Leo-sprint is different from other vocabulary trainings in several aspects:
1. It always uses all words from the dictionary, regardless of their status. So you might see that the word count doesn't decrease in the training.
2. It can add words from basic words sets that match your language level (or lower), checking how well your vocabulary matches your level.
3. Currently, this is how Leo-sprint assigns points: XP are only given for words that you're practicing in a sprint for the first time. If you've already successfully learned this word in this training, you won't get double the XP for it.