There is absolutely nothing better for developing your strokes than hitting against the backboard!
Remember, though, perfect practice makes perfect.
You have to be mindful of what you are doing. Since you hit so many balls during a short period time, you will groove whatever you are doing - if you are using bad habits, that is what you will groove.
rkelley has some good points you have to watch out for, but aren't reasons not to hit the backboard.
I think hitting against the wall is great practice for ground strokes and basic serving. You can hit a lot of balls in a short amount of time and really focus on form and contact point. I think it works well hitting both soft and hard. Try to hit 30 hard hit balls that would be in with good form. It's not easy. It's also a killer workout.
Volleys are harder to practice on the wall because as you get closer the reaction time starts getting very small.
There are some limitations:
- The balls never have the spin and nasty bounces that balls from a real partner would have.
- You have to be honest about whether or not the ball would have really been in or not. If you blast it into the wall and it hits still on the rise, that ball was probably going out.
- It's hard to practice cross court shots. Conversely it's easy to get grooved into hitting back-to-center and down the line shots.
- It's harder to see the effect of spin (but you can see it), especially on serves.
At some courts the wall is also a great place to find a hitting partner.
Rich
Volleys take a while to get the knack of hitting, but Tony Roche, the best volleyer of all time, learned volleys by practicing against the wall.
You can somewhat control the spin you get back by how you hit, but more usefully, the spin you get back is a good indicator of what spin you put on the ball, once you learn to gauge it.
[*]You have to be honest about whether or not the ball would have really been in or not. -- this is critcally important!
There is nothing better for getting in shape than hitting crosscourt balls on a backboard. Very tough to do it for very long.
Also, you can work point patterns on the backboard. Serve, half volley, volley. Crosscourt, crosscourt, down-the-line. Etc.
You can get a lot of practice on overheads by hitting them downward in front of the backboard (lots of underspin, though).
Hit to specific points on the backboard - great target practice. Make up games to play against yourself.
Fun and entertainng for hours!
Most pros learned their strokes against the backboard.
My theory is that there are two reasons for this: 1) the backboard is great practice and 2) - probably the biggest reason - is that those who love to hit the ball so much that they will spend hours on the backboard are more likely to become pros.