What studies, or even a series of documented obervations, say that 10% is optimum? Remember, some here are coaching football, not sprinters. I like heavy sleds and steep hills, along with Olys and squats, because they are one step closer to actual sprinting. I feel that the heavy sleds and steep hill are a bridge between the gym and actual acceleration. I haven’t seen any negative effects and haven’t seen anything that suggests its wrong. If you have such data, please post it.
