The body is made up of components that are interconnected with one another. These components are seen as parts that make up the human movement system. The key integrated systems that make up the human movement system are: central nervous system(brain and spinal cord), the skeletal muscular system and the articular system(ligaments, joints, & capsules).
These systems coordinate with each other to give us optimal movement performance. The human movement system is also known as the kinetic chain. The human movement system is reliant on optimal length tension relations and neuromuscular efficiency between each of these respected systems.
During an injury, the component that is affected (i.e. the knee joint) will significantly impair movement within the other components in the lower kinetic chain. The injury causes trauma to the tissue surrounding the knee joint (i.e: the VMO, the quadriceps tendon, collateral ligaments etc…) and inflammation will surround the tissues.RELATED: RECOMMENDED PLANS FOR YOU
This will cause the tissues (muscles) around the area to go into spasm creating pain and decrease in proper function of concentric knee extension and eccentric knee flexion during normal gait. During the healing process, the inflammation will dissipate out of the injury. After the inflammation phase, the proliferation phase begins. In this phase scar tissue is laid down to repair the injury in the muscle1,5. The last phase of inflammation is the remolding or maturation stage5.
In this stage, the scar tissue is remolded into permanent scar tissue(type 3). The scar tissue does not replace the ease of motion as the original anatomical muscle tissue. As a result, the scar tissue does not allow normal sliding within the fascia. The scar tissue is known as an adhesion. These adhesions disturb the natural sliding filaments of the actin and myosin fibers and prevent proper contraction to take place.
Knots of bounded up muscle fibers become “stuck” to each other like glue; these become the adhesions. When the adhesions are settled in the muscle; optimal movement is prevented. The formation of the adhesions will cause tightness in the muscle causing the normal length tension relationship within the lower kinetic chain to be imbalanced. This is known as the cumulative injury cycle. This concept is considered a cycle because this phenomenon can continue over and over again creating movement compensations.
Muscular imbalance are formed because of the adhesions in the muscle. An example would be the knee joint and the muscles around the joint that create the motion. Some muscles around the knee joint can create tightness on one side of a joint (i.e. vastus lateralis and IT-band) and weakness or lengthening of muscles (i.e. VMO) on the other side of the joint.
As for the example of the injury to the knee joint, the muscular imbalance is caused by tightness of the vastus lateralis in relation to the other muscles in the lower kinetic chain. Muscles in the lower kinetic chain such as the VMO, anterior and posterior tibialis, medial gastroc/soleus and medial hamstrings become weak and lengthened.
These altered length tension relationships will cause altered neuromuscular movement and reduced optimal performance. The muscular imbalances will decreases neural drive from the central nervous system into the main muscle group and increase neural drive into the opposing muscle groups causing reciprocal inhibition. Reciprocal inhibition is caused by altered neural drive into the antagonist instead of going to the primary agonist(quadriceps)muscle.
The area of muscular imbalance (the agonist with the adhesions that are formed in it) will not activate properly. This muscular imbalance will cause the increase in the neural drive to the antagonist creating compensations in movement during walking, squatting and other functional movements. This is the effect cumulative injury cycle has on movement in the kinetic chain.
This cycle will continue until proper intervention of corrective exercise is presented to the client. Without corrective exercise intervention, the cumulative injury cycle will continue to contribute to movement compensations. This will cause a decrease in movement efficiency and future injuries to other areas of the kinetic chain as a result of this muscular imbalance1,3.
Corrective Exercise Intervention:
A corrective exercise intervention to prevent adhesions from forming on muscles is implementing stretching into an exercise program. Stretching promotes flexibility within muscles and increases range of motion(ROM) within the joints. Two kinds of stretching are static stretching and self-myofascial release(SMR).
Static stretching can be performed my holding either the distal or proximal portion of the tendon attachment to the bone and move the opposite component away from starting position(i.e.: the stretch the quadriceps muscles; stand erect and hold on to a wall; grab the foot of the side of the quads you wish to stretch, flex the knee and bring the foot behind you towards the buttocks area). According to research, holding a static stretch for 30 seconds is the appropriate time to cause deformation of the stiffness of the muscle to gain an adequate stretching effect2,3
Other types of stretching are active and dynamic stretching. Active stretching refers to stretching a joint and/or muscles around the joint to its limits of range of motion. Active stretching involves activating the agonist muscle to stretch the antagonist(i.e. stretching the triceps by performing elbow flexion using the biceps muscle: the biceps is the agonist and the triceps are the antagonist)3. Active stretching usually targets muscles that are either single or multiple joint in function(i.e. soleus vs. rectus femoris)3. Dynamic stretching refers to an activity that brings the joint to its limits of range of motion but can be used as an exercise(i.e. a lunge or shackles walks)3,2
Another form of stretching is known as self myofascial release. Using a foam roller is one of the common methods to perform self myofascial release. Myofascial release is performed by using one’s own body weight and gravity to induce a ischemic pressure over an extremity or portion of the body to “release” a tight muscle fiber3. According to research, a bout of self myofascial release for approximately 2 minutes in duration increased the range of motion of the knee joint by releasing the muscles of the quadriceps group that were tight and restricting normal ROM3.
The duration of performing SMR varies depending on the size and length of the extremity being rolled. However, it is important that the foam rolling needs to be performed correctly and in conjunction with an exercise program. To perform foam rolling correctly, first assume a position in which the foam roller is under the extremity(i.e. thigh) and the roller is positioned superiorly or inferiorly to the muscle(s) to be rolled. It is important that the person takes their time and slowly rolls over the entire area to be stretched. When a tender spot is identified, the person should stop and allow the ischemic pressure to commence for 10-20 seconds over the tender spot1,3,4
The tender spots that are encountered in the muscles are the adhesions that have formed from past injuries(results from the cumulative injury cycle or from sedentary practices which results in muscles becoming tight)1,2,4. It is important that when performing SMR, each tender spot is identified and treated using the foam roller and body weight. According to research, the total duration of foam rolling for the upper portion of the lower extremity(thigh muscles) was approximately 1 minute3. This includes the 10-20 second pauses over the tender areas within the muscle belly.
In summary, the cumulative injury cycle can impede function and athletic performance. During and after an injury, it is important to remain active and mobile as much as possible. The addition of stretching and self myofascial release(SMR) can benefit a person in maintaining flexibility within the human movement system. A duration of as little as 10 minutes devoted to SMR(up to a minute on each extremity, the back and chest) can increase flexibility, decrease accumulation of adhesions formed on muscle fibers and prevent stiffness and changes in muscle fiber(degenerative changes) caused from sedentary lifestyle. Remember mobility of muscles equates functional fitness.
1. Clark, MA, and Lucett, SL. NASM Essentials of Corrective Exercise Training. (1st ed.) Baltimore, MD: Lippincott Williams & Wilkins; 2011
2. Sands W, McNeal JR, Murray SR, Ramsey MW, Sato K, Mizuguchi S, Stone MH. Stretching and Its Effects on Recovery: A Review. Strength Cond. 2013; 35(5): 30-36.
3. MacDonald GZ, Penney MDH, Mullaley ME, Cuconato AL, Drake CDJ, Behem DG, Button DC. An Acute Bout of Self-Myofascial Release Increases Range of Motion Without a Subsequent Decrease in Muscle Activation or Force. J Strength Cond Res. 2013; 27 (3): 812-821.
4. Okamoto, T, Masuhara, M, Ikuta, K. Acute effects of self myofascial release using a foam roller on arterial function. J Strength Cond Res. 2014; 28(1): 69–73.
5. Mishra A, Woodall J, Vieira A. Treatment of Tendon and Muscle Using Platelet-Rich Plasma. Clin Sports Med. 2009;28:113-125.
6. Chazaud B, Brigitte M, Yacoub-Youssef H, Arnold L, Gherardi R, Sonnet C, Lafuste P, Chretien F. Dual and beneficial roles of macrophages during skeletal muscle regeneration. Exerc. Sport Sci. Rev. 2009; 37(1):18-22