Stretching is only for improving flexibility, right? Ever since elementary school gym class, it's been ingrained in your head that stretching is to help make your muscles longer.
And this is true. Static stretching—the technical term for when you hold a stretch—improves a muscle's ability to lengthen. This is the intention behind the design of stretching exercises, and how they are typically used in a workout.
Side note: Static stretches should be done at the end of a workout, not during your warm-up.
However, according to new research by Dr. Jacob Wilson and his team at the University of Tampa, it appears that static stretching during the rest period of a strength exercise has the capability to cause serious muscle growth. You read that right: Stretching can increase muscle size.
You might be dubious, and that's OK. Stretching and strength training—the typical means of gaining muscle mass—appear to be opposing methods. But when they are combined together, you can get some impressive results.
"Some say static stretching is dead, and I partially agree," says John Rusin in his Functional Hypertrophy Training Program. "Sure, static stretching before a big training day is less than ideal, but there are still some serious gains to be had out of static stretching—that is if you know when and how to strategically implement it."
The concept is simple. You strengthen a muscle group as you normally would, then hold a stretched position immediately afterward instead of resting between sets.
"The premise here is to challenge the muscles under loading in a set, and go directly into stretching those muscles deeply while they are full of blood and tightened by the set that was just completed," explains Rusin.
It's extremely challenging and will make your muscles absolutely scream. But Rusin says it's well worth it. You can increase muscle size while also decreasing the amount of time you need to stretch, because you are working on flexibility and mobility in the middle of a strength exercise.
Although the technique is highly efficient and effective, you should limit intra-set stretching to one or two exercises per workout Why? Because it induces fatigue and causes lots of muscle damage.
You can use the technique with almost any strength exercise. Here are two examples from Rusin of intra-set stretching exercise pairs.
Heels-Elevated Front Squat + Standing Quad Stretch
Rusin's Coaching Notes: To engage the quads more deeply in this movement, place a 2x4 or a 5-pound plate under your heels. Make your reps slow and controlled, reaching a little below parallel and coming all the way back up between reps. When you get to the top, drop back down into your next rep with complete control. These should burn a little. Directly after you complete your final rep on the Front Squat, stretch your quads one at a time for 30 seconds during your rest period. Start with your tighter side, then move to the other leg.
Sets/Reps: 4x12 + 30-second Quad Stretch each side
Wide-Grip Pull Up + Loaded Stretch
Rusin's Coaching Notes: Grab the pull-up bar with a wider-than-shoulder-width grip. You will be ramping up with full range of motion sets of 3 reps, then 5 reps, to keep vertical pulling fatigue to a minimum. Once you get into your working sets, perform as many reps as possible per set with a strict 60-second rest period to accumulate metabolic stress. If you can't get eight picture-perfect Pull-Ups, use banded assistance around the knees to get your numbers into the strength and hypertrophy ranges. On the last rep of each working set, hang onto the bar and let your lats stretch under your body weight, loading for 10 full seconds. Don't just let go and hang out on the ligaments—keep good position of the shoulders throughout to ensure targeting a muscular stretch.
Sets/Reps: 4xmax (minimum of 8) + 10-second Loaded Stretch + 50-second rest
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