The latest research says it doesn’t matter.
For years, trainers, coaches, athletes and those who work out, have debated the merits of splitting weight training and cardio training, with proponents in each camp giving reasons why doing so has its benefits.
So researchers from Karolinska Institute in Sweden and McMaster University in Canada recruited volunteers to test the idea that there is more physiological benefit from performing only one type of exercise on any given day.
The two groups of scientists studied a variety of people with varying backgrounds. The Swedish research used active healthy young men who regularly worked out but were not competitive athletes. The Canadian volunteers were sedentary, middle-aged men who performed little to no exercise within the past year.
The Swedish volunteers performed exercise by pedaling a stationary bicycle for 45 minutes, using only one leg that would represent the aerobic component of the experiment. Six hours later, they performed a series of strenuous leg extension exercises using both legs. The scientists took muscle biopsies before and after each session.
The Canadian researchers had their volunteers finish three different workouts. For the first workout, the men rode a stationary bicycle for 40 minutes at a moderate pace. For the second workout, the same volunteers performed eight strenuous sets of leg extension exercises. In the third workout, the men completed four sets of leg extensions and then rode the bicycle for 20 minutes, finishing half as much of each type of exercise, but in rapid succession.
“Our hypothesis had been that we would see a greater response to each exercise individually,” says Stuart Phillips, a professor of kinesiology at McMaster who oversaw the Canadian study.
Specifically, he says, the scientists had expected that endurance training on its own would significantly affect portions of the muscle cell related to energy production, while resistance training would increase protein synthesis within muscles, the first step toward enlarging the muscles. Combined training, the Canadian scientists had hypothesized, would dampen at least one of the molecular changes; physiologically, one of the responses would predominate and interfere with the other.
That didn’t happen.
Instead, after combined training, the men’smuscles displayed the same amount of change within both cellular pathways as after either type of exercise on its own, even though the men had actually completed only half as muc h of each.
In other words, “aerobic exercise can precede resistance exercise on the same day without compromising” muscle building was the consensus of the scientists.
What is interesting to note – especially for those that prefer weights before cardio – is that the Canadian study’s participants performed their resistance work before the bike riding and it didn’t affect the results for either type of exercise.
“It appears that you can set up a workout regimen that happens to be convenient for you,” in terms of how and when you shuffle the endurance and resistance elements, says Dr. Phillips, “and you’re not going to get less training response.”
The studies were published in The Journal of Applied Physiology and Medicine & Science in Sports & Exercise.