Really both Strife and Outburst could do with better names, unfortunately they seem to be the closest thing.
Strife can also be exuberance, nerves, excitement, frustration, disappointment. It really is a measure of how composed your character is, how controlled and measured their approach, exactly as the threshold is named. There's really not a word in the English language to describe everything that the number is tracking.
Outbutburst has the same problem, it indicates the character has lost composure but tries to use a single word to do it. It probably is better than Strife in that regard since Outbursts can be "an Outburst of Joy." But it suffers from trying to describ a complex mechanic with a single word