The 7 Key Features: What are they?
The 7 key features are a set of movement-related guidelines that describe how someone should organize their bodies when completing certain movement tasks. Why are such guidelines even necessary? Our bodies have almost infinite degrees of freedom of organization when faced with a movement problem, like lifting a load off the ground, why then should one way of moving be more desirable/better than another?
These important questions will be addressed throughout this article, however, the main motivation for encouraging these guidelines is for injury risk reduction and performance enhancement. Each key feature corresponds with a way of moving that results in the forces being applied to the body by external objects, and the forces being produced by the body in response to external objects, to be done so (that is, applied and produced) in an optimal way.
For example, lifting heavy loads, or moderate/low loads very quickly, with excessive spine flexion, has been found to be a mechanism for various low back disorders. This is so because when the spine flexes under these conditions the way forces are absorbed and produced by the body changes. The angle of pull of muscles running along the spine becomes smaller reducing their ability to contribute to spine stabilization and resulting in more force being applied to passive structures such as ligaments and discs [1].
However, when the spine retains its normal curvature (sometimes referred to as a “neutral” spine) under the same conditions, passive structures are spared and forces are applied to the spine differently; for example, lower shear stress across spinal segments is observed. If a performer is able to maintain a normal low back curve and also utilize their hips when performing a lift, this represents a far superior movement solution from both an injury risk reduction and performance standpoint [1].
NORMAL LOW BACK CURVE
Represents a far superior movement solution from both an injury risk reduction and performance standpoint.
FLEXED LOW BACK CURVE
Represents a riskier movement solution from an injury risk perspective and can limit performance.
The other six key features also describe ways of moving that nudge people away from riskier movement patterns, especially under certain circumstances. The important concept underpinning the key features is that how we move directly impacts how our bodies are loaded [2].
This fact is neither good or bad in and of itself. Anyone who designs and implements exercise programs takes full advantage of loading the body using different movements, frequencies, intensities and durations. The body is only able to adapt to become stronger, more aerobically fit, etc., because it is sensitive to loading in the first place!
How We Move Matters. But What Influences How We Move?
Having established that the key features describe certain ways of moving that are more desirable than others when performing certain tasks, does it follow that one should always move in these ways, never deviating from the guidelines or participating in activities that make it harder to follow them? The short answer is, no. However, unpacking why this is the case with help develop a better understanding of the key features and how to practically apply them.
How someone moves is influenced by many factors. For convenience, these factors can be grouped into three categories: task-, environment-, and individual-related factors [3].
- Task-related factors are things like the rules of a game, the objective(s) that need to be achieved, the implements that need to be used, etc. For example, consider the forcible entry of a door. The task-related factors for forcing a door (e.g., the required tools, the forces required, the resulting change to the environment due to actions taken) will shape how a fire fighter moves in a much different way when compared to another task, such as throwing a ladder.
- Environment-related factors, as the name would suggest, refer to things about the world around us such as temperature, space, features of the built environment, how slippery the floor is, etc. Taking up the example of a forcible entry one could imagine how the movement of a fire fighter could be shaped by two different environments: 1) A temperature controlled training environment with the absence of a sense of urgency, vs. 2) A live fire where a door must be forced to access the fire floor where there are confirmed victims.
- Individual-related factors are things unique to a given performer such as her/his body mass, height, injury history, skill level, confidence, etc. Unlike task and environmental factors, which are mostly commonly shared across performers, each person can have a widely different set of individual factors that can shape their movement. For example, it is likely that a fire fighter of smaller stature will employ a different approach to performing a forcible entry compared to a larger counterpart.
Looking at the 7 key features through the lenses of these three movement-influencing categories can assist in unpacking how they can be applied in a fire fighter’s life.
The Task(s) at Hand
When it comes to task-related factors, there are at least as many as there are unique tasks/activities that fire fighters might need and want to do; which is an infinite number! Among these infinite tasks, successful performance in some do not depend on, and in fact might be compromised at times, by following the key features.
For example, to swing a golf club successfully there needs to be a dissociation between movements of the hip and shoulder. Further, most road cyclists would agree that to go fast being in an “aero” position (i.e. having the trunk flexed over the bike frame), is going to be far superior than sitting upright in the saddle and trying to maintain a neutral spine. And lastly, you would be hard pressed to tell a jiu jitsu practitioner that they can’t flex their spine, or violate any of the other key features, in service of trying to submit an opponent and avoid being submitted in the process.
If a fire fighter loves engaging in any of these activities it is almost certain that they should not strictly apply most, if not all, of the key features as guides for their movement. Whatever the risks involved in these or other such activities are, the task constraints are such that successful performance demands that a performer move their bodies in ways that will not always conform to the key features.
However, many of the tasks that fire fighters need and want to do are enhanced from a performance and injury risk reduction perspective if the key features are used to guide movement.
For example, almost all strength and conditioning based tasks, especially those that impose external loads on the body and/or have a speed component, would fall into this category. Many manual material handling tasks that require objects to be lifted, carried, pushed, pulled or otherwise manipulated in some way, could be performed safer and more effectively if a performer maintained (or could maintain) relevant key features. And this is also true for many activities of daily living such as carrying groceries, as well as common tasks at a fire department, such as stepping into and out of an apparatus.
The key features are far from hard-and-fast rules that dictate how someone should squat, pull hose or carry groceries home from the corner store. Rather, they describe features of movement that a performer should attempt to stabilize while the body is organized to achieve the specific goal(s) of a given task.
For instance, there isn’t one “right” way to perform a lunge. Step width and depth, trunk angle, and the speed of movement (all different ways of describing motion) can vary drastically according the task at hand. The key features relevant to the lunge pattern simple guide a performer to stabilize certain features (e.g., the relationship between the direction the toes and knee on the same side of the body are pointing) while the performer organizes his/her body in the most appropriate way to tackle the unique constraints of a given task (e.g., lunging holding a heavy medicine ball fixed to the chest, or climbing stairs while carrying hose on one shoulder).
KEY FEATURES ARE NOT RULES
They describe features of movement that a performer should attempt to stabilize while the body is organized to achieve the specific goal(s) of a given task.
The Environment and Constraints
A very common piece of feedback that fire fighters often provide when first learning about the key features, especially those related to the spine, is that they are impossible/unrealistic to follow in many “real life” fire ground scenarios.
The quintessential example is the victim who is collapsed in a confined space that must be lifted and maneuvered to safety. “It is impossible to get set in a good position to lift in a safe way when a person is collapsed between the toilet and the tub”, fire fighters often report. Perhaps without even knowing it, these fire fighters are pointing out how the environment can significantly shape how someone can, or chooses to move.
A helpful way to think about how the environment can have such an effect is using the concept of a constraint. A constraint is something that eliminates certain possibilities, or options for action [4]. When fire fighters invoke the example of a patient lift in a confined space, they are describing a highly constrained environment to act in. For example, the space between the tub and toilet (and likely the dimensions of the space in general) is very small and would preclude fire fighters from assuming certain lifting postures that would be possible in more open environments. Further, time might also be a constraint in this example, such that as the time to act necessarily becomes smaller and smaller, so to do the available solutions that can be explored to complete the task.
It is certainly true that given how environmental constraints can shape the demands of a fire ground task, it may be impossible or very, very difficult to move according to the key features. Fire fighters often like to say that the “task is the task” or “the job is the job, and it needs to get done”. Does this self-evident truth invalidate the key features? No, because the key features are not rules that dictate how someone should move under all circumstances. This is a common error that is easy to make when bringing to mind all the different movement scenarios where the key feature “rules” might need to be broken to meet a task objective.
In many of the environments that fire fighters are called to act in, however, the constraints are not so impermissible to different movement solutions. To be clear, the environment is always shaping our movement in some way, but very often the range of movement solutions a fire fighter can employ to successfully complete a task is large. When the environmental constraints permit, fire fighters are encouraged to integrate the key features into their search of movement solutions as they interact with the environment, task-specific constraints, and individual factors and/or constraints (which will be discussed next), to “get the job done”.
Individual Differences
The last lens to look at the key features through is that of individual-related factors, which produce movement variability. As already mentioned, these factors are the most diverse, and, by definition, the most specific to any given performer. For the purposes of this article, we will focus on a few specific factors, which will be framed using the idea of constraints.
Throughout this article an assumption has been made that a performer who wants to guide their movement using they key features is actually able to do so. A fire fighter lifting something off the floor might actively be trying to move through their hips, while maintaining a neutral spine angle and a braced torso, however, not posses the ability or awareness to actually do so. What things might be constraining such a fire fighter’s motion?
In the field of biomechanics the body is modelled as a kinetic chain, which describes how motion (or the lack of motion) in one joint segment, can influence how other joint segments move, and in turn how force is produced and absorbed by the body. For example, restricting the range of motion at the ankle, such that the knee is limited in moving forward past the toe (a motion referred to as dorsiflexion), has been shown to alter whole-body movement patterns during lifting tasks in such a way that makes it more challenging to maintain a neutral spine angle [5].
So if a fire fighter has limited range of motion about a joint(s) but the demands of a task require that large ranges of motion be expressed about that joint(s), he/she will be likely to compensate for the limitation(s) by adopting riskier, less effective movement solutions. Any factor that may limit the range of motion expressed at a joint, then, such as the extensibility of muscles, joint restrictions arising from past injuries, tight fitting clothing, and even a performer’s perception of risk, can all potentially make it more challenging to follow the key features.
Another factor that could be limiting a fire fighter’s ability to move according to the key features is their capacity in relation to the demands of the tasks they need to perform. Capacities in this case are things like a fire fighter’s level of strength, endurance, and power, in addition to their skill and coordination, which rely on their ability to use information in the environment to act in effective ways. Many fire ground tasks and those associated with sports and extracurricular activities require individuals to move bearing external loads, move at high, or changing rates of speed, and/or sustain movements for prolonged durations. These requirements increase the demands under which range of motion must be expressed to complete a given task safely and effectively.
If a fire fighter’s capacities do not at least match the demands of their activities, such a scenario represents a constraint that will very likely limit the movement solutions available to the fire fighter for action. For example, in a study investigating how elevated demands influenced movement it was found that some fire fighters who were able to maintain the key features of the knee while performing an unloaded lunge at a low speed, were not able to keep these features stable when performing a simulated hose advance [6].
LOW DEMAND CONDITION
Knee key features are stabilized by the performer.
ELEVATED DEMANDS CONDITION
The same performer is unable to keep the knee key features stabilized.
The Effect of Elevated Demands
The image containing the three skeletal models was created using the motion capture technology used in the study to evaluate fire fighters’ movement. This particular image displays the exact movement patterns used by one of the fire fighters who participated in the study to perform the simulated hose advance. The introduction of elevated demands associated with this higher demand task (both load and speed demands are increased) destabilized features that were controllable by this fire fighter when demands were lower.
Applying the Key Features in Work, Life, and Play
As mentioned multiple times in this article, the key features are not movement rules, nor should they govern the activities people want, or love to engage in. It also shouldn’t be the case that fire fighters micro manage all their movements, by cognitively appraising, in real time, if they are following or violating the key features. Even though a fire fighter might actively “think” about a relevant feature when first learning about it, or even when performing certain tasks, the goal is for these features to emerge as part of the unique movement solutions that a fire fighter employs when engaging in relevant activities associated with their work, life, and recreational activities.
What exactly is meant by emerge? In essence what we want is for the key features to become stable movement outcomes; meaning, that as many other aspects of a movement pattern vary according to the task and/or environmental constraints, the relevant key features do not.
For example, the task constraints of the two different lunge pattern examples mentioned earlier in the article (lunging holding a heavy medicine ball fixed to the chest, and climbing stairs while carrying hose on one shoulder) would require a fire fighter to organize their bodies in different ways. Changes to the demands (e.g., increased load, speed, or duration), and/or environment (e.g., surface, temperature) would also likely force a fire fighter to adapt their movement to successfully complete these tasks. A skillful fire fighter will be able to make such adaptations; in other words, they have the ability to access and apply different movement solutions. At the same time, a skillful fire fighter would also have the ability to retain the key features relevant to the lunge (e.g., the direction the toes and knee on the same side of the body are pointing) as features of the different movement solutions they employ to complete each task.
Perhaps the most powerful application of the key features is in a structured training environment. There is nothing wrong with deliberately thinking about, and applying a key feature(s) when performing a task. However, this might not be the most robust approach to rely on since it requires the dedicated attention of a performer. There is evidence to show that deliberately coaching performers to move according to the key features in a structured training environment can actually lead to those features being stabilized in un-related movements where the same performers aren’t coached at all, but are rather free to move as they like.
In a study conducted by Frost et al [7], 52 fire fighters were used to examine the differences between the fitness and movement adaptations arising in response to two different training methodologies. The fire fighters were randomly allocated into two training groups (and one control group) that were both subjected to 12-week, periodized exercise programs designed to improve fire fighter fitness. Both training groups engaged in 3, 1.5 hour training sessions each week that were administered by Certified Strength and Conditioning Specialists. One of the training groups (called the MOVE group) was actively coached by the strength and conditioning specialists on how to move when executing the programs. In other words, the MOVE group were coached on the key features. By contrast, the other group (called the FIT group) did not receive this specialized instruction, but rather coaches provided typical feedback related to performance outcomes such as reps completed and load lifted.
Before and after the 12 weeks of training the participants performed a fitness evaluation and, more relevant for this article, a movement evaluation. The movement evaluation consisted of 5 specific tasks (Lift-, squat-, lunge-, push-, and pull-patterns, respectively) completed under different conditions (load and velocity), and administered using standardized instructions. Participants’ movement was measured using laboratory-based motion capture technology that allowed the researchers to measure specific features of the movements such as frontal plane knee motion, and spine flexion/extension, lateral bend, and axial twist; in other words, the key features! Importantly, these 5 tasks were not included in the training interventions. This allowed the researchers to evaluate how, if at all, the different training interventions influenced how the participants controlled the key features.
Unsurprisingly, both the MOVE and FIT groups experienced significant improvements in all of the fitness metrics evaluated. However, only the MOVE group exhibited improvements in the control of spine and frontal plane knee motion when performing the 5 movement evaluation tasks. The FIT group, by contrast, was found to have less controlled spine and frontal plane knee motion when performing the 5 tasks. To the authors, these results showed that the specialized coaching related to the key features that the MOVE group received, and which was emphasized across the 12-week intervention, transferred to how the fire fighters moved outside of the gym-based setting. The absence of these positive post-training movement adaptations in the FIT group, was attributed to the absence of the specialized coaching focused on the key features.
These results emphasize how impactful training can be to improve fitness and movement adaptations, and how applying the key features as part of a coaching/instruction practice is critical to the transfer of movement-related adaptations outside of a training environment. F2T ambassadors stand to make big changes in their peers’ lives (not to mention their own) by applying the key features as guides to movement when appropriate. Since training, whether in the gym, or on the fire ground, is part of every fire fighter’s life, these opportunities can also be leveraged by F2T ambassadors to teach and engrain the key features in their peers’ movement. The 7 key features, displayed in the table below, are powerful tools that all fire fighters can use when engaging in the activities they need and love to do. The remaining posts in this series will be dedicated to unpacking each feature in detail to help equip F2T ambassadors with the knowledge and skills to take advantage of these powerful tools.
References
1. S.M. McGill, Low back disorders: Evidence based prevention and rehabilitation, Human Kinetic Publishers, Champaign, IL, 2002.
2. Zajac, F.E. and M.E. Gordon, Determining muscle’s force and action in multi-articular movement. Exerc Sport Sci Rev, 1989. 17: p. 187-230.
3. Armstrong, D.P., et al., Considering movement competency within physical employment standards. Work, 2019. 63(4): p. 603-613.
4. R. Gray, How we learn to move: A revolution in the way we coach & practice sports skills, Perception and Action Consulting & Education LLC, 2021
5. Beach, T.A., et al., Unilateral ankle immobilization alters the kinematics and kinetics of lifting. Work, 2014. 47(2): p. 221-34.
6. Frost, D.M., et al., The Influence of Load and Speed on Individuals’ Movement Behavior. J Strength Cond Res, 2015. 29(9): p. 2417-25.
7. Frost, D.M., et al., Exercise-Based Performance Enhancement and Injury Prevention for Firefighters: Contrasting the Fitness- and Movement-Related Adaptations to Two Training Methodologies. J Strength Cond Res, 2015. 29(9): p. 2441-59.
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