You know that strength training is key for crushing your fitness goals, especially if building muscle and definition is the name of your game. But did you know it's the kind of strength training you do that matters? When it comes to how effectively you're actually building muscle strength and mass, your chosen speed is everything, says the Journal of Applied Physiology.
Researchers compared the results of super short explosive exercises compared to more sustained contractions during longer moves. Specifically, one group of healthy young men did isometric knee extensions using short, explosive movements and the same amount of weight (you could compare this to jump squats, high knees, or the explosive moves in this calorie-torching tabata workout). Another group performed the knee extensions using more sustained, slow contractions, progressively upping the torque (much like those grueling leg presses you do with heavier weights). Both groups completed 40 reps of each exercise three times a week for three months.
The researchers found that the short-burst contractions (only about 1 second each) were a much more efficient way to build strength. But if it's mass you're looking for, slow and sustained movements are more effective at building up those fit-girl muscles.
Which training method you use totally depends on your goals. If you're looking to bulk up and create definition, stick with sustained moves like slow and steady squats presses or weighted leg presses. If you're looking to get faster as you train for your next race, throw in some explosive squats and box jumps like these 5 Exercises That Sculpt Strong Legs (and Glutes Too!) Better yet, do a balanced mix of both.