North Carolina did an official study on MJ. his legit vert is 46
plus guys like DRose, DSJ used to get their eyes to rim level. is it a stretch that 1 guy only 3 inches taller than them got the same vert
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max vertical is measured
without a basketball in hand. Having a basketball in your hand and attempting to dunk it significantly lowers your vertical jump height. Here is a study that involved Jordan from 1983 by the University of North Carolina, his maximum vertical was measured at 45.76". This was at age 20, given his increased strength and agility he may very well have improved on this in his early Bulls years.
Here is an extract from the study....
MICHAEL JORDAN VERTICAL JUMP. Krugh J, LeVeau B. University of North Carolina at Chapel Hill, Chapel = Hill, NC.
PURPOSE: The purpose of this study, which was part of an advanced master motion analysis class project in 1983, was to determine Michael Jordan's maximum vertical jump.
SUBJECT: Michael Jordan
METHODS: Surface markers: Left lateral malleolus, left femoral epicondyle, left greater trochanter, left pelvic crest, and right distal phalanges of digits 2 and 3 of the hand.
Tasks (in order) were:
Vertical reach while standing flat-footed - baseline
Vertical reach during a jump from standing
Vertical reach during a jump from running
Vertical reach during a 1 hand dunk
Vertical reach during a 2 hand dunk
All tasks, except baseline vertical reach were done with free swing of the upper limb(s). Equipment / instrumentation: Camera, lighting, markers, meter stick, and standard basketball. Location: Fetzer Gymnasium, University of North Carolina at Chapel Hill.
DATA ANALYSIS:
Distance measurements were analyzed by comparison to a meter stick in view of the camera. Displacement measurements of reach (pelvis) involved measurement of vertical height to the tip of fingers 2 and 3 (pelvis) during a task minus vertical height to the tip of fingers 2 and 3 (pelvis) during bilateral flat-footed stance. Velocity measurements were analyzed by dividing vertical height distance traveled divided by time taken for the tasks. A VanGuard Motion Analyzer was used to analyze motion frame by frame.
RESULTS:
Maximum measurements:
Vertical reach while standing flat-footed 93.67 in.
Floor to pelvic crest while standing 49.00 in.
Vertical reach displacement during a jump from standing 35.93 in.
Vertical displacement of the pelvis during a jump from running 38.07 in.
Vertical velocity during a jump from running 701.00 o/sec.
Vertical reach displacement during a jump from running 45.76 in.
Vertical reach displacement during a 1 hand dunk 41.70 in.
Vertical reach displacement during a 2 hand dunk 40.93 in.
During the vertical reach from standing, push from the floor was with both feet. During the vertical reach during a jump from running, push from the floor was with one foot and momentum of the body, two upper limbs, and one lower limb was used to the maximum.
CONCLUSION / CLINICAL RELEVANCE: Maximum displacement for vertical reach was achieved with a jump from a running start, a 2 hand dunk, a 1 hand dunk, and a jump from standing, respectively. This is consistent with use of momentum of the body and limbs to assist with the vertical displacement. Michael Jordan vertical jump ability during several tasks provides a standard with which athletic achievement by others can be compared.
So, I find it hard to absolutely verify the validity of this study, it's only a copy/paste from a forum comment after all. Is there any way to corroborate this study? Well from video evidence of his in-game or dunk contest dunking.
From the above study, we see that Jordan's one handed dunk vertical was measured at 41.7". Jordan is 198cm which is actually a shade under 6'6". Given these two measurements we can approximate Jordan's maximum head height while performing a one handed dunk, which would be 77.95" + 41.7" = 119.65". That's 0.35" below the level of the rim. Now onto the video evidence.
Here we can see Jordan performing in a slam dunk competition. If you trace a line from the bottom of the square on the backboard, which runs exactly parallel with the rim, you will see his head slightly above that line. Given perspective is distorting reality a little here, as MJ is a bit closer to the camera than the line, we can safely say that his head is, at worse, around half an inch below the rim. This would put his head at 119.5". As mentioned, the study above suggests it would be at 119.65". Now MJ would certainly
not have been attempting a spectacular highlight dunk during the study that very likely would have limited his jumping ability a little so I think it's a good bet to say that this part of the study was indeed accurate.
A good comparison to Jordan's vertical jumping ability would be Gerald Green. He was only measured with a 39" maximum vertical at the draft combine but video evidence clearly proves this to be a gross under estimation.
This video from a Pacers practice session shows Green's head well above the rim, in fact between half and three quarters of his entire head is above the rim. This was performed
without a basketball in hand so it would be the same type of vertical that measures a maximum vertical. Most estimates of his max vertical are around 46". Given that Green's measured height is 6'7.25" (from the draft combine) we can again accurately predict how high his head would be with a vertical of 46" - 79.25" + 46" = 125.25". So his head would be 5.25" above the rim.
Studies show that the height of a human head is between 8.6 and 9.4". At the extreme range we'll give Green a 9.4" head height which means that, based on my estimation above, between 4.7 and 7.05" of Green's head would be above the rim. This fits right in with the 5.25" stated above. This suggests the 46" rumour for Green is pretty accurate.
Now if you look at
this video of Green in the slam dunk contest, his head is slightly above the rim (at best, 3/4 of an inch higher). This would be his one hand dunk vertical, so a much better comparison to the Jordan video linked above. Again, follow the bottom part of the box on the backboard, and you can see his head is slightly above that line, 1/2 to 3/4 of an inch above. This would give Green a one handed dunk vertical of around 40" which is actually 1.7" worse than Jordan's
but that's comparing a dunk preformed in a dunk contest vs one performed in a scientific study, which as stated is apples and oranges.
However, in a similar environment ie in the two videos linked above, there is a
maximum difference in head height of 1.25" between the two. The difference in height between the two players is 3cm or 1.2". That almost matches the difference in head height in these two dunks (MJ -0.5" vs GG +0.75" = 1.25") so we can estimate that Michael Jordan and Gerald Green had a similar vertical jump height for one handed dunks performed in a dunk contest environment. Therefore we can also estimate that Jordan would have had a similar max vertical jump of 46" which corroborates the study once again that measured it at 45.76".
what difference does it make if it isn't in combine history. NBA MEASURES RUNNING VERTICALS
if jordan has 48 inches we would've seen his head above the rim at least few times in his career. that never happened. highest he ever jumped his head was right at the rim and that's 42 inches vert. 
but i'll buy 4.3 
