When a body is in peak condition, biceps lift labradors with ease, calves climb ziggurats without agony, and aching backs stop making wheezy accordion noises. Get your body into tune with today’s Groupon: for $49, you get an eight-class punchcard plus three introductory classes (a $239.25 total value) at Flux Crossfit, located on McTavish Street.

Flux Crossfit zeroes in on fitness with a host of high-energy workouts and the support of small group instruction. Ease into the flexible, sinewy world of strength training with eight exhilarating group training sessions and three introductory classes. Both training sessions and classes are limited to a maximum of eight participants, granting pupils one-on-one guidance along with the support of a small group. Like a brigade of mercenary circus strongmen, certifiably fit coaches keep muscles on their toes and calories looking for cover with a fast-paced flurry of functional strength-training workouts, such as kettlebells, lifting, running, or rowing. Students are trained in general physical preparedness, honing their bodies into fighting shape for such physical ordeals as bewildering arrogant weight-guessers or beating up a waterfall.

Flux Crossfit is conveniently located in the Cathedral Village, and surrounded by green space where students enliven outdoor exercise with fresh air in the summer and snowshoe trampabouts on warmer days in winter. Call to schedule sessions.