> Jen says researchers suspect that treadmill running is more intense and leads to improvements in muscle aerobic capacity, and this increased aerobic capacity, in turn, affects the brain more than the wheel jogging.

So the subjects didn't know how to lift and the researchers didn't know how to instruct the subjects to lift. The suggestion that a proper 20 minute lifting session would be less intense than 20 minutes on a treadmill is ridiculous. Done correctly lifting will leave you gasping for air.