Trainees often are told to use a full range of motion, especially to get a deep stretch, without understanding why.
Growth does not just occur from overload, which is best described as using more weight over time, but from overstretch too.
Overstretch occurs when a muscle works at long lengths, even more so during eccentric or lowering contractions. This stimulates hypertrophy by adding sarcomeres in-series to reposition the optimal length of the muscle. This allows it to better contract in otherwise weak positions.
The key to stretching a muscle is to lengthen it at more than one attachment, or to reverse more than one of its functions.
You can stretch the pectoralis major through horizontal abduction and external rotation. Enough horizontal abduction, as occurs at the bottom of a dumbbell fly with your elbows behind you, combines with external rotation, by using a neutral grip and keeping the wrists outside the elbows. This combination will elongate all the fibers of the chest.
If you want to focus on the lower part, you allow more shoulder flexion through a decline bench at a slight angle or by raising the elbows up as you descend. To emphasize the upper chest, you extend the shoulders by using an incline bench or keeping the elbows down as you lower the dumbbells.
The chest is straightforward to stretch.
Some muscles though require you to think beyond the usual exercises to really lengthen them. This is where cross-body exercises, done one limb at a time, are invaluable.
Imagination is more important than knowledge.
– Albert Einstein
- Side Lying Lateral Raise
This is not the more popular version that has the dumbbell travel across your body while perpendicular to it.
Instead, you have the dumbbell pass over your body from behind, with the arm parallel at midpoint. Keep the dumbbell close to your body while slightly dipping the front bell to lower as deeply as possible.
This allows adduction to occur, which stretches the lateral head of the deltoid, reversing its function. This increases passive tension, leading to the unique form of longitudinal growth mentioned earlier.
Due to its shorter sarcomere lengths though, the deltoid may have less capacity for this form of growth versus other muscles more easily stretched. This likely still happens, just to a smaller extent.
Even with less passive tension versus other muscles, the deltoid actually has its strongest length with the arm at the side. The fibers are at resting length and generate the most active tension. We know this active tension stimulates growth via overload by adding sarcomeres in-parallel.
The dumbbell is furthest away from your shoulder in this position, aligning the parabolic strength curve of the side lying lateral raise exactly where the fibers work strongest.
A disadvantage is that the deltoid has a less than ideal internal moment arm length during this exercise, so it does less work than during a normal lateral raise. The compromise may be to use a slight incline of about 15°.
Another solution is to include both the side lying lateral raise and a conventional upright row or lateral raise, creating both active and passive tension along with performing work.
- Side Lying Rear Raise
This exercise, unlike the previous, has the dumbbell travel perpendicular to your body. You lie on your side while having the dumbbell cross your body around the midpoint, achieving a stretch at the bottom.
For an even deeper stretch, you can try this lying on your back or standing while facing away from the pulley on a cable machine. Move the dumbbell or attachment at about the lower chest-upper ribcage area. This means less continuous tension but a better stretch.
This exercise maximizes transverse adduction or horizontal flexion. It pulls on not only the rear deltoid but the infraspinatus and teres minor muscles that partially form the rotator cuff complex. From a bodybuilding perspective, developing these muscles etches fine detail into the outside of the upper back.
The arm about 90° to the body during the motion will evenly stretch out all three muscles. For emphasis, you can raise the dumbbell above your shoulder to target the rear deltoid, bringing in its shoulder extension function. You can also go below to emphasize internal rotation, which focuses on the infraspinatus and teres minor.
- Cross-Body Overhand Cable Curl
This allows you to combine elbow flexion while pronating the wrist for a maximal stretch of the brachioradialis, the large elbow flexor within the forearm. This will lower EMG signals yet stimulate it to grow via passive tension. A neutral grip works better for active tension.
A cable machine will work better than a dumbbell, which can impede the movement by hitting your torso.
This exercise works even better than a cambered bar reverse curl.
- Single-Arm Kneeling Cable Pull-Down
The latissimus dorsi is difficult to stretch with the default exercises. Pull-ups or pull-downs and rows, while generating active tension for the lats, fail to lengthen them much. These exercises tend to stretch the teres major and trapezius respectively.
Since the lats attach to the lower back along with the shoulder, they get further stretched through trunk flexion and rotation.
By performing a single-arm pulldown while kneeling, you can twist toward the pulley. This combines shoulder abduction and flexion while rotating away from the active lat at the waist, for the ultimate deep stretch.
Cross-Body Exercises to Overstretch Muscles
Due to high passive tension at long muscle lengths, you will notice delayed onset muscle soreness with these exercises, at least at first. Nonetheless, you will adapt to reap muscle-building rewards from the overstretch.
Though a lot of research has shown similar growth between positive and negative reps, high and low reps, and different workouts when equated for volume, an important point is usually missed.
Growth in all these circumstances appear to occur through different means. Each represent different potentials for muscle size. You have cross-sectional vs. longitudinal growth, sarcoplasmic vs. myofibrillar hypertrophy, and slow-twitch vs. fast-twitch fiber development.
It seems sensible, as a natural bodybuilder, to address all possibilities for larger muscles.
Try cross-body exercises to overstretch the muscles, maximizing a unique form of growth possible via passive tension.