Written by Sam Coleman | Co-founder
Fact checked by Kirsten Yovino, CPT Brookbush Institute
FACT CHECKED
In the fitness world, people like to compare various exercises. One of the most common matchups is planks vs crunches. In this post, we dissect both planks and crunches to look at what they are, the benefits of doing them, how to do them, muscles worked, plus we give a few variations of each.
If you want to know all about planks vs crunches, then continue to read on.
PLANKS VS CRUNCHES, WHICH IS THE BETTER CORE EXERCISE?
Both exercises have their merits, but if we had to go with one exercise, planks would be our choice. We would choose planks over crunches because they engage more muscles and are a more complete exercise in terms of the amount of muscles being worked and muscle activation. Put simply, planks do a better job of building overall core strength AND improving overall performance.
Crunches aren't one of the most effective core exercises as shown in this study by ACE, which demonstrates that the traditional crunch ranks towards the back of the pack compared to 13 other ab/core exercises.
THAT SAID, crunches have their place too. The crunch is an isolation exercise for the abs (rectus abdominis...particularly the upper rectus abdominis). So, if you want ab specific work? Enter the crunch.
The nitty-gritty comes down to the fact that crunches purely work the abs and somewhat the obliques while planks hit muscles throughout the body (even non-core muscles). Planks are also a better choice for people who have back or neck issues as they are an isometric holding exercise that doesn't put much pressure on these regions. Isometric exercise also tend to be best for building strength, and when it comes to the core, it's really all about building strength (as diet is what makes your abs show - although the abs can be developed to some degree).
BUT, the truth is, you really can't compare planks and crunches...
They are very different, and they actually complement each other to a degree. But, while you can get away without doing crunches, in our opinion, planks are a must.
It's sort of like comparing squats to leg presses (or maybe even leg extensions). Planks being the squat (although not an isometric exercise, it's a big compound exercise, so you get the point).
If you are looking for an exercise that focuses on isolating the abs, crunches make sense. Sometimes, you really need to hone in on a muscle with an isolation exercise to give it enough volume/attention, especially as your training becomes more advanced and your progress.
You may find planks don't give your abs (specifically) enough activation alone anymore. With that, you can slide crunches into your core workout routine for a few sets every week to good success.
What's more, there are many variations of crunches that are more effective and complete exercises. We will provide you with some of the best crunch variations, as well as plank variations below.
Below, we are going to cover planks and crunches in-depth, starting with planks. For both, we will provide how to do them with correct form, the muscles worked, benefits, and best variations. Let's begin...
WHAT ARE PLANKS?
Planks are sometimes referred to as an ab bridge, or front hold. The exercise is a core strengthening exercise that works by isometrically holding a fixed position for as long as you can.
Isometric = holding a fixed position (which is different than concentric-eccentric exercises which move the muscles through a range of motion).
There are many variations of planks, but the two standard versions are the high plank and low plank. Both are front planks, meaning you are facing the ground.
A high plank essentially holds the top of a push up position.
A low plank is similar to a pushup position except with elbows on the ground under your shoulders.
By planting your elbows and forearms on the floor (or hands, in context of a high plank), you'll stabilize your body.
Planks are a fantastic exercise to work the core, including the abs (both the rectus and transverse abdominis) , obliques, and lower back, plus your glutes and shoulders (and even upper back) will be engaged as well. Planks are also a great exercise to mitigate potential back pain as they help bolster the core strength needed to relieve pressure on the lower back.
Note: The high plank places more emphasis on your shoulders and upper body, but is slightly easier than the low plank, which places more emphasis on the core. The reason the low plank is harder is because of the emphasis placed on the core! Most people are weaker in their core than the arms.
The goal of the plank is to progressively challenge yourself by holding the position for more extended periods, using less rest time between sets, and/or trying harder plank variations.
There are both harder and easier plank variations.
HOW TO DO PLANKS:
We'll cover the cues on how to execute the perfect standard plank (which is generally considered to be the low plank, aka elbow plank):
- Get onto the ground on hands and knees.
- Bring your feet behind you so that you're in a pushup position.
- Lower the top half of your body down by placing your elbows and forearms are on the ground.
- At this point, your body should be in a straight line without your hips sagging.
- Engage your abs to stay in this position as you maintain a neutral spine.
- Hold this position as long as possible.
Note: Keep your head and neck in line with your spine with your back flat. Remember to breathe throughout the exercise.
PLANKS MUSCLES WORKED
Planks are an isometric exercise that engages muscles from head to toe. Starting from the top, let's go over some of the muscles you'll use when performing planks.
Core: The core has up to 35 muscle groups usually split into four groups; back extensors, lateral trunk muscles, hip muscles, and abdominals. We will cover the back extensors more below, so let's look at the core muscles on the anterior or front side of the body. When doing planks, you'll be engaging your entire core to keep your body aligned without letting your hips sag. The main muscles working here to make this happen are the rectus abdominis AKA the 6-pack muscles, the transverse abdominis, and the internal/external obliques. The rectus abdominis' primary function is to flex the trunk anteriorly, stabilize the pelvis and help with other bodily functions such as breathing. The transverse abdominis located under the internal obliques helps stabilize the pelvis and the spine and keep the core compressed (this is an important aspect of the plank - abdominal compression, which you won't get to the same degree with many of ab exercises). The obliques run on the outside of the rectus abdominis act to stabilize the spine and counteract the rotation of the trunk.
Shoulders: The shoulders comprise three deltoid muscles; the anterior deltoid, lateral deltoid, and the posterior deltoid. These muscles are primarily responsible for the movement of the arms. The deltoids are engaged to keep your upper body stable when performing planks.
Arms: Surprisingly, the muscles of the upper arm, both the biceps and triceps, support proper plank execution. The biceps primary responsibility is flexion of the arm at the elbow, while the triceps are the primary mover in elbow extension. The muscles are activated as your upper body's weight is being supported.
Chest: Most would think of the chest muscles as the pectoralis major and minor because they are the big muscles that create the shape. However, when doing planks, the other chest muscle, the serratus anterior, is the one that goes to work. The serratus anterior is the fanlike muscle found on the upper ribs. This muscle helps to keep your upper body in a stabilized, fixed position, so your chest doesn't drop towards the ground.
Back: The back consists of 40 muscles, but we'll only focus on the engaged ones while doing planks. The main muscles of the back worked are the erector spinae, trapezius, and rhomboids. The erector spinae are the muscles running alongside your spine that support spinal extension and flexion. The trapezius is the large muscle triangular muscle found on the upper mid-back that is mainly responsible for the movement of the head and shoulder blades. The rhomboids consist of the major and minor rhomboids that are found in the upper back between the shoulder blades, and their main function is to move the arms and stabilize the shoulder girdle. These back muscles work to keep your body in a stabilized fixed position while doing planks. The latissimus dorsi also plays a minor role in ensuring your upper body remains aligned in a plank position.
Glutes: The glutes are comprised of three muscles; the gluteus maximus, gluteus minimus and gluteus medius. These muscles connect the pelvis to the femur, so they primarily function to support the movement of the legs at the hip joint. Squeezing your glutes when doing planks gives extra stability in keeping your body aligned. Another muscle to mention here, although not technically a gluteal muscle, is the tensor fascia latae that helps with knee flexion and lateral rotation. This little muscle found deep to the IT band assists the glutes to provide hip movements while also helping with pelvic stability.
Legs: The legs get a decent workout while doing planks as the quadriceps on the front of the thigh help stabilize the hips. In addition, the hamstrings play also play a role to counterbalance your body against gravity, helping to maintain trunk and leg alignment. Last but not least, the tibialis anterior on the front of your lower leg is activated as your toes press against the floor.
BENEFITS OF PLANKS
Even though planks are an isometric exercise, they require multiple muscles to be engaged in the upper and lower body.
Here's a quick look at the benefits of doing planks.
- Improve Core Strength: Planks activate muscles throughout your core. Your core is the foundation of many movements you make in everyday life, so a stronger core will lead to living a healthier life. Planks work the core muscles on both the front and backside of the body making them an awesome exercise.
- Better Posture: Planks work the muscles of your core to improve your posture. Many people are sitting at their desks all day, leading to bad posture. You can start to counteract the effects of sitting all day by keeping your bones aligned in the plank position. By bracing yourself in the plank, you will work the abdominals, spinal erectors, rhomboids, and traps, all of which help improve your overall posture.
- Reduce Back Lower Back Pain: The benefits of improving posture and strengthening the core compound to help reduce lower back pain. In addition, the alignment and strengthening of the spinal erectors can lower the pressure felt in the lower back area. This, combined with stronger ab muscles, take some of the burden off of the lower back when supporting the body.
- Improve Flexibility: You wouldn't usually think of the plank as an exercise related to flexibility, but if you've ever done yoga, you know that planks play an essential part in many sessions. For example, planks can help with flexibility in the shoulder region. Other planks can work your flexibility even more by rocking planks or side planks.
- Burn Calories: Yes, planks can burn a good number of other calories even though you're not moving. You will be engaging multiple muscles throughout your body to stay in the proper position, which requires your heart to pump blood throughout your body leading to calories burned.
TOP 3 PLANK VARIATIONS
You can use these variations of planks to shift the emphasis to various muscles so that you cover all your bases.
1. SIDE PLANK
Side planks are an excellent exercise to hit the obliques. Strong, healthy obliques are necessary for movements that require any rotation or bending of the trunk, plus they help protect the spine. In addition to working the obliques, the quadratus lumborum is engaged, which stabilizes the spine. This exercise is no walk in the park; if you've never done side planks, you should add them to your workout routine.
How To:
- Lie on your side with your legs fully extended with your feet on top of each other
- Stack your lower arm's elbow under your shoulder with your forearm angled away from you as you make a fist with your hand and your pinky is resting against the floor
- Exhale while bracing your core as you lift your hips off the ground
- Keep your body aligned from head to toe as you hold this position for as long as you can but shoot for 30-60 seconds
- Repeat desired number of reps, then complete on the opposite side
2. PLANK WITH SHOULDER TAP
This plank variation adds an extra layer of difficulty. Your core muscles are forced to help you balance as you reach one arm off the ground. The plank with shoulder tap is a fantastic bodyweight core exercise that you can do just about anywhere. This is a real calorie killer; we always encourage people to incorporate this movement into their workouts once they're mastered the traditional plank.
How To:
- Get into a high plank position. So, the starting position is essentially the push up position, although the feet can be spread a little more than hip width for balance.
- Then lift one arm up off the floor while keeping your torso squared forward and touch your opposite shoulder.
- Alternate this movement for desired reps.
3. REVERSE PLANK
The reverse plank is another body position that you're likely to see in yoga. This plank variation hits the posterior chain while also engaging the abs. It's a great core strengthening exercise that will help to stabilize the spine. The glutes and hamstrings will have to work harder here to keep your body aligned while your hips don't drop. If you have any shoulder, neck, or wrist issues, you might want to avoid this exercise due to the pressure placed on these areas.
How To:
- Sit on the ground, then extend your legs out
- Place your palms on the floor just behind your hips
- Push into the floor through your hands while lifting your hips on the ground as you look up towards the ceiling
- Engage your core and hold this position with your body in a straight line for 30-60 seconds
- Lower your hips to the floor
- Repeat for desired reps
Want more plank variations? Here are the 29 best plank variations (this includes some easy variations for newbies and much harder variations!)
WHAT ARE CRUNCHES?
Crunches are one of the most popular core exercises. This core exercise emphasizes the abdominals and obliques. Like planks, this is a bodyweight exercise with many variations. However, the standard crunch is done by lying on your back with your knees bent and feet on the floor while you crunch up, bringing your upper back off the floor. Hand positioning for this exercise can vary with hands behind the head or with your fingers at your temples.
A significant difference between a crunch and a plank is that you will be moving your body while working the muscles with a concentric contraction rather than an isometric hold.
HOW TO DO CRUNCHES:
Below you'll find the cues on how to perform the standard crunch:
- Lie down on your back, then bend your knees to plant your feet on the floor hip-width apart
- Bend at the elbows, then bring your fingertips to your temples (you could also fold your arms across your chest with your hands by your shoulders)
- Inhale, then squeeze your abs
- Exhale, then lift your upper back off the floor, bringing your chest towards your knees while you keep your neck relaxed
- Slowly lower down to the ground as you inhale
- Repeat for desired reps
Note: Try to avoid placing your hands behind your head as some people tend to pull up from here, which can cause injury. Only lift your upper back off the floor by engaging your core.
CRUNCHES MUSCLES WORKED
Crunches target specific muscles in your core, but there are only a few targeted muscles due to their limited range of motion. Here's a glimpse at the muscles that are activated when doing crunches.
Rectus Abdominis: Touched on above, the rectus abdominis is an important muscle to help with spinal flexion. To crunch your body up off the ground, this muscle is activated.
Tranverse Abdominis: The transverse abdominis lies underneath the rectus abdominis and obliques and actually wraps all the way around your core to your spine. You can think of it like a corset. Crunches also work the transverse abdominis through abdominal compression.
Obliques: Both the internal and external obliques work alongside the rectus abdominis to perform movements that require spinal flexion, so they play a supporting role in crunches.
BENEFITS OF CRUNCHES
As one of the most popular core exercises, there are numerous benefits offered by crunches.
Let's have a look below.
- Isolation for the Abs: Crunches target the ab muscles and help you chisel out that 6-pack. Besides having a great-looking stomach area, strong abs will allow you to move better in many daily activities. The improvement in core strength can also help to lessen lower back issues. The primary mover in crunches is the rectus abdominis which is activated more in the crunch than the sit-up. Overall, isolation exercises are good just to ensure you have given enough volume and attention to a specific muscle. For many people, they find planks simply aren't enough to activate the abs to the degree needed.
- Increased Stability: Crunches work the abdominal muscles, which are partly responsible for keeping you stable and upright as you move. Crunches assist in building up the endurance of the ab muscles so that they can perform better, thus helping you execute daily activities with ease.
- Burn Calories: Crunches may seem like an easy exercise to do, but when performed correctly, you can burn some serious calories.
TOP 3 CRUNCH VARIATIONS
There are many types of crunches that you can do with your body weight at home. Here are three of the most effective types of crunches to build those rock-solid abs.
1. BICYCLE CRUNCH
First, bicycle crunches involve two movements that act on the core rather than one, and that is hip flexion and spinal flexion. That means you will be working both your upper and lower portion of the abs (as the lower abs are better activated through hip flexion). It will also bring your hip flexors into play. What's more, this movement involves a degree of rotation, which is great for your obliques, making it a well-rounded exercise to bulletproof your core. This study shows that bicycle crunches activated the rectus abdominis more effectively than twelve other typical ab exercises.
How To:
- Lie down on your back with your upper back and head just above the floor
- Set your hands to the sides of your head on your ears
- Raise one leg off the ground with it fully extended while bending the other leg up towards your chest
- Twist at your core to bring your opposite arm towards your bent knee by driving your shoulder in that direction
- Lower your bent leg while bringing your extended leg up towards your chest and at the same time twist your core the opposite way to mirror the movement
- Repeat for desired equal reps to each direction
2. EXERCISE BALL CRUNCH
The exercise ball crunch engages the abdominal muscles more than a traditional crunch. This is due to the increased need to stabilize your body on the ball, as well as the increased range of motion.
How to:
- Set up the exercise ball
- Lie on the ball, so your mid-lower back is in contact with the ball with your legs in front you bent at the knees with feet firmly planted on the floor hip-width apart
- Follow the same cues from a traditional crunch by bringing your chest towards your knees as you contract your abs
3. VERTICAL LEG CRUNCH
The vertical leg crunch mainly focuses on working the external obliques and rectus abdominis. You'll also get a secondary benefit of hitting the internal obliques hip flexors by having your leg extended upwards. The transverse abdominis is activated as you exhale when you lift your upper back off the floor.
How To:
- Lie down on your back, then raise your legs off the ground so that they're perpendicular to the floor
- Place your fingertips to the side of your head
- Repeat desired reps
FINAL THOUGHTS ON DOING PLANKS OR CRUNCHES:
There are a few contributing factors when looking at doing planks or crunches and which are better. Overall, the plank is a more complete exercise that will yield better results (both on core strength and overall performance) for most people. However, crunches are good for the abdominals specifically.
In the end, when comparing planks vs crunches, you can see they are really different exercises and they actually compliment each other. We believe in using a variety of exercises when training, so if you still want to get some work on the abs, it won't hurt to add some crunches to the mix. But, planks are a must.
More Core Workout Resources:
Sam Coleman
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