You see here a great example of playful acting. These two actors looked and kept looking for ways to display that the two young rivals, whilst thinking they are mature and serious in their love of Helena, are actually very juvenile in their desire to win. You will see that they don’t discuss what they could do beforehand; instead they commit to saying ‘yes’ mentally to whatever the other throws at them. This is an early rehearsal and it became more choreographed as the process developed (so it didn’t disrupt the text in the scene) but the immature mood of their fighting came from this initial playful experiment.