A thief got his exercise breaking into lockers in a Queens gym, as its members were busily working out, police said Saturday.

The first break-in at Planet Fitness, 329 Wyckoff Avenue in Ridgewood took place Jan. 3, when the crook made off with $900 from a wallet he stole.

The next day, the robber made off with $700 from one locker and $200 from another.

He was caught on surveillance video and police are asking the public’s help identifying locker thief so they can lock him up.