Range of motion is the distance a joint or set of joints may move between the positions of full extension and full flexion. It seems some range of motion is important, but not too much nor too little. A good range of motion differs for each exercise, but you should never include the extreme endpoints for any movement. These endpoints often feel unnatural anyway yet trainees move through them due to poor info that states you always need a full range of motion.
- Tension is best in the middle of any normal exercise.
The length-tension relationship shows that our muscles have an ideal area where they produce the greatest tension. The type of tension that contributes most to growing bigger muscles (active) occurs at the midpoint for any normal movement. An exercise must train a muscle in a range close to this length. Choosing good compound, free weight exercises maximize tension in this range by nature.
- All phases serve a purpose.
Muscle contracts by lifting, lowering, and holding against resistance. Although the negative seems most important for gaining strength, each phase serves a purpose.
- Some studies show strength gains specific to a joint angle or range.
This makes little sense physiologically. The same muscle fibers work regardless of your position throughout the range of motion since they all attach to the same joints. When you pull on one end of an attached rope, can you control which strands tighten up?
Neural factors may explain why this occurs. You become more skilled throughout the range of motion with experience. On some poor exercises with non-uniform motion, there also may be a real difference since the muscles contribute unequally throughout the range of motion. If some muscles operate weakly, other muscles compensate for the deficiency too. For example, when the biceps operate weakly during a pull with an overhand grip, the brachialis and brachioradialis may contract harder to make up the difference. This only happens though by placing the biceps in a weak position instead of bolstering the other elbow flexors. With an underhand grip you could hit them all hard.
This research fails to justify the risks you take by trying to build strength in harmful positions.
- You need a long enough stroke to generate power.
Without enough range of motion, you have too little time to create tension. Use as much range of motion as you need while avoiding any extreme endpoints. You would also lose the benefits associated with the lowering phase and the pre-stretch if you limit the range of motion too much.
Enough range of motion may indirectly prevent someone from using too heavy of a weight for them to control anyway.
- You need enough range of motion for a pre-stretch.
Passive tension allows a pre-stretch or stretch-shorten cycle. A pre-stretch occurs when a muscle stretches followed by a positive movement within a short time. A pre-stretch helps produce force.
- Avoid end feels.
End feels are hard or soft barriers depending on the type of tissue that limits the range of motion. Many push through these end feels despite feeling pain and discomfort. This comes in no small part from the poor advice to use a full range of motion.
Hard refers to muscle, ligaments, or other connective tissue that limit movement. Soft refers to the contact of adjacent parts such as the arm smashed against the forearm at the top of a biceps curl. Either way, end feels exist to prevent movement or represent areas where no movement should occur anyway.
Some mistakenly work muscles at weaker lengths, arguing that more mechanical work provides a greater effect. This actually leads to less tension. When using a good compound exercise though, the endpoints are not as harmful. This refers more so to extremes such as letting your shoulder blades relax during a pull-up or row in order to gain an extra inch or trying to squat until your butt rests against your heels. In these positions, you would feel tissue compressing. Slight contact may not be a bad thing though and can give you a standard.
- You need a standard.
Standards make sense as our bodies aim to avoid hard work. Our bodies will seek to reduce the range of motion and use leverage to make the exercise easier to perform but with less tension. Much of proper training involves teaching yourself to overcome your instincts.
Although these standards vary for the exercise and person, having something to touch or see can help you. On the bench press, you may choose your chest as an endpoint, so long as this feels fine on your shoulders. Someone with long arms and a small torso may choose the elbows dropping below their shoulders instead.
This gives you measurability to make sure your routine leads to progress.
Get Just Enough Range of Motion
You cannot have a complete discussion on range of motion without analyzing the exercise in question.
Nonetheless, all exercises must focus on the middle range and avoid endpoints that bring harm.
Use some common sense and avoid any parts of an exercise that feels badly. Use as much range of motion as you need to gain the benefits of negative work, the pre-stretch, and enough time to muster your power. Strike a balance to stay safe and get strong.