When you inflate your ball, you should inflate it to the diameter that the sizing instructions show. You want to fill the ball with air only until it feels like it has a slight give and it's not too taut or firm.
There's a big difference between filling your ball with air so it's tight like a drum and filling it with just enough air so that it's firm and stabilizing as it should be. Filling your ball with air is like striking the perfect balance when you purchase a new mattress to sleep on: You don't want it to be too hard, and you definitely don't want it to be too soft, either. Read on to find the best way to check your ball's air level so it feels just right for you.
When you first inflate your ball, it may seem too small. Give it at least 24 hours for the material to adapt to the expansion before you add more air to it.
Going for firmness
The general rule when you're filling the ball with air is that you want it to have a little give when you sit on it. However, you don't want it to be squishy or soggy. Your ball should feel firm and supportive but not tight like a drum.
If you look at yourself in the mirror when you're sitting on your ball, you should be able to see a slight indentation where the weight of your body is resting.
If your height to weight ratio is larger than it should be, you need to use a larger ball than the instructions prescribe for you because your extra weight will flatten out the ball when you sit on it. After you purchase a larger ball, under-inflate it until your feet are flat on the ground to adjust the level of firmness.
Doing the bounce test
Besides sitting on the ball to test the air level, you can also give it the bounce test. After you've filled your ball with air, check the following list to see whether it meets all these requirements when you're bouncing on it:
- Make sure that your feet are flat on the floor and that your weight is evenly distributed. Both hips and sides of your body should be level with each other.
- Make sure that your knees are level or slightly lower than your hips, creating a 90-degree angle. Your thighs should be parallel to the ground or pointed down slightly.
- Make sure that your hips, shoulders, and ears are all in a vertical line when you're sitting tall on the ball. To test this function and to align yourself properly, try bouncing up and down lightly.
Adjusting your air levels
When you fill your ball with air, you'll find that your ball has some adjustability to it. In other words, you can adapt your ball to your own individual level of comfort.
If you find that your hips are much higher than your knees (as if you were sitting on a pillow that's on top of a chair), you can release some air until your knees and hips are level or slightly elevated. Also, if you use your ball regularly, expect your ball to lose pressure and to have to inflate it as necessary.
Keep in mind that if you do release air from your ball, it may cause your ball to lose air pressure, which actually makes the ball a more stable base because it'll be flatter and easier for you to sit on.
When you become comfortable doing ball exercises, you want to make the ball a bit more taut to increase your level of training. The firmer the ball, the more difficult staying seated on it becomes because it requires more strength from your stabilizing muscles. You need to have stronger abdominal muscles just to keep the ball in place.
