Summary of “How Long Should You Workout”

Now, new research shows that not only can the right kind of resistance training put more power in your pedals, but also you can start gaining strength in less time than it takes to set up a pair of tubeless tires-just 13 minutes a session, according to the study in Medicine & Science in Sports & Exercise.
In the study, researchers at CUNY Lehman College in the Bronx and other institutions set out to determine the impact various set and repetition combinations would have on muscle strength, endurance, and hypertrophy, or how big their muscles grew.
One group performed five sets of each exercise, with about 90 seconds of rest between sets-a high volume approach that had them in the gym for over an hour.
The second, medium-volume group performed three sets of each exercise, which took about 40 minutes to complete.
Finally, a low-volume group performed just one set of each exercise, getting them in and out of the gym in just 13 minutes.
Each group performed their assigned workout three times per week for eight weeks.
Surprisingly, there were no significant difference among the groups in strength and endurance gains: The quick-hit lifters enjoyed the same improvements as those who were in the gym five times as long.
In short, the more sets the men lifted, the bigger their muscles got.

The orginal article.