What the other guys said is partially correct.
There are training regimes that are by default 1 positional like PA, OD, JR, HA, IS, ID and SB. For these the basic options are those in black and you have a choice of training single position, 2 or 3 or team. Using the black option with 2 positions will yield just less than 70% of the black option with one position as Big Dogs said. The coloured options are positional deviations from the basic options and come with a penalty (the percentage) compared to the black option immediately above them. So if you are training PA:
- 1 position at PG = 100% of max possible speed, whatever it may be. You can only train 3 players at this speed
- 2 position training at PG/SG = ca. 65%-70% of max possible speed (this was estimated by the userbase after putting together a dataset of training pops). This is of course for up to 6 players in a week
- 1 position at C = 100%*60% = exactly 60% of the max possible speed (for up to 3 players)
- 2 position training at SF/PF = 65%-70%*80% = ca. 52%-56% of the max possible speed (for 6 players)
Then there are training regimes that are by default 2 positional: DR, RB and JS. For these, of course the 100% speed is achievable for 6 players and other than the penalty options the basic alternative is team training which would train all of the players irrespective of minutes at around 35%-40% efficiency.
Bottom line: black options are the standard options. You can find the estimated training speed for these options in Coach Parrot or other training simulators. The coloured options were added later, they are deviations (in the training positions) from the black options and come at a penalty compared to them