Exercise · Shoulders

Serratus punch

Lying on your back with the arm pointed at the ceiling, you push the fist a few inches higher — the elbow stays locked, so the only thing that can move is the shoulder blade sliding forward around the ribs. That slide is the serratus anterior, the fan of muscle along the side of the ribcage that both holds the shoulder blade against the chest wall and helps rotate it upward as you reach. Momentum's upper-body chart lists it as commonly weak, and its shoulder flow names it explicitly in the activation step.