There has been at least one user that said that his team did not perform well if he did not do the required number of trainings as indicated before each match. Also, one user said that his team had a decrease in performance when he performed the required number of training sessions but used only low intensity drills.
Today, given that I had at least 8% bonuses on all the four areas, I did only one training session instead of two before a match. My team unexpectedly lost the match 2-0 to a weaker team. The tactics used seemed to be good on paper, but during the match, the opponent got through the middle from the midfield area to the goal way too easily despite the fact that I have matched the middle (3 MC against 3 MC) and also used a blue arrow on the middle MC. Also, from the highlights, it seemed that the players were not following the instructions (orders) given; they were passing the ball into the congested middle and lost the ball despite having players free (non-marked or not tightly marked) on the flanks to receive the ball, and also despite having ordered them to pass through the flanks. It was as if it was like a sort of 'punishment' from the game for not doing the required number of trainings. This might be coincidence also.
To be able to make proper deductions, more observations are required. Post about your experience when you did not do the required number of training sessions.