By Ben Oakley
Head of Sport and Fitness, Open University
Identical twins have the same DNA. They may look alike, but do they have the same chances when it comes to sport?
Jonathan and Kevin Borlée both competed in Friday's European Championships 400m final in Barcelona but how did Kevin snatch the gold medal while his identical twin, with all the same genetic attributes, trail behind in seventh?
Scientists love to study those who have come from the same sperm-egg combination since it means they can investigate to what extent our DNA and other influences determine talent.
Scientist Claude Bouchard in Canada investigated this further. In one experiment he found that when inactive people trained in exactly the same way for 20 weeks, the improvement in aerobic capacity amongst twins was almost identical compared to the randomness of the general population.
He suggested that people's baseline aerobic capacity and the way they respond to training was 50% due to the presence or absence of specific genes.
Such studies are drawn from the general population with only 20 weeks of training so how much does this apply to elite athletes who might train for 10 years to reach the top?
BORLÉE SIBLINGS - THE FACTS
Age: 22 and 24
Career highlights: Kevin won gold in the 400m at the 2010 European Championships and Olivia won silver in the 4x100m relay at the Beijing Olympics 2008
When you look at elite-level athletic twins, such as Jonathan and Kevin Borlée, one of the twins will eventually be more successful than the other. Dead heats in running are rare so some additional factors must play a part.
In 2001, scientists in Italy investigated identical twins who had both competed at the Olympics in the 20km race walking discipline.
The twin brothers had trained together between the ages of 15 and 33 under the same coach and a virtually identical regime but one became a gold medallist and was more successful.
Afterwards in "retirement" (aged 40), they were extensively tested and as predicted their physical abilities were almost identical. Clues to the twins' performance differences were found only in their contrasting personality and psychology.
Measuring personality is problematic but psychological profiles of the Olympic medallist scored very high on "anger reaction" and his tendency to keep it buttoned up. His twin scored very low on anger reaction and but he was more likely to "vent" and express his frustration.
It was suggested that these mental differences may be significant and contributed to deepening his competitive drive.
This study reminded one expert in twin studies of what 1984 USA Olympic skiing gold medallist Phil Mahre told his identical twin brother, Steve, when it appeared that Phil had won the event: "Here's what you have to do to beat me."
Need for perfection
Perhaps slight variations in anger, drive, confidence, or all three explain the difference between talented sports twins, the study also suggested.
The need for an all-consuming "hunger" for success might be one of the main success factors in elite sport.
A champion does not just get to the podium just by a strong work ethic, they have a deep-seated "need" or "desire" to win; it might be that they need to constantly prove themselves, that they are a perfectionist, or other factors.
Ben Oakley: An all-consuming "hunger" for success might be one of the main success factors in elite sport
What of sporting twins, is their special relationship a help or hindrance to motivation?
Researchers think that athletes' older siblings are as good role models for work ethic ie. older brothers or sisters showed, in a positive way, the amount of work/training needed to win. Certainly, the Borlée silver medallist sister might be an inspiration to them.
Listening to what top-level athlete siblings say about their relationships backs this up. Their explanations describe the presence of both a healthy rivalry and closeness.
Here are a couple of comments from an unidentified athlete that I think represent the mainly positive aspects of sibling competition and encouragement.
"Competition [with my sister] pushes me harder because if someone else is beating me I'm like, 'OK, she's better than me, I can accept that', but if it's my sister? You are like, 'no, I can beat her. Let's go.' I think it pushes you that much harder."
"[She] kind of just pulled me aside and said, 'get your head out of your ass! You've got two more events to swim. You've got two events to make your mark ... just go out there and do it."
As we watch the progress of the Borlée twins and their sister towards 2012 and beyond, I for one will be interested to hear what they have to say about their motivation, drive and psychological aspects of performance.
This, combined with the different training environments they are now following, will present a real insight into the complex explanations about the role of genes, training and psychological influences.
Ben Oakley is Head of Sport and Fitness at the Open University and previously worked as the Olympic windsurfing coach, attending the Games in 1988 and 1992. He has worked in higher education since 1995 and published work on professional practices in coaching and sports policy.
Recently he has led the development of online teaching materials in sport and been the academic consultant for the BBC Olympic Dreams series.