what muscle works in a pair with the biceps brachii?
Source(s): 30 years in sports medicine and clinical nutrition. The biceps brachii is a antagonist of the triceps brachii. If the triceps brachii will contract, the biceps brachii will stretch and vice versa. Pushups. I do about 500 per day (200 AM, 300 PM) and my arms aren't huge, but they're toned pretty well, I guess.