Your lower back. Generally the most neglected body-part in the average dude’s workout, those erector spinae muscles will be crucial for all the lifting and bending.
Do this
Back extensions. If they’re not already part of your fitness routine, start very slowly. Try 3 sets of 8 reps on a back-extension bench, and once you feel comfortable with that, add reps, or try it while hugging a 25-pound plate to your chest.
our quads and core, which will allow you to descend in a straight, steady motion without your baby toppling forward out of your grasp. (Trust me, the kid’s mother will never let you hear the end of it.)
Do this
Dumbbell/goblet squats. The point is to keep your back as straight as possible, so you may want to practice without weights until your form is perfect. Once you’ve got it down, I suggest these two variations: Squatting with a pair of 25-pound dumbbells held vertically against your chest (3 sets x 8, increasing dumbbell weight as necessary), and squatting with a 45-pound weight plate held directly over your head (3 sets x 8, increasing reps as necessary). Get good at this, and balancing an infant will seem like a piece of cake.