Muscle injury (6)
I believe the answer is:
strain
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">muscle injury</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for strain that I've seen before include "Pass through a filter" , "Melody; filter" , "Tension on trains" , "Muscle injury, put liquid through sieve" , "Distinct breed (of animal); overexert" .)