Very firm!! I am using this for P90X. Works great for the program!!! doesn't sink in like other medicine balls I have used in the past. Would recommend it to all P90X fans!!!
This is a good product with a non slip surface. The dimpling is not as pronounced as I prefer. There are other medicine balls available some better and a little cheaper so do your shopping. You can do push ups using this ball without it losing its shape. It's solid so its not a bounce back type. It has an odor but that's gone after a week or so. I'm not dissatisfied. It fit in with my home gym equipment and get regular use. I'm a product person so if the grip surface holds up under use I will keep it.
Perfect for strengthening & muscling-up abdominal muscles. As easy to hold-on to as a basketball. Twist & turn for as many repetitions as possible for fast results. Great for all exercises!