Editor's Note: Due to member request, Rob has revised his popular 1999 article on the functional continuum. We hope you enjoy this expanded and updated version of the article!
The term “functional training” is a training catch phrase and/or concept that at its simplest definition implies exercises with a high movement value, traversing the multiple planes of movement and combining movement patterns, all in a “living” environment. With this in mind, however, there is unfortunately little guidance on how to apply the concept into tradition training program development.
The functional continuum has been updated from previous concepts (1999 and 2003) and now serves as a means of not only exploring the “functionality” of an exercise, by determining the amount of movement required to complete the exercise as well as the influence of the “living” environment, but providing a continuum upon which to build training programs for clients. Furthermore, the functional continuum allows exercise prescriptors to understand whether a designed program or a single specific exercise has a high functional/high movement focus or a low functional/high muscle focus, thereby allowing trainers to increase or decrease their training focus in order to meet their clients’ needs.
What is Function?
Many people, when asked what functional training is, have vague answers, yet this is the basis of their exercise selection. A simple question to determine whether an exercise or program is functional is to ask, “Functional for what?” A classic example is to ask instructors why they have prescribed the “plank hold" as an exercise. The most common answers are that the exercise trains the core muscles and/or is “functional.” Firstly, more often than not, the plank muscles do NOT train the core. In fact, for many if not all people, the plank/prone hold detrains the core. Holding the position is too intense for the core muscles, and as such, the obliques and even rectus are often employed in a long phasic contraction. This can lead to programming the global muscles to activate as part of the local muscle profile. Worse still, the core muscles, which should be subconscious and precede activation of global muscles, tend to take on global muscle patterns by being taught to activate in time with a conscious movement. For many clients, we are then taking a group of muscles that are functioning fine and teaching them incorrect patterns. The second point of consideration is what is functional about holding your body a few feet off the ground in the prone position? The answer may be to increase push up ability through improving synergistic fixation of the body, but was this the intent when the program was prescribed?
A final reminder comes from the basics of human anatomy, which, while meant to be the prime focus of training, has become an afterthought. Therefore, before we move into discussing the functional continuum, here are a few reminders as to the role of skeletal muscle. Through contractions, muscles perform three important functions: motion, maintenance of posture and heat production (Tortora & Anagnostakos 1987). Skeletal muscles are responsible for:
- Activities such as walking and manipulating objects in the external environment (Spence 1990)
- Motion of our bodies, our posture and the production of heat (Clark 2005)
- Producing movement, maintaining posture, stabilizing joints and generating heat (Marieb 2007)
Note: None of these references have the function of skeletal muscle as either hypertrophy or aesthetics. All of them do, however, mention its importance in movement and motion. Further to the muscular system come the other systems of the body. The skeletal system provides the framework, albeit limited (e.g., the hinge joint of the knee) through which the muscles act. The nervous system coordinates the movement by selecting recruiting and controlling the muscles that are acting on the bone, with the metabolic system providing the energy for movement.
Training Aims/Needs
As with all training programs, the key design factor would be the client’s aims and needs, with the aims being what the client wants to achieve and the needs being what is needed for the client to achieve this. Likewise, a thorough training and injury history is required because, without this, a client's ability and capability to perform certain movements safely is not known.
Are the Needs “Trainable?”
Once the client’s aims and needs have been outlined, a determination as to whether his needs are “trainable” must be determined. In this context, “trainability” refers to both whether you have the skills and knowledge to instruct the client and whether it is safe to train the client for an identified need. For example, a rugby player is tackled constantly during a game, particularly around the legs. Does this mean that we should take a baseball bat to his legs to teach him to handle impact? A fireman is required to “duck waddle” or walk in a deep squat with a fire hose on his shoulders. Should you load him up with a squat bar and get him to walk in a deep squat around the gym?
If you determine the need is untrainable, you must then consider the best way in which to address the client’s needs. It could mean referring the client to a specific coach or a nutritionist. Alternatively, if the reason for determining the need to be untrainable is due to safety concerns, you must look for alternatives through which you can best meet the training needs safely.
Movement Patterns to Train?
“Functional exercise” involves multiple planes and multiple joints. Most human action (work) seems to involve a relatively limited number of fundamental movements (such as lifting, pushing, pulling, throwing and locomotion).
Where previously we used to design programs by body parts (such as chest, back, shoulders, legs, abs, etc.), the functional approach to training revolves around determining what movement patterns the client needs to train in order to meet his goals and needs.
Number of Joints in the Movement
Movement can be categorized by the amount of joints involved in an exercise movement. Isolation movements involve actions that cover only one joint. A compound movement involves actions that take place over more than one joint.
When we progress from the concepts of isolation and compound movements, we come to kinetic link movements, which involve several compound movements being performed concurrently or progressively. In the kinetic link, a complex movement is one in which more than one compound movement is linked together to complete an action (e.g., Clean and Press). Multi-plane exercises are those that would involve movement across more than one plane (e.g., bounding plyometrics). Not only can plyometric activities be complex, but they also can involve movement across more than one plane (e.g., wood chop action).
As can be expected, with more muscles and joints involved in a movement, the need for nervous system control and muscle coordination is increased.
Figure 1
Number of Planes Across which the Movement Occurs
The body can be described in three anatomical planes of reference: the sagittal, coronal and transverse plane. Across these planes, specific joint movements occur. These are flexion and extension across the sagittal plane, lateral flexion, abduction and adduction across the coronal plane and rotation, horizontal flexion/adduction and horizontal extension/adduction across the transverse plane. Following a musculoskeletal injury, it is these specific movements at specific joints that are assessed by physiotherapists to determine functional deficits. These joint movements generate six primary patterns of movement: push, pull, bend, twist, lift and gait (see Figure 2 - movement patterns of functional movement). While the push, pull and lift patterns can be performed unilaterally (one limb at a time) or bilaterally (both limbs simultaneously), bending is only performed bilaterally, while twisting and gait are performed unilaterally.
Figure 2
Functional vs Counter Functional Movement?
Once we have established what movements are needed and are/may be being performed (sport, other training, etc), we must consider the nature of the functional training. Consider if all of our training is towards functional life, and we perform certain activities everyday for our functional needs. Would these muscle groups not continually receive a greater training stimulus than those not used in functional everyday movements? If we were to further train these “functional” movements, would we not create muscular imbalances and hence decrease our TRUE INTENDED functional goal?
Almost everything we do in life is in front of us: eating, reading, typing, writing, etc. All of these actions require shoulder flexion and horizontal shoulder adduction (often internal rotation as well). Thus, muscles like the pectoralis major/minor and anterior deltoid are used to a high extent daily. Do we therefore want to increase our stimulation of these “functional” muscles? Or would it be more advisable to prescribe counter functional training? For sporting athletes, sports specific training and competition often overloads the muscles in the functional movement patterns of their sport. A baseball pitcher or javelin thrower, for example, completes thousands of unilateral repetitions with his dominant arm. Does this mean that his functional training should focus only on this limb, or should it include training to return balance to the body, thus employing counter functional training?
What tends to make these matters worse is the current concept of training body parts without complete appreciation of their movement roles. For example, to counter the training of the chest, most trainers employ training exercises of the back. After all, the back is on the opposite side to the chest, right?
Unfortunately, the muscles trained in “chest” exercises, like the pectoralis major/minor, anterior deltoid and muscles trained in “back” exercises like latissimus dorsi, are all internal rotators. Therefore, rather than avoid muscle imbalances and improve posture through complementary movement pattern exercises, we are creating a training situation that will turn our clients into kyphotic hunchbacks. Add to this the thousands of rectus abdominous training that is often prescribed, and they almost collapse inwards.
Synergy Profile?
The term “synergy” comes from the Latin words meaning “work together” and relates to the controlled coordination of muscles to perform a given task. One of the most notable factors in strength gains for beginners comes from an increase in muscle synergy. This is because the motor pathways develop to make the action more efficient by not sending neural impulses to the antagonists and non essential muscles. Synergy develops to allow a coordinated activation of the agonists, synergists and fixators in their correct roles, without interference from the antagonists (see Figure 3).
Figure 3
The body adapts to the level of performance required. If the level required is below the current level developed, then detraining will take place (e.g., when you take time off, your body detrains to your current sedentary levels). For the sedentary person who takes up resistance training, there is a positive adaptation to the new level of synergy and stabilization required (the inter-muscular adaptations that bring strength gains). However, for the general resistance trained individual who performs the generic isolated, machine or supported exercises, the stabilization/synergy requirement is still below that required for functional activity and sport. With this in mind, strength for function needs to be developed in a functional setting (remembering that strength is transferable from an unstable environment to a stable environment but not the other way around).
Therefore, when determining the movement need (e.g., push, pull, lift), you need to determine the amount of synergy required, both from the exercise (as will be discussed further on) and for the client’s need. That is, they must both match, or you must have a concept on how to progress the current synergy for a given movement up to the standard required. Figure 4 provides an example of distributing a given bilateral lifting exercise, the squat, on a continuum based on synergistic requirements.
Figure 4
Stabilization Profile?
It is important to realize, when determining the stabilization profile of the client’s training need, that there is marked difference between stability and rigidity, and these are both often confused (the plank/prone hold exercise being a prime example.) Where joints are fixated by activation of muscles undertaking a specialized synergistic role, called fixators (e.g., the wrist in a biceps curl fixated in a neutral position), stabilization involves the ability of the body to respond to internal and external forces in order to maintain a stable or uniform (if moving) position.
There are in essence two forms of balance. There is balance against internal forces (perturbations) or self balance (e.g., standing on one leg) and balance against external forces (perturbations) or counterbalance (maintaining balance when the foot slips on uneven ground). While many forms of training typically employ a self balance requirement, like maintaining balance during a squat or when running on a gym floor or paved road, few employ a counterbalance profile where the body is subjected to external influences attempting to disrupt balance. Even fewer conditioning sessions employ strategies to develop both forms simultaneously, yet both forms of balance are required in everyday life. Consider standing up on a bus. There is a need for internal balance to stand and for counterbalance to adapt to the movement of the bus underfoot.
Furthermore, balance and counterbalance can be either static or dynamic in nature. Static balance involves maintaining balance when the center of gravity (COG) is within the base of support (BOS), whereas dynamic balance is balance where the COG is outside of the BOS and the body is moving itself. Now consider moving to the exit doors of the bus while it is in motion, and to add a little more counterbalance, you bump into another person.
With this in mind, developing balance and counterbalance strategies in isolation and in combination are essential in improving functional ability. (This is especially true with elderly or neurologically compromised clients who have a decreased balance and counterbalance strategy.)
Figure 5: An example of applying a balance profile to a selected exercise
Finally, the position in which stabilization is trained to increase is also important. In the upright position, humans use their abdominals as stabilizers as opposed to just movers. However, stabilization exercises are often trained in supine/prone lying positions. As Ellison (1995) states, “A muscle’s function in the upright position is a priority in training.”
Choosing the Exercises
The next step is to choose the exercises that meet all of the prescriptors above. These prescriptors are: training need, number of joints moved and their movement patterns, whether there is a need for counter functional training, the synergy profile of the training need and the balance profile of the training need.
Once these exercises have been selected, each individual exercise must be further fine tuned by considering the key factors that influence the functional value of each exercise as well as the program as a whole.
Factors Influencing the Functional Value
Isolation vs compound exercises
“The technology of the fitness boom with its muscle isolating machines and focus on parts of the body produces the body as an object of increasingly isolated and fragmented parts” (Costa 1995).
One must ask how functional isolated exercises are. Not only is the cross over to function of single joint exercise poor (Chek 1998a), but when in life are isolated movements performed? Name any sport that utilizes a purely isolated action. When in life does the knee perform extension alone, as in the leg extension, while the back and upper thighs are supported?
There are few benefits of an isolated action for the general fitness trainer or even advanced athletes. Some of the common reasons (or excuses) given by resistance training instructors for the implementation of isolated exercises include:
- Pre-fatiguing and the Weakest Link - The means of isolating a muscle to ensure it is the limiting factor in an exercise is utilized by body builders to target a specific muscle requiring growth. However, this value is almost purely aesthetic and of limited use for athletes. For example, if an Olympic lifter always fatigues in the glutes when dead lifting, what good would pre-fatiguing the quadriceps be (to ensure the quads are the limiting factor in his dead lift) to performance?
- Synergy - The importance of synergy cannot be over emphasized. When isolating a muscle, you are effectively breaking down the communication systems between that muscle and others. The effect of this is a break in intermuscle communication and the decreased ability of the body to work as a single effective unit. “Just because you know the letters of the alphabet doesn’t mean you can read” (Orr 2002, on muscle synergy and muscle isolation). Furthermore, with many articulations in the body being bi-articulate, when employed in movement, they move through passive and active insufficiencies (Steele 1991) and require “concurrent shifts” in order to complete actions. By training a muscle in isolation, these required roles cannot be facilitated, and therefore inappropriate motor patterns may be developed.
- Segmentational Force Velocity - When developing force, the body acts like a relay team. As the current sprinter moves to the exchange area, the following runner begins to accelerate to “transfer the speed of the baton.” Following this train of thought, the body learns to begin accelerating while the preceding segment nears the end of its involvement (usually the more proximal and/or larger segment). Again, consider the boxing punch. Velocity is generated from the hips through the torso, thorax, shoulder and finally the elbow, culminating in impact. If speed at the elbow is developed through an exercise like an elbow extension, the ability to transfer force is negatively influenced (Elliott 1991).
- Rehabilitation - Even though an isolated exercise may be prescribed by a physiotherapist (e.g., the leg extension, prescribed to strengthen the vastus medialis obliques or rotator cuff work), it is done so in conjunction with functional movement and mobility work. You will find that for most physiotherapists, it is the return to function that is of primary concern, and the re-strengthening exercises are so directed. Therefore, although isolation exercises may be utilized initially to re-strengthen a muscle, the muscle’s actions will then be integrated back into its functional application (e.g., the VMO re-strengthened through the leg extension to prevent a tracking concern is then employed back into a compound/complex action where it is required to perform it’s role in it’s true application).
- Muscle Balance - Would not a compound exercise provide the same muscle strengthening benefits while providing a greater functional movement and coordination aspect? For unilateral actions like javelin throwing or bowling, where one side is trained more than the other, the same gross action can be performed on the weaker side, utilizing weighted balls like medicine balls.
Machine weights vs free weights
“80 percent of injuries in the US are from machines like a Pec Deck” (Chek 1998a).
Synergy - For many years, it has been commonly advised that beginners utilize machine weights rather than free weights. The predominant reason for this is safety, as less synergy and balance is required. However, what happens in real life when the client is required to utilize the muscles in a functional capacity, a capacity that requires synergy and balance? For example: Many novices perform a squat utilizing machine weights. What happens then when they get home in the afternoon and attempt to lift a box? The muscles may be further developed, but how has the synergy, proprioception and balance improved to aid in the movement? To see this in action, compare a novice weight trainer doing a free squat and a universal squat. Which one do they wobble around more on?
“Since pin weight machines consist of preset lines, it is often argued that the stabilizers are neglected. It is often these stabilizers that are prone to injury” (McEvoy, Rawson & Ridley 1993).
Stabilization - “If the stabilizing muscles of the shoulder joint are weak, then innervation of the prime movers will decrease during the performance of a movement” (Ostrowski 1998, on developing the stabilizers for the bench press).
“You can only pull what you can stabilize” (Chek 1998b).
Muscle stabilization forms part of the synergy equation. When training on a supported bench for example, the trunk is provided with external stabilization and the stabilizing muscles are trained to synergistically work with the prime moving global muscles. With motor patterns being centrally generated, if the core is not stable, the amount of force that the global muscles can apply to a specific task is reduced, thus the transferability of gains made on machines are questionable.
Try this. Perform a single leg extension on a leg extension machine with a weight that will allow only 10 to 15 repetitions. Now stand on one leg and perform a single leg extension with the same weight for the same amount of repetitions. Can you do it? Probably not. Even though your legs can still produce the same amount of force, it is not able to because the rest of the body is unstable. The body is also accustomed to producing this force with your core supported, the way you trained it in the gym on the leg extension machine. Yet which position are you in on the sports field when kicking a ball. Are you standing on one leg while moving and rotating, or are you sitting down with a back support? As Ellison (1995) states, “It is important to develop active, internal stabilization as opposed to passive external stabilization.”
The more you stabilize a movement, the stronger the movement becomes. Transferability from functional to stable exercises is therefore high, yet these gains are low in the reverse situation.
Biomechanical Design - Not only do machines fail to follow the body’s natural strength curves (Zatsiorsky 1995, Shield 1995), but by fixing lines and planes of movement, the chance of injury may actually increase as opposed to decrease. Poliquin (1997 as cited by Ostrowski 1998), in regards to the Smith machine bench press, states, “Because of the mechanics of the human shoulder joint, the body will alter the natural pathway during a free weight bench press to accommodate efficient movement at the shoulder. A fixed bar pathway does not allow variation for efficient movement at the joint, thereby predisposing the shoulder to harmful overload from the lack of accommodation.”
With this in mind, and the curvilinear movement created by the musculo-skeletal system across articulations, simple circular or linear resistance based machines do not allow the articulations to follow their natural movement patterns and hence increase the chance of injury.
Furthermore, when lever systems are utilized, friction created by the rollers and slides add to the total weight lifted. This friction is less in the lowering actions of these machines (now gravity assisted). This would mean that when performing a concentric action, the muscle moves a greater load than when contracting eccentrically. This eccentric unloading does not suit the capability profiles of muscles, being that eccentric contractions are stronger than concentric ones (Shield 1995). In line with this, often the position in which the muscles are loaded is inappropriate. Two examples of this are 1) the start of the pec dec where the arm is often fully abducted and externally rotated and 2) the start of the leg extension where the knee is not only fully loaded in an open joint position but the start angle is often greater than 90*. Both of these positions not only have to overcome Newton’s first law but also suddenly become maximally loaded.
Local or Global Exercises
Over the past few years, the concept of local and global muscle systems have surfaced. Global muscles are typically muscles that cross two or more joints and are responsible for dynamic/global movements. By covering more than one joint, these muscles allow for complex movements and the effective transfer of energy along the kinetic chain to optimize the summation of velocity (see segmentational force velocity). With this in mind, by covering several joints, these muscles cannot control segments or joints in between and, as such, local muscle control is lost (see Figure 6). This is where local muscles that cover one joint are important. These local muscle systems, like the transverse abdominals, vastus medialis obliques and medial gluteals are responsible for providing joint security. If these local muscles are inhibited or not employed correctly, joint security and integrity is compromised as the global muscles try and compensate.
Figure 6
Figure 6a: Local and global muscles providing spinal stability.
Figure 6b: Breakdown of spinal integrity due to inactive local muscles with global muscle contraction.
Furthermore, with motor patterns being centrally generated, if the core is not stable, the amount of force that the global muscles can apply to a specific task is reduced. For example, if the stabilizing muscles of the shoulder joint are weak, then innervation of the prime movers will decrease during the performance of a movement. This occurs in order to protect local shoulder joint integrity when the global muscles produce a large force. The analogy by Chek (1997) of firing a cannon from a rowing boat is suitably effective.
Conditioning Profile?
The final construct of the program, the part with most trainers are familiar with, is the conditioning profile. The conditioning profile relates primarily to the specific adaptation required to perform the given functional task and includes metabolic and neuromuscular parameters.
To this end, the number of exercises and repetitions, the Time Under Tension (TUT), the amount of rest between sets and the recovery between workouts must be considered, as well as the training dose of volume and intensity along a periodized training plan (See Periodized Programs - Parts 1 through 3 under "related content" at right).
Encapsulation
Figure 7 below encapsulates the functional continuum process for program design. While, at first, the process may seem long and complicated, once practiced and experienced, the process becomes easy to apply practically and expeditiously.
Figure 7
Some Final Basic “Programming for Function” Guidelines
- In general, the easiest thing to do to each exercise is to add more movement. Rather than moving only one joint, move more. The more they move, the more functional the exercise. Furthermore, aim to move the joints through more than one plane in order to prevent “pattern overload” and/or overuse injuries. With this in mind, avoid increasing functional complexity to a point that surpasses requirement.
- Decrease the influence of pre-fatiguing exercises. If you want the triceps muscle to be the dominant factor in the push up, military press, bench press, etc. then isolation before compound/complex may have a place. If, however, you want to fatigue the larger muscle groups, then the fatigued triceps may provide a limiting factor.
- If isolating for rehabilitation, remember to rehabilitate then integrate (rehabilitate the muscle then integrate the muscle into its place in functional movements).
- Where required, decrease support and increase the requirement to balance. Moving off the machines and onto free weight can be a simple progressive step (if you regressed to machines in the first place). Once barbells have been mastered, move onto dumbbells. From there, the choices are endless. Use medicine balls, body weight, ropes, cables and kettlebells. Throw away the bench and use a fitball or dura disc if the training need requires a less stable platform.
- Consider the synergy, force development patterns, balance and speed of movement profile for the sport or every day (including working) lifestyle of the person for whom you are writing the program. Then consider whether the program needs to focus on functional movements of counter functional movements.
- When prescribing and advising on exercises and their techniques, consider the anatomical, biomechanical and kinesiological effect of the exercise.
- Progression is the most important aspect of programming. It is hard, due to ego, but vital that they start at the beginning. The method of progression should be from technique and stabilization to hypertrophy and/or strength (then, if required, power). “We should never break the stability - strength - power rule of progression, or we break the client/athlete” (Chek 1998a).
- I know, the primary goal of most clients is aesthetically based. They want the muscles of their legs to look good, so they want to do leg extensions and leg presses. Have you ever seen a sprinter’s legs? Pec decs and flyes for the upper body? Seen a gymnast? Yes, they do perform weight training exercises, but their dominant training is kinetic link and they do their weight training after functional training.
- Finally, review, review, review. Constantly review your client’s needs, the exercises you have selected and the reasons you have selected them.
Safety First!!
- Follow the guide of developing technique and core stabilization FIRST then strength then power.
- Move from exercises with the higher stabilization requirement to those more stable during a training session.
- Progression - DO NOT increase weight too rapidly. Remember the first rule.
- Always ask yourself why you selected this exercise. Is it advanced and potentially dangerous simply for the sake of being highly technical and “functional?”
References
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