Forgive me because I didn’t have the time to read through all the previous posts but I think I got the gist of the latest debate and I’m going to try to reconcile some thoughts and provide some information that I think might be useful.
2 seemingly opposing views are actually correct here but I think the context of the way statements are made needs to be taken in to account.
For instance, we can say “to be an elite jumper you need to be able to jump 8m and this can be done either by having high takeoff velocity and lower takeoff angle or lower takeoff velocity and higher takeoff angle” and it is 100% true. At the same time, it can be true to say we can’t have both maximal velocity and maximal takeoff angle. This is because the 2 variables are inextricably linked…for a given performer, as one variable goes up the other goes down.
With this in mind, what’s the best way to takeoff? Well, it kinda depends on your strengths and weaknesses. Putting the foot out far in front of the COM will definitely produce a big vertical component at takeoff. HOWEVER, it can also potentially lead to a loss of horizontal velocity, especially if the setup for that takeoff has the athlete putting the feet out in front in the last couple steps.
This brings me to another point. What is more important - takeoff velocity or takeoff height? To be honest, from a mechanical standpoint it isn’t even close. Velocity is far and away the most important variable in any projectile motion situation when distance is the primary concern. It’s not even close. Distance is a product of velocity squared (velocity x velocity) while only a product of projection angle. This means that velocity has a much bigger impact on the distance traveled. In fact, my research on the throwing events (where these questions also arise) suggest that the release velocity can explain up to 95% of the variance of a performance. Basically, that means, if you tell me what the velocity is, I can tell you whether it’s a great, good, or bad performance. The same cannot be said for takeoff or release angle.
With that said, takeoff angle IS important because if you do not achieve a minimal level projection then you won’t have the time to cover any distance through the air. This effect is amplified the further you are expecting to jump.
I’ll conclude by saying this, don’t look to physics books as they won’t tell the entire story. Athletics is about BIOmechanics….with an emphasis on the bio. We have to remember that the human organism is a living breathing machine that doesn’t operate like the perfectly mechanical physics world would have us believe. Instead there are a host of factors ranging from muscle fiber types, fiber angles, muscle insertions, joint positions, secondary limb positions, and even training state that affect what is ‘optimal’ for human movement. I am actually not aware of any circumstances where the mathematically predicted ‘optimal’ joint angles, release angles, projection angles, etc, etc are actually equivalent to the biomechanically optimal parameters. This is actually the topic of my doctoral dissertation so I feel that I can safely say that I am an expert on the issue. In a nutshell, nothing operates independently of other functions in the human body. This goes for biological processes as well as movement patterns. With that said, we can’t take one parameter, expect to hold it constant and not expect to observe changes in any other variables. Think of it as a sliding scale system with multiple variables where there’s a finite quantity to spread amongst those variables and you have to choose what combination or distribution will produce the best outcome.
. That may also have been the difference between 8.60 and 8.90. 
