Question 29·Medium·Command of Evidence
Exercise physiologist Nia Rao and colleagues studied whether six weeks of altitude training would improve athletes’ ability to carry oxygen in the blood and their short, all-out sprint performance. The researchers measured participants’ hemoglobin levels (a component of red blood cells) and their average power during a 30-second cycling sprint at multiple points during training. They concluded that altitude training increased hemoglobin levels but did not improve sprint performance.
Which choice best describes data from the graph that support Rao and colleagues’ conclusion?
For command-of-evidence questions tied to a graph, restate the claim in your own words as a specific pattern you should see (for example, “A goes up while B does not”). Then verify that pattern by comparing the most relevant points—often the beginning and end of the study—and choose the option that accurately reports those data without adding extra conclusions or focusing on only a small part of the graph.
Hints
Focus on the researchers’ claim
The conclusion compares two outcomes: hemoglobin levels and sprint power. You need a choice that addresses both.
Compare the start and end points
Look at week 0 versus week 6 for each line. Decide whether each measure increased, decreased, or stayed roughly the same.
Prefer overall trends over a single spike
A choice that focuses only on an early week may not support a conclusion about the full six-week training period.
Step-by-step Explanation
Identify what the conclusion predicts
Rao and colleagues claim hemoglobin increases with altitude training, but sprint power does not improve.
Check the overall change from week 0 to week 6
From the graph, hemoglobin goes up from about 100% at week 0 to about 112% at week 6. Sprint power stays near baseline but ends lower, at about 98% at week 6.
Match the option that states both trends
The choice that describes hemoglobin increasing while sprint power fails to increase (and slightly decreases) is: Hemoglobin increased from about 100% at week 0 to about 112% at week 6, while sprint power decreased from about 100% to about 98% over the same period.