An olympic sprinter readies for a race. after the sound of the starting gun, he propels himself forward from the starting block and immediately grimaces in pain, grabbing for the back of his thigh. within 48 hours he begins noticing extensive bruising on the back of his thigh extending into the back of the knee. he now has difficulty rising from a seated position and flexing his knee. bending at the waist generates more pain. which muscle is likely injured?

His legs and thigh muscles ached as he trudged through the final swampland.

He tried to thrust off  Rohan’s shoulders to push himself over in as though they were in a game of leap frog.

Just then, an old elf released a great eagle from its shackles, a signal for the race to start.  When it squawked to freedom, the race began.  

The gentle foothills ended quickly, and the runners made a steep scramble to the top of a cliff, followed by a daylong run up across uneven terrain of hard, coarse-grained rock.

Explanation: