VO2 max is more than merely a trendy buzzword for workout aficionados to bandy about. As athletics grows ever more scientific in orientation, measurable indicators of performance grow in importance. For the endurance athlete, the ability to keep muscles supplied with oxygen is currently viewed as the single most effective indicator of ability. This measurement, VO2 max, can range from 40 ml/kg/min for an average fit young adult to in excess of 90 ml/kg/min for a cardiovascular superstar like Lance Armstrong.

For sprinters, on the other hand, oxygen replenishment is a peripheral concern since the short duration of the activity ensures that almost all energy production relies on the phosphagen or lactic acid processes. While the exact method of energy production shifts after approximately thirty seconds of activity, this general rule holds true for any athlete where the period of exertion is less than approximately two minutes. Short distance runners and swimmers, weight lifters, and those participating in team sports where individual effort varies over time are all examples of athletes for whom oxygen uptake primarily affects the length of the recovery period following exertion. In these cases a training program centered on VO2 max may not provide optimum results.

Once this initial period of exertion is over, however, energy production shifts to the aerobic process of glycogen metabolism and, eventually, fat metabolism. It is at this point that the ability of the body to supply muscle tissue with oxygen, as measured by VO2 max, becomes a key component. Training efforts in this area are highly variable, with studies showing negligible improvement in some participants but a doubling of VO2 max in others. The average VO2-max-centered training program sees approximately 17% improvement in measured capacity. The detailed mechanism that is at work in the transfer of oxygen to muscle tissue remains poorly understood. Lung capacity, circulatory capacity, blood chemistry, and as yet unknown characteristics of individual muscle cells may all play a role.

(1) Assuming that the information contained within this article is accurate, which of the following claims about VO2 max can be most reasonably made?

(A) Some individuals have more than twice the VO2 max of an average fit young adult.
(B) It depends primarily on unexplained properties of individual muscle cells.
(C) It contributes to the metabolism of lactic acid and phosphagen.
(D) The mechanism of VO2 max shifts after thirty seconds of activity.
(E) It can be increased by up to 17% through a focused training program.




(2) In the passage, the author's opinion regarding VO2 max could best be characterized by which of the following statements?

(A) It is a useful indicator of performance for endurance athletes but should be ignored by those with events lasting over thirty seconds.
(B) It is merely a trendy buzzword in the athletic community.
(C) At least some of its popularity may be due to the increasingly scientific orientation of sports training.
(D) It is a good indicator of the performance of distance runners, cyclists, and weightlifters.
(E) Eventually its popularity as a performance indicator will be eclipsed by other measures.




(3) A top-level sprinter can run 400 meters in approximately 45 seconds. Based on this information and that contained within the article, assuming that it is correct, which of the following claims can be most reasonably made?

(A) During a 400 meter sprint, a top level athlete's primary energy source is some combination of the phosphagen and lactic acid processes.
(B) VO2 max only plays a role in the final stages of a 400 meter race when run by a top-level sprinter.
(C) Fat metabolism plays a significant role in the performance of a top-level sprinter during a 400 meter race.
(D) VO2 max plays no role in the recovery period at the conclusion of a top-level sprinter's 400 meter race.
(E) No top-level sprinter should consider VO2 max in his or her training.




(4) According to the information in this article, which of the following can be inferred about the role of VO2 max in exercise?

(A) It is entirely unimportant to sprinters.
(B) It plays a greater role early in exertion.
(C) It should not be a part of the training regimen of a professional football player.
(D) It is the only area of fitness that is scientifically measured.
(E) It is a strong indicator of performance for endurance athletes.