Still going to be weak as a kitten, though.
That was my take. You can usually get very high results, in terms of percentage, when you go from nothing to something. E.g. going from 0 to 1 is an infinite percent increase! ...but then you get diminishing returns as you do more. It seems all the test subjects never did anything. I’d be more curious about somebody going from exercising 15mins/day to 30mins/day, or 20m/day to 1hr/day.
I tend to live by the 80/20 rule...I want 80% of the benefits with 20% cost/effort.