5 Questions with Christian Baumgart

Christian Baumgart, lead author of new study, Pubished Ahead of Print

It’s been a while since I’ve had the chance to ask a guest ‘5 questions,’ a recurring feature of this blog.  Our May issue is still a few days from being published…..too soon for guests!  And so I thought it was time to give readers a taste of our ‘Published Online First’ feature.

Once a manuscript has passed CJSM’s rigorous peer review process, ‘made the grade’ and been accepted, it is still a few months away from being published in print.  Like many journals, we have a healthy backlog of manuscripts which have been accepted but await publication.

But it’s not too soon for the authors to break out the champagne, because the article can be fully formatted and made available electronically prior to print–fully searchable in PubMed, prime time for the C.V.

One such study came to us from researchers in the Department of Movement Science at the University of Wuppertal in Germany: Effects of Static Stretching and Playing Soccer on Knee Laxity.  This is a randomized clinical trial looking at the effects of static stretching and playing soccer on anterior tibial translation.  I emailed the lead author, Christian Baumgart, and he was more than happy to join us on funf fragen…er, five questions!

Danke Christian!  I hope to meet you some day in Germany.

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1) CJSM: What would you say was the most notable finding in your study?

CB: Previous studies have shown that different exercises lead to an increase in the sagittal knee laxity. The surprising finding of our study was that static stretching also increases the sagittal knee laxity and even to a greater extent than playing soccer. From a biomechanical point of view this fact seems to be logical, because in healthy athletes the joint mobility during stretching is limited primarily by ligaments and capsules. Subsequently, these connective tissues were short-termed plastic deformed. It is unclear whether the connective tissues adapts structurally, if the external load is applied long-term.

2) CJSM: Do you think the statistically significant increases in anterior tibial translation (ATT) you found both in static stretching and playing football (soccer) are clinically significant?

CB: Concerning the kinematics of the knee joint mean increases in knee laxity of up to 2.1 mm are quite remarkable, with the maximum measured changes were 4.8 mm in the soccer group and 5.8 mm in the stretching group. It should be considered that the increase in knee laxity must be compensated by the sensorimotor system to ensure the joint stability (rolling and gliding motion). In terms of responder and non-responder, it is conceivable that some athletes (hyper- and hypo-mobility) are particularly “vulnerable” and exposed, due to a reduced mechanical joint stability and altered sensorimotor function, a higher risk of injury. It should be noted also that the increase in knee laxity induced by the static stretching occurred immediately, while this happens gradually during exercise, which allow the sensorimotor system to adapt.

3) CJSM: You used three different applied forces with the KT-1000 (67N, 89N, maximal force) to evaluate increases in laxity after the study interventions (static stretching, playing soccer). What is the thinking behind using three different forces? Are there different types of information one gets with each force applied?

CB: The applied forces and procedures are prescribed by the measuring instrument (KT-1000) and represent the international standard, which allow the comparability to other studies. Normally, the measured values of the different applied forces are related strongly.

4) CJSM: Taking a broader view of this study, and the work you do in general, do you have an opinion about preferred warmups and what, if any, stretching should be incorporated into the training regimen of football (soccer) players?

CB: In our opinion, the warming-up should be sport-specific generally, and in professional soccer individually. In team sports, only short dynamic stretching exercises should therefore, if at all, be performed. On the basis of the long experience in professional sports (e.g. soccer), we use individualized stretching exercises only for therapeutic reasons and under medical and physiotherapeutic supervision. A general and non-individualized stretching program (in soccer) is not useful.

What direction Christian?

5) CJSM: What directions are you taking your research next?

CB: In the field of prevention and rehabilitation one of our priorities is the ACL-injury. Among other issues, we are interested in motor control during the rehabilitation process as well as potential risk factors of osteoarthritis. In addition, we try to validate current trends in sport scientifically. Currently, we are examining self-myofascial release in more detail.

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