I posted about this a while ago and want to share some of my training I've started doing again. I did this last year and my diving really improved. The fact is after I started a new job late last year and with the kids growing up, I kind of stopped training and diving for a while. You must have a buddy though!
I think it's helpful, especially when diving frequency is low. I've never found anything more helpful for diving (other than the diving itself) than dynamic pool training. Tables never did anything for me, however, pool training improved my diving 50%. Examples last year when I was training and diving often, dive times went from 1:10-1:15 avg to 1:45, with many dives between 2-2:30, comfortably diving 80'+
Here is the workout routine, based on some recommended exercises by Pelizzari, and info from Deeperblue members (Mullins)
Start up by relaxing in the water for 3-5 minutes.
try a long swim (not a max), for me now this is between 75-100m
recover 2 mins, do a 75m x2
Recover 2-3 mins, do a 25m, hold (x secs), 25m back x3 or 4 times
this one will really help your reflex kick in strongly. you can hold as long as you can, start with 15-20 secs, work from there. It takes about 30 secs to slowly swim 25m, so your total swim times will be from 1:20 or so up. My PB in this is now 3:10, hoping to hit 4 mins
After you these holds, try a max swim. My PB is approx 110m, I really freak out after the 100m touch, I think it's mental. It takes about 1:50 to do 100m. My partner and I have a goal of 150m by the end of the year
then try some 50m or 75m swims with shorter recovery, say 1-1:30 mins x6-8 times
then do some 25 or 50m sprints with 1 min recovery x6 -8 times
that's it!
be safe