id like to know what causes the triceps atrophy that is so predominant in older pros.
Spinal stenosis caused by cervical vertebrate/disc damage. The correlation is undeniable.
Damage to the cervical vertebrate and their disc often result in the reduced ability to recruit or fire your triceps. The damage occurs to the radial nerve. It happens more often to the left arm than the right arm. Ruhl and Coleman were text book examples.