Whether you're still religiously following your New Year's workout resolution or thinking ahead to beach bod season, here are 30 photos of celebrities sweating it out—for inspiration.

See how stars are staying healthy and happy in our best workout photos here. Ready to rev things ... or something else! Trying out different routines is crucial when it comes to keeping exercise ...

From Muhammad Ali and Diego Maradona to Serena Williams and Michael Jordan, Camera Work Gallery showcases some of the ...