When considering overall function, it is important to understand the concepts of mobility and stability. Mobility and stability must coexist in order to create efficient movement in the human body.
While flexibility is the ability to elongate muscles, such as when the hamstrings elongate (lengthen) while bending over to touch one’s toes, the concept of mobility involves both the muscles and the joints. When either movement of the muscles or joints is impaired, overall mobility will be affected. A good example of good mobility is the ability to perform a squat, while maintaining an upright trunk posture so that it is parallel to the tibias (shin bones), and having the buttock drop so that the femur may break the horizontal plane, and maintain the arms straight overhead (as shown in the picture below). In this case, it is not just flexibility that is important, but mobility of the spine, shoulders, hips, knees, and ankles as well.
A common misconception is that strength and stability are the same. However, one can be strong and unstable, and (although not as common) stable but not strong. Strength can be understood as the ability to produce force or movement, while stability is the ability to control force or movement. In most cases, proper stability is a good precursor to developing strength. Both mobility and stability are key components to developing proper motor patterns and functional movements, and should precede strength and power training in most training or rehabilitation programs.
Here is a good example: children usually do not lack mobility or flexibility, but lack stability, not just strength. As they learn to control their movements, they increase their stability. They will start by crawling, progress to standing, and finally walking. Each step of the way, they learn to control their movements, therefore earning stability, which improves their movement patterns as they learn to move in their environments. They learn by trial and error, and usually do not repeat or learn movements that perpetually fail over and over. Pay attention the next time you see a healthy 2 year old play: when they drop a toy, or pick something up from the ground, they do not bend over at the waist like most adults do. They squat down, lower their center of gravity, keeping their trunk upright and bringing their bottoms lower than their heels.
No one taught this child how to squat properly. This movement was acquired naturally through trial and error, as it is a movement pattern which is energy efficient, stable, and most importantly, functional. While younger individuals may have more flexibility than adults, this is not the primary limitation to proper movement patterns. As adults, we have forgotten how to move properly, as our development as a society does not require us to perform movements such as the deep squat on a daily basis. There are cultural differences that lead us to move certain ways, and in turn these affect our health in the long run. In various parts of Asia, it is common to sit or rest in a deep squat position, instead of using a chair. Evidently, if people perform a deep squat multiple times a day for extended periods of time throughout their life, their subsequent movement pattern for this particular movement will probably be well developed.
As we develop and learn to move in our environments, our brain forms patterns in order to move efficiently with our daily activities. The brain does not remember individual muscle action (such as a biceps contraction), it remembers movements and patterns. Movements involve multiple muscles working in unison, creating proper balance around joints and controlling motion (stability), while allowing us to perform certain activities (mobility). If we do not train certain movement patterns, the connections between the brain and body necessary to perform these movements will weaken, and eventually we will forget how to move.
This brings us to brain-body connection.
The brain is connected to the body and communicates millions of commands throughout the day, in order for us to move and operate in our daily lives. Most people know this. What is less obvious is the communication between body and brain (therefore forming a 2 way street). The body is constantly sending input to the brain as well, which in turn processes the information in order to send the next commands based on what the body is experiencing. The various tissues in our bodies (nerves, arteries, veins, muscles, skin, tendons, ligaments, organs etc…) all communicate with the brain and provide the brain with essential information about body position, stress, movements, and balance. Often time, this communication between the body and brain has been compromised when it comes to movement patterns.
There are certain movements that have been associated with proper mobility and stability of the human body. The Functional Movement Screen (FMS) has been developed in order to identify mobility and stability dysfunctions, and to identify the potential for injury based on performance during the screen. The FMS consists of a series of seven different movements (squat, lunge, hurdle step, straight leg raise, push up, shoulder mobility test, and rotary stability test), This screen is meant to be performed on un-injured people, in order to identify poor movement patterns, asymmetries, and potential impairments and limitations. The goal of correcting the deficiencies noted on the FMS is to prevent injuries.
When injury or pain is present, the patient/athlete will benefit from a rehabilitation program in order to address the pain and dysfunctions, prior to return to full function and performing the functional movements without limitations or asymmetries.
During the Functional Movement Screen, the health professional at SP.OR.T.S Therapy will be able to identify dysfunctions, asymmetries, and impairments in motor patterns, which need to improve in order to maximize function for performance in daily activities or athletics. Based on the findings, a series of corrective exercises can be incorporated into a rehabilitation program or fitness program to address the impairments. These corrective exercises will include a variety of tasks, involving stability and mobility training, strengthening, flexibility and stretching exercises, neuromuscular reeducation, and movement pattern training.
At SP.OR.T.S. Therapy, the use of the Functional Movement Screen allows for an increased appreciation of people’s abilities to perform these various functional movements, the more we see the link between healthy body movements, mobility, and stability vs. individuals demonstrating dysfunction.
Oftentimes, we develop some muscle tightness in response to lack of movement or other reasons (such as improper muscle balance, leading to hyperactivity or overuse of muscles, which leads to tightness and tension). However, muscle tightness is not always the cause for limited mobility or flexibility. As we have discussed, our brains form patterns of movement, which can be lost over time when we do not perform certain activities. Muscles may start behaving inappropriately because they have not been used in functional ways regularly. For example, when asking most people to bend over and touch their toes, they will report that the back of their legs (hamstrings) are tight, and preventing them from touching their toes. In some cases, this may be true. Other times, the motor pattern of bending over and touching our toes has been lost, and there is inappropriate muscle activation during the bending over, that limits out descent. For instance, the hamstrings may start contracting (unconsciously) in conjunction with the calf muscles when we bend over, as this is a protective response to prevent excessive motion, when what we would want is to activate these muscles in a controlled manner in order to lower ourselves slowly to our toes. With a simple corrective exercise, some people are able to touch their toes (or at least reach a lot further down) in about 10 minutes, which supports the notion that hamstring tightness was not the primary limiting factor, but poor movement pattern was.
Other times, the hamstrings (or other muscles) may actually be tight and limit motion, in which case stretching may be appropriate in order to elongate these muscles and increase our flexibility.
Stretching is an important part of improving flexibility and range of motion, which is an important component of mobility. As discussed earlier, the tissues (muscles, ligaments, tendons, nerves, skin, etc.) communicate with our brains in order to provide it with information about our body position, alignment, and balance in order for the brain to make appropriate changes and adjustments to move effectively and safely. When stretching muscles, there are certain receptors in our tendons that induce relaxation when a stretch is felt. These receptors are called the Golgi Tendon Organs (GTOs), and play an important part in muscle relaxation and the ability to release our muscles to allow for a stretch to take place.
Muscles and tendons in our body all have certain stretch properties, and it is important to consider this when attempting to stretch. Time plays an important role when stretching. A good visual example is to think about a rubber band. If you stretch out a rubber band for 10 seconds, and then let it go, it will go right back to where it was. If a rubber band is stretched, and kept in a stretched position for a few days, it will lose its elasticity. The human body works the same way, but not as extreme. Below are some safe stretching parameters to keep in mind when attempting to make a change in our body’s flexibility.
For people under 60 years of age, stretches should be held for at least 30 seconds in order to make significant changes to the targeted tissues.
For people of age 61 and older, stretches should be held for 60 seconds in order to make significant changes to the targeted tissues.
Another important concept is intensity. If we think back to the rubber band example, and pull as hard as we can on the rubber band, it will most likely rupture or tear. The same applies to our muscles and tissues in our bodies. When stretching, it is important not to pull as hard as possible, as this may cause some micro (and sometimes major) damage or tearing of the structures we are trying to stretch. A safe way to stretch is to be in a moderate stretch zone. If we consider “0” to be no stretch felt, and “10” being the maximum stretch we can possibly feel, the moderate stretch zone will be at about a 4 -5 / 10.
Here are some good references related to body movement, stability, and stretching:
Bandy, W. D., & Irion, J. M. (1994). The effect of time on static stretch on the flexibility of the hamstring muscles. Journal of the American Physical Therapy Assoaciation, 845-850.
Cook, G. (2003). Athletic body in balance.
Page, P. (2012). Current concepts in muscle stretching for exercise and rehabilitation. The International Journal of Sports Physical Therapy, 109-119.
*** If you need help obtaining these references, just ask one the Physical Therapists here at SPORTS, and we will be happy to assist you.****