Lenght of training session?

How long can the speed session be, if theres no timelimits caused by work or other everyday life hassle? I just read the forum review and if I undrerstood right the speed session could end up being up to 90-120 minutes long. Is this long training sessions only beneficial for the top guys who have access to limitless massage and other kind of recovery methods? I have came to understand that over 60 minutes sessions are worthless, offcourse this is what they teach to bodybuilders so that could be the difference. If its ok to do longer than 60 minutes sessions is there any difference keeping it at one session or dividing it to two shorter sessions over the same day. I personally would like to do it on one training session cause for me its hard to get my concentration back to 100% so quicly.

what are your thoughts

I think its mainly just based on how long you can go without declining.

Actually Fin
I have been wondering about the same thing recently and which energy systems the body moves between over a 2 hours period considering we move from speed to weights so the total training time could be 3 hours long.
Is catabolism an issue over 3 hours of training?

Isn’t the research clear? Also concentration is key…not just catabolic reactions!

Doesnt the research say that you should keep the training inside the 1 hour period, but its impossible to get all components done in one hour.

Clemson if you are referring on some other research please share it with me.