IPA: /dɪˈtreɪnmənt/
KK: /dɪˈtreɪnmənt/
The process of stopping training or exercise, often leading to a decrease in physical fitness or performance.
After a long break from running, I experienced some detrainment and had to work hard to regain my stamina.
Detrainment → It is formed from "de-" (meaning down or away) and "train" (from Old French *traïner*, meaning to pull or drag). The word refers to the act of getting down from or away from a train, or the process of removing someone from a train.
Think of 'getting down' ('de-') from a 'train' — that's what detrainment means.