First, where is the bar chart? You need to attach it ! You can do it here itself... use the "Attach file(s) " feature.
The bar chart provides male and female fitness membership between the period 1970 and 2000.
[i]The bar chart provides the statistics of fitness levels of the male and female membership during the period of 1970 to 2000.[/i]
The male memberships zigzagged...
All these detailed information should be put in one paragraph. Last paragraph should give an overall conclusion about the graphical presentation.