How many hollow rocks should you do when you are new to the exercise?

Three or four sets of 10 to 15 rocks with the low back flat, or work in time with three sets of 20 to 30 seconds. End the set on the first rep where the back lifts, not at a number. Build toward three sets of 30 seconds, then progress by lengthening the lever rather than by adding minutes. Two or three sessions a week is plenty.

How do I make hollow rocks easier or harder?

Easier: bend the knees, bring the arms down by your hips or onto your thighs, or hold a tucked shape and rock from there. If the back still lifts, go back to a static hollow hold until it does not. Harder: extend the arms fully overhead with the legs long, hold a light ball or plate overhead, slow each direction to a two-second count, or pause briefly at each end of the rock.

What are hollow rocks good for, and when should I choose something else?

They build the reflexive full-body tension that gymnastics and calisthenics skills rely on, and they teach the exact shape a handstand or a lever wants. Choose something else if your low back will not stay on the floor, since the static hold is the honest regression. They also do nothing for rotation, so pair them with side planks or Pallof presses if that is what you need.

Intermediate

Hollow Rock

The hollow rock takes the hollow-body hold and adds motion: keeping the whole trunk locked into a tight, banana-free hollow shape, you rock gently along the spine using the abs to drive the rhythm. Because the body must stay rigid, the rectus abdominis works continuously to resist any loss of shape while you rock. It is a favorite for building the reflexive core tension that gymnastics and calisthenics skills rely on.

Equipment: Body Weight
Body part: Abs
Type: Strength
Browse by muscle: Upper Rectus Abdominals, Lower Rectus Abdominals
Browse by movement: Core Brace

How to do it

1
Lie on your back and lift the arms overhead and the legs off the floor into a hollow shape.
2
Press the lower back into the floor and squeeze the whole body tight.
3
Rock backward toward the shoulders using core tension, not a leg kick.
4
Rock forward toward the hips, keeping the same rigid hollow shape throughout.
5
Continue rocking smoothly while the low back never loses contact with the floor.
6
Stop when you can no longer hold the shape, then reset.

Tips

Keep the arms and legs long and the ribs down; the whole body should move as one rigid unit.
Drive the rock from the trunk rather than swinging the legs to cheat the motion.
If your low back pops off the floor, shorten the shape by tucking the knees slightly until you build strength.

Variations

Common mistakes

A hard floor bruises the spine within a couple of sets, so the set ends because your back is sore rather than because the abs are done; put a mat or folded towel under the mid-back.
The head bobs up and down with each rock and the neck ends up doing the work; keep the chin lightly tucked and the ears between the arms so the head travels with the body.
The rock keeps getting bigger because a large one feels more impressive, when a small, tight rock with the shape intact is worth more than a wide one that opens up.
The feet ride high, well above the level of the hips, which quietly shortens the lever; the heels should sit low, no more than a hand's width off the floor.
Once the pace goes up, the shape starts flapping open and closed at each end of the rock, and speed is exactly what hides that from you.

Frequently asked

How many hollow rocks should you do when you are new to the exercise?: Three or four sets of 10 to 15 rocks with the low back flat, or work in time with three sets of 20 to 30 seconds. End the set on the first rep where the back lifts, not at a number. Build toward three sets of 30 seconds, then progress by lengthening the lever rather than by adding minutes. Two or three sessions a week is plenty.
How do I make hollow rocks easier or harder?: Easier: bend the knees, bring the arms down by your hips or onto your thighs, or hold a tucked shape and rock from there. If the back still lifts, go back to a static hollow hold until it does not. Harder: extend the arms fully overhead with the legs long, hold a light ball or plate overhead, slow each direction to a two-second count, or pause briefly at each end of the rock.
What are hollow rocks good for, and when should I choose something else?: They build the reflexive full-body tension that gymnastics and calisthenics skills rely on, and they teach the exact shape a handstand or a lever wants. Choose something else if your low back will not stay on the floor, since the static hold is the honest regression. They also do nothing for rotation, so pair them with side planks or Pallof presses if that is what you need.

Related exercises

Other movements among FitRay's 2,000+ exercises that load the same target muscle — same equipment and level first.

All Abs exercises