Do you mean twitching? If so, No. Muscle doesn't jump.
I believe when your lips are "jumping", that you're just having a muscle spasm.
Quads; the quadriceps.
It's probably just fatigued
The purpose of your femur muscle is to make or have movement in your legs. Like: running walking, jumping, etc.
Yes if applied directly to the heart muscle.
No. But it gives you really good leg muscle.
Do the jumping-jacks with your shirt off see if you jiggle....if you do its fat there
Stretch it gently and hold the position, repeat as often as needed.
Your penis because it allows for a large boost of momentum, Source: Porn star
There is one gastrocnemius muscle in each hind leg, between the knee and the foot. Its contraction provides propulsion, whether the frog is swimming or jumping.
Try squats wtih and without weight along with jump rope. Plyometrics will work too.
This happened to me once and it was a torn muscle that was affecting my ribs. The cause of it was trampoline jumping.