Anaerobic
Hope this helps :D
A link between the skeletal system and the muscular system are tendons, which connect bones to muscles.
A link between the skeletal system and the nervous system is how the vertebrae are linked to the nerves in the spinal cord.
A link between the muscular system and the nervous system is how muscles respond when nerves signal them to after responding to the stimulus and traveling to the brain and back.
Simply walking alone can actually do both of these however if you are looking for multiple answers then here are some examples:
-Playing Sports
-Jogging
-Lifting Weights
-Swimming
-Dancing
-Bike Riding
etc...
Anyways, hope I helped!