2. How does the training intensity effect the amount of training points received?
Depending on the training intensity you can gain or lose training points and gain or lose energy. See details below:
Maximum: + 6 training points and - 5 to - 10 energy
High: + 2 training points and - 3 to - 6 energy
Average: 0 training points and 0 to + 2 energy
Low: - 2 training points and + 3 to + 6 energy
Very low: - 4 training points and + 5 to + 6 energy

Keep also in mind that higher training intensity also means higher chance for players to get injured during the training.