Q & A: Squaring the centre circle . . . and points round the clock

With a pair of old-style wooden tennis rackets it was possible to check that the net was the right height. In the age of the wide-bodied racket, is there a quick and easy way of doing it?

At least one tennis racket manufacturer - Wilson - now produces a racket cover with a short piece of tape attached to it for net-measuring purposes. - Andrew Weale, Moseley, Birmingham.

What purpose does the centre circle serve in football?

At a kick-off, both teams must be stationed on their respective sides of the halfway line. But a kick-off is also, in effect, a free-kick and opposing players must be at least 10 yards away from the ball, so the centre circle is drawn at a radius of 10 yards from the centre spot. - Chiz Szymanski, London E10.

The laws of football require that when one team kicks off, the opposing players are a regulation distance from the ball. By not allowing players inside the circle you can be sure that they will all be the appropriate distance away. - Tim Humphrey, Saldean, East Sussex.

The area of the centre circle, pi x 10 yards squared, has been calculated as the ideal size to accommodate two teams of players and their water bottles during a penalty shoot-out. - Colin Swash, London SE10.

Why do so many English football supporters wave the Union Flag instead of the Flag of St George?

The red cross on the Union Flag is wider than the St George's red cross, which means that when a fan writes the name of his/her team on the horizontal bar of the cross it can be seen more easily. It is now possible to buy a St George's flag with a wider cross, but it is not as easily available as the Union Flag. - Tom Gough, no address given.

As an England fan I held the same view. However, on travelling to Sweden v England in Stockholm I set out to test my perception. Five minutes prior to kick-pff I counted the flags in the main stand - 16 were the Union Jack and 33 the George Cross. - Paul Johnston, Stillington, North Yorkshire.

What is the origin of the scoring system in tennis?

The basic scoring system of tennis is based on the clock face and was so represented in early Real Tennis courts in France in the 16th and 17th centuries, with the points marked off on the quarters thus: 15, 30 and 45 (later simplified to 40). Two specific elements of scoring relate to the French origins of the sport. 'Deuce' dereives from the French deux a gagner (two to win). 'Love' is an image deriving from l'oeuf (egg). Most sporting vocabulary is basically English, deformed to varying degrees. Tennis provides a refreshing exception. - Richard Waller, Birkenhead, Merseyside.

Which sport is the most physically arduous?

This question, like so many others, has no definitive answer but relies upon the exact definition of 'arduous'. I can see four areas of sport that would qualify. The first is contact sport with rugby league the winner ahead of boxing in this category. The second is that of marathon or, more precisely, ultra-marathon events. The Tour de France or the Race Across America, whilst being very different events, are in competition for the premier place in this category. Thirdly, there are the 'battle against the elements' events such as the Iditarod. I would put round-the-world single-handed yacht races top of this list. The last category comprises sports that require all the elements in each area that make up fitness - cardio-vascular fitness, muscular endurance, strength and flexibility. In this area I would place rowing as the most arduous as it requires all the stated elements in large quantities and uses all the major muscles simultaneously. - Edward Fryer, London SW11.

If Charles Blake wishes to tune in to Channel 4's coverage of the Tour de France over the coming three weeks, I think he will have his answer. - Julian Barkway, Wilmslow, Cheshire.

The Basque game Pelota, which is to be a demonstration sport at the Barcelona Olympics. The very speed of it] - Jean Kiers-Stubbington, Geldermalsen, Netherlands.

Why do some right-arm bowlers bat left-handed, and some left-arm bowlers bat right-handed?

Like my father and my son, I am left- handed. When I was a little boy, some well-meaning person (who had not noticed I was left-handed) taught me how to hold and swing a cricket bat: right- handed, of course. By the time, many years later, I realised this did not suit me, it was too late to make such a drastic change. As for bowling, I naturally threw left-handed and, by the time I began to bowl properly, I naturally did it with my throwing arm. - Bill Canham, no address given.

The term right-handed or left- handed batsman is a misnomer. I am right-handed, but bat left-handed because my right hand takes the dominant role at the top of the bat handle controlling direction, angle and, above all, swing. The left hand merely provides punch. A right-handed batsman feels more comfortable with his dominant right hand at the bottom of the handle doing most of the work.

It is a shame that the term is used at all as batsmen sometimes feel they should take up the batting stance which describes their dominant hand. However, my right-handed brother-in-law, aged around 40, finally decided to try batting left-handed and in one season he doubled his average. - Grahame Dixie, Blandford Forum, Dorset.

ANSWERS PLEASE

Have any of the officials who wander around the infield at athletics meetings with such apparent nonchalance ever meet a sticky end at the point of a javelin? - Mr G Wood, London NW1

Why is a shot over the boundary in cricket worth six runs and not eight? - Kevin Maguire, Batley, West Yorkshire.

What is the thinking behind the use of nightwatchmen in cricket? - Charles Carlisle, London N10

What is the origin of darts and how long has the board been laid out as it is today? Is the number distribution an optimum arrangement suiting both right and left-handed throwers? - Mr J H Penny, Coventry.

If an 'amateur' is a person who cultivates his/her sport for love and not money, why are the athletics governing bodies called the 'International Amateur Athletics Federation' and 'Amateur Athletic Association' when some of their members obviously earn a healthy living from the sport? - Paul Weston, Southsea, Hampshire.

If the football kit of national teams reflects the colours of their countries' flags, why are England's shorts navy blue? - Geoffrey Loe, Dunstable, Beds.

Have the batsmen's scores in an innings ever conformed to their positions in the order with No. 1 scoring the most, No. 2 the next highest down to No. 11 the least? - James Nicholson, Leeds.

Why are the English and Scottish FA Cup finals played simultaneously so that no-one can enjoy them both live? - Tim Jupp, St Andrews, Fife.

What is the origin of the tiddlywinks term 'nurdled'? - Julian Wiseman, London SW9.

In the second Test at Lord's, England fielded a side which consisted of 11 players all from different counties. Has this ever happened before? - Peter Wanless, London N8.

Given that he is a two-handed player who times his shots impeccably, hits the ball extremely hard and manages to combine accuracy with keeping the ball low, would Andre Agassi not make an extremely useful middle-order batsman? - Philip Moore, London SW20.