Video Explanation

Text Explanation

Premise #1 – A > B (VO2 max) after moderate aerobic activity.

Conclusion: Runners will begin identical intensive training, A will continue to have greater V02 max.

Assumption: The effects of intensive training on the two runners are equivalent to the effects of moderate aerobic training.

(A) is irrelevant to the argument. The first set of sessions in the experiment was performed to establish a baseline for the two runners:  A had a greater max VO2 than B.  The conclusion then is about what happens AFTER the end of that first round of sessions. Thus, the VO2 maxes before the experiment even started aren't an issue.

(B), if it is not true, represents a possible flaw in the conclusion. Say Runner A responds to intensive training differently than Runner B, then it is possible that Runner A will NOT have a greater VO2 max than runner B.

(C) just quantifies what is meant by intensive training. It doesn’t relate to the argument as a whole.

(D) is tempting but remember the argument says that “both will train with similar intensity” and will engage in “identical intensive training”.

(E) is somewhat of a weakener. That is, it points to the possibility that the VO2 max fluctuated throughout the experiment and Runner A just happened to have the higher VO2 max at the very end of training.

An assumption, however, doesn’t weaken the conclusion, but is the very foundation upon which the conclusion rests. That’s why we negate assumptions. In other words, if I pull the foundation out from under the house and that house still stands, then the original assumption was not one that supported the conclusion. However, if I negate the assumption and the conclusion then totally falls apart, we know the original assumption is one upon which the argument depends.

By negating (E), “Runner A always had the greater VO2 max…”, we actually strengthen the conclusion. Therefore, (E) is not the answer.