Shape Studio: Groundwork HIIT Session

Heat and humidity making you cranky? You're not alone. Studies have shown that when it's hotter and muggier outside, we're generally more anxious and irritable.

And while getting even sweatier with an outdoor workout might seem like the last thing you want to do, for celebrity trainer Ashley Joi, it's one of her go-to mood-boosting methods. "Outdoor workouts bring me so much joy," she explains. That joy is backed by science, too: A recent consensus in the Journal of Happiness Studies asked experts to rate 68 strategies for lifting one's happiness level. Being active ranked third, while working out took fifth place. (

Ready to get started? Here, Joi shares her favorite HIIT routine for hot, muggy days outdoors. And since the workout is mostly ground-level, you'll be less likely to feel fatigued quickly from the hot weather.

That being said, if at any point you start to feel too spent, stop, says Joi. "Since it's a warm, hot day, listen to your body and go at your own pace."

And don't forget to hydrate!

Groundwork HIIT Session

How it works: Warm up for five to 10 minutes before starting. Do each move for 40 seconds, resting for 20 seconds in between. Move through each of the seven exercises, then repeat for three total rounds.

You'll need: A resistance band with handles and a small looped band (or booty band)

Banded Thruster

A. Stand with feet hip-width apart. Loop the resistance band with handles under both feet. Hold onto a handle with each hand, bringing hands to shoulders in a front rack position.

B. Hinge at hips to sink into a squat, pausing briefly when thighs are parallel to the floor (or as low as is comfortable).

C. Push into the mid-foot while using the glutes and hamstrings to drive hips upward to a standing position. At the same time,press arms overhead, handles directly over shoulders. Brace core, and exhale at the top.

D. Immediately lower hands — to shoulders/hips — and sink into a squat to begin the next rep.

Repeat for 40 seconds. Rest for 20 seconds.

Scale it up: Add a pulse at the bottom of the squat.

Scale it down: Remove the resistance band.

Banded Mountain Climber

A. Loop a mini band around both feet so it goes underneath heels. Crawl out to a high plank position. Arms should be fully extended, palms pressing firmly into the ground, fingers splayed slightly. Back should be flat and core and glutes engaged to start.

B. Drive right knee into chest, pulling the band along with it. Immediately return the knee to the start.

C. As soon as the right knee hits the starting position, drive the left knee into the chest. Continue quickly alternating legs.

Repeat for 40 seconds. Rest for 20 seconds.

Scale it up: Twist the band for extra resistance.

Scale it down: Remove the resistance band or tap each knee to chest slowly with control.

Banded Bear Jack

A. Loop a mini band around both feet so it goes underneath heels. Come onto all fours, hands under shoulders and knees under hips, toes tucked. Hover knees roughly one inch above the ground to start. (This is bear position.)

C. Holding hold bear position, jump both feet a few inches out to either side, then immediately jump them closer together to return to start. Repeat.

Repeat for 40 seconds. Rest for 20 seconds.

Scale it up: Twist the band for added resistance.

Scale it down: Remove the resistance band or step out one leg at a time with control.

Reverse Lunge to Banded Bicep Curl

A. Loop a resistance band with handles under the right foot. Stand with feet hip-width apart, holding onto a handle with each hand, arms by each side, wrists facing inward.

B. Step the left foot back into a reverse lunge, both legs forming 90-degree angles with the left knee hovering slightly above the ground.

C. Step the left leg forward to stand. Once upright, curl the handles up toward shoulders, keeping the chest proud and upper arms as still as possible.

D. Lower handles with control to return to start.

Repeat for 40 seconds. Rest for 20 seconds. Switch sides; repeat.

Scale it up: Add a pulse at the bottom of the movement.

Scale it down: Remove resistance band. If arms feel fatigued, curl the band every other rep.

Banded Jumping Jack

A. Loop a mini band around both legs just above the knees. Stand with feet together and arms by sides.

B. Bending the knees slightly, jump feet out wide, reaching arms out to the sides and overhead.

C. Jump feet together, lowering arms by sides.

Repeat for 40 seconds. Rest for 20 seconds.

Scale it up: Twist the band for added resistance.

Scale it down: Step out one leg at a time with control.

Banded Bear Crawl

A. Loop a mini band midway up the shins and assume bear position.

B. Holding bear position, walk the left hand forward while also walking the right foot forward. Then, walk the right hand forward while also walking the left foot forward.

C. Continue the crawling motion for four to five reps forward, then move four to five reps backwards, depending on the length of the mat. Keep core engaged and back flat the entire time.

Repeat for 40 seconds. Rest for 20 seconds.

Scale it up: Move as quickly as possible (while maintaining proper form) forward and backward.

Scale it down: Remove the resistance band entirely.

Banded Cross-Body Mountain Climber with Push-up

A. Loop a mini band midway up the shins and assume high plank position to start.

B. Lower the chest to the ground (or as low as possible) in a push-up, keeping elbows tucked close to the torso and core engaged, so body forms a straight line from head to toe.

C. Press body back up to high plank.

D. Drive the left knee to the right side of the chest. Return to high a high plank position, then repeat on the other side.

E. Do 8 reps of mountain climbers (4 on each side), then begin the next rep with a push-up.

Repeat for 40 seconds. Rest for 20 seconds.

Scale it up: Twist the band for added resistance.

Scale it down: Remove the resistance band or do the pushup on the knees. (Just ensure that the body forms a straight line from head to knee, and elbows stay tucked into the torso.)