
If you’re someone who does core workouts regularly, it’s definitely wise to have a lot of different crunch variations in your exercise arsenal to keep things fresh. I always take note when I come across something that looks new and interesting so I can mix up my training sessions.
The "crunch smash" is a move I came across on the Instagram account of fitness trainer Kyle Knapp, who is well worth a follow if you’re looking for interesting workout and exercise ideas.
It’s a variation on the crunch that adds a twisting move as well as a "smash," and from my initial testing of the exercise, it’s both effective and enjoyable for boosting your core strength.
You don’t need any equipment to do the crunch smash, but if you’re lying on a hard floor, rolling out the best yoga mats will certainly make the move more comfortable.
How to do the 'crunch smash'
Knapp demonstrates the crunch smash in his Instagram post, both at full speed and a slower variation of the move.
- Start lying on the floor, and lift your feet to bring your knees up to tabletop position.
- Hold your hands lightly against your temples with your elbows out to the sides.
- Engage your abs to raise your shoulders off the floor and bring your elbows to your knees.
- Twist your torso to lower your right elbow to the floor, then bring it back up and "smash" it into your right knee.
- Do the same movement on your left side. Continue to alternate.
As per Knapp’s post, you can also throw in a regular crunch after smashing on each side to make the move even more complete in targeting the upper and lower abs, along with your obliques.
I swapped the standard crunch for the smash in my core workout; here’s what I took away from trying it.
The smash really makes you engage your abs

Knapp suggests that the more smash between elbow and knee, the deeper the effect of the move on your core, and I really noticed how much I engaged my abs when smashing my elbow into my knee.
It forces you to brace, and after only a few smashes, I could feel the burn in my abs begin to build, because they’re working harder than they do even with a similar twisting move like the bicycle crunch. I’m sold.
Holding the position is good for endurance

Throughout a set, you keep your shoulders and feet raised, so you’re holding your body in a position that forces your core to work to maintain stability. This is great for your core endurance, and I liked it more than a simpler static move like the hollow-body hold, because the crunch smash is more interesting to do.
It works the whole core

The twist in the move engages the obliques while the upper and lower abs are working when you bring your elbow up to your knee and smash them together. If you add in a regular crunch, the abs will work even harder.
Add in the fact you’re holding a tough position throughout to challenge the deep stabilizer muscles in your midsection, and the crunch smash is a comprehensive core-burner.
Follow Tom's Guide fitness below!
More from Tom's Guide
- Not sit-ups, planks, or crunches: I do this simple Pilates exercise every single day to build a strong and stable core and work on my hip flexor mobility
- Not sit-ups or lunges — I use this simple Pilates exercise to sculpt strong obliques, inner thighs and hip stabilizers
- 'I’m a Pilates instructor, and I recommend these 5 core exercises to help older clients build strength and improve posture'