Ideally you'd never skip your warm-up if you're training first thing in the morning, since your body needs to ease into movement after being still overnight.
At any other time of day, abbreviated routines will do when you're short on time.
It’s safe to skip stretches before a run as long as you start with 5 minutes of walking and 10 walking lunges per side, says Kevon Daley, master instructor and personal training manager at Equinox Brickell Heights in Miami.
Before heavy lifting and HIIT, though, mobility exercises are essential for activating your muscles and aligning your joints to avoid damage. Daley recommends you at least move through the World’s Greatest Stretch and Cat/Cow for 20 seconds each. Both drills target the hips and spine, which are often tight from sitting but highly engaged during plyometrics and lifts.
The bottom line: