I make it a point to get the kids out nearly every day, and they are now too fast for me to chase on their bikes. They have separately asked to go running with me, and are faster over short distances than I. One kiddo offered to coach me, and then proceeded to tell me 'my secret to being fast is to look fast' and demonstrated in slow-mo her running, arms swinging wildly and suggesting 'you have to alternate a chopping hand and a fist as you swing them back and forth." I'm going to take her up on the coaching and see what other gems she has to dole out.