tips to keep the whole hand loose while tremolo picking

Hi

I'm practicing picking technique (lesson https://www.guitartricks.com/lesson/10337) and I feel my bycepts work and not wrist only. I try to loose, but not the bycepts. Any additional tip, maybe I'm doing the wrong movement therefore getting bycepts involved?

Thanks 

This is a matter of consciously reminding yourself to stay relaxed until it gradually becomes second nature.  Any time you notice tension from your back, neck, arms, down to your fingers you need to stop & remind yourself to relax!