I would like to have confidence if i get a low short ball
For example dropshot or low slice
I believe that a lot of mini tennis warmups are done wrong. I encourage the high school teams I coach to use "mini-ball", but to treat the shots like volleys and not like ground strokes. Those short court "make believe" topspin balls that the guys are hitting at the start of their demonstrations in the video up top are exactly what I try to stay away from with the kids. Doing that reinforces terrible habits that are easy to see - completely arming the ball, feet stuck in one place, dead legs with straight knees... Practicing those bad habits from no deeper than the service line only makes them easier to recall in the middle of point play and make us more error prone.
For mini tennis to be effective, I think the focus needs to be on the footwork. Soft hands are generally quiet hands that hold the racquet relatively still. So when the hands need to go "soft", the feet need to do the work of carrying the racquet through the ball. That's what I'm always reinforcing with mini-ball.
The one drill they did that I do like is the double hit where they bump the incoming ball gently up to themselves and then hit it back. This helps big-time with developing a lighter grip for hitting touch shots. That double hit drill can be good for better players, but for others who don't quite have the good hands and quick feet needed to sustain that sort of rally with the self-volley, the next step down in terms of intensity is to bump the ball up to yourself, let it bounce instead of volleying your own bump, reset your feet (!!!!!!!), and send it back to your warmup partner.
I do believe that there's a version of short court topspin hitting that can be an productive warmup. This is where the hitters exchange exaggerated topspin strokes - lots of spin with low pace - from one or two steps inside the baseline. A little down the line, but also a little cross-court forehand to forehand as well as backhand to backhand. Compared with the dead-leg pretend topspin shots hit from one service line to the other, these exaggerated topspin strokes engage everything needed for baseline rallies minus the full speed pace of shot. I've seen stronger kids effectively use this as part of a decent pre-match warmup on many occasions.
Gotta find willing hitting partners who are game for several minutes of "volley rallies" where you're volleying to each other from different areas. When we're trying to sustain a volley rally instead of putting the ball away, that forces us to employ more touch shots in rapid succession. A good alternative to straight ahead volley rallies can be setting up on opposite corners of the service line (where it meets the sideline). That sort of volley rally is great for controlling those more extreme cross-court angles that are really useful on game day. Use some variations to keep it fresh.
