CrossFit is promoted as both a physical exercise philosophy and a
competitive fitness sport, incorporating elements from high-intensity
interval training (HIIT), Olympic weightlifting, plyometrics,
powerlifting, gymnastics, kettlebell lifting, calisthenics, strongman,
and other exercises. CrossFit presents its training program as one
that can best prepare its trainees for any physical contingency,
preparing them for what may be "unknown" and "unknowable". It is
practiced by members in CrossFit-affiliated gyms, and by individuals
who complete daily workouts (otherwise known as "WODs" or "Workouts of
the Day").
For me, Crossfit works because you always do different things, you can
practise lots of exercices from various disciplines and you can see
results quickly, mentally and phisically.