If exercise really has no effect on heart rate, as stated in the null hypothesis, these two groups really have about the same pulse rates, and there should be no tendency for the lower ranks to fall in one group or the other;
(exercise; really has; no effect on heart rate) (these two groups; really have; about the same pulse rates) (the lower ranks; to fall; L:in one group or the other)
exercise these two groups the lower ranks
really has really have to fall
no effect on heart rate
about the same pulse rates
L:in one group or the other