Is there a single exercise that could meet all your fitness needs? We asked five athletes, experts, and fitness instructors what their “pick one” choice would be.

Forearm Plank

Megan Bentley Kerr is a Pilates instructor at Pilates Plus OC in California. She says, “I'd recommend a plank hold. Having a strong core is so important and holding plank is one of the best isometric exercises you can do.”

Here’s how to do a forearm plank: Lie facedown on your mat. Extend your legs straight behind you and place your feet hip-width apart. Bend your elbows and place them directly under your shoulders. Place your forearms on the ground and clasp your hands. Then, contract your abdominal muscles, tuck your toes and lift your body. Try to form a straight line “plank” from your head to your heels and hold for as long as possible (20-60 seconds).

Walking & Pushups

Kelly Carlson is a two-time Iron Man Triathlete who lives and trains in Germany. She couldn’t quite pick one exercise, so she picked two—one for cardio and one for strength. She says, "For cardio fitness, I’d recommend walking. You can walk anywhere, anytime, any season and you can incorporate hills to boost intensity. If you have kids they can join easily by stroller, tricycle, bike, skateboard, or their own feet. For strength training I say push-ups."

Here’s how you do a pushup: Lie face down on your mat and place your hands about shoulder-width apart. Fully extend your arms while you push your body up. Then, lower yourself down until your chest almost touches the floor. Repeat for as many repetitions as possible. Build up to two sets of ten and increase repetitions as you grow stronger.

Squats

Michelle Jones is a Zumba Instructor in Portland, Oregon. She says, “If I could pick one exercise, I would definitely pick a squat. Squatting uses our larger muscle groups and gives us the most bang for our exercise buck. Not only does it benefit our leg muscles, but it also creates an anabolic environment, which promotes body-wide muscle building. The more muscle you have the more calories you burn. In addition to fabulous legs, you'll get a nice butt and great abs from squats."

Here’s how to do a squat: Stand up straight with your feet hip-width apart and your arms by your side. Lower your body by pushing your hips back and bending your knees while keeping your body weight on your heels. Raise your arms straight out in front of you for balance. Keep your spine straight and avoid letting your knees go past your toes. Lift in a controlled motion and repeat from your starting position for two sets of ten squats.

Running

Sarah Bowen Shea is a marathon runner, author, podcaster, and founder of Another Mother Runner, an online community and resource site for mothers who run. She says, “If I could only do one exercise, it would be running. I adore running's head-out-the-door-and-go simplicity, and the fact it takes no skill or coordination. There's no learning curve, yet you can always improve and hone your running. It's also my favorite way to be outside and enjoy my surroundings, whether exploring a city I'm visiting on business or enjoying the gardens and homes in my neighborhood."

Modified Planks

Roma Van der Walt is a fitness expert, trainer, marathoner, and founder of Chitta Wellness. She’s a fan of the “good old-fashioned plank” too, but with a few modifications. She says, “Once you’ve perfected a basic plank, try lifting a leg or arm or both, or doing ‘mountain climbers’ with the knee straight towards the elbow or across. Overall planks are great for working the core, glutes, quads, back. It even works for cardio exercise when the plank is sustained for 30-60 seconds.”

Roma Van der Walt, founder of Chitta Wellness, reviewed this article.