I have access to a speed ball (a freestanding one) for training. It's great for the purpose it was made, hand-eye coordination, punching accuracy, and quickness, but I need something that offers more resistance. I want to train the power of my punch. Normally one would use a heavy bag for this, but I don't have any. Is it OK to lean it against a wall for that?
Technically it's possible, but it may be ill-advised. The speed ball will provide you with a marginally padded target surface to punch. Putting it up against the wall will keep it from rebounding as much, providing more resistance and preventing it from moving as much. However, a speed bag is generally built with a less yielding surface than a heavy bag, and the smaller size can exacerbate the problem with the curve of the bag, or even corners, creating more wear and tear on the fist. Lastly, consider what happens when you miss the bag, or hit it less than squarely. Behind the bag is the wall, which is likely very inflexible since putting the bag up against something like drywall will damage the wall with repeated strikes.
TL;DR Unless you're in really dire straits financially, you're better off getting a heavy bag, or adding a padded mat to the wall.
I doubt a speed ball will work well at all...so you can
Make one yourself: Go to Walmart or some sporting goods store and get either a held punching pad which you can strap to the wall, or get about 4-6 pillows, a yoga mat, and some duct tape.
If you were able to get the actual pad you can attach that to the wall with whatever you feel comfortable doing to your wall (superglue, hooks with rope, rubber cement, etc...)
If you got the other supplies this is what you will need to do.
- Duct tape the pillows together in a clump that is about the desired size. Be sure to fully encapsulate the pillows in duct tape so there is a solid mass.
- Either super glue or duct tape the yoga mat to the pillow mass (fold to fit and add more surface layer). Depending on if you have gloves/wraps(I recommend something) or bare knuckles you will want to ensure a smooth striking surface.
- Mount this to the wall in whatever way you feel comfortable doing to your wall. Usually a rope taped to the pillow mass and hooked to the wall would work, but depends on what you want to do to the wall.
Optionally: Get a heavy bag with stand as this will ultimately be the best bet in the long run.