They studied the effects of caffeine on two groups of male exercisers: those who usually consumed little caffeine and those with an average intake of four cups a day.

• 他们研究了咖啡因对两组男性锻炼者的作用：一组是通常很少饮用咖啡的，另一组则是保持着平均每天四杯咖啡的吸收量。