These days, the inseams of men's shorts seem to be getting shorter and shorter.

So whether you're tired of baring your chicken legs at the beach or simply looking to bulk up your legs for a season in which they're most likely showing all the time, we have the workout to bulk up your quads, hamstrings, and calves. Sculpt a thicker, more muscular lower half with this mass-doubling routine, courtesy of trainer Mike Donavanik, C.S.C.S., who's worked with celebrities like Rumer Willis and Katie Holmes.

After a few weeks of this, you'll not only look damn good in whatever swimsuit suits your body type, but also be more productive during heavier lifts, since your legs and core are what give you the most power. Strong legs can also prevent injuries. And if you've been neglecting legs day, you're more likely to have muscle imbalances and run the risk of pulling a hamstring or tearing your ACL.

How it works

This routine has two workouts. Rest for three or four days between these workouts, because they're definitely intense. Add this workout into your routine for at least four weeks for best results.

Almost any compound legs exercise will hit both your quads and hamstrings. Day one focuses on your quads and glutes, while day two focuses on your hamstrings.

Directions

Donavanik has divided each workout into several "blocks." In cases where the exercises of each block are labeled with 'A' and 'B,' like supersets, do the 'A' exercise, then go directly to the 'B' exercise without rest. Rest 90-120 seconds between blocks.

Exercises labeled with a rep scheme 10+10* are performed as drop sets: Complete 10 reps at heavy weight and a regular pace, then drop to a lighter weight and complete 10 more reps at a slow, controlled pace.

By the way, Donavanik says that the 10-minute block of deficit reverse lunges at the end of day one is not a joke—and after a few weeks of this routine, your leg gains won't be, either.