WHAT IS FUNCTIONAL TRAINING?
Functional fitness training is not a new concept. With its formal origin in physical rehabilitation, activities such as yoga, Pilates, and sports conditioning incorporate components of functional training into their movements. Functional training is designed to specifically enhance the performance of activities of daily living (ADL), recreational pursuits, and/or sports performance. It targets the neuromuscular system, meaning, it trains movements (muscle groups and the nervous system), not just muscles (2). Using a progressive and individualized program of primarily weight-bearing multijoint and multiplanar exercises, functional training includes challenges to improve dynamic and static balance, coordination, and proprioception (2). This involves the integration of the nervous system, muscles that produce joint movement, as well as the muscles responsible for stabilization of the spine (core), hip, and scapulae.
For the body to move efficiently, it must act as a kinetic chain where energy and force are successfully transferred from one body part or joint to another. Any weak links limit the strength of the entire chain (6). Hence, postural instability and poor strength or range of motion at one joint can affect movement patterns and decrease force production. This can lead to compensation patterns and may contribute to injury (11). More traditional resistance training methods using machines or free weights are capable of providing larger amounts of constant or variable resistance but often limit range of motion and require less stabilization and balance than functional training. Both types of training, traditional and functional, are important. For example, although functional training may incorporate exercises to improve muscular power, a sufficient level of muscular strength is required to achieve optimal improvements in power.
BENEFITS OF FUNCTIONAL TRAINING
Michael Whitehurst, Ph.D., and his colleagues (17) investigated the benefits of functional exercise training in 119 older adults with an average age of 74 years. Researchers performed pretesting and posttesting for functional tasks involving flexibility, aerobic endurance, balance, and agility. Subjects participated in a functional exercise circuit 3 days per week for 12 weeks. The circuit used balance and directional challenges, weight transfer activities, and required participants to negotiate obstacles. Researchers reported significant improvements in agility, balance, and flexibility after training. In addition, self-reported ratings of physical functioning were higher after the training program, and subjects reported significantly fewer doctors' visits. This study and others (1,7) support a role for functional training in older adults.
Wayne Peate, M.D., and his colleagues (13) studied the effects of functional training on injury rate and lost work time caused by injury in 433 firefighters (average age 42 years for men and 37 years for women). They implemented a program that included instruction in proper body mechanics, exercises to improve core stability, and functional exercises that mimicked firefighting tasks. The number of injuries decreased 42% and lost work time caused by injuries declined 62% during the 12-month period after the training program.
Although there are many "testimonials" and Web sites promoting the benefits of functional training in the fitness setting, more research is needed to determine 1) the extent to which functional training exercises alone or in combination with traditional resistance training lead to improvements in the performance of other activities, 2) the best assessments to evaluate function, and 3) the most effective exercises and optimal progression to produce improvements in specific activities. Currently, there are a variety of assessment tools that can be used for pretesting/posttesting to measure improvement, identify potential areas of weakness and injury, and establish a safe and effective starting level for exercise prescription and progression. To date, however, most studies were performed in athletic or senior populations and have not been validated in the average population.
Fitness professionals planning to incorporate functional training exercises into their clients' programs should first perform a functional assessment to guide exercise selection and provide a baseline for measuring progress. Although many assessments are reliable and easily administered, some measure specific components of overall function such as balance whereas others have a more holistic approach. These tests are often population specific and have not been studied in different groups-young, elderly, sedentary, fit, and athletic populations. Furthermore, ADL, as well as job-specific tasks and sports activities, will vary between clients and also should be considered when selecting an appropriate functional assessment. Hence, it may be difficult to develop one valid test to meet the needs of all clients. The Table lists important factors to consider when selecting an assessment. The optimal functional assessment also would be linked to an exercise prescription template that would guide the fitness professional as to specific exercises, level of difficulty, and appropriate progression to target deficiencies. As with other fitness assessments, a preparticipation screening, such as the Physical Activity Readiness Questionnaire or American Heart Association/American College of Sports Medicine Health/Fitness Facility Preparticipation Screening Questionnaire, should always precede a functional assessment to determine if the test is safe and appropriate for that client. The following is a description of some of the functional assessments available to the health/fitness specialist.
STAR EXCURSION BALANCE TEST
The Star Excursion Balance Test (10) was developed for use in individuals aged 20 to 39 years. This test measures lower body dynamic balance, strength, and proprioception. The individual stands on one leg and reaches as far as possible with the opposite leg in eight prescribed directions. Notably, the Star Excursion Balance Test helps identify asymmetries in balance between sides of the body and was shown to effectively predict levels of risk for lower body injuries in high school basketball players (14). This study by Phillip Plisky, P.T., and his colleagues showed that individuals with an anterior right/left reach distance difference greater than 4 cm were 2.5 times more likely to sustain a lower extremity injury. Females in this study with a composite reach distance less that 94% of their limb lengths were 6.5 times more likely to sustain a lower extremity injury.
FUNCTIONAL ASSESSMENT IN OLDER ADULTS
Balance is critical to optimal athletic performance and equally important in the elderly, given that falls are the leading cause of death from injury among adults 65 years and older (16). For seniors, researchers have developed several tests to assess balance, including the Berg Balance Scale (BBS), which measures static and dynamic balance during reaching, bending, transferring, and standing activities (16). Often used by health care providers in the clinical or retirement home setting, this test is recommended for assessment of lower functioning older adults. However, it may not be sensitive enough to identify small early declines in balance in more active older adults living independently. In other words, unless ability to function is significantly impaired, the test results may not detect small early declines in function. In contrast, the Fullerton Advanced Balance Scale (FABS) assessment is designed to measure static and dynamic balance in different sensory environments, including unstable surfaces, walking, stepping, and jumping in higher functioning older adults (16). Both the BBS and the FABS provide a list of recommended exercises for specific impairments identified during testing. For example, a senior scores poorly on the FABS test requiring them to step up onto and over a 6-inch bench. During the movement, if the individual demonstrated difficulty controlling his or her center of gravity, a progression of weight shift exercises is recommended, progressing from more to less stable surfaces as follows: 1) seated on a disc in a chair, 2) seated on a stability ball in a holder, and 3) seated on a stability ball without a holder. These exercises also can be performed with the eyes closed before progressing to the next level. It is important to consider that many factors contribute to fall risk, including indoor and outdoor environmental hazards, medications, and sensory and cognitive deficits (16).
Another test battery developed specifically to measure independent functioning in older adults aged 60 to 94 years is the Senior Fitness Test (15). This 6-item test battery measures upper and lower body strength, aerobic endurance, flexibility, dynamic balance, and agility. With documented reliability and validity, it requires little space, minimal equipment and time to administer, and is safe for use in seniors with a wide range of physical abilities. The test provides reference or threshold points to help identify individuals at risk for loss of function.
FUNCTIONAL MOVEMENT SCREEN
One group of tests designed to measure overall function in an active younger population is the Functional Movement Screen (FMS) (4,5). This assessment analyzes the ability to perform fundamental movement patterns such as the overhead squat, in-line lunge, hurdle step, shoulder reaching, straight leg raise, push-up, and rotational stability. Rather than quantify the number of repetitions or amount of weight lifted, quality of movement is assessed on a scale of 0 to 3 for each of the seven movement patterns based on compensation required to complete the task. Using these data, individuals can first work on deficiencies in primal or basic movement patterns such as crawling, kneeling, and squatting before more demanding movements such as lunges and single leg stance exercises. This program also recommends stretches to improve mobility and corrective exercises for areas of deficiency and asymmetry (3). Research using the FMS assessment battery has focused primarily on athletic populations and firefighters. A study (9) by Kyle Kiesel, Ph.D., and his colleagues that used the FMS to evaluate the risk of serious injury in the National Football League showed that players who scored 14 or less out of 21 total points on the assessment had higher injury rates. The risk of injury in players with low scores (≤14) was 11 times greater than those with higher scores (>14).
FUNCTIONAL VERSUS TRADITIONAL ASSESSMENTS
Traditional fitness assessments should be used in conjunction with functional assessments because they provide valuable information for the fitness professional, however, they were not designed to measure ability to perform ADL, recreational activities, or sports skills. For example, firefighters and law enforcement officers need good upper body strength to perform their job tasks effectively. Hence, a 1 RM bench press test would allow assessment of upper body strength. However, good upper body strength alone does not necessarily infer good upper body functional capacity as mobility, stabilization, or balance may be suboptimal, leading to poor body mechanics, injury, and possible disability. In contrast, someone with average upper body strength may actually have no problem performing functional tasks requiring upper body muscular endurance, mobility, balance, and stabilization. Hence, tests for both upper body strength and functional capacity would provide valuable information when assessing a firefighter. The best assessments for a client will depend on his or her goals, ADL, job tasks, and any sports or recreational activities in which he or she participates.
After a functional assessment, program design should first focus on areas of deficiency. Determining the specific areas of deficiency can be difficult because the movements assessed during functional testing often require multiple skills including strength, balance, flexibility/mobility, and/or aerobic fitness. General guidelines to address deficiencies (3) would be to start with the most basic movement patterns that could not be completed. For example, before adding lunge movements to a client's exercise program, the client should first be able to perform a squat properly. Next, the focus should move to areas with asymmetries, which is supported by research studies showing an increased risk of injury when asymmetries are present (11). Finally, design should focus on the next lowest scored task and most basic movement patterns. If an individual cannot complete basic movements, then more complex movements will elicit only further compensation.
CORRECTION OF MOVEMENT DEFICIENCIES
Notice that in an analysis of deficiencies, the focus should be on inefficient movement patterns rather than specific skills. Basic and complex movement patterns require the efficient interaction and coordination of the musculoskeletal and nervous systems. For this reason, it is often difficult to isolate one particular cause of poor performance. It is more efficient and effective to train movement patterns rather than isolated single joint movements, which are rarely performed as part of daily activities. Therefore, it is important to focus on the entire movement and choose exercises that involve multiplanar and multijoint movements that require progressively challenging levels of core strength, stability, and balance. The FMS assessment program recommends three approaches to correction of movement deficiencies when training movement patterns (3). Although this is not the only approach, it can be used as a template for overload and progression.
- Assisted exercises use exercise tubing positioned to assist the individual in performing the exercise caused by a weakness or poor form (3). For example, a client that scored poorly on the FMS push-up test could start with an assisted push-up. It is performed using an elastic band that is placed around the client's waist and anchored above and behind the client. The exercise band assists the client in performing the more challenging "up or pushing" part of the movement.
- Reactive neuromuscular training (RNT) challenges core stabilization and balance while improving coordination and proprioception. It uses weight shifts that force the body to maintain postural stability while addressing muscle compensation (12). For example, a client has difficulty performing the FMS overhead squat. You notice that the client's knees rotate toward the midline (valgus position) during the squat. One exercise to correct this movement pattern uses exercise tubing placed around the client's thighs just above the knees. The tubing is crossed in front of the body and anchored while the client performs the squat movement. This position exaggerates the mistake (3) by pulling the thighs toward the midline. The weight shift requires the hip abductors to contribute more to the squat movement which improves form and enhances proprioception and motor learning.
- Resisted exercises use resistance tubing or weights to improve muscular strength and endurance. After an individual can perform an exercise properly without compensation, resistance is added. For example, a forward lunge can be performed with a band placed around the waist and anchored at a low point in front of the body. The band provides added resistance while pushing back into the standing (starting) position. Thicker tubing can be used to increase the resistance.
There are many exercises that can be used to address deficiencies in functional movements. Although some of the assessments including the FMS, BBS, and FABS recommend corrective exercises, more research is needed, especially for the average population, in regard to the best exercises to address specific movement deficiencies. Two case studies outlining assessment deficiencies and appropriate corrective exercises are presented (1, senior; 2, firefighter). The primary goal should be to individualize the corrective exercises while finding the optimal balance between functional and traditional resistance training exercises to meet the client's needs. Keep in mind that core stability is crucial for the performance of most weight-bearing activities. Hence, core stability may need to be addressed before progressing to more functional weight-bearing exercises. It is important to remember that just choosing an exercise that uses an unstable surface does not necessarily make it an effective and appropriate functional training exercise for that individual. The results of the assessment and the client's goals and ADL (specificity) should guide exercise selection and progression, as well as the client's ability to learn new exercises. In addition, proper form is critical to ensure client safety and optimal transfer of skills to ADL.
Existing research supports the inclusion of functional training as part of a client's exercise program as it may provide additional improvements in balance, mobility, proprioception, core stability, and neuromuscular coordination, leading to improved function of the entire kinetic chain. More research is needed to determine the best methods of training that will transfer to self-initiated ADL. An appropriate assessment will assist the fitness professional in the identification of weak and suboptimal movement patterns, imbalances in strength and mobility, and compensation patterns while providing a mechanism to evaluate client progress. Based on the assessment, appropriately chosen exercises can be incorporated into the client's exercise program to improve overall function. It is important to emphasize that functional training is one of many tools available for training clients, in addition to more traditional forms of resistance training targeting improvements in muscular endurance, strength, and hypertrophy. Hence, functional training is one piece of a healthy holistic approach to resistance training, which can benefit individuals of all ages.
CONDENSED VERSION AND BOTTOM LINE
Research suggests that functional training exercises may provide additional benefits over traditional resistance training. A functional assessment appropriate for the target population will allow the fitness professional to identify specific areas of movement deficiency and asymmetry. Based on the results, corrective exercises to target deficiencies and enhance balance, mobility, proprioception, core stability, and neuromuscular coordination can then be incorporated into the client's fitness program.
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