A positive drugs test looks to have put Matt Calland's rumoured comeback on ice until the end of the year. Reports in the media state that he tested positive for Nandrolone and the RL authorities have slapped him with a ban that runs until December this year.

A favourite of scaremongering tabloid journalists, Nandrolone is an anabolic steroid - and it has recently caused a great deal of controversy after a number of big name athletes have been banned from competition after failing tests for this drug. They include

Linford Christie, British sprinter
Merlene Ottey, Jamaican sprinter
Doug Walker, British sprinter
Mark Richardson, British swimmer
Petr Korda, Czech tennis player
Djamel Bouras, French judo fighter
Spencer Smith, British triathlete
Igor Shalimov, Russian footballer
Christophe Dugarry, French rugby *nion fat-lad

But the fact that so many high profile competitors have tested positive for the same substance in such a short space of time has led to speculation that the testing procedure may be flawed, or inaccurate.

Give us a 'P'!
Even though a drug test may indicate that the subject has apparently taken nandrolone to boost muscle growth and increase strength, this does not necessarily prove that they've cheated.

It is possible that the body may naturally create a form of nandrolone - and research has shown that dietary supplements taken perfectly legally by some athletes are broken down by the body to produce the same substances that are created when nandrolone is broken down.

So what's in it'
Nandrolone - known commercially as Deca-Durabolin - is the pseudonym of a compound called 17b -hydroxy-19-nor-4-andro-sten-3-one. It's a muscle-building chemical which occurs naturally in the human body, but only in tiny quantities. It is very similar in structure to the male hormone testosterone, and has many of the same effects in terms of increasing muscle mass.

However, what is detected in the drug tests is a metabolic by-product of Nandrolone called 19-norandrosterone. This is excreted from the body in urine, making it easy to obtain samples. A limit of 2 ng per ml of urine (a figure set by the International Olympic Committee) is the maximum concentration thought possible to occur in human body by 'natural means' - if this is exceeded the drug test is considered 'positive'.

How did that get there?
Many theories have been put forward to suggest why Nandrolone is sometimes present in much higher concentrations than it should be.

A likely theory has emerged following investigations at Aberdeen University. The findings are that dietary supplements themselves are harmless and produce no increased levels of Nandrolone.

Exercise alone, too, doesn't cause any problems. But a combination of both dietary supplements (none of which contain a banned substance) and exercise, can result in a positive Nandrolone test. The reason for this is still unclear, but one theory is that there is a link between the dehydration that comes with heavy training and its effects upon the components of high protein diets.

So, go easy on the Slimfast if you're planning a jog round the block!