Collocations for strained - adj.

be, feel, look, seem, sound

extremely, fairly, very, etc.
She looked rather strained and miserable.

a little, slightly, etc.

be
become, grow
remain
The atmosphere remained somewhat strained all evening.

extremely, fairly, very, etc.
Relations between us were rather strained.

severely
Relations between the two countries had become severely strained.

increasingly
a little, slightly, etc.
already
Their already strained relationship was made worse by this incident.

Strained is used with these nouns:
atmosphere, muscle, relation, relationship, silence, voice