By default, your streak mode will be set to Explosive.
But you can change your streak mode to training before starting any Box class. All you need to do is follow the steps below.
Choose the class you want to play
Select the settings icon from the class details screen (this is the ⚙️ just across from Start Class)
Finally, select which streak mode you'd like to use for your class
NB: If you have Community Mode ON, you’ll only receive bonus points for your streak if you’re also using Explosive Mode. Any players in Training Mode will have (*) in the ‘Best Streak’ column on the leaderboard.