38 inch to get wrist to rim, anotehr 3 more for the loss of height with ball in your hands, means you need 41 inch running jump to land a clean dunk. IF you get a lot of extra inches off a run, then it will be easier.
As for what SquatDR does, why don’t you PM him? 
Pretty vague question, because he has been training for over 10 years. But from what I gather, he pretty much adds weight to the bar and tries to squat a PR for 1-2 worksets, and then hits the assistant lifts to bring up weakpoints etc
What your doing looks fine, keep adding weight to bar, when you stall back off the weights and volume to deload and freshen up, repeat.
Eventually your gonna need to add a lot of muscle mass to keep driving up strength and performance. So spend some time piling on some size, then spend some time to peak the size into actual strength gains, then spend some time to use that strength to improve your jump, by actually practising jumps
IMO, once someone has a baseline of skill, and can recruit all the muscles properly in the right order and what not, the quickest way to improve performance from here on it is to increase the size of the power source - the muscles. Increase the wattage potential
nice post by Kelly Baggett backing up my viewpoint -
FWIW Col’s thinking has been researched fairly heavily in sprinting and has found to hold true for the most part.
The thing is if you have what it takes neurologically and structurewise to jump high, hypertrophy will probably be extremely positive because you’re already naturally closer to the peak of any neural gains you’re gonna make. I’ve trained 5 guys from the mid to high 20’s up to 37 inches or better and the common theme is all of them got a lot out of simply getting bigger lowerbody wise.
For each individual body structure there is an “optimal” muscular bodyweight that optimizes their leverages for jumping. Look at the NFL combine. On a fairly consistent basis defensive lineman and outside linebackers consistently jump as high if not higher than all the other positions. Why is that? They combine fairly long levers with a lot of muscle and many of them put on a good 40-50 pounds from the time they come in as college freshman to the time they graduate. Someone with shorter levers might not need that much.
Another key is that hypertrophy has to take place in the right muscle groups. Chris K doesn’t squat much but he does use a variety of strength movements and his guys are assuredly getting larger, more powerful glutes over time. Many high school kids will grow just running sprints on the track. For a lot of folks squatting carried to the extreme can cause postural functions that negate the optimal alignments and muscle balance needed to drive off the toes with power. A large percentage of powerlifters and o-lifters seem to have this “look.” Also it takes extra food intake to feed hypertrophy and a lot of people are fat. If a guy has 30 pounds of extra fat do you make them even fatter just so they can have an extra few pounds of muscle?
Relative strength is really more about body-fat than muscle mass IMO. With regards to muscle mass any sorta training will make muscles bigger to some extent. Even in Pilates class women get bigger muscles to some extent. On the internet guys should be able to gain 250 pounds on their squat and only increase their muscle mass 2 pounds? Bull. In olympic lifting and even gymnastics guys train big and eat big and gain weight to gain strength. Pure newbie neurological gains don’t come long. Why do you think Rippetoe has folks drinking a gallon of milk a day on his program? With his basic program complete newbies oughta be able to make pure neural gains for ages. Probly because he got tired of dudes not eating enough to make gains. Glenn Pendlay trains a lot of top national O-lifters and from what I recall his advice wrt bodyweight and strength is very similar to Ripp’s. Guys go up in bodyweight then come down to whatever weight class they can make it at the top of. The “relative” part of relative strength has more to do with bodyfat levels and body composition over time and less about muscle. Few people stay completely static bodyweight and musclewise and make many changes of any kind on a long term basis. Now, you might find someone that loses 20 pounds of fat along with some lower body size and strength but his VJ goes up. Well, in this case the fat loss overshadowed the muscle size loss. But for the most part anyone who increases hypertrophy while staying fairly lean will be rewarded in a good way. The “lean” part and the individually optimized structure is where the “relative” part comes in.
Will lower body lifts help in the absence of any hypertrophy whatsoever? Due to the stimulating effect on the nervous system they probably will to a certain extent, yes, but the gains are likely to be short lived.
Going back to the original question, you may only be able to jump as high as you can drop, but the factor most closely correlated with power absorption (ADA) is maximum eccentric strength. So, as you get eccentrically stronger you automatically get better at that type of activity. Guess what muscular quality most closely correlates to eccentric strength? Cross sectional size.
