With the corrected training rules it seems, that training fitness is slower, than training a skill. Interesting... I thought fitness is faster, as it is not a primary skill.

Eg.:
Avg Teamwork/2=5
Avg base training=10
Max. coaches=20
Max. training hall=20
Max. fitness center=20%

Training fitness looks like the following:
(5+10+20)*1,2=42 (no training hall)

Training a skill:
5+10+20+20=55

Ps.:
Normal vs. focused training modifies the above numbers further by 50% or 75%.

I always thought the training hall bonus was also given to fitness skills, however I wouldn't know until the end of this season. And granted, if it works this way, fitness is still much, much cheaper to train than training skills.