Catherine, your hack may prevent hundreds of back strains this summer:
I just bought my 3 year-old a tricycle this weekend and after assembly, she immediately wanted me to push her while she steered. My father and I took turns breaking our backs with this exercise, then he stepped into the house and returned with a mop. I watched in amazement as he quicky turned our standard sponge mop into a makeshift handle for the tricycle. Just place the rectangular head of the mop up against the base or seat back and push away. Worked like a charm!