The comfortably off, white and middle-aged are the most likely to participate in sporting activities, a new study suggests.
Furthermore, the gap between rich and poor and black and white appears to have widened, rather than narrowed in a decade, as overall participation in sports has actually increased, the research suggests.
The findings are based on data from several of the annual Health Surveys for England between 1997 and 2006. These draw on a nationally representative sample of households.
The entire sample comprised 61,000 adults, just under half of whom (27,217) were men.
In 2006, men were around 10% more likely, and women around 20% more likely, to participate regularly in sports compared with the figures for 1997. This suggests that the perception of a much talked about overall decline in sporting activities may be "oversimplistic", say the authors.
The increase is mainly attributable to gym and fitness activities, with both sexes around 20% more likely to participate in them than they were in 1997. The proportion of regular female runners/joggers also doubled to 4% over the decade.
But the increases in sports participation was largely restricted to middle-aged and older people, with clear increasing trends seen among both sexes over the age of 45 upwards, and among 30-44-year-old women.
And the proportion of younger men under 30 taking part in cycling, dancing and racquet sports fell sharply.
Excess weight was a deterrent for both sexes, while higher household income, car ownership, higher social class, and general good health were positively associated with taking part in sports.
Ethnicity was also an issue, with fewer participants from black or Asian backgrounds.
The authors conclude that the decline in sporting activity among younger people is a cause for concern.
"Another cause for concern is that there are no signs that the gap between high and low socioeconomic groups and white and nonwhite ethnic groups is narrowing," they add.