Sports Medicine Research: In the Lab & In the Field: Jumping Ability is a Risk Factor for the Development of Jumper’s Knee (Sports Med Res)
Wednesday, November 7, 2012

Jumping Ability is a Risk Factor for the Development of Jumper’s Knee

Jumper’s Knee paradox – jumping ability is a risk factor for developing jumper’s knee: a 5-year prospective study

Visnes H, Aandahl HA, and Bahr R. Br J Sports Med. 2012; [Eup Ahead of Print].

Jumping is essential to volleyball as it is a key component of spiking, blocking, and serving. Unfortunately, this activity will often results in the development of jumper’s knee (patellar tendonitis). The jumper’s knee paradox, where symptomatic athletes perform substantially better in counter movement jumps (CMJ; ballistic movement with rapid eccentric action followed by maximal concentric contraction) compared to asymptomatic controls, has never been adequately explained in the literature. Therefore, Visnes and colleagues performed a 5-year prospective study to determine if jumping ability and change in jumping ability affects risk of developing jumper’s knee. The authors recruited students (n=189) at an elite volleyball training program/high-school boarding school in Norway who were free of jumper’s knee at the time of baseline testing. Baseline testing included recording of height, weight, and previous training. A portable force plate was used to assess jumping ability by estimating vertical jump heights for both counter movement jumps and squat jumps (jumping from a standing flexed position with no counter movement). These two tests were performed twice a year. Once at the start of school (approximately, August/September) and the end of volleyball season (approximately March/April) and training volume was recorded on a weekly basis. A diagnosis of jumper’s knee was made if the subject had a history of quadriceps or patellar tendon pain and tenderness to palpation in the area of complaint for at least 12 weeks. If these symptoms were reported, the subject would then undergo a standard knee examination to exclude any other diagnoses and complete a VISA-P questionnaire to assess the severity of the symptoms. At the conclusion of the study, 28 of the final 150 student sample (19%) developed jumper’s knee during their time at the school (on average 1.6 years). The authors found no differences in height, weight, and previous strength training between those that developed jumper’s knee and those who did not. Males who developed jumper’s knee reported more volleyball training and less other training, as well as better baseline CMJ results compared to asymptomatic males. No difference in squat jump ability was observed.

The authors present an interesting look at how higher CMJ heights is associated with developing jumper’s knee. This data could become useful to clinicians as a method for preemptively identifying those at a high risk of developing jumper’s knee. Preventative treatment could then be applied to attenuate pain caused by jumper’s knee. Caution should be exercised interpreting these results for clinical applicability. First, this study was conducted in high-level volleyball players. These athletes have been trained in proper jumping and landing techniques. It is possible that lesser trained athletes may lack the ability to land properly and may develop jumper’s knee at a different rate than trained athletes. Therefore, this study should be repeated with athletes of various training levels. Also, a limitation of this study was the high level of subjectivity in the diagnosis of jumper’s knee. To be diagnosed with jumper’s knee subjects had to “consider that the symptoms were sufficient to represent a substantial problem.” This subjectivity raises the possibility that some athletes may have experienced symptoms of jumper’s knee but self-treated and therefore did not report this as a case of jumper’s knee. Therefore, future research should focus on using more objective measurements to diagnose jumper’s knee. Tell us what you think. Is jumper’s knee a condition that you see often in your athletes? If so, do you think this information could be applicable to you in identifying athletes at risk of developing jumper’s knee?

Written by: Kyle Harris
Reviewed by: Laura McDonald

Related Posts:
Visnes H, Aandahl HA, & Bahr R (2012). Jumper's knee paradox--jumping ability is a risk factor for developing jumper's knee: a 5-year prospective study. British Journal of Sports Medicine PMID: 23060653

6 comments:

Zahida Mitha said...

I think the theory presented in this article is interesting. It would be interesting to see the results of this study if it used subjects participating in different sports such as basketball, track, etc. I don't think the results of this article are convincing enough for me to start using this information in order to flag athletes who might develop patellar tendonitis. However, I am excited to see future research on this topic and what effect it will have on prevention practices!

Kyle said...

Zahida,

Thanks for the great comment! I too think your idea of looking at different sports would be quite interesting. Further, I would love to see this study completed with groups of jumping compared to non-jumping athletes. Do you see many cases of jumper's knee in your athletes currently? Is this something that is not worth implementing because you see relatively few cases or are you looking for more convincing evidence? Thanks again for the post!

Megan said...

I completely agree Zahida's entire response. I must say that I do not see many cases of jumper's knee with my high school athletes. I would say that if I did see more cases of jumper's knee that I would definitely try to implement a prevention program with my athletes if more research is produced on this topic in support of it.

Kyle said...

Megan,

I am in complete agreement with you and Zahida. I think the other thing that would be helpful, which I referred to in the post, would be to look at a similar study which assesses prevalence of jumper's knee in lesser trained athletes. Do you have your athletes do extensive landing training for preventative measures? If so, perhaps this is a reason you do not see many cases of jumper's knee. Thanks again, great comment!

Kale Songy said...

I think an important question to ask is if jumper's knee symptoms are being created from the different landing strategies, or from the mere repetition of jumps. I think the chronicity of the jumping action, along with force production of jumps has a lot to do with the syndrome. I would like to see these factors studied along with jumping and landing mechanics.

Kyle said...

Kale,

Excellent comment, thanks for making it! I think you bring up a good point. I would even take your question a step further and ask if we could also be seeing a combination of factors simultaneously causing jumper's knee symptoms. Further, could the factors be different when comparing one athlete to another? My experience working with jumping athletes is fairly limited so I would ask if anyone else has seen these factors come into play, or more than one factor affect these athletes simultaneously?

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