The “Ironman” is a version of the triathlon, a race that includes three events: swimming,
bicycling, and running. In an Ironman, an athlete must swim 2.4 miles, bike 112 miles,
and run 26.2 miles, in that order, without a break. The annual Ironman World
Championship is held in Hawaii every year. The men’s course record was set in 2011 by
Australia’s Craig Alexander with a time of 8 hours, 18 minutes, and 37 seconds, and the
women’s course record was set in 2009 by England’s Chrissie Wellington with a time of
8 hours, 54 minutes, and 2 seconds.
What type of muscle fibers would likely be found in the legs of athletes who attempt to
complete this race?
A) fast, fatigue-resistant fibers
B) fast, fatigue-susceptible fibers
C) slow, fatigue-resistant fibers
D) slow, fatigue-susceptible fibers
Oxytocin is a hormone produced by the posterior pituitary gland that causes female
uterine muscles to contract during childbirth and female mammary glands to eject milk
during nursing. Oxytocin also occurs naturally in males and is involved in movement of
sperm and production of testosterone. It has been given the common name of “the love
hormone” because oxytocin is linked to human behaviors including sexual arousal and
trust.
In 2012, The Atlantic (a popular news source) published a brief online news summary
that explained that when scientists in Germany gave men who were in a monogamous
relationship with a woman a nasal spray containing oxytocin, the men were less
attracted to an attractive female stranger than men who were given a nasal spray with
no oxytocin. While The Atlantic provided a link to the original scientific study, they
drew conclusions and stated implications of it that included the following: