Going Negative

by Bob Albright, D.O.

Not to worry, elections are still two years away… I still plan to give you all my usual upbeat, perhaps overly glib effort.

Today’s subject is one most all of us have encountered, chronic tendon injuries and whether eccentric exercises are a major part of the solution. I hope to also discuss their effectiveness and perhaps how they may work.

Loosely defined, a tendon injury which goes on for months (or years -- anyone?) with associated tenderness, limitation to range of motion and overall function may be determined to be a tendinosis. Tendinosis implies the tendon is no longer actively inflamed, but instead its tissue has entered a static phase characterized by fibrous tissue replacing healthy tendon. The situation may even be made worse by anti-inflammatory medications.

Unfortunately, this condition is very common, with Achilles tendinosis afflicting an estimated 11% of runners. Interestingly, 20% of knee injuries seen at a major university’s sports medicine clinic were diagnosed as patellar tendinosis.

The usual protocol of rest, ice compression and elevation (RICE), is useful during the early (hours/weeks following injury) injury phase. However, once the injured tendon has failed conservative therapy, multiple modalities have been tried to provide return to full athletic function. Modalities such as non-steroidal anti-inflammatory drugs, corticosteroid injections, ultrasound, electrostimulation therapy, deep tissue massage and more recently platelet rich plasma injection have been utilized with varying success. The modality which arguably has been most successful has been utilization of eccentric exercises (EE).

Muscle contractions are categorized as concentric exercises (CE), during which the muscle shortens during use -- think of a bicep curl. Eccentric exercise (EE) , during which the muscle is under tension as it lengthens (think lowering bar during a dead lift) or isometric exercises (IE) during which the muscle stays the same length during contraction (think Jack Lalane -- and the “push your hands together in front of your chest!”).

EEs are known to most of us as “negative repetitions” or negatives. The movement involves a focus on the gradual lengthening of the affected muscle-tendon against resistance, with avoidance of the CE. Classically this is illustrated by “negative calf raises.” One rises up on the unaffected leg and lowers with the affected side. This concept can be utilized for the patellar tendon, the hamstring (and is tendon) the plantar fascia the wrist extensors, and generally any area of the body with opposing joint movement. An excellent recourse is the Rehab section written by Dr J. Shilt in Gordo’s recent volume of “Going Long.” The specific exercises are best prescribed by rehab experts, but there are many on-line resources and Gordo’s book for specific protocols for doing EEs.

Do EEs work?
Yup! Well, mostly anyway.

There are many clinical trials on this subject. Study design can be difficult, as you can imagine, (trying to avoid CE with the EE and controlling activity levels to name a few problems), but the majority of trials show either a complete resolution of symptoms or improvement of symptoms in 60-80% of the athletes studied. One glaring exception may be insertional Achilles tendinosis, where results compared with other modalities was equally abysmal. (Personally, this is a real problem for me!) Many times insertional Achilles problems may be due to other issues as well, such as retrocalcaneal bursitis.

How do these EEs work?

EEs cause relatively more muscle fiber disruption, micro-trauma and hence incite a return to the inflammatory state. Studies have found more force can be applied during an EE, and depending on the body area, more muscle hypertrophy and hence strength gains may actually be realized with EEs versus CEs! Most studies however still confirm a combination of EE and CEs are most effective for strength work.

As I stated previously -- tendinosis may be an “arrested” injury state. The relatively poorly vascularized tendon goes into hibernation and healing ceases. NSAIDs (and perhaps steroids) may even promote this maladaptive behavior. Sports medicine experts suspect part of the reason EEs work is by stimulating a “completion” of the injury-inflammation-healing/repair cycle.

Another proposed mechanism is the “sinusoidal” or wave-like pattern of muscular and tendon force activity seen during EEs. This force-to-less force stimuli may allow enough stress with rest intervals during the maneuver to get the “good without the bad” strain. Finally, there may be enhanced blood flow in the microcirculation during lengthening of the muscle tendon unit which does not occur during CE (perhaps contraction shuts off flow?)

Final Recommendations:

• See an expert.
• Don’t let these issues become chronic!
• Begin EEs as soon as the swelling is gone.
• Think twice about long-term NSAID use (or maybe even steroid injections).
• Oh… and stay away from Mark Renshaw during a sprint unless you have a football helmet.

[Editor's note: Check out Jeff Shilt’s recent article on eccentric exercises to increase run durability.]

References:
Rees, JD, Wolman RL, Wilson A. Br J Sports Med 2009;43:242-246
Wasielewski N J, Kotsko K M. Jnl of Athletic Training 2007;42(3):409-21
Going Long: Friel and Byrn c. 2009

Bob Albright, D.O., is a Nephrologist and Assistant Professor of Medicine at the Mayo Clinic in Rochester, Minn. You can contact him at albright.robert@mayo.edu. To learn more about Bob, check out his recent EC team profile.