 12 female) were obtained during overground and treadmill running at slow, preferred and fast self-selected running speeds.