But under scientific scrutiny, none of those beliefs stand up well.
In a representative study published last year in The Journal of Human Kinetics, a group of 36 active adults undertook a strenuous, one-time program of forward lunges while holding barbells, an exercise almost guaranteed to make untrained people extremely sore the next day. Some of the volunteers warmed up beforehand by pedaling a stationary bicycle at a very gentle pace for 20 minutes. Others didn’t warm up but cooled down after the exercise with the same 20 minutes of easy cycling. The rest just lunged, neither warming up nor cooling down.
The next day, all of the volunteers submitted to a pain threshold test, in which their muscles were prodded until they reported discomfort. The volunteers who’d warmed up before exercising had the highest pain threshold, meaning their muscles were relatively pain-free.
Those who’d cooled down, on the other hand, had a much lower pain threshold; their muscles hurt. The cool-down group’s pain threshold was, in fact, the same as among the control group. Cooling down had bought the exercisers nothing in terms of pain relief.
Similarly, in two other studies published last year, one in The Journal of Human Kinetics and the other in The Journal of Strength and Conditioning Research, professional soccer players in Spain underwent a series of physical tests to benchmark their vertical leap, sprinting speed, agility and leg muscle flexibility, and then completed a normal soccer practice. Afterward, some of the players simply stopped exercising and sat quietly on a bench for 20 minutes, while others formally cooled down with 12 minutes of jogging and 8 minutes of stretching. ...
It turned out that there were almost no differences between the two groups of players. ...
The available data “quite strongly suggest a cool-down does not reduce postexercise soreness,” says Rob Herbert, a senior research fellow at Neuroscience Research Australia and senior author of what is probably the foundational study of cooling down, from 2007. In that experiment, healthy adults walked backward downhill on a treadmill for 30 minutes, courting sore muscles and curious stares from fellow gymgoers. Some of the volunteers first walked forward for 10 minutes as a warm-up; others did the same afterward, to cool down. Others didn’t warm up or cool down.
Two days later, the group that had cooled down was every bit as sore as the control group.
--Gretchen Reynolds, NYT, on yet another way to save time on your workout