legs
forearms biceps
butt muscle
Bivalves (which include the Mussel family) do have muscles. The muscles are in the creature's 'foot', which is typically used for digging.
your legs because you have to jump high enough
yes
mainly leg muscules....some arm
For all these sports the muscles of the legs are needed.
Serving Digging / receiving Setting Spiking
Playing volleyball can benefit health. It increases heart rate and respiration, and also keeps the body moving. Muscles in the arms, legs, and core are used.
your fingers do most of the work when doing a set
No, you can wear knee pads that go on your knees to help with digging.