Amongst officers: Strategic, Tough, Ready Around the Clock.
Amongst enlisted: SHIT! The Russians are coming!
The second sense referring jocularly to the readiness level that was needed in "rapid deployment" units -- troops who would need to activate/deploy in as little as 2 hours if the Russians really were coming (Cold War)
"You've all got inspection at 0700 hours tomorrow. That's a full gear inspection by the CO, and you BETTER be looking STRAC!"