We almost never walk sideways over long distances, preferring to face forward. Researchers at Ohio State University have given this issue a lot of thought, and have found that sideways walking costs us a lot of energy, but when we do it, we do it well.
Their study showed that, per unit distance, a sideways gait could be three times as expensive energetically as walking forward. "We think this is mostly because sideways walking involves a lot of stopping and starting: you slow down almost to a stop when you bring the two feet together and then you have to increase your speed back up again," says Manoj Srinivasan, who, with Matthew L Handford, wrote the study in Biology Letters. "Normal walking involves much less acceleration and deceleration, and does not waste forward momentum as much."
Yet when 10 volunteers were asked to walk sideways, they tended to walk at or near an optimal rate. “Even with almost no practice, when they were asked to pick a speed that felt comfortable, they picked a speed that had close to the minimum possible energy consumption within the constraints of sideways walking,” says Handford.
And take note, Garth Brooks fans: moving sideways in line-dancing torches calories too. "Moving sideways during a line dance would cost you two to three times more energy than walking the same distance normally," says Srinivasan.
