I see that official explanations are not published yet, so please let me put my two cents. I'm happy to discuss, if anything is unclear.
(1) Assuming that the information contained within this article is accurate, which of the following claims about VO2 max can be most reasonably made? Quote:
(A) Some individuals have more than twice the VO2 max of an average fit young adult.
That information is supported by the passage.
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. Looks good, let's keep it.
Quote:
(B) It depends primarily on unexplained properties of individual muscle cells.
We don't know what influences VO2 max. It's a trap answer that mixes some wording that was used in the passage. "Individual muscle cells" may play a role in the process of transfering oxygen to muscle tissues, but we don't know if they affect the level of VO2 max.
Quote:
(C) It contributes to the metabolism of lactic acid and phosphagen.
Not supported. We only know that lactic acid and phosphagen processes are the main (almost the only) source of energy in the initial phases of exertion. We can't claim that VO2 max contributes to "metabolism" of these.
Quote:
(D) The mechanism of VO2 max shifts after thirty seconds of activity.
According to the passage, in short duration activities almost all the energy comes from lactic acid or phosphagen processes and the exact method of energy production (lactic acid process or phosphagen process) shifts after approximately thirty seconds of activity. This answer choice confuses VO2 max with lacid acid and phosphagen.
Quote:
(E) It can be increased by up to 17% through a focused training program.
The passage states that the average VO2-max-centered training program improves it by 17%, but we can't say that we 17% is the upper limit, since we know that
some training efforts in this area are highly variable, with studies showing negligible improvement in some participants but a doubling of VO2 max in others. So, basing on the passage, the claim stated in answer choice (A) is true and hence it is our best option.
(2) In the passage, the author's opinion regarding VO2 max could best be characterized by which of the following statements? Quote:
(A) It is a useful indicator of performance for endurance athletes but should be ignored by those with events lasting over thirty seconds.
The first part is OK, but
should be ignored by those with events lasting over thirty seconds. is definitely not author's opinion on VO2 max. We know that for short duration activities VO2 max does not play a major role, but it does for endurance athletes (i.e. long duration activity athletes). So, e.g. cyclists SHOULDN'T ignore it since it's an important component of their ability. Moreover, even short-duration-athletes shouldn't IGNORE it, since
oxygen uptake primarily affects the length of the recovery period following exertion.
Quote:
(B) It is merely a trendy buzzword in the athletic community.
Not supported. Check first sentence of the first paragraph:
VO2 max is more than merely a trendy buzzword [...].
Quote:
(C) At least some of its popularity may be due to the increasingly scientific orientation of sports training.
Correct answer. Check paragraph 1:
As athletics grows ever more scientific in orientation, measurable indicators of performance grow in importance. Quote:
(D) It is a good indicator of the performance of distance runners, cyclists, and weightlifters.
The last word makes this choice incorrect. VO2 max is a good indicator for endurance athletes such as distance runners and cyclists, but it's not for weightlifters, because weightlifting is a discipline in which time of exertion is relatively short.
Quote:
(E) Eventually its popularity as a performance indicator will be eclipsed by other measures.
The passage states that
the ability to keep muscles supplied with oxygen is currently viewed as the single most effective indicator of ability and that VO2 max is a measurement of this ability, but the author says nothing about its usefulness in the future. (the author doesn't even mention 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?Quote:
(A) During a 400 meter sprint, a top level athlete's primary energy source is some combination of the phosphagen and lactic acid processes.
It's quite tricky and subtle, but that's the correct answer. Because we know that in short duration sports, such as 400m sprint,
almost all energy production relies on the phosphagen or lactic acid processes and that
the exact method of energy production shifts after approximately thirty seconds of activity, we can conclude that during a 45-second sprint, mentioned processes are the main source of energy for athletes. Notice, that the author by stating
almost all energy production relies on the phosphagen OR lactic acid processes doesn't mean that during short exertion ALL the energy comes from one or the other, but if this exertion lasts longer than 30 seconds, its source of energy is a combination of these. See it this way:
|Beginning of the sprint| -> during the first 30 seconds athlete's energy comes from lactic acid processes -> |ENERGY PRODUCTION SHIFT| -> during the last 15 seconds athlete's energy comes from phosphagen processes -> |End of the sprint|
So we can see that during 45-second sprint, the athlete at first uses energy from LC processes and later from P processes. Thus, it's a COMBINATION of different energy sources.
Quote:
(B) VO2 max only plays a role in the final stages of a 400 meter race when run by a top-level sprinter.
In 45-second sprint, VO2 max doesn't play a role at all. We know that it becomes really important when
initial period of exertion is over, energy production shifts to the aerobic process of glycogen metabolism and, eventually, fat metabolism. (see paragraph 3)
Quote:
(C) Fat metabolism plays a significant role in the performance of a top-level sprinter during a 400 meter race.
Similar as in (B). It becomes important after two minutes. (see paragraph 2)
Quote:
(D) VO2 max plays no role in the recovery period at the conclusion of a top-level sprinter's 400 meter race.
Not true, because
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.Quote:
E) No top-level sprinter should consider VO2 max in his or her training.
Training efforts in this area are highly variable, with studies showing negligible improvement in some participants but a doubling of VO2 max in others.
As we see, it depends, but we can't say that top-level sprinters should NOT CONSIDER including it in trainings.
(4) According to the information in this article, which of the following can be inferred about the role of VO2 max in exercise?Quote:
(A) It is entirely unimportant to sprinters.
Not true, because VO2 max
affects the length of the recovery period following exertion.
Quote:
(B) It plays a greater role early in exertion.
Not true, it's exactly the opposite. VO2 max begins to play a greater role when
the initial period of exertion is over.
Quote:
(C) It should not be a part of the training regimen of a professional football player.
Not true, because
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. Quote:
(D) It is the only area of fitness that is scientifically measured.
We can't infer that. The passage states that
as athletics grows ever more scientific in orientation, measurable indicators of performance grow in importance, but we can't infer that it's the ONLY area of fitness that is scientifically measured.
Quote:
(E) It is a strong indicator of performance for endurance athletes.
Correct. See paragraph 1:
For the endurance athlete, the ability to keep muscles supplied with oxygen is currently viewed as the single most effective indicator of ability. And, as we know, VO2 max is a measurement related to the ability to keep muscles supplied with oxygen. If it's the single MOST EFFECTIVE indicator for endurance athletes, we can safely infer that "it is a strong indicator of performance".
Uff, I think that's all. Hope it helps!