There's one surefire way to make a hard-hitting, quick and dirty workout challenging: lots and lots of reps. That's the approach Charlie Meredith, NASM-CPT, Barry's Chief Curriculum Lead in New York City, took when he designed this five-minute session.

The routine is simple. You'll only need to do three exercises, but the cumulative work will pile up quickly, since your delts will be taking on the entire load. You'll need three sets of dumbbells—a heavy, medium, and light set, depending on your fitness level—but it won't be a bad idea to have some lighter weights in reserve as the reps pile up.

You'll probably start strong, then find you're struggling to complete all of the reps as the rounds press on. That's just fine. Rather than pushing through pain, be smart. Do what Men's Health senior editor Brett Williams, NASM did when he took on the workout: Drop down to lower weights and slow your movements to prioritise form over speed once you feel your form starting to slip. You'll still get a nasty upper body challenge without as much risk of injury or total muscular failure.

The Barry's Delt Destroyer Workout

Perform each exercise for the allotted number of reps, then move on to the next with little to no rest. Repeat for as many rounds as possible within the five-minute time frame. Add on the optional finisher with any leftover time. Once form begins to slip, switch to lighter weights and emphasise proper movement over speed.

Dumbbell Overhead Press

12 to 15 reps

Dumbbell Around the World

12 reps

Lateral Iso Hold

10 seconds

Optional Finisher: Partial Lateral Raise Pulse

20 reps

From: Men's Health US