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Neurological Rationale for Integrated Training


Integrated (functional) training (IT) has become the vogue concept in the health and fitness industry and many people think it is just a fad that will soon pass. However, when you take a look at the neurological rationale behind "IT" it makes sense. The following article will elaborate on the neurological structures and processes that support IT.

Spinal Cord

The spinal cord allows for the sensory (afferent) fibers to convey proprioceptive input from mechanoreceptors (skin, muscle, tendon and joint receptors) to higher levels of the CNS and the motor (efferent) fibers to descend from the brain to the muscles. Input from the mechanoreceptors, such as muscle spindles and Golgi tendon organs, is mediated in the spinal cord to produce reflexes necessary for muscle tone and joint stabilization as well as antagonistic and synergistic  patterns of muscle contraction.

Think of yourself standing on a balance board. Do you have time to think about what muscles are going to activate and when? No. The same holds true for training in a controlled unstable environment as seen integrated training (IT). By placing a person in an environment that challenges their reflexive ability to stabilize intrinsically we begin to enhance joint stability and muscle coordination between functional synergist and antagonist muscles.

Lower Brain

The lower brain consists of the brain stem, basal ganglia and the cerebellum. Sensory (afferent) is integrated with motor (efferent) information in this region to modify and manipulate movement.

Brain Stem

The brain stem bridges all sensory and motor nerves from the brain to the body (periphery) and vice versa. It plays a very important role in the coordination and control of movement and balance (equilibrium). Further, the brain stem contains the necessary circuitry for posture stabilization.

Again, by challenging the body’s postural stabilization (balance) mechanisms through IT we feed necessary sensory information to the lower mid-brain region that relays the input to higher cognitive centers. This process begins establishing proper connections for optimal coordination and control of movement not necessarily seen in traditional forms of training.

Cerebellum

The cerebellum compares the intended muscular actions to those that are actually occurring. Essentially, it assists in smoothing and coordinating movements.

The cerebellum can be subdivided into three distinct regions:

The vestibulocerebellum is vital for balance regulation as well as eye-head movement. Input into the vestibulocerebellum signals a change in the position and orientation of the head related to gravity. Output from this region effects the axial postural muscles as well as controlling eye movement to coordinate eye-head motion. This supports manipulating eye-head motion seen in IT. For example, progressing from both eyes open and the head static to one eye closed and then both eyes closed with cervical rotation.

The cerebrocerebellum appears to assist in the decision to move as well as the initiation of movement. By providing multi-planar movement with a variety of manipulations the CNS is introduced to many different movement patterns. In turn, this may aid in the proper decision and selection of the appropriate action to be performed.

The spinocerebellum aids in the regulation of movement execution and muscle force to overcome load variations that may occur. In IT this is trained by manipulating load symmetry and variation. An example would be using a 20lb dumbbell in one hand and a 30lb dumbbell in the other while performing shoulder presses on a stability ball.

The cerebellum has been implicated as deciding the best way to produce a movement via the sensory input. Herein lies the need for proper sensory input into the kinetic chain. If the sensory system is not being utilized optimally it will not be able to respond appropriately and can lead to compensations. By challenging the sensory system through integrated training we can maximize neuromuscular efficiency.

Basal Ganglia

A primary role of the basal ganglia is the initiation and control (sustaining) of repetitive voluntary movements such as walking and running. It is also responsible in aiding postural maintenance and muscle tone. and scaling specific movement parameters such as velocity, direction and amplitude.

Cerebral Cortex

The cerebral cortex is the outermost portion of the brain. It is involved in cognition or thought production and integration and the controlling of complex skilled movements. Voluntary movement involves conscious or cognitive activity. Thus the cerebral cortex works simultaneously with the above mentioned structures to produce and initiate the voluntary movement.

The cerebral cortex can be further divided into posterior the primary motor cortex, the premotor area, the supplementary area and parietal cortex.

Primary Motor Cortex

The primary motor cortex is responsible for conscious control of skeletal muscle and voluntary skilled movement. This region is also involved in regulation of muscle force development and maintenance of steady force.

Premotor Area

The premotor area works synergistically with the primary motor cortex, the basal ganglia and the thalamus (not mentioned) to coordinate muscle activity as well as being involved in motor skill development. It is also implicated in response preparation to a "go" command.

By progressing from stabilization training through stabilization strength and into reactive (plyometrics) training we develop skilled movement and reactive neuromuscular control that utilizes the primary and pre-motor cortexes as well as the basal ganglia. For example, starting someone out with DB chest press on a ball we challenge postural mechanisms and use feedback to initiate the motor learning process. The stabilization strength training involves more strength production and maintenance of force seen in the primary cortex. By utilizing reactive neuromuscular training (plyometrics), we challenge the reactive components of the premotor and primary motor cortexes as well as the basal ganglia.

Supplementary Area

The supplementary area works in conjunction with the premotor area to provide postural movements and bilateral movement. Integrated training utilizes bilateral motion as a variation to all movements in all planes of motion.

Posterior Parietal Cortex

The posterior parietal cortex is interconnected with the premotor area and processes sensory information that provides input about the spatial orientation for movements aimed toward a target. This is an important component of IT as it requires eccentric (deceleration) and isometric (stabilization) manipulation of muscle action. This is important for activities that range from reaching for a glass to throwing a football.

Furthermore, because we have sensory receptors in muscles, tendons, ligaments, joints, skin as well as vision and vestibular, they must be appropriately challenged to enhance the input they produce. In turn, this will enhance the output of the kinetic chain by increasing structural efficiency, functional efficiency and neuromuscular efficiency.

Integrated training is based on proprioceptively enriched training and synergistic muscle function. This is achieved through multi-joint, multi-planar training in controlled unstable environments that allows challenge to be introduced to the joint and postural stabilizers. Research has demonstrated that proprioceptive forms of training do improve dynamic joint stabilization.

By placing stabilization demands on the kinetic chain we force muscles to work together synergistically to produce movement. This means that muscles are recruited as agonist and synergists accelerate the movement while antagonist, neutralizers and stabilizers help control or decelerate the movement, eliminate unwanted movement and provide dynamic support to allow efficient movement to occur, respectively. Synergistic utilization of muscle synergies increases the sensory feedback into the nervous system that, when optimal, enhances movement awareness, production and learning.

This is particularly important in today’s society. Whether you are training or reconditioning an athlete, rehabilitating a patient or training the gym member it is imperative to focus on their functional capacity. Today’s society does not afford the same movement opportunities as seen in the past due to technological advances. Therefore, how we train our respective client is important.

Specificity of training is important to establish neuromuscular carryover from our exercise movement to the movements of sports or everyday life. Integrated training allows better carryover to sport and everyday life because it involves three-dimensional multi-joint movements in unstable (unpredictable) environments. Furthermore, it affords more variety of practice as movements can be performed differently (different plane, different symmetry, different base of support, etc) with each repetition. This, however, is not always the case with traditional forms of training that rely predominantly on fixed machinery.

This is easy to demonstrate in sports and everyday activities. Watch someone lifting groceries out of a shopping cart and place them into their trunk or simply get in and out of their car. Or next time you view a football game watch the offensive linemen as they block. You will notice all of these activities require three-dimensional, multi-joint movement to be performed in an unstable, unpredictable environment.

It all comes back to sensory information or proprioception. The more optimal sensory input you feed into the nervous system the more optimal output you will achieve. Furthermore, through practice and experience these movements can begin to occur more automatically which allows for increased skill acquisition regardless of whether it is sport or everyday activity.

From Biological psychology. Rosenzweig MR, Leiman AL, Breedlove SM.  Sunderland, MA: Sinuaer Associates, Inc; 1996. p.375.
Figure 11.5.
From A multilevel approach to the study of motor control and learning. Rose DJ. Needham Heights, MA: Allyn and Bacon; 1997. p.63.
Figure 3.3.
From Brain, mind, and behavior. 2nd edition. Bloom FE, Lazerson A.  New York: WH Freeman and Company; 1988. p.130.
Figure 4.23.

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