The Carry (or Farmer’s Walk) is a full-body core exercise but if you can’t grip it, you can’t lift it. That’s why it’s listed in the UPPER category. As the load & time-under-tension grows on this exercise, so will your entire upper body. The key to getting the most out of this drill is to keep the weights away from your thighs & sustain an active rear delt contraction throughout. Go slow and keep your knees soft & toes pointing forward as if taking a sobriety test.
There are 3 key holding positions, from easiest to hardest: hip-level, shoulder-level & overhead. In terms of loading, you should be able to carry at least twice the weight at hip-level that you can overhead. I love doing level-change drop sets where I start with overhead carries for a minute then drop to shoulder-level for a minute & finish with hip-level for another minute.
To increase core & hip activation, work in single-arm variations. An awesome starter or finisher is to do a minute on each arm back-to-back for 10 straight minutes.