The 4 one minute sprints twice a week is not, that I know, of a recommended form of exercise. The researchers were interested in the minimum amount of exercise out of scientific curiosity.
As you can imagine they experimented with other schedules less than and greater than 4 min x 2 time per week. Blood sugar was under excellent control with the minimum stated.
Strength, flexibility, co-ordination, fat loss, etc. are other considerations: but they did demonstrate their hypothesis that you need to deplete energy from your muscles to make room to sop up glucose in the blood.
p.s., you can imagine the horror we will soon face on late night TV as an infomercial selling a cheap exercise bike promises you CONTROL DIABETES AND LOSE WEIGHT WITH 8 MINUTES EXERCISE A WEEK. NO MONEY DOWN, PAY IN 8 EASY INSTALLMENTS, IF YOU ORDER NOW YOU GET A FREE ABERCISER. ORDER NOW OPERATORS ARE STANDING BY
Money cannot buy love, nor even friendship.