stiffens up
Loses its flexibility
To stiffen up is to become rigid or less flexible, usually referring to muscles or joints that grow sore and resistant to movement: My back always stiffens up after a long drive.
The phrase can also describe becoming more formal or defensive in manner: He stiffened up when she mentioned his ex.
- toughensBecomes more resistant
- hardensBecomes firm or solid
- tensingMaking or becoming taut
- muscle tightnessInflexibility in soft tissue
- inflexibilityQuality of being unbending
locks up · petrifying · rigor mortis · muscle contraction · stubbornness · anxiety · freezing · solidifying · unyieldingness · rigidity · fear response · fight or flight · bracing · cramping · obstinacy · hesitation · locking · nervousness
physical flexibility/rigidity
stiffens uploosens up
Becomes more relaxed
relaxes · limbers up · loosens · unwinds · chills out
stiffen, stiff, stiffly, stiffness, stiffs, stiffened, stiffening, stiffener, stiffeners