Stretching is a ritual we often perform before a workout to warm up the body and get it ready for the intense nature of the exercise.
Although we don’t have much research about muscle shaking, many people agree that body parts, like your legs, shaking while you stretch is a sign of functioning stretch reflexes.
This powerful reflex is monitored by muscle spindles which are designed to keep muscles within a certain range of lengths.
Keep reading to learn more about why your legs or other body parts shake when you stretch as well as some frequently asked questions about these curious muscle movements.
Is it Normal?
Shaking during a particularly intense workout or stretch is a perfectly normal response your body has to physical stimuli. However, if your legs or the rest of your body are shaking at other times, stretching may not be the cause.
What is thought to happen when you shake a bunch of small, involuntary movements (some may call them spasms) as the body tries to return muscle bodies to normal lengths against the power of a stretch?
While it is a normal bodily process, it can indicate that you’ve reached a limit and that it is time to reduce the intensity of a workout or stretch.
Should You Stop Doing it Then?
When you shake during a stretch, there isn’t much cause for concern. Because it can indicate that you’ve reached a physical limit, it’s a natural sign that you are pushing your body and, hopefully, reaping the benefits of physical exercise.
Aside from during a stretch, you may also shake or tremble towards the end of a workout. These kinds of shaking are more likely to be caused by muscle fatigue or low blood glucose near the muscle bodies.
Both stretching and exercise, in general, are beneficial for your health. However, if you are still concerned about the shaking, consider consulting a medical professional who can advise you further.
How Often Should it Happen?
The frequency with which muscle shaking occurs comes down mostly to how much you exercise or stretch.
If you work out five times a week and focus solely on one set of muscles (say, arm muscles like the biceps and triceps), then you might expect to shake about five times a week at the end of each day’s workout.
If you’ve never done much physical exercise before, you may find that you are shaking more often than others. This is likely because your physical limits are lower than others who have been working out regularly.
Can You Get Injured from it?
When you shake because of a stretch, it is likely because one or more muscle spindles are attempting to shorten a group of muscles back to an acceptable range of lengths for everyday movements.
It is unlikely but possible to get injured while stretching because your body and mind typically struggle to break limits that lead to self-harm.
However, shaking can signal that your body is close to injury when doing exercises like weightlifting. Depending on your exercise, you may want to call it quits immediately or soon after you start shaking to prevent serious injury to yourself.
How Long Does it Take to Get Used to it?
Because of how infrequent the involuntary shaking sensation usually is, you may never become accustomed to the feeling.
That being said, if you are consistent about your exercise and know what your boundaries are, you will likely get used to the feeling after the first few times.
People who keep up with a routine on a semi-regular basis might find that it takes a couple of weeks to months to get used to the shaking.
Eventually, if you are determined to stay in shape, you may even chase the shaking sensation in the hopes that it means you’ve done a good workout.
Final Thoughts on Why Do I Shake When I Stretch My Legs
Shaking when you stretch your legs or any other part of your body is a natural but involuntary process that can be scary when you first experience it.
The prevailing theory about why you shake is that muscle spindles relay information about a muscle’s length to the brain via proprioception.
When you stretch, you go outside of the parameters of regular motion, so the muscle spindles attempt to shorten/contract the muscle back to normal. This resistance to the stretch is what causes the shaking.
Luckily, little harm is likely to come from shaking while you stretch because your body resists pushing itself until it gets hurt.