Unfair advantage?

DW: Mr. Willwacher, the sensational victory of Markus Rehm at the German Championship in Ulm has triggered a fierce debate. Many are asking the question: Did Markus Rehm jump so far despite his prosthetic leg, or because of his artificial limb?

Steffen Willwacher: This question cannot be answered by science at the moment because no scientific studies have been conducted on the subject of "prosthetic long jumping." We are waiting for the results of research that was conducted during the competition in Ulm. But this examination was very rough. You'd have to take a decidedly more differentiated look at the sequence of movement and compare it with that of a long jumper who is not an amputee.

Critics claim that Rehm's prosthesis gave him a considerable advantage. When is a prosthesis advantageous?

Speaking in purely theoretical terms, a prosthesis is advantageous when it makes the jump more efficient; for example, if it succeeds in taking the kinetic energy built up during the run and efficiently converting it into the jump. We know from research on healthy jumpers that during the jump, there's always a loss of energy. The energy is expended in the tendons, ligaments and muscles. If the loss of energy is less with a prosthetic leg, then that would be an advantage.

Biomechanics have collected data during the competition in Ulm to analyze whether Rehm's performance is comparable with the other jumpers. Which criteria must be fulfilled for the performances to be comparable?

I find it important that both athletes make the same movements. Then you can compare them in a competition. In addition, one has to take a look at exactly how the movement looks, what's the net energy on the individual joints, like the ankle, knee and hip joints. Then you can see whether it's the same movement or not. But the research that is being conducted in Ulm is too rough for that.

There are many athletes with prosthetic limbs that aren't able to jump anywhere near as far as Markus Rehm. Is Rehm a better jumper? Or does he have a better prosthesis?

I don't believe that he has a better prosthesis. The carbon fiber that he uses is easily accessible to everyone. And the attachment of the prosthesis to the leg is done as a general rule by an experienced orthopedic technician. I believe that Rehm is better because he's a very talented athlete and has trained under professional conditions. And that is reflected in his performance.

Would you support Rehm's participation in the European championships for athletes who are not handicapped?

If a differentiated biomechanical analysis found that his movements are comparable to those of athletes who are not amputees, then I would support it. In my view, however, there's a pressing need for an examination in order to conclude whether this is the case or not.

Steffen Willwacher, born in 1984, is a researcher and doctoral student at the Institute for Biomechanics and Orthopedics. His thesis (2008) was entitled "Examination of the kinematic and kinetic spring of a bipedal transtibial amputee." His dissertation is called "Neuromuscular biomechanics and environment: Interaction in running." Willwacher is an expert in biomechanics and prosthetics, particularly in track and field, at the German Sport University (DSHS) in Cologne.