Possible Clues:

• Bodybuilder's focus, sometimes
• Gazetteer abbr.
• Muscle strengthened by a pulldown exercise, in brief
• Bit of your back, briefly
• Cato's lang.
• It's 0 at the equator: Abbr.
• Partner of long. in a G.P.S. location
• Back muscle, familiarly (m)
• Pec neighbor
• Opp. of longitude