Orthopedic/Injuries>>Reducing Shoulder Injuries for Athletes & Wheelchair Users - 1/4/2007
Muscle Balance for Injury Prevention and Improved Athletic Performance
By Kevin Lockette PT
Ohana Pacific Rehab Services
Proper muscle balance is essential in order to prevent injuries and to enhance athletic performance. Common sport related injuries such as rotator cuff tendonitis or bicepital tendonitis are to great part due to overuse/improper muscular balance. These injuries are common in certain sports but are also common to the everyday wheelchair user.
Some studies estimate that up to 75% of manual wheelchair users will develop shoulder pain during their lifetime. It makes sense when you think about that the shoulder was not designed for weight-bearing and locomotion. The impact of a shoulder injury can be devastating for the wheelchair user impacting both their functional mobility and independence.
The intent of this article is to offer helpful hints to avoid or at least minimize the incidence of shoulder pain. As a clinician, we can play a direct role in prevention via proper wheelchair prescription and set-up as well as providing education to our clients on muscular balance.
Before we focus on prevention, it is necessary to briefly review the etiology of shoulder injuries. Rotator cuff tears, degenerative changes and other pathologies about the coracroacromial arch are commonly found in wheelchair users with symptomatic shoulder pain. These degenerative changes occur from repeated microtraumas when the joint space between the humeral head (upper arm) and the acromioclavicular (A/C) shelf decreases to the point where repeated contact occurs on the same area on the supraspinatus tendon. The position and the repetitive loading of the shoulder joint for propulsion and transfers most likely contribute to these changes.
As clinicians, we have three opportunities to assist in the prevention of shoulder related injuries in our manual wheelchair clients. The opportunities are during the prescription phase for a new or replacement wheelchair, the adjustment/fitting of a wheelchair, and the assessment and treatment for muscular imbalances.
1.) Wheelchair prescription: Since we are nearly certain that repetitive stress or loading is the underlying cause of injury, it would make sense that we attempt to reduce the amount of loading or resistance to the stroke for wheelchair propulsion. One simply way is to minimize the weight that has to be overcome with each stroke. In regards to the wheelchair, simply prescribe the lightest chair possible. When dealing with Medicare and other 3rd party payers, you can not expect to have coverage for light weight or ultra-lite wheelchairs without some resistance or requirement of strong medical necessity for this in your documentation. For active wheelchair users, the chairs that are most appropriate are the more expensive wheelchairs and fall under the K0005 code due to weight and adjustability. Fortunately, over the last few years, Medicare allows for an “Advance Determination Process” for wheelchairs that fall under this code so you as a clinician have an opportunity to medically justify the need for the lighter, more adjustable wheelchair. Other considerations in the weight of the wheelchair are the components and seating devices. There are many different considerations in regards to the components and keep in mind that the lightest option may not be the most appropriate due to other factors such as capability, transportation issues etc. Having said this, the following are 3 more strategies to reduce the overall weight of the wheelchair:
a. Spoke wheels versus Mag wheels:
b. Rigid versus folding frame: Rigid frames are lighter due to not having the cross frame and hardware that the folding chairs have. The one consideration is possibly transportation.
c. Seat cushions: Most active users may not need a high end pressure relief cushion; however, most wheelchair users may have higher risk for skin breakdown due to lack of sensation or ineffective pressure reliefs if they are a higher level of injury without full use of the triceps. The point here is that you want to prescribe the lightest cushion that provides adequate skin protection. It makes no sense to prescribe a light-weight wheelchair and then place a heavy gel-style or dense foam cushion when a hybrid or air style cushion is adequate.
Lastly, one more issue worth mentioning in regards to prescription. 10 to 15 years ago, the school of thought of many of the physicians and therapists was that if a client has the capability to propel a manual wheelchair, then a manual wheelchair should be prescribed over a power wheelchair. In regards to paraplegics and lower quadriplegics, I still feel this to be so; however, for higher quadriplegics, in particular, C5-C6 quadriplegics who do not have full function of their tricep, I now question this school of thought and think that there should be greater consideration for power mobility. These clients are operating with a very limited muscle mass and are not only more likely to be susceptible to shoulder injury but also are at great risk for bicep tendonitis and wrist injuries which could eventually lead to loss of independence with transfers and self-care. Manual mobility in the community for many of these clients is extremely difficult and puts additional stresses on the joints of the upper extremities. Power mobility would spare the repeated stresses and micro-trauma sparing the available upper extremity musculature for transfers and other functional tasks more likely maintaining greater independence over time.
CMS is re-evaluating and revising the requirements for wheelchair coverage and is now considering community mobility versus the rigid restriction within the home only in regards to qualification for mobility devices.
2.) Wheelchair adjustments and pushing techniques: The wheelchair set-up will influence the propulsion technique and ultimately the amount of resistance or reactive force/stress that is translated back to the shoulder joint. The more rearward the seat position in relation to the wheel, the less rolling resistance and the more efficiency with propulsion. A more rearward seat positioning will promote a long and smooth stroke that limit high forces and the rate of loading on the pushrim that you will see with a short and abrupt “pumping” style stroke. This is of course only true if the wheelchair user has adequate range of motion in his or hers shoulder joint. A rearward seat position basically has less drag because you are not loading the front casters as much not allowing a “plowing” effect. The trade off is stability. The more rear the seat position the less stable or more likely for the wheelchair to tip backwards. For experienced users with a very low level of injury, this is not typically a problem; however, more inexperienced users or wheelchair users with a higher level of injury may not have the seat set-back as much or may need to use anti-tippers.
3.) Muscle Imbalances: Most rotator cuff injuries are due to muscle imbalances of the shoulder. Shoulder strength and muscular length/ROM imbalance can cause impingement of the soft tissue structures of the acromiohumeral space. Wheelchair users are even more susceptible to muscle imbalances. Nearly every motion and all repetitive motions are anterior working the pecs, shoulder internal rotators, anterior deltoid, etc. These anterior muscles become tight and shortened while the upper back muscles become weak and elongated. You can see these imbalances in the postures of chronic wheelchair users. A typical posture is rounded shoulders with mild thoracic kyphosis and forward head. This posture is even more accentuated by non-supportive wheelchair back that is stretched out accommodating this poor posture. It is important that we teach wheelchair users stretches to the anterior musculature while strengthening the upper back, posterior shoulder and scapular muscles. This is best achieved by having these clients perform exercises in prone or at least modified prone by flexing forward in their wheelchairs so that they can work the upper/lower trapezius, posterior deltoid and rhomboids. A focus should also be on the external rotators of the shoulder. By restoring muscle balance, the acromiohumeral space can be preserved minimizing the pressure on the rotator cuff.
The consequences of shoulder injury to the wheelchair user can be devastating. Preventative measures such as proper wheelchair prescription/fit and restoring muscular balance can greatly assist in minimizing overuse injuries to the shoulder maintaining independence.