Hi! Jon’s very focused here with a 10lb dumbbell in a sidebridge. This works ‘core’ muscles which he needs to strengthen in various planes to compliment his golf and running with his athletic son. He’s got great control. He will hold for 20-30 seconds, 2 sets each side. I love that he never misses a session. Consistency is key!
This is a an excellent, very valuable article by Dr. Kenneth P. Moritsugu, formerly Deputy Surgeon General and the Acting Surgeon General of the United States.