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A Big Bang Theory of Pits


1976 saw the US gymnastics club market gain its footing and take-off. Innovations in gymnastics apparel and equipment grew in tandem with the sport and the community, as athletes and businesses sought to improve performance in the humans and the apparatuses involved.

Now a must-have feature for a gymnastics or cheer gym with any serious intention, the gymnastics pit was not always the staple we see today.

We thank former gymnast and coach, Eric Malmberg. Malmberg began coaching college gymnastics in the1970’s winning NCAA titles into the 90’s. Among his many contributions to American gymnastics, Malmberg brought the US this revolutionary landing surface he’d seen in the Soviet Union: the gymnastics pit.

The gymnastics pit is a cushioned landing surface for gymnasts to train advanced skills that often see the gymnast taking to the air, hurtling their body through space at accelerated speeds.

As the saying goes: what goes up, must come down!

Gymnastics is a sport that can only safely be learned in progressive succession of skill difficulty. Simone Biles wasn’t built in a day. 

BIles Bling

Until a gymnast has perfected the landing portion of a tumbling pass, a vault, a rings or a bars set, it’s crucial to provide them a forgiving surface onto which they can make the mistakes that are a natural part of the skills development process.

Enter the pit.

Picture a pool and a diver. Instead of water, the gymnast (who never, EVER, dives head first — more on that later) enters a hole in the ground filled with bouncy, springy foam. The added depth of the hole, rather than just the flat ground with a cushiony mat over it, gives the gymnast added space to decelerate the forces accumulated from the vault, revolutions around the bar or rings, or the hard run of a tumbling pass. The foam absorbs those forces in impact like the air bag in your car.

When pits were first introduced, some time in the 1970’s, they were about 4 or 5 feet deep. This was altogether too shallow, but nobody really knew that back then. The shallow depths were fine for little kids, but not so much for larger bodies and their accompanying more forceful physics.

The first foam pits were filled with scraps of foam. There was no rhyme or reason to their shape, thickness, density or size. They were generally around 2 or 3 inches. This was too thin. After absorbing the impact of bodies in motion over and over, the foam in the pit would get packed down. Of course, that’s not something that can be avoided entirely, even with today’s 6 x 6 or 8 x 8 foam blocks. However, the scrap foam of yesteryear began to get matted down like sheets of paper. This matted down foam stopped performing its ultimate function of deceleration and shock absorption.

When gymnasts weren’t being slowed down or prevented from bottoming out ie. hitting the floor of the pit, clever coaches began to add six inch layers of skill cushion foam underneath the random shapes to soften the blow. While it helped a bit; it still wasn’t enough.

Also, digging a deeper pit offered its own (lol, please forgive us) pitfall in that the pit got too deep for the athlete to easily climb out.

Sometimes, there would be as much as two feet of air space before the gymnast would even hit the cubes! Alas, there are still some gyms today that have that issue. (Give us a call!)

Southlake Gymnastics Pit


Thus beget, the foam cube or block. Thinking was, and still is, that changing the shape of the foam would prevent it from getting matted together and packed down so quickly, as well as offer more cushion and deceleration. While that is true, it still doesn’t offer enough deceleration or shock absorption on its own.

Therein, some crafty Canadians came up with an idea to put a trampoline bed in the bottom of the pit.

When you want bounce, add springs!

The question was: Where do we put the trampoline bed within the pit hole? Again, necessity paired with trial and error became the parents of invention. First attempts strung the trampoline bed at around 4 feet from the top of a 6 foot pit. This left 2 feet underneath into which the weight of the gymnast and the foam could dip on impact.

The problem was that in order to support all of that weight at force, you had to string the trampoline bed really tight to hold it up above ground and keep the gymnast from hitting the bottom.

This basically defeated much of the purpose of putting in the trampoline bed, in the first place. The trampoline bed got really hard with very little bounce and was not very forgiving. It essentially shortened your deep pit. No bueno. Unfortunately, there are some gyms out there that still do it this way. (We’re here for you!)

Round about 2000, we tried something different. Upon the suggestion of our friend and renowned gymnastics coach Hideo “Mizo” Mizoguchi, we raised the trampoline pit bed frame to 2 to 3 feet from the top, dependent on the rest of the pit dimensions.

Coaches screamed, “No! You can’t do that”!

Naturally, there’s a method to our madness!

Ever looking to improve, innovate and solve problems, By GMR invented “The Sag Bed” to eliminate the conditions native to the common configuration that weren’t serving the needs of our clients and their athletes.


First off, we got rid of the super taut trampoline surface. Instead, we string the bed more loose, so that it sags a bit. Sort of like a bowl, if you will. In fact, just the bed alone sags to between 12 and 18 inches before the weight of the foam pit cubes and the gymnast.

The Sag Bed Trampoline Pit offers a forgiving landing surface that’s soft and shock absorbent. Starting closer to the top allows us to make efficient and effective use of the pit’s depth while preventing the gymnast from bottoming out. Sagging the bed also allows for greater range of motion, creating a more dynamic pit bed, with a lot of movement that keeps the cubes from getting packed down so easily. That means you fluff less often!

In the past, the rule was 80% volume for the fill of pit cubes. Any company that recommends 80% volume has never been in a pit and doesn’t know what they’re talking about.

We mix in what we like to call “a mountain of pit cubes”, almost to overflowing, and you’ve got all the makings for the necessary deceleration and shock absorption that gives your athletes a safer space to train their advanced skills. Fill rates vary depending on the size, depth and shape of your pit, but we usually recommend in the neighborhood of 115% to 130% fill to accommodate the sag.

Because the trampoline bed frame is installed only 2-ish feet down, your gymnasts can climb out without having to call the fire department for a rescue!

Our By GMR sag bed pit system is a total turnkey solution. We provide all the necessaries: bed, springs, frame, wall padding, frame padding, spring padding, pit pads — custom cut to fit your equipment — and pit cubes. You provide the gymnast!


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