go for the burn
To push oneself to exercise more intensely (which will often cause one to experience a burning sensation in the muscles). We're going to pick up the pace now, everybody! Come one, go for the burn! That's it, go for the burn, everyone—just one more mile to go! The instructor kept urging us to go for the burn, and, instead of being motivational, it just made me want to slap him in the face!
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