Can't do back squats? Try one of these: front squat, barbell hack squat, Jefferson squat, Zercher squat, one-leg squat, Smith Machine squat.

Holiday Shred Challenge female winner Alisa Tetrault transformed her body – and her life – in under a year's time. Here were her steps to success, in her own words.

Reap all the muscle- and strength-building benefits of both positive and negative reps with this unique four-week training program.

Burn fat, enhance overall conditioning and build muscle with this challenging station workout.

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Target all four areas of the midsection for a fully developed washboard stomach with this ab-training routine.

Build perfectly peaked arms with this sample two-days-a-week biceps routine.

Build size and functional pulling strength with these four inverted row back routines.

Be active on Christmas Day – while also enjoying great food, of course – by taking this 24-hour challenge. Crush your reps and you may just win yourself a belated Christmas present!