Before I discuss what a slam ball is, we need to explain the context in which such a training tool is used. And the context is High Intensity Interval Training (HIIT), and specifically, Tabata intervals.
What is a tabata interval? It is a High Intensity Interval Training protocol originally devised by Dr. Izumi Tabata to increase anaerobic capacity (in particular the glycolytic and phosphagen metabolic pathways). In a tabata interval, an exercise is executed as fast and with as many repetetions as possible for 20 seconds followed by 10 seconds of rest. This is repeated again and again, usually in rounds of 2, 3, 5 or 10-minute rounds.
This is done as a means of implementing anaerobic metabolic conditioning and, ideally, as part of a plan for achieving and maintaining acceptable levels of general physical preparedness (GPP). And an increase in GPP allows one to train harder, with more volume and increase intensity. Moreover, it allows one to recover faster.
There are different exercises that can be used in these 20-10 second intervals. And, as wacky as it may seem to you, taking a hard object and throwing it to the ground is one.
This is where a slam ball comes into place. I recently built a 17-pound, non-rebounding ball that can be thrown multiple times without risking bursting it or the floor. This is me slamming the living crap out of it in three tabata intervals (a 1.5-minute round.)
How To Build One
To build one, I followed online instructions found at the CrossFit and Ross Enamait’s websites. I believe I’m contributing an improvement onto those instructions by introducing more efficient funnels for pouring sand into the balls.
First, I started using an empty bottle of saline solution. It worked well as first, but I got impatient. As I tried to increase the size of the hole using a hand file, I tore it bigger than planned. That pretty much screwed it for a slam ball. Eventually I filled it up to make it a 25-lbs medicine ball, so it wasn’t that much of a loss.
Notice the obligatory beer bottle:
So, I took another basketball, and I was careful in punching a hole in it. For a funnel, I decided to insert a baby drop dispenser. It is important to keep the needle in the ball to allow air to come out as you pour sand:
Then I put an empty bottle of saline solution I was using first (with its end cut off) inside the drop dispenser, and voila, I got a nice, efficient funnel. It took about 10 minutes to fill it up with sand.
You can see the sand quickly going inside the ball. It was kinda cool.
Later you use a tire patch kit to patch the whole, you let the thing dry, put another patch, and begin to tape the crap out of it with duct tape.
Does it work well?
I think so. I’ve been slamming the living crap out of it, and so far, it hasn’t busted open. The trick is not to completely fill the ball. A basketball may take about 17lbs, maybe 18lbs, but that’s it. You need to leave room to be filled up with air.
This is not a bouncing slam ball. If you slam it on concrete it will barely bounce. This is good since it avoids having that thing accidentally bouncing on your face and it forces you to pick it up off the ground.
I do most of my slamming indoors, and I’m a bit worried about the floor. So I slam it on a rubber mat under a piece of plywood. I’ve also tried two and three rubber mats. Three is great as you get it to bounce (just be careful as the bouncing is erratic and can bounce with force right into your face.)
I find this to be much better than sledge hammer workout. Or I should say that I like it better. I don’t have to worry about switching sides, it works my forearms more and the downward pulling/throwing action in the trajectory it takes (right on front and above you) does an even work on your lats. Take a wide stance and contract the glutes as in a squat when doing this.
Anecdotal evidence suggests that individuals can cut down their training time by 60% using tabata sets (or other similar HIIT protocols) and achieve superior anaerobic conditioning that other, more “aerobic” activities such as jogging or using a stationary bike. This is another incentive why I (or anyone else) should pursue this type of training.
I’d strongly suggest you use a rubber mat or a 2x2x1/4 plywood when slamming the ball. This will allow the ball to last longer as opposed to being slammed against the concrete. Furthermore, if you are doing this indoors, you want to protect your floor from the pounding.
And it goes without saying not to try this if you live in an apartment building