Isometric Contractions for In-Season Treatment of Patellar Tendinopathy


Guest blogger Dr. Napolitano grinding it out on the water.

One of the great features of modern medical journals like CJSM is the ability to publish studies ahead of print – we call it “Published Online First.”

With the flexibility  allowed by the internet and emerging media, we are able to get studies that have gone through peer review and are in the queue for printing out to the reading public months before they otherwise would see the light of day.

We have one of our “Published Online First” studies burning things up on emerging media.  At CJSM we follow the Altmetrics on the studies in our pages, and this new one — Isometric Contractions Are More Analgesic Than Isotonic Contractions for Patellar Tendon Pain: An In-Season Randomized Clinical Trial — currently has a very hot rating of 107 (and climbing).

The treatment of such a common condition will be of inherent interest to those who practice sports medicine. Moreover, managing this nagging condition in mid-season can prove to be a Sisyphean task for the athlete and clinician.  This study has great promise to make a significant impact on your care of the athletes you see.

I asked the physician fellow working with me at NCH sports medicine, Jonathan Napolitano, MD, to do a guest post on this study authored by Rio et al.  Dr. Napolitano’s commentary, forthwith:


Basketball season is upon us and our clinics have begun to fill with athletes ailing from patellar tendinopathy, seeking pain relief and a quick return to the hardwood.  As a sports medicine fellow with a residency background in physical medicine and rehabilitation I have used this time to step back and review the therapeutic exercises we prescribe for tendinopathies.  I have always paired the concept of eccentric strengthening with tendon repair.  However, various other types of muscle contraction and strengthening exercises can (and perhaps should be) prescribed as well.


In between isotonic beer curls at World Series 2017 game (L – R): Drs. Stephen Cuff, Reno Ravindran, Jonathan Napolitano

As an educational exercise I would like to take a moment to review the types of muscle contractions.  Isometric contraction occurs without any movement of the joint on which the muscle acts.  Isokinetic contraction occurs at a constant speed across a joint range of motion with variable resistance.  Finally, isotonic exercises are performed through normal joint range of motion with a consistent resistance at variable speed.  Isotonic contractions are further divided into concentric (muscle shortening) and eccentric (muscle lengthening).

Tendon pain is a factor that limits participation and performance in athletes.  Eccentric strengthening has shown good clinical outcomes in the long-term; however, this intervention can lead to increased pain in the short-term, and in 2005 Visnes et al showed eccentric strengthening to be of no benefit for in-season athletes.

Recent research by Dr. Rio et al [including senior author Dr. Jill Cook] compared rehabilitation programs for in-season athletes with patellar tendon pain.  This randomized clinical trial set out to analyze the immediate analgesic effect of resistance training of isometric verses isotonic rehab programs.  Researchers randomly divided their population of twenty-nine male and female basketball and volleyball athletes with clinical patellar tendinopathy confirmed with ultrasound imaging into two equal groups and given a home exercise regimen with strict guidance and follow-up.  After a four-week period both groups showed improvement in pain with single leg decline squat, with the isometric group exhibiting a greater statistically significant change.  Both groups improved in the functional measurement of their tendon pain; however, in this underpowered study, neither group’s median was greater than the minimum clinically important difference of this measure.  The isometric group did report a greater change from baseline .  The athletes of both groups missed no time from training or competition while undergoing their rehab.  The authors also introduced an interesting discussion on the benefits of “active” analgesia versus “passive” modalities in behavioral health a sense of control and self-efficacy.

Despite a small sample size and only a short-term follow-up, this article has impacted my treatment of athletes with tendinopathy.  My prescriptions to physical therapy now read: “Begin with isometric tendon strengthening for analgesia and only progress to eccentric loading as tolerated”.  I have discussed this innovative research with the physical therapists I work closely with and suggest each of you consider engaging in similar conversations.


Thanks so much for taking the time to share your thoughts Jonathan.

And readers of the blog, go to this link to get the study.  Let us know your thoughts.

About sportingjim
I work at Nationwide Children's Hospital in Columbus, Ohio USA, where I am a specialist in pediatric sports medicine. My academic appointment as an Associate Professor of Pediatrics is through Ohio State University. I am a public health advocate for kids' health and safety. I am also the Deputy Editor for the Clinical Journal of Sport Medicine.

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