I like this! It's metaphorical enough to apply to a wide variety of context, in my opinion."The only time I back up is when I take a run-up" doesn't sounds good. I would say "when preparing for a run-up", and you almost need to be more specific about what the run-up is for. I am really not sure what the best translations would be for that particular sentence (even after plenty of sleep). Perhaps "I only step back when preparing to leap forward" captures the intention...?