CrossFit is a strength and conditioning system built on constantly varied, if not randomized, functional movements executed at high intensity.

Let’s give life to this description and see how this program, honed from years of clinical experience, goes about forging elite fitness.

Man’s world, nature, is full of movement. Our standing, sitting, throwing, lifting, pushing, pulling, climbing, running, and of course, punching are all quite natural. They got us where we are. They are part of our design.

These natural, primal, movements influence the exercises included in CrossFit’s workouts.

A major and natural division occurs in movement types between those requiring control of the body alone and those that require the control of an external object as well.

We have also denoted movement types as being from the “arboreal” or “terrestrial” realms in recognition of man’s history.

The anthropologist’s notion that our ancestors practice of brachiating (swinging through the trees with relatively straight arms) effected an upright view and posture that transferred perfectly to bipedal movement on ground allowing the hands to use weapons and other tools is captivating in that it gives a full range of man’s physical capacities.

Those intertwined yet distinct demands are wonderfully expressed by the classical sports of gymnastics and weightlifting and what are for us their subsidiary domains, climbing and throwing. In the combined capacities of the weightlifter and gymnast we see a broad and powerful representation of the physical abilities of man for moving himself and things.

It’s from these wells, gymnastics and weightlifting, that we’ve drawn the exercises that form the basis of CrossFit’s programming. We use the term “functional” to describe the exercises utilizing movements most representative of natural movement. Functional movements generally use universal motor recruitment patterns, recruit in a wave of contraction from core to extremity, move the body or other object effectively and efficiently, and are multi-joint “compound” movements, which are neurologically irreducible.

The movements we’ve selected are in large part responsible for the potency of the CrossFit protocol. We say, “The magic is in the movements.”

For us the process of reviewing, testing, and evaluating exercises for selection is constant. Criteria for selection include, range of joint motion, uniqueness of line of action, length of line of action, strength of line of action, commonness of motor pattern, demands on flexibility, irreducibility, utility, foundational value, neurological value, measurable impact on adherents, and, frankly, potential for metabolically induced discomfort.

Our workhorse movements include deadlifts, squats, pull-ups, running and lunging, pushups and dips, presses and jerks, cleans and snatches, rope climbing, sit-ups, jumping, throwing, pressing to handstand and some hybrid movements like the muscle-up, clean & jerk, “wall-ball,” and “thruster.”

This cast of characters well represents the range of useful natural movements found in man; they are the “alphabet” from which more complex and natural movements are formed.

Our toolbox contains gymnastics rings, barbells, bumper plates, dumbbells, parallel bars, pull-up bars, medicine balls, rope, mats, and some odds and ends like kettlebells, a giant tire, and sandbags.

Our tools and exercises have long records of distinction outside of and long before CrossFit. In earlier times every “gymnasium” had parallel bars, rings, vaulting horse, dumbbells, barbells, and heavy bags. The rudiments of gymnastics and weightlifting were taught to all school kids. They were also an integral part of military physical training.

Today, outside of the CrossFit community, gymnastics and weightlifting protocols rarely mix. The most effective stimulus for developing agility, balance, coordination, accuracy, flexibility, trunk control, and upper body strength rarely mixes with the most effective stimulus for developing overall strength, power, speed, and explosive hip extension.

CrossFit’s vast clinical experience with functional movements strongly suggests that these movements are not only safe but also absolutely essential to health and fitness. Provocatively, it is our contention that non-functional movements not only render a seriously blunted training response, but that they are collectively, in contrast to functional movements, unsafe.

Our protocol has been tested across the broadest spans of human capacity with but minor modifications to exercises and workouts. Our claim of a universally scalable program has been proven sound.

Beyond safe and essential, we’ve found that functional movements form the basis for dramatically effective rehabilitation from injury and illness. Be sure that we are talking about squats, deadlifts, pull-ups, and pushups and not rolling around on Swiss balls and playing with Theraband. Functional movements scaled to capacity, that is, coupled with common sense and patience offer the quickest path to full habilitation.

We believe that this is the future of physical therapy.

In terms of performance, the functional exercises are singularly unique in developing strength, speed, and power. Several of our functional exercises, the deadlift, clean, and squat to name three, have been shown to alter hormone and neurotransmitter production. This “neuroendocrine” response is widely held to explain curious phenomenon like the squat’s development of upper body strength. The neuroendocrine response offers a more systemic and less mechanical view of strength development. Neuroendocrine response has nothing to do with our selection of exercises, however. We’ve chosen the exercises we have because of their observed leverage in conferring strength and capacity past their more apparent or obvious, mechanical or anatomical, advantages. Neuroendocrine response may explain our program’s efficacy, however.

We’re making the important point here that our protocol has been developed experientially or empirically. We call it the black-box model. We don’t know or care so much about what goes on inside, we’re keeping our eye on inputs and outputs, workouts and results alone. This approach has kept us a generation or two ahead of theory-based programming. Experts offering fitness, nutrition, or health regimens that they claim are distilled from first principles rather than clinical practice are fooling those who listen to them and, as often as not, themselves as well.

The concept of neuroendocrine response provides a theory as to how and why not only an exercise, but an entire regimen might contain distinct and powerful biochemical advantages. It is our suspicion that CrossFit’s entire repertoire of movements and even workouts themselves, elicit a powerful neuroendocrine response. We’re waiting for some professor to prove it.

Until then, let’s examine how we mix the functional movements to distinct advantage and then explore those advantages. On the potency of functional exercises we say, “The magic is in the movements,” but our line on maximally effective programming is, “The art is in the mixing.”

The fitness that CrossFit advocates and develops is broad, general, and inclusive. Our specialty is not specializing. Combat, survival, many sports, and life reward this kind of fitness and, on average, punish the specialist.

In practice, this encourages the athlete to disinvest in any fixed notions of sets, rest periods, reps, exercises, order of exercises, routines, peridodization, etc. Nature frequently provides largely unforeseeable challenges; we train for that by striving to keep the training stimulus broad and constantly varied.

We want to develop the capacity for elite performance in any combination of functional movement across a broad range of challenges or demands. (See “What is Fitness?”)

Introducing the idea of the “functional couplet” and using a simple design template shows how simple and yet how much artistry can go into making CrossFit workouts.

A “functional couplet” is a pairing of two functional exercises. Period. The most intriguing, and perhaps effective, are those comprised of a classic weightlifting or weight training movement coupled with a classic gymnastic or calisthenic movement. The best couplets are whole body monsters like thrusters and pull-ups or deadlifts and handstand push-ups.

Functional couplets make perfect CrossFit workouts when used as timed circuits where the athlete either attempts a predetermined number of rounds for best time (task priority) or works to complete as many rounds as possible in a predetermined time period (time priority).

Generally, the task priority couplets will go 3-5 rounds and the time priority couplets no more than 20 minutes but anything is possible and fair game. These workouts will last between 3-20 minutes and probably average 15. One hour including warm-up and cool down and stretching is plenty. The workouts can be worked at such blistering intensity, and should be, so that on the following day some rest, or at least a change of tempo is needed. For our simple template we will call these days “focus days.”

A focus day would be ideally spent in one of three manners. The first would be a distance effort, i.e., bike, run, swim, or row long. The second would be to focus on developing a gymnastics skill, e.g., press to handstand, pirouette, back flip. The third manner would be to focus on single rep efforts of a basic lift or, perhaps, concentrate on technique as with the O’lifts. This is a great day to work on fixing chinks in your fitness armor.

Following the focus day is another couplet and the fourth day is a rest day. So, a single cycle of our template looks like this: Couplet, Focus, Couplet, Off. This is a three days on one day off regimen.

In these workouts the reps, sets, length of workout, exercises, and combinations of exercises vary greatly while the intensity stays relatively high and the movements are all functional.