When it comes to sports, there are physiological factors that ensure sexual equality is not possible
UNTIL THE recent past it was common practice for young girls to be discouraged from participating in vigorous physical exercise, while boys openly engaged in a wide range of physical endeavours and sports. This was based on the misplaced notion that girls were somehow "weaker" and unsuited to rigours of strenuous physical activity and sports participation.
Whereas in the past many women would have avoided engaging in vigorous training for fear of social stigma, causing injury or doing permanent damage themselves, it is now becoming increasingly clear that females can benefit from the regular training in much the same way as males.
It is hard to believe that, prior to the 1960s, women were prevented from running any race longer than 800m and were only allowed to officially participate in the marathon from 1970. Fortunately, in more recent times, attitudes have changed and opportunities for girls and women to participate in a variety of recreational and sporting activities have improved noticeably - with a dramatic outcome.
There has been a marked rise in women engaging in recreational physical activity and those taking part in competitive sport has risen exponentially. Ladies' Gaelic football, for example, is one of the fastest-growing sports in Ireland and only last weekend more than 40,000 women took part in the Women's Mini Marathon.
From an elite sport perspective, over the past couple of decades there has been a narrowing of the gap between the performance differences of men and women, which are now typically, for many sports and events,
6-13 per cent or less, although the gender gap in strength-based events is usually wider at 25-30 per cent.
In 2003, competing in the London marathon, Paula Radcliffe posted a world record time of two hours, 15 minutes and 25 seconds, which would have been fast enough for a top 12 placing in the men's event at the 2004 Athens Olympics!
So why do these differences exist, and will the performance gap between men and women ever be fully closed? To answer this we need to examine the key factors that influence athletic performance and, in particular, at basic physiological differences between the sexes.
Prior to puberty, overall body size and composition are similar for boys and girls. During adolescence, predominantly associated with hormonal influences of testosterone in boys and oestrogen in girls, body composition changes markedly with females laying down more fat and males more muscle mass.
In response to training, both men and women may experience reductions in both body weight and body fat percentage. The magnitude of these changes appears to be similar for both sexes and appears to be related to total energy expenditure during training.
Despite this, females will generally have higher body fat levels and a lower muscle mass than a male of a similar training status. For most women there is a need to balance the requirement for a minimum level of body fat for normal physiological and reproductive function with excessive levels and the associated impact of overweight and obesity on everyday health.
Being generally shorter, lighter and possessing a smaller muscle mass, females will usually have a lower absolute strength which is generally about two-thirds the strength of males.
When expressed relative to body weight, lower body strength of both sexes is usually quite similar, however upper body strength is still somewhat less due to males having a larger proportion of their muscle mass in the upper extremities.
Nevertheless, both men and women can experience similar improvements in strength gains as a result of resistance training which is usually in the region of about 0-20 per cent.
In terms of cardiovascular endurance fitness, which is usually determined by the maximum amount of oxygen that can be consumed by the body during exercise (also referenced to as VO2 max), in absolute terms men typically have a 40 per cent higher VO2 max.
This figure falls to a differential of about 20 per cent when expressed relative to body size. Similar to strength, gains in aerobic fitness in response to training do not appear to be gender-specific, with both males and females experiencing similar increases in VO2 max, typically in the region of about 20 per cent.
Although many questions relating to gender-specific adaptations to training are still to be evaluated, the current body of research suggests there is no scientific basis for restricting the participation of any healthy female athlete from any endurance-, strength- or power-based sports. It appears that many of the physiological adaptations in response to a period of training are very similar for both sexes. This is probably unsurprising when you consider that, although the human body is a complex biological system, many of the physiological, cellular and biochemical mechanisms that regulate our responses to exercise are essentially similar for men and women.
Clearly, drawing comparisons between men and women in relation to sports participation and performance is problematical and they are influenced by the interaction of a number of factors, including opportunities, coaching, training techniques and facilities as well as lifestyle and nutrition. Furthermore, for comparative purposes, it is extremely difficult to match males and females for fitness level, training history or performance.
Although few differences exist between the sexes regarding physiological responses to training, it is important that when prescribing exercise programmes, gender issues, as well as the specific needs of the individual, are taken into account.
As a consequence, the question as to whether women will ever fully close the gap and even surpass the performances of men is a controversial and complex one.
Researchers at the University of Wolverhampton have been studying this issue. Based on a thorough analysis of the historical data, and using complex mathematical modelling, they have concluded that for many sports and events, world records are nearing their limits and, therefore, women's performances are unlikely to match or eclipse those of men.
• Dr Giles Warrington is a sport and exercise physiologist and lecturer in the School of Health and Human Performance at Dublin City University