It's the sign of the right weight when the burn starts at around 3/4ths of the way through a set, and so is the same when Sephiroth reaches around 17 reps. His eyes avert downwards into the floor so slightly as he steels his resolve against that boundary at which the untrained would give up, to push out a further three or four movements before resting the weight back on the floor and stretching his own arm out in a similar way Nesir did.

Then he raises his gaze to meet Nesir's just in time for her next question. Silver eyebrows twitch together for a second while he ties it back up to his comment before; of course, it's her turn for the question.

"Not at all. It's a force of will over physics."