Hold a dumbbell in one hand, stagger your feet, and bend the knees and hips to lean the free forearm on the same side thigh.
 
Keeping the forearm on the thigh, perform a dumbbell row using some push of the legs and rotation of the trunk to help accelerate the weight up to maximal height—squeeze the shoulder blade back and down at the top of the pull.
 
Purpose
The chainsaw row allows very heavy loading because of the contribution of the whole body to accelerating the weight. That contribution can be adjusted for the desired effect and loading, and can be increased as a set progresses to allow more reps under fatigue.
 
Programming
Generally sets of 6-15 are appropriate.