What is the Rotator Cuff?

The rotator cuff (often times mispronounced as the rotator cup) consists of four muscles which hold the ball of the shoulder (a.k.a. humeral head) into the socket (a.k.a. glenoid). The four muscles can be remembered by the acronym “SITS.” They stand for Supraspinatus, Infraspinatus, Teres Minor and Subscapularis. Each muscle is responsible for a select motion. They are as follows:

• Supraspinatus- abduction (a.k.a. elevation of the arm)
• Infraspinatus- external rotation (a.k.a. rolling the arm outward)
• Teres Minor- external rotation (a.k.a. rolling the arm outward)
• Subscapularis- internal rotation (a.k.a. rolling though arm inward)

Collectively, these muscles and their tendons work together by surrounding the ball (head of the humerus) and, with tension, help seat the ball into the socket (glenoid).
Since your ball is three times the size of your socket, the rotator cuff requires a lot of help in holding the joint together. There are two other structures which are instrumental in holding the ball into the socket (a.k.a. glenohumeral joint). The first structure is called your glenoid labrum. The glenoid labrum attaches the larger ball to the smaller socket and acts like a suction cup (like the end of a toy dart) in order to hold the two together. In fact, the labrum is of similar makeup as the aforementioned suction cup. It
has a rubbery-like texture. The second structure is the joint capsule. The joint capsule is a stiff fibrous membrane composed of avascular tissue (no blood flow) which envelops the shoulder joint (glenohumeral joint) and assists the rotator cuff and the labrum in holding the ball into the socket. Since the shoulder joint (glenohumeral joint) is classified as a synovial joint (a joint that holds fluid), the joint capsule helps hold the synovium (a viscous fluid) in and around the joint for lubrication. Any one of the four rotator cuff muscles, the labrum or the joint capsule can be acutely injured (traumatic) or chronically injured (happens over time, normal wear and tear). Regardless of the mechanism of injury (MOI), acute or chronic, they are classified as a Grade I (1/3 tear), Grade II (2/3 tear) or a Grade III (full-thickness tear). The treatment, whether conservative (physical therapy) or aggressive (surgery), depends upon the Grade, location and number of structures torn.

Dr. Brett Purdom, PT, DPT, ATC, CSCS
Owner of The Foot Mechanic™
www.thefootmechanic.com
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What does Tendinitis mean?

Tendinitis literally means inflammation of the tendon. In fact, any time you see the suffix “-itis” behind a name of a body part it means inflammation of that body part. As an example, inflammation of the Larynx is called laryngitis. But let’s get back to the causality of tendinitis. Every tissue in the body is formed on what is called a “collagen matrix.” In fact, we can consider collagen as the building blocks of all tissue. Each tissue has varying amounts of collagen. Collagen is in its highest concentration based on the stiffness of that tissue (or, it’s resistance to injury). The collagen matrix concentration in the Skeletal-Muscle System in order is; bone, ligament, tendon and finally muscle. Further, the collagen fibers are uniquely positioned such that they are aligned in positions which offer the greatest resistance to the forces under which that tissue must absorb. As an example, jumping off the tailgate of a truck will not fracture the bones in your leg. However, if the same force hits your thigh bone (femur) directly from the side, it will immediately fracture. This is due to the directional nature of the collagen matrix. In the femur, the matrix is set up only to absorb forces that transfer the length of the bone. It is also important that you understand blood flow in these tissues. Blood flow is inversely proportional to the amount of collagen a tissue contains. Muscle has the greatest amount of blood flow and the lowest concentration of collagen, while bone has the least amount of blood flow in the highest concentrations of collagen. When put under a microscope muscle fibers appear red and bone fibers appear white. When put under a microscope, a tendon will also appear white. This means its blood flow is relatively low. When a tendon is stressed in a manner which goes against its collagen alignment, an injury can occur. This injury will cause micro tearing of the tissue and bleeding. This is why we call it “tendinitis.” Over time, and as the tendinitis continues to go untreated, the micro tearing can increase in size rendering the tendon too painful to use. Couple this with the fact that a tendon has relatively low blood flow, it is clear why a tendon will take longer to heal. Muscle, because it has a greater amount of blood flow typically takes about 2 to 4 weeks to heal. Tendons usually take 4 to 6 weeks to heal. Ligaments typically take 6 to 8 weeks to heal. And this is why when you have a fracture, you are casted for 8 weeks. Bone has the least amount of blood flow.

Treatment: if you feel it tendinitis coming on or, have been diagnosed with the tendinitis, here is the treatment protocol:

1. Follow the principles of RICE (Rest, Ice, Compression, and Elevation) for the first 24-48 hours
2. 0-2 weeks, stretching and isometric exercise, alternate heat and ice
3. 2-4 weeks, stretching, light warm-up (exercise bike), strengthening exercises at 25-50% PME in the same alignment of the collagen matrix, stretch and ice after
4. 4-6 weeks, stretching, moderate warm-up (exercise bike/treadmill/elliptical/fast walking), strengthening exercises at 50-75% PME in the same alignment of the collagen matrix, do not exercise through pain, stretch and ice after
5. 6 + weeks, reintegration of normal exercise routine, do not exercise through pain, stretch and ice after.

Dr. Brett Purdom, PT, DPT, ATC, CSCS
Owner of The Foot Mechanic™
www.thefootmechanic.com

What is an Overuse Injury?

An overuse injury is any repetitive movement whose force requirement exceeds that which a muscle and/or its tendon (a.k.a. muscle-tendon complex) are able to sustain over a given amount of time. The result is tearing of either the muscle or tendons’ fibers. When this occurs there is a small amount of bleeding. In this case, bleeding is advantageous as it will bring in all of the healing constituents necessary to repair the tear. Here, the old adage RICE (Rest, Ice, Compression, Elevation) applies. The underlying problem is most will “chalk” this up as a minor setback. They will not treat it appropriately and will continue to perform the repetitive movement while tolerating the minor pain. Here is where the problem exists: there are 3 stages to injury. The 1^st phase is the acute phase. The acute phase is the 1^st 24 to 48 hours. It is no coincidence that this is the timeperiod where icing an overuse injury is often recommended. It is in this acute phase where this injury is most easily treated. The 2^nd phase is called subacute phase and it is from 48-72 hours. It is generally advocated that during this phase of treatment a person should alternate heat and ice while doing light stretching exercises. If left untreated, during this timeperiod the blood flow to the injured area begins to stagnate and become nonfunctional. An overuse injury is much more difficult to treat during this phase. From 72 hours-on an overuse injury enters its chronic phase. In this phase, the injury must be brought back to the acute phase in order to be treated. This is usually done in physical therapy with the use of physical therapy modalities such as cross-friction massage, ultrasound, electrical stimulation (E-Stim) and/or provoking exercises. Too many times overuse injuries are allowed to enter the chronic phase. Over time and as the overuse injury continues to go untreated, it can increase in size rendering the muscle-tendon complex too painful to use. Continuing, muscle-tendon tearing worsens and can eventually lead to rupture. In summary, overuse injuries are very common in the recreational athlete. If treated immediately using the principles of RICE, these such injuries can be cleared up in a short period of 2 weeks. If left untreated over weeks of repetitive motion, a person might need a minimum 30 days of physical therapy at a frequency of 2 × per week. If longer periods of overuse occur (1+ months), surgical intervention might be the only option.

Dr. Brett Purdom, PT, DPT, ATC, CSCS
Owner of The Foot Mechanic™
www.thefootmechanic.com

Barefoot/Minimalist Running Debunked

Barefoot and minimalist running styles are dangerous for your feet. In fact, they fail to recognize the most primitive biomechanics of running or the deleterious effects of this type of running style on the human foot. Simply stated, longitudinal studies outline the foot must start in a rigid position (closed-packed or supinated) position. It then must transition into a malleable (loose-packed or pronated) position in order to adapt to the ground surface. Finally, its 3rd phase is to re-transition into a rigid (closed-packed or supinated) position in order to gain a rigid lever for push off. The 26 bones in the foot are intimately and precisely positioned to go through these phases (heel strike, mid stance and push-off) in order to prevent injury. By altering the mechanics of walking/running by using toe-running or midfoot striking a person sets themselves up to what we call “retro loading” which puts extreme non-biomechanical forces across the bones of the midfoot (tarsal bones). This can cause, but is not limited to, acute pain, plantar fasciitis, early arthritic changes, stress reactions and even stress fractures. This doesn’t even mention the adverse effects which may occur up what we call the kinetic chain (ankle, shin, knee, hip and low back). The evolution of the human running shoe is not a manifestation of the shoe companies’ attempt to sell more shoes. Rather, the running shoe is a product of evolution based on longitudinal studies of human biomechanics. If they were not we would all still be running barefoot. It seems that this whole “barefoot” running craze/phase is attempting to de-evolve the human foot back centuries. The only reason there are so many advocates for this type of running style is the mere fact that it is so relatively new we do not yet have longer-term longitudinal studies proving the aforementioned osteoarthritic/stress reaction/stress fracture data. However, if you browse around the Internet you will certainly find anecdotal testimonials as to such. I would refer you to the following two articles:

Barefoot Running Problems – Men’s Health www.menshealth.com/fitness/barefoot-running-problems

competitor.com
http://running.competitor.com/2010/05/features/the-barefoot-running-injury-epidemic_10118/4

Dr. Brett Purdom, PT, DPT, ATC, CSCS
Owner of The Foot Mechanic™
http://www.thefootmechanic.com