Forearms and Hands: Grippers
This tool improves dexterity as well as forearm and hand strength. Just squeeze the handles together until they touch. Next time you have a conference call or webinar viewing, do a few sets (8-10 reps) in each hand. It'll also prime you for a day of typing emails or client reports.
Core: Exercise Ball
Surely some fitness-minded rebel in your office already does this: Swap out your chair for a large exercise ball, and you'll be forced to hold proper posture throughout the day. You'll have to keep a tense core to maintain balance, which does wonders for your abdominals and breathing patterns.
Quads and Core: Table Toners
You can sneak this in at your desk, or during team meetings: Just straighten your legs and raise them up to the underside the table. At the same time, press down on the surface with both palms. You should feel this working in your abs and legs, while fooling your colleagues into thinking you're just peacefully watching their Powerpoint presentation.
Calves: Isometric Raises
Isometric workouts don't require any joint movement or muscle lengthening; they're largely used in strength training. Try this one while waiting for the microwave, or during a ho-hum conference call: While standing, support yourself on one leg and wrap your other foot directly behind (it should feel and look natural). Raise up on the toes of your base foot for 15-30 seconds, and then go back down. Do this three times, the switch feet and do it again.
Butt: Gluteal Squeezes
We would advocate lunging to the kitchen if it weren't so obnoxious. Instead, here is a work-appropriate (and isometric) alternative: While you're sitting on your hindquarters for hours on end, try a couple minutes of tightening and relaxing the gluteal muscles. Do this in ten second intervals in as many sets as you can (which is to say, until your spreadsheet starts to suffer).
Image Credit: DreamWorks
This article is part of the Birchbox Man 31-Day Challenge for January 2015. Click to see all daily challenges and to learn how you can win sweet stuff all month.