These five isometric core exercises (and their modifications) are foundational to establishing lasting, functional core strength. The exercises in this category focus on getting the muscles of the core that tend to be the laziest to wake up and start doing some work.
Almost every exercise in this series requires you to hold a specific pose for a designated amount of time (this is what makes it isometric), which can be challenging and a bit frustrating. You need to remain focused on the quality of your form during these routines, so don’t zone out! Developing your ability to engage the deep muscles of the core is essential to completing the more complex exercises in the other routines.
Work a few of these isometric core exercises into your cool down or strength training program two to three times each week.
Core focus: All the muscles from your shoulders to the bottom of your hips.
It’s no coincidence that we begin our core strength routine with one of the most iconic of core exercises: the plank. By positioning your body parallel to the ground, you are removing the benefit of gravity in supporting your body weight. Instead, your core muscles must support the weight of your body.
On Your Knees | 20–30 seconds
Lie facedown on the floor. Place your forearms parallel to each other, like a sphinx. Keeping your neck neutral (don’t look up or down), push up onto your forearms and lift your chest. Keep your knees on the floor but actively engage your abdominals and glutes to hold your body in alignment. Think of gently puffing your low back up toward the ceiling while dropping your tailbone toward the floor. This should be a subtle, natural movement. Continue to breathe while holding this position.
On Your Toes | 30–45 seconds
Place your forearms parallel to each other on the floor. Push up onto your forearms and lift your chest. Actively engage your abdominals and glutes to hold the position. Be sure to keep your neck neutral and your ears in line with your shoulders, continuing to breathe as you hold this position. You might find yourself tempted to rock backward and lift your hips toward the ceiling as you fatigue. Fight to keep those hips low, shoulders directly over the hands, and tailbone slightly tucked!
With Elbow Raise | 10 reps each side
This version of the plank hold still focuses on an isometric hold in the trunk, but the arms will slowly lift out to the side to challenge that hold. Start in the basic plank position, then slowly raise one elbow out to the side, stopping when your elbow reaches shoulder height. Bring your forearm back down to the floor, then lift the opposite arm. Continue alternating arms to complete the set.
Core focus: Internal and external obliques.
Side planks are a must-have exercise when it comes to strengthening the core because they recruit so many muscle fibers. This one is tough but well worth it!
With Knee Support | 20–30 seconds each side
Begin by lying on one side with your elbow positioned on the floor directly below your shoulder. Bend your bottom leg for stability and extend your top leg out straight. You can keep your top hand on the ground in front of your chest for extra support if you need it, but the goal is to rest your arm on your side or hip so you can engage more of your core muscles. Push down through your bottom elbow and lift your hips as high as possible from the floor. Your bottom knee will remain on the ground. Hold that position for 20 to 30 seconds and repeat on the opposite side.
Without Support | 30–45 seconds each side
Start on your side with your elbow lined up beneath your shoulder and extend both legs out straight. Rest your top arm along your side and push down through your bottom elbow and forearm as you lift your hips high. Check to make sure that your body makes a straight line from your shoulders all the way down to your ankles.
With Reach | 45–60 seconds each side
Get into side plank position with your elbow positioned below your shoulder and both legs extended. Push into the floor with your bottom elbow and forearm and lift your hips to make a straight line from your shoulders to your ankles. Reach your top hand toward the ceiling and hold steady to complete the set before repeating on the other side.
Core focus: The entire core musculature.
The bird dog gives the body practice in executing a cross-hemisphere movement, where the opposite hand and foot move in coordination with each other. This is one of those exercises that looks simple but is actually quite challenging. Don’t rush through this—breathe with the movement and focus on the quality of the movement not the speed.
From Quadruped Position | 10 reps each side
Begin in a quadruped position (on your hands and knees) with your hands directly below your shoulders and knees directly below your hips. Keeping your ears in line with your shoulders, reach one hand forward while you extend the opposite leg back. Keep your arm and leg parallel to the ground and think about trying to stretch the extension as much as possible. Hold for a few seconds, return to the starting position, and finish the repetitions before switching sides.
From Plank on Forearms | 12 reps each side
Start in a forearm plank position with your elbows directly below your shoulders. Extend one arm forward and lift the opposite leg while keeping your hips up. Stretch the extension from your fingertips to your toes, remaining parallel to the ground. Hold this position for a few seconds before returning to the starting position. Do 12 extensions before switching sides. (If the plank position is too challenging, put your knees on the floor in modified plank position.)
From High Plank | 15 reps each side
Start from a high plank or push-up position. Focus on squeezing the glutes while you lift one leg and extend the opposite arm forward. Hold it for a few seconds before lowering your arm and leg back into the starting position, working to lower the hand and foot to touch the ground at the same time. This exercise is more challenging, so try to slow down your breathing as you complete a set of 15 reaches, then switch sides.
RELATED: 6 Yoga Poses Runners Should Avoid
Core focus: Transverse abdominis, spinal erectors.
Boat pose is one of the iconic yoga poses that builds balance from a seated position. There are myriad variations, but for this routine we will focus on the isometric aspect.
With Feet on Floor | 20–30 seconds
Begin in a seated position. Bend your knees and place your heels lightly on the floor, approximately 2 feet from your glutes. Elongate your spine, pull your shoulder blades down and back, and keep your neck neutral by gazing forward at the horizon. Extend your arms out straight in front of the body, parallel to the floor and palms open to the ceiling. Slowly begin to lean back until you feel a good shake in the core muscles. Maintain an elongated posture through the spine as you hold this position.
With Feet Up | 30–45 seconds
Lean back into boat pose from a seated position. Keep your spine long and neck neutral as you pull your shoulder blades down and back. Lift your heels until your shins are parallel to the floor. Extend your arms forward, palms facing the ceiling and arms parallel to the floor—hold this position.
With Arms Extended | 45–60 seconds
From a seated position, tip back onto your tailbone into boat pose. Keep your spine long and neck neutral as you pull your shoulder blades down and back. Lift your heels until your shins are parallel to the floor. Extend your arms overhead, palms facing forward. Remember to breathe normally as you hold this position.
Core focus: Spinal erectors, quadratus lumbar.
The muscles of the back are frequently neglected in our core training routines, though they are just as important as the muscles on the front side of the body in terms of establishing muscle tone, good posture, and functional strength.
Upper Body | 10–15 seconds
Begin lying facedown on the floor or mat with your arms extended straight overhead. Keep the back of your neck long by looking down at the floor. Squeeze your glutes and raise your hands and chest off the ground, aiming to get your hands 6 inches off the floor. Hold this position.
Upper Body with Arm Sweep | 12 reps
Begin lying facedown on the floor or mat, arms extended down by your sides with palms facing the floor. Keeping the back of your neck long, squeeze your glutes and shoulder blades, raise your chest off the ground, and sweep your arms in a big arc until they are overhead. Bring your arms back down to starting position and relax your chest back to the floor between each repetition.
Upper and Lower Body | 15 reps each side, alternating
Lie facedown on the floor or mat with your arms extended in front of you, palms facing the floor. Raise one foot 6 inches off the ground and focus on squeezing the glute and extending the leg. At the same time, lift your chest and extend the opposite arm. Return to your starting position before reaching with the opposite leg and arm. Continue alternating sides until you complete the set.
Adapted from Core Envy: A 3-Step Guide to a Strong, Sexy Core by Allison Westfahl with permission of VeloPress.