Questions and answers should be concise.

We reserve the right to edit items for clarity

and style. Include a daytime telephone

number and email address if you have

one. Restrict questions to scientifi c

enquiries about everyday phenomena.

The writers of published answers will

receive a cheque for £25 (or US$

equivalent). Reed Business Information Ltd

reserves all rights to reuse question and

answer material submitted by readers in

any medium or format.

New Scientist retains total editorial control

over the content of The Last Word. Send

questions and answers to The Last Word,

New Scientist, Lacon House, 84 Theobald’s

Road, London WC1X 8NS, UK, by email to

lastword@newscientist.com or visit

www.last-word.com (please include a

postal address in order to receive payment

for answers).

For a list of all unanswered questions

send an SAE to LWQlist at the above

address.

A brand new collection -serious enquiry, brilliant insight and the hilariously unexpected

Available from booksellers and at www.newscientist.com/polarbears

ight cted

m/

Do Polar BearsGet Lonely?

THE LAST WORD

Studying form

When closely matched athletes are

competing in events that involve

running, swimming, throwing or

lifting, why does one of them win

one day and another the next?

Surely whoever is the fastest or

strongest will remain so, for a while

at least. Often the original winner

will return a few days later and win

again, so why did he or she lose the

race between the two victories?

■ The questioner must not belong to a gym. If you regularly take exercise in a quantifiable way, you soon notice that there are “strong” days and “weak” days. The most obvious factors influencing these are the amount and quality of sleep achieved beforehand, and how one is nourished. Elite athletes may

eliminate variation in their food intake on race days, and may even manage to regularise their sleep schedules, but one or another may be fighting off a minor viral infection, or the temperature or humidity may be more to one’s liking than to another’s.Steve Gisselbrecht

Boston, Massachusetts, US

■ The answer to this question lies in another question within the query: how closely matched are the athletes?

If the athletes were identical in skill, strength, speed and motivation, presumably they would never beat one another. But they do, because there are always factors both innate and environmental that interfere.

Nowadays most athletic events involving covering a distance are timed to one-thousandth of a second, so any competitor who beats another by less than this margin is declared to have equalled the other’s time. That is extremely unlikely, so in fact there is almost always a winner and a loser.

At a more macro level, the environment, plus the athletes’ mental and physical states are likely to vary by more than, say, 0.1 per cent and this makes all the difference at the elite level. When you add in diet, will to win, fit of shoes, distance from starting gun and such like, it’s surprising there are any dead heats at all. Mike Rennie

Professor of clinical physiology,

University of Nottingham Medical

School, Derby, UK

■ An athlete’s form reflects many different and constantly varying factors, any of which could prevent a win if overdone, underdone, or in the wrong combination.

Whether psychological or physiological, any changes in the body’s status will take time to resolve, causing cyclical or quasi-cyclical performance as they do. Effective coaches try to time the optimum for the day of performance and the optima may

be brief, sometimes ended by the reaction to victory itself – for example, through overconfidence or a lapse in commitment.

Athletes don’t perform according to fixed standards

of precision like machine tools. The bell curve , or normal distribution, is ubiquitous. It describes the statistical variability of any athlete’s performance and of differences between athletes. Each component variable has its own normal curve, and how they combine affects the athlete’s overall variability. Different athletes’ curves of variation can overlap far enough to reverse the outcomes of competitions dramatically.

Some variation in form is unpredictable, such as injury, illness, personal events, psyching

or luck on the day. Other effects are systematic, such as maturing, declining or cumulative stress, whether mental or physical. Any of those could cause gradual eclipse; almost any could cause sudden loss of form, even mid-game, and most setbacks are at least temporarily reversible.Jon Richfield

Somerset West, South Africa

This week’s questions

RAMBLING ROSE BUG

What is this little critter (see picture)? Where does it come from, what does it turn into and what was it doing pottering around my roses?Paul Martlew

Wildwood, Staffordshire, UK

COINS OF THE REALM

Photographs of the clock mechanism in the tower of the UK’s Houses of Parliament (Big Ben) show coins on a tray attached to the pendulum being used to tune the oscillation period. Since we all know that mass doesn’t affect the period of a pendulum, why is this done? Tony Richardson

Ironbridge, Shropshire, UK

EYES DOWN

How do bifocal contact lenses work? Specifically how is the reading part of the lens held in the correct position?Gino Trulli

Terracina, Italy

Last words past and present, plus questions, at www.last-word.com

“Elite athletes may eliminate variation from their diets and regularise their sleep schedules”

“Athletes do not perform according to fixed standards of precision like machine tools”