The human body is a dynamic machine. Every movement, simple or complex, is electronically choreographed synergistically between the nervous and musculoskeletal system. By understanding how these systems interact with one another, this will provide you with the vital knowledge on how human movement occurs scientifically enabling you to work with any client.
For the past twenty years, previous traditional training methods have focused on training specific muscles or body parts in typically one plane of motion (figure 1). Functional training emerged in the 1990s and grew in popularity, because it was perceived that people have to be strong “functionally,” therefore, they must be trained “functionally.” However, there is a problem with this training approach: Very few movements a person performs occur strictly in one plane or in isolation. Most everyday functional movements and sport specific movements occur in multiple planes.
Figure 1. Side raising arm
For example, reaching for a seatbelt with the right arm involves movement in the frontal, sagittal and transverse planes. Playing sports such as golf requires hitting a golf ball in the frontal and transverse plane as seen in figure 2.
Therefore, instead of training a client “functionally,” training should focus on understanding the movement that occurs biomechanically and the muscles that produce the movement. In a traditional golf swing (figure 2), the golf swing occurs both in the frontal and transverse planes requiring multiple primary and secondary movers (muscles). The muscles will be explained in the musculoskeletal system section.
Figure 2. Golf swing
The Neural Connection
In order for movement to occur, there has to be a starting point. The starting point occurs in the front part of the brain called the frontal lobe. This is where a perceived thought such as I want to reach (figure 3) begins. Movement occurs rapidly between the nervous and musculoskeletal system. How does it occur so quickly? Continue reading to learn how.
Figure 3. Regions of the human brain.
This is coordinated within the brain via several structures (basal ganglia/cerebellum/cortex). The central nervous system(CNS) coordinates this intended activity from the brain via the spinal cord through the peripheral nerve roots to the extremities or arms and legs. Within the weight-bearing joints (such as the feet), there are receptors that provide the brain with a sense of the body’s position. This acts as a relay system for balance and proprioception. Whether we are standing still or moving, these receptors send a signal up our spinal cord via the “sensory” pathways (feeling) to the brain, where the information is interpreted. Then the human body can do one of two things: Do nothing, or move. Therefore, when we move, the “motor” pathway is recruited. This rapidly fires where the body will contract not only the appropriate muscles, but the exact amount of force needed for the desired movement. Therefore, movement is a result of harmonious interaction between the neurologic and muscular systems.
The Musculoskeletal System
The musculoskeletal system is comprised of bones, muscles, ligaments, tendons, fascia and other structures that support the body. When a movement occurs, such as a golf swing, multiple muscles are activated. Biomechanically, in the initial phase called the preparatory phase. The golfer prepares mentally to hit the ball. In the second phase, backswing, there is a transfer of weight from the front to the back leg. At the top of the backswing, the shoulders are coiled, the hands are swung high and the arms are extended.
Muscularly, the trunk rotates, recruiting the primary movers; latissimus dorsi, medial deltoid and triceps accompanied by the rectus abdominis, external obliques and forearm flexors. Secondary movers are hip flexors, glutes and calves. During the downswing and follow-through phase, this is initiated by hip rotation.
At this point, the golfer must lengthen the lever arm, which results in an increased acceleration of the club. Simultaneously while the hip turns, a transfer of weight occurs from the back foot to the front foot. During the downward swing, rectus abdominis, obliques, transverse abdominis and the opposite latissimus dorsi along with the hip flexors. The turning of the hips unwinds the upper part of the torso allowing the shoulders and arms to flow easily into the swing. At the point of impact, the forearm flexors and extensors are contracted along with the quadriceps.
Biomechanically, the wrists straighten while the trunk produces the force with other muscles producing a maximum striking effort. During the follow-through phase, the abdominals, quads, hip flexors and anterior tibialis are lengthened, while glute maximus and calves are contracted concentrically.
The human body is a dynamic machine that executes all types of movement in a synchronistic manner. Whether it is reaching for a seatbelt of hitting a golf club, both the nervous and musculoskeletal system are synergistically recruited. By understanding how these two systems work together, this will provide additional insight into exercise prescription and programming. Understand the movement and the muscles required to produce that movement and strengthen the muscles accordingly.
About the Author
Chris Gellert, PT, MPT, CSCS, CPT is the President of Pinnacle Training & Consulting Systems, a consulting and educational company that provides advanced continuing education material and live seminars to personal trainers on human movement and evidenced based research with practical application. For more information, visit www.pinnacle-tcs.com or email Chris at [email protected].