Linda Green 2001 S01E08 (Requested)

Episode: Fitness Freak. Linda is delighted when she heads out one morning, and watches a fine figure of a man jogging by. She starts deliberately leaving home as he jogs past, and exercising in the front garden. It does the trick, he introduces himself. Karl is in training for a 100 mile triathlon. Linda embarks on a fitness regime to try and impress him. Darren and Jimmy won't admit to being unfit, so end up roped into attending the circuit training sessions Karl runs.