Possible Clues:

• __ dips: upper-arm workout
• Aid in reaching out
• __ exercise: upper arm strengthener
• Upper arm muscle, informally
• ___ extensions (workout)
• Muscle attached to the humerus, informally
• Three-headed arm muscle, informally
• Muscle controlled by the radial nerve, informally
• Push-up target, informally
• It's needed for a push-up, informally