Sixty volunteers (志愿者) were alphabetically (按照字母顺序地)
divided into two equal groups, Group A to take part in a seven-week exercise
program, and Group B to avoid (避免) deliberate (刻意的；有意的) exercise of any sort. On
the day before the exercise program began, all 60 men took part in a step-test.
This included stepping up and down on a 15-inch bench at 40 steps per minute for
5 minutes. One minute later, the pulse rate (脉搏速度) of each subject was taken and
recorded. This served as the pretest for the experiment. For the next 7 weeks,
subjects in the experimental group (Group A) rode an exercycle (a motor-driven
bicycle-type exercise machine) for 20 minutes each day. The exercise schedule
(日程表) called for riders to ride a relaxed (放松的) way during the first day’s fide,
only holding on to the handle bars and foot pedals (脚踏板) as the machine moved.
Then, for the next 3 days, they rode a relaxed way for 50 seconds of each
minute, and pushed, pulled, and pedaled actively for 10 seconds of each minute.
The ratio (比率) of active riding was increased every few days, by the seventh
week the riders were performing 20 solid (连续的) minutes of active
riding. At the end of the seven weeks, the step-test was again
given to all the subjects, and their pulses taken. The post-exercise pulse rates
of subjects in the experimental group were found to have decreased an average of
30 heart beats per minute, with the lowest decrease 29 and the highest decrease
45. The pulse rates of subjects in the control group remained the same or
changed by no more than 4 beats, with an average difference between the
beginning and final tests of zero. What might the author continue to talk about after this passage
A. Another experiment.
B. Effects of doing exercises on human being.
C. The disadvantages of riding a bicycle.
D. The feeling of each subject of the experiment.