Walking versus elliptical machine, redux

SNIPPETS

How does walking compare with working out on an elliptical machine? This is a perennially popular issue. I answered a similar question last year, but there is more science worth discussing about elliptical training and walking.

As repeated studies show, the two activities differ significantly in terms of how much force is applied to various joints and how many calories each burns. Minute for minute, using an elliptical machine is likely to burn more calories than walking.

According to recent estimates by the Mayo Clinic, a 160-pound person using an elliptical machine for an hour would burn 365 calories. The same person walking for an hour would burn 314 calories. If that person used a stair-stepping machine, he or she would burn 657 calories, by the calculations.

What’s better?
The person on the elliptical machine also would put far less stress on his or her joints during the workout. You generate forces equivalent to about 110 per cent of your body weight with each step while walking, according to a 2014 study, but only about three-quarters of your body weight while using an elliptical machine, making the latter training preferable for people with achy, arthritic knees and hips.

The arm movements associated with using an elliptical machine do not seem to provide much of an upper-body workout, but they do increase the activation of muscles around the hip joints and in the lower back, studies show, which would be useful for people who want stronger midsections.

On the other hand, walking provides a substantially better workout than elliptical machines for the hamstrings, calves and small muscles around the ankles, according to biomechanical studies. These muscles are important for balance and, if strong, reduce the risk of falls as people age.

It is also worth noting that elliptical machines were voted the least enjoyable and most confusing equipment in a 2014 test of gym machines. Overall, the latest research suggests that elliptical machines are a good choice for people with creaky knees and the patience to master the machine’s operations. Others may prefer to walk.


The moon, going through a phase

Recently, on the weather and astronomy page of a newspaper, I saw a “first-quarter moon” depicted as a moon with a vertical slice off the left side. I had always thought of this as a half moon. But if it is a quarter moon, is there such a thing as a half moon?

The thing is the half-illuminated disk of the moon that we see and often refer to informally as a half moon is a quarter of the way along its journey in time from new moon (dark) to crescent moon to full moon (fully illuminated) and back again.

It is also a quarter of the way along the moon’s journey in space as it orbits Earth. For that reason, modern astronomers refer to this phase as the first-quarter moon. They also refer to a later “half moon” phase, seen with the vertical slice off the right side, as the third-quarter moon. The sides are reversed when viewed from the Southern Hemisphere.

“Half moon” was a familiar term to poets like Shakespeare (1564-1619) and to the Dutchmen who called Henry Hudson’s ship the Halve Maen when it sailed into New York Harbor in 1609. But to confuse matters further, such older sources were often referring to the crescent moon, either waxing or waning.

In reality, of course, exactly half the surface of the moon is illuminated by the sun at all times. What waxes and wanes is not the moon itself but the part of the illuminated side that can be seen by observers on Earth, owing to the changing angles formed by the sun, Earth and the moon.