Bodybuilders are always looking for ways to boost muscle growth by switching or upgrading their strength-training techniques. There’s no shortage of ways to change the stimulus you place on your muscles. For example, you can change the resistance, number of reps, number of sets, lifting tempo, number of exercises, how often you train, or the exercises you do.
Another way to change the stimulus on your muscles and enhance muscle growth is to work your muscles from a stretched position, a technique called loaded stretching. You might wonder whether working your muscles from a stretched position can jumpstart muscle growth and whether it offers additional benefits. Let’s look at what science shows so far.
Loaded Stretching to Build Muscle
Why would training your muscles from a stretched position trigger muscle growth? When you load a muscle and hold it in a stretched position, you emphasize the eccentric portion of a movement since the muscle is resisting a force while in a stretched position. Eccentric contractions apply greater force to a muscle than a concentric contraction. In some cases, that can lead to greater muscle growth.
Let’s use biceps curls to illustrate an eccentric contraction. The portion where you raise the barbell or dumbbells toward your shoulders during a curl is the concentric phase of the exercise. You’re contracting and shortening the muscles. The phase where you lower the weight or weight back down to the starting position is the eccentric phase because you’re lengthening the muscles against resistance. Your muscles are still doing work since you brake to control the movement and keep the weight from dropping too fast.
Studies show that eccentric contractions are more damaging to muscle fibers. Therefore, emphasizing the eccentric phase of a muscle contraction leads to more soreness and, if other conditions are right, greater muscle hypertrophy. There’s another reason eccentric contractions trigger greater muscle growth. Emphasizing the eccentric portion of a movement turns on the mTOR pathway, a major pathway for muscle growth more than focusing on the concentric phase of an exercise.
Some people do eccentric training to boost muscle growth by slowing the eccentric phase of an exercise. They do the concentric phase of the exercise at the normal 1-2 second tempo, but extend the tempo for the eccentric phase to 4 or 5 seconds. Some serious bodybuilders even do super-slow training where they extend the eccentric phase to 10 seconds or longer. The goal of eccentric training is to maximize muscle protein synthesis by turning on mTOR, a signaling pathway that ramps up muscle protein synthesis.
Loaded Stretching Increases Passive Tension
Loaded stretching also stimulates muscle growth. When you stretch a muscle, you create passive tension in the muscle, in contrast to the active tension you create when you contract a muscle. Although active tension may drop off at the point a muscle reaches its maximal stretch, passive tension increases and you still have some active tension in the muscle. The combination of passive tension combined with active tension is most effective at turning on the mTOR pathway, and greater activation of this pathway leads to greater muscle gains.
Another reason loaded stretching boosts muscle hypertrophy has to do with muscle blood flow. If you hold a loaded stretch for 45 seconds or longer, it reduces the amount of oxygen that reaches the muscles and lactate builds up. In turn, the build-up of lactate triggers the release of anabolic hormones, like IGF-1, that boost muscle protein synthesis, and muscle hypertrophy.
What happens when you finally release the contraction and the tension on the muscle? A rush of nutrient and oxygen-filled blood floods the working muscles, supplying them with the nutrients they need for hypertrophy. This phenomenon is called intramuscular hyperhemia and the added influx of nutrients can help your muscles grow. So, it’s easy to see how loaded stretching can help you build muscle.
How to Do It
How do you load a stretched muscle? When you do an exercise, hold the position at the point of maximal stretch. While in this stretched position, contract the muscle and hold it isometrically for as long as you can. When you do this, fatigue will set in quickly and it will feel uncomfortable, but it will place a strong growth stimulus on the muscles you’re working. When you first start, try to hold the loaded stretch for 30 seconds and gradually work up to 45 seconds or longer. Some people progress to holding a loaded stretch for 1 or 2 minutes. Don’t attempt this type of training until you’re comfortable with the movements and can do them with good form.
Other Benefits of Loaded Stretching
Loaded stretching is primarily for maximizing muscle growth, but loading a stretched muscle also benefits your tendons, the thick bands of connective tissue that connect muscle to bone. Studies show loaded stretching increases the thickness of tendons and strengthens them. Since tendons store elastic energy, stronger, thicker tendons can help you become more powerful and explosive. Stronger tendons also reduce the risk of injury. Another perk: Loaded stretching improves mobility too.
The Bottom Line
Now you have another technique that will help you boost muscle growth. Holding a loaded stretch is challenging in the beginning, so you may not be able to hold it for long at first, but you should improve over time if you stick with it. The best time to use this technique is at the end of a workout. Otherwise, the fatigue it creates may interfere with the rest of your training session. Give this method a try! It’ll improve your muscle and joint mobility and may also give your muscles a new stimulus for growth.
References:
- Vogt M, Hoppeler HH. Eccentric exercise: mechanisms and effects when used as training regime or training adjunct. J Appl Physiol. 2014;116(11):1446–1454. doi:10.1152/japplphysiol.00146.2013.
- Int J Sports Phys Ther. 2012 Feb; 7(1): 109–119.
- Front Physiol. 2019; 10: 536. Published online 2019 May 3. doi: 10.3389/fphys.2019.00536.
- Volume 21.Issue 5. October 2006. Pages 362-369.
- com. “Loaded Mobility for Improving and Maintaining Flexibility”
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