Momentum Graphs track the progress of teams over the last seven minutes of the game. If the team did a lot in the last seven minutes, a lot of points. If not, low points. Just to confuse you even more:
Okay maybe information overload on that last picture but here's the end result:
Complexity made simple! USA started the second half with a band, fizzled, then from 75+ (to their goal in the 7th minute of stoppage time) the pressed Venezuela.