The crunch and plank exercises are two of the most popular movements to strengthen and develop the core. But which exercise wins in a plank vs crunches showdown? The answer depends on your training goal.

Crunches are an ideal exercise to isolate and strengthen the rectus abdominis, the sheet of muscle at the front of the stomach responsible for the sought-after six-pack. They’re a dynamic exercise that challenges the abs through their full range of motion.

In contrast, the plank is an isometric exercise, so the muscles involved do not shorten or lengthen during performance. The goal is to engage the core muscles to prevent spinal flexion or extension. The plank creates tension throughout the core, legs, and upper body. As a result, the crunch is a better exercise for working the entire core, with secondary emphasis on the legs and torso.

Planks Vs. Crunches: Key Information

Primary Muscles Worked

The plank is an isometric exercise that primarily works the rectus abdominis muscle, transverse abdominis, and obliques. It also engages the deltoids, erector spinae, glutes, and quadriceps to stabilize the body. As a result, the plank is an effective movement for overall core stability and strength.

The crunch is a dynamic exercise that moves the rectus abdominis through spinal flexion and extension.

The hip flexors and obliques are engaged as secondary muscles to stabilize the core. The crunch does a better job of isolating, strengthening, and developing the rectus abdominis. It does not significantly work other major muscle groups like the plank.

Key Benefits

The plank emphasizes core stability and muscular endurance. This exercise engages the entire core, which includes the rectus abdominis, transverse abdominis, obliques, and erector spinae. The stronger your core, the better your balance and stability will be.

Muscle endurance exercises, such as the plank, require you to perform movements for an extended period of time. For example, increasing core endurance with the plank will help you perform repetitive movements like rowing.

Strong core muscles also make it easier to perform everyday activities, such as lifting and carrying items. They promote proper body mechanics, reducing potential lower body strain.

The plank engages the shoulders, back, glutes, and quads as the body maintains its rigid isometric position, improving muscle endurance.

The plank also improves posture by strengthening the muscles supporting the pelvis and spine. The exercise promotes a neutral spine position, which helps counteract the tendency to slouch or round the back.

On the other hand, the crunch dynamically engages the rectus abdominis or six-pack muscles. This isolation exercise primarily strengthens and develops this specific muscle. When performed in conjunction with a healthy diet that reduces abdominal body fat, the crunch helps build strong, defined abs.

Form And Technique

Plank

1. Get down on the floor with your toes and forearms resting on the floor. Your legs should be extended with your feet together.
2. Engage your core by pulling the belly button in and tightening the lower back muscles. Maintain a straight line from your neck to your toes.
3. Push the ground away from you as you tense your entire body.
4. Hold for the required period, looking straight ahead the entire time. Remember to breathe.

Crunch

1. Lie on your back with your knees bent and your feet hip-width apart. Place your hands behind your head with fingers interlaced.
2. Look up as you lift your upper body off the floor using your core. Tense your abdominal muscles in the top position.
3. Lower under control and repeat.
4. Exhale as you crunch up; inhale as you lower to the start position.

Difficulty Level

The difficulty level of the plank varies according to the length of time the position is held. There are also different ways to do the exercise to make it more difficult. The forearm version of the exercise, as described above, is the least difficult.

The isometric hold nature of the exercise demands sustained muscle contraction, which becomes more demanding as time passes. This exercise tests core strength, muscle endurance, and mental strength.

The crunch is a beginner- to intermediate-level exercise in terms of difficulty. The standard crunch is a simple exercise to perform, but it becomes more challenging as you increase the rep count. There are a number of versions of the crunch that make it more difficult. These include weighted crunches and bicycle crunches, where your feet are elevated. 

Potential Risks

When performed correctly, the plank and crunch are safe exercises. Here are some potential risks that may result from poor technique:

Plank

If you allow your lower back to sag during the exercise, you will lose core engagement and alignment, which can cause lower back strain. Neck strain may also result if you look up or down during the exercise. That is why you should always look directly ahead.

Crunch

Pulling on your neck with your hands as you lift your upper body may result in neck strain. Excessively arching your lower back as you lift can also worsen an existing lower back condition.

Who Should Prioritize Planks?

Planks should be prioritized by individuals looking for a comprehensive core workout that enhances overall stability and endurance. 

It is especially beneficial for athletes who perform dynamic movements. Strong core stability is needed for sports like tennis, gymnastics, and martial arts.

People who follow a sedentary lifestyle will find this exercise beneficial for building up weak core muscles. Those with lower back pain will benefit from the core strengthening that this exercise provides. This will support the spine, helping to relieve pain.

The plank is better suited to people wanting a full-body workout compared to crunches.

Who Should Prioritize Crunches?

Crunches should be prioritized by people who want to isolate and strengthen the abdominal muscles. They are ideal for bodybuilders who wish to define the appearance of their abs.

People who want to strengthen their abdominals primarily will benefit more from this exercise than the plank. 

How To Program Each Exercise

The plank and crunch can both be part of effective core and ab workouts for women and men. Here’s a breakdown of how to program each exercise. 

Plank

Beginners should hold the plank position for 15–30 seconds several times per week. Intermediate-level exercisers should aim for 30–60 seconds, and advanced exercisers should aim for a 60–second or longer hold.

If the standard plank is too challenging, you can begin with your knees on the ground. Advanced plank versions may involve doing the exercise on your hands, performing shoulder taps, and doing side planks.

Planks can be part of your core workout. Pair them with other deep core exercises, such as Russian twists, leg raises, and mountain climbers.

Crunch

The best way to make crunches more challenging is to perform more reps. Beginners should perform 2–3 sets of 10–15 reps several times per week. Intermediate-level exercisers can increase to 3–4 sets of 15–20 reps, and advanced exercisers should aim for 4–5 sets of 20–25 reps.

Beginners should perform the basic crunch with their feet on the floor. Intermediate-level exercisers may introduce more challenging versions, such as bicycle crunches and reverse crunches. Advanced exercisers may perform weighted crunches, stability ball crunches, and decline bench crunches.

Crunches can be programmed as part of a core circuit, along with planks, leg raises, and Russian twists.  It can also be used as the main exercise in an abdominal-specific routine. 

Conclusion

Planks and crunches are both effective core exercises. The plank is an isometric exercise that better engages all of the core muscles and activates other major muscles of the body. In contrast, the crunch is more focused on strengthening and developing the rectus abdominal muscle. It’s a better exercise for people who want stronger, more muscular abs. 

Frequently Asked Questions