Placing an emphasis on how we move move while exercising can be critical to facilitating behavioral changes beyond the gym environment. For physically active populations and occupational athletes such as firefighters, soldiers and police officers this implies that exercise programs designed with a movement focus could have a direct impact on their safety and effectiveness by engraining desirable movement patterns that transfer to job and/or life-relevant tasks. This post provides a brief summary of the 2015 study conducted by Frost, DM, Beach, TAC, Callaghan, JP, and McGill, SM. Exercise-based performance enhancement and injury prevention for firefighters: Contrasting the fitness- and movement related adaptations to two training methodologies. J Strength Cond Res 29(9): 2441–2459, 2015.
STUDY BACKGROUND
Exercise can be an amazing tool. It can be used to make difficult tasks easier and more enjoyable; it can be used to prevent musculoskeletal injuries and pain; and it can allow us to perform at levels that far exceed any expectations that we might have…that is, if there is an emphasis on the transfer to non-exercise related tasks. To improve the transfer of training it has been suggested that exercises be prescribed to replicate the tasks of interest, which for firefighters, would imply that various high-risk, physically demanding job-tasks be simulated in a gym setting. Though such an approach may seem logical, it is very unlikely to afford the most favorable adaptations – enhancing capacity to match the demands of one’s job (or life) cannot be accomplished by simply recommending a particular exercise, intensity or training volume. It is not about the exercise. Feedback and coaching are essential as is an appreciation for movement to guarantee that the motion strategies being used are safe, effective and suited to the training objectives. It is this type of training that may afford the best possible opportunity to change an individual’s habitual way of performing.
STUDY DESIGN
Fifty-two incumbent firefighters completed a comprehensive fitness test, the Functional Movement Screen (FMS) and a laboratory-based biomechanical assessment wherein they were asked to perform five fundamental movement patterns (i.e. squat, lunge, push, pull and lift) with varying loads and speeds. Following their baseline tests, individuals were assigned to one of three groups: 1) movement–centered intervention, 2) fitness-centered intervention, or 3) control. Participants in the intervention groups attended three 1.5-hour coach-administered training sessions each week for 12 weeks, after which time they were reevaluated with the original battery of tests.
Throughout the investigation the coaches were blind to the testing protocols and the researchers were removed from training. The firefighters were not privy to the study objectives nor were they given any coaching or feedback regarding their performance on the FMS or any lab-based test. In this way, changes in their habitual movement patterns could be evaluated. All movement patterns were characterized with 7 or 8 variables; however, only changes to “key features” that have been previously linked to injury (i.e. spine and frontal plane knee motion) are presented.
KEY FINDINGS
Following twelve weeks of training, both intervention groups exhibited substantial changes in body composition, aerobic capacity, muscular strength and endurance, and upper and lower body power. However, only those participants in the movement-centered group demonstrated a positive adaptation to each lab-based transfer task – their habitual movement patterns changed. In each instance, participants exhibited less aberrant motion with one or more of the “key features” that have been previously linked to injury: spine flexion while lifting and lunging, lateral bend and twist while lunging, pushing and pulling, and frontal plane knee motion while squatting. The firefighters who participated in the fitness-centered intervention did exhibit an improved ability to resist spine motion in the lateral bend and twist directions while lunging, pushing and pulling; however, these changes were noted along with increased spine flexion and frontal plane knee motion while squatting, lunging, pushing and pulling.
Important to note was that the firefighters’ adaptations to training were also task specific. That is, had only the lifting tasks, for example, been used as transfer tests our interpretation of the results would be dramatically different. The fitness-centered group did not exhibit any observable changes (positive or negative) post-training, and thus we would have failed see how poorly or how well they did adapt to select tasks. Likewise, using the FMS to interpret the effectiveness of training would have skewed the results by masking the substantial improvements observed amongst firefighters who participated in the movement-centered training. Despite demonstrating a superior ability to resist aberrant motion, and thus move in a more controlled manner, there were no changes noted in the post-training FMS scores of the movement-trained firefighters.
IMPLICATIONS
1. Exercise can be used to change an individual’s habitual movement patterns
Periodized exercise programs and well-designed feedback protocols work – they can (and should) be used to improve capacity. Whether targeting fitness (e.g. strength) on a specific test or the kinematics of a task, most interventions are able to elicit changes in the direction hypothesized by the researchers/coaches to be of benefit. For example, scientists have been able to reduce the knee abduction moment in females performing a drop jump (Myer et al, 2007), alleviate patellofemoral pain in runners (Noehren et al, 2010), lower spinal moments during lifting (Kernozek et al, 2006) and improve performance in the clean (Rucci and Tomporowski, 2010) and snatch (Winchester et al, 2009). However, there had been little evidence to suggest that an exercise-based intervention could significantly alter the movement patterns used to perform a transfer task, let alone five distinct patterns of varying demands. Developing coordination (ultimately what we are trying to do) is not a simple process given that the adaptations demonstrated by each individual are influenced by their prior experience, inherent aptitudes and personal objectives, not to mention the characteristics of each task being learned. The fact that the movement-trained firefighters demonstrated a superior ability post-training to resist spine and frontal plane knee motion across all lab-based tests provides a tremendous framework with which to approach the prevention of future musculoskeletal injury.
2. Placing an emphasis on fitness alone may increase one’s risk of injury
Being physically fit, in the traditional sense, may not equate to being physically prepared for one’s job (or life). Fitness is essential, particularly for fire fighters (or soldiers, police officers, etc), but alone it is not sufficient to ensure peak performance and long-term durability. It simply reflects an individual’s potential. For example, poor torso extensor endurance has been cited as a marker for future low-back troubles in men (Beiring-Sorensen, 1984), although it is not one of the commonly described mechanisms of low-back injury (e.g. spine posture) (Callaghan and McGill, 2001). A possible explanation is that superior endurance provides the opportunity to maintain spine-sparing postures for extended periods of time by delaying the onset of fatigue. But, if individuals cannot, or choose not to adopt these postures for any number of reasons, muscular endurance becomes secondary and will have little bearing on the risk of injury. Great fitness in the presence of poor movement, or great movement in the presence of poor fitness, will limit performance and increase one’s chances of sustaining a musculoskeletal injury. Firefighters in the fitness-centered group exhibited tremendous improvements in aerobic capacity, strength, endurance and power, but may have actually increased their risk of future injury given their propensity to increase spine flexion and frontal plane knee motion when performing each of the transfer tasks.
3. An individual’s movement patterns do not simply reflect their ability to perform
The degree to which a movement strategy is altered in response to an increased/decreased task demand will depend on factors such as perception of risk, awareness, coordination, strength, endurance and mobility. Speculating as to the exact reason why a pattern is changed would therefore be very difficult, particularly given the lack of evidence to support a homogeneous response. Faced with the task of picking up a pencil off the floor, highly astute, physically capable firefighters may not choose to adopt the same strategy that they would to lift a heavy piece of equipment, if the perception of the pencil task was such that it could not cause harm. On the other hand, highly astute firefighters with poor fitness may exhibit similar patterns for both tasks because they lack the strength necessary to perform the heavy lift in such as manner that would be viewed as “safe” or “good”; the demands of the task exceed their capacity to perform in a safe and effective manner. Whole-body movement screens are frequently used to assess one’s ability to perform various general patterns (e.g. squat, lunge), yet little consideration is ever given to the possibility that a task’s demands may influence the way an individual moves. Screens typically comprise bodyweight patterns and individuals are instructed to perform in a slow, controlled manner, irrespective of the population being tested, the most commonly cited injuries (location and type) amongst this population, or the long-term rationale behind the evaluation.