Denti
One of the conditions to determine V1, at least in the Boeing world, is that it may not be less than Vmcg.
Logic demands this as well - given that after V1 you are committed to fly it will be unpleasant if you are unable to control the aircraft for a while.
It was a post in the context of this thread, which is about derated take offs. Yes, V1 must be above Vmcg. However, if using derates, it is above the Vmcg for the derate used, which might differ quite a bit from the full thrust available. Which in turn means that Vmcg, if the pilot increases thrust above the derated thrust, increases as well.
If the Vmcg for the lowest usable derate is , for example, 20 kts below the Vmcg for full rated thrust, and i believe on the 737NG it is even lower, the pilot will violate the certification specs of the performance data if he increases thrust above the derate. In the air, if done slowly and once the flight path is stable, that is not that bad a suggestion. On the ground just passing the V1 of a low thrust rating slamming the thrust levers forward "because we are commited and safe now that we are above V1" might very well be a recipe for disaster.
If one uses user selectable thrust derates, V1 may be below Vmcg, for a higher thrust rating. That is why Boeing is pretty insistent that pilots do not increase thrust when using derates. Especially on the 737 where there is absolutely no indication what the thrust limit for the used derate is, no idea if it is different on other boeings.