doctorSpoc said:advice... never use videos like those on rollers.
you'd be surprised how engrained your instinct is to turn around corners is.. i've been watching TdF mountain stages and ridden right off my rollers trying to follow the pack around some of those curvy decents.. and i just couldn't stop my self from doing either... ended up having to look away every time a curve came up.
Cartoon on page 20 of the latest VeloNews (28 January, with Slipstream on the cover):
A guy with his arm in a sling is standing over a guy rebuilding a wheel. The caption says: "If you have to get injured, this is the time of year you want." The guy with his arm in a sling says, "On the downside, everybody knows you did it leaning into a curve watching a Giro DVD on rollers." 😄