Does Oscar Pistorius have an unfair advantage over other Olympic
8 August updated 3 Sept 2012
The Institute of Biomechanics in Valencia has reviewed the
advantages and disadvantages that a prosthetic leg could give to a
runner such as Oscar Pistorius.
He reached the semi-finals of the London 2012 Olympic 400m
competition, coming eighth. He became the first amputee
sprinter to compete in the Olympics.
Oscar Pistorius was embroiled in further controversy on 2 September
after he was beaten in the Paralympics T44 200m final by Brazilian
Alan Oliveira. In a TV interview after the race Pistorius claimed
the legs of winner Alan Oliveira were too long, giving him an unfair
advantage. He subsequently apologised for the timing of his comment,
but has requested a meeting with the International Paralympic
Committee to discuss the length of prosthetic legs (blades) allowed
by the rules.
The selection of Pistorius in the Olympics reopened the debate whether he should compete with other athletes. In both, World Athletics
Osaka 2007 and 2008 Olympic Games, the IAAF banned him participating
claiming that his prosthetic legs gave a biomechanical advantage over its
However, also in 2008, the Court of Arbitration for Sport ruled
that Pistorius could participate in the IAFF competitions because
the biomechanical studies carried out had not made clear whether Pistorius had a complete advantage.
The Institute of Biomechanics (IBV) considers that this
controversy stems from the lack of technical regulation. First, it
is necessary that official organizations make clear in each case
whether they are allowed to
participate in non-Paralympic competitions. The first question to
answer must be can an athlete with
prostheses who reaches the qualifying standards participate in
official athletics competitions? If the answer is yes, then the
organizations need to assess whether
the prostheses are suitable for competition.
It appears that this first question has been answered in the case
of Pistorius, and the core of the current conflict is to determine
whether his prostheses provide an advantage over other athletes.
The response to this conflict has a great complexity as it is
very difficult to assess the balance between the advantages and
disadvantages of the prostheses. Biomechanical studies have shown
that Pistorius obtains advantages in some aspects such as increased
energy return, but also has disadvantages such as a decreased use of
At this point, there is evidence of the need for rules to decide
if it is or is not possible to use a specific prosthesis. This
policy should dictate the biomechanical properties of the
prostheses, and establish appropriate ranges they must meet
to make their use legal.
This same problem happened in other disciplines where rules
have been brought in to solve a conflict. Well known examples are the
establishment of a minimum weight for bicycles by the UCI
(International Cycling Union) or the annual need for approval of
swimsuits by FINA (International Swimming Federation) in the
evaluation of parameters such as buoyancy or permeability.
While a clear technical regulation is not developed, the
controversy and doubts will exist regarding the legitimacy of the
participation of Oscar Pistorius in Olympic games.
How Pistorius runs
US and German researchers have shown in various studies in 2008
and 2009 the following aspects of the biomechanics in how Pistorius runs.
First, Pistorius has a
greater length of stride, but offsets this disadvantage by
performing a greater stride frequency.
The mechanical work of the knee, understood as the force that can
be applied to the knee in its displacement, is smaller than the rest
of runners. Putting numbers to this result, mechanical work applied
by Pistorius was 11 times lower in the braking phase support, and 8
times less in the propulsive phase of walking. This means obtaining
a 22% less vertical reaction force than runners with normal limbs, resulting in a lower speed rate.
During running, the ground returns to the athletes energy that
they are able to reuse in a percentage useful to keep running. 400m
runners are able to reuse 41% of this energy. On the contrary,
thanks to metal blades, Pistorius achieves a 90% reuse. That
difference of 49% less energy loss allows Pistorius to sprint as
fast as a runner without a prostheses with a lower metabolic cost.
In the first step of the start is when the performance of
Pistorius may be much less than its opponents. At this point, as he
is unable to take the energy return of previous steps, it is
essential to generate impulse with his muscles. This impulse is
shown to be lower than the other runners. This disadvantage in the
start is more influential during the shorter races. In the 100m has a great influence, while in 400m is usually not critical
to the final result of the race.
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