Verb
cause to be tense and uneasy or nervous or anxious
become tense, nervous, or uneasy
Source: WordNetThe girls always think we're going to throw them over a table or toss them in the air. Their muscles tense up right away. So Fred and I go and sit in a corner and pretend we're talking business. Fred Astaire
The mist was so challenging and the winds hit me, definitely more than I expected. It was definitely those winds, you can't re-enact them, you can't recreate them. Then my forearms started to tense up and you feel like running. Nik Wallenda
he got a phone call from his lawyer that tensed him up Source: Internet
He tensed up when he saw his opponent enter the room Source: Internet