"Weasel words". Great. What's your best reply to him then?

Sustained aerobic activity is a sign of being able to feed the muscles as you know. I can sprint to 50kph or just saunter along at 25kph. I keep a decent cadence at 35. It's an example for him to understand that his average of 12.6mph can be improved with commitment.

So instead of harping on what you perceive as a weasel word offer something constructive. Can you?