Why Muscles Shake During Exercise
It usually happens near the end of a long workout. You may feel yourself getting tired, and your muscles start to twitch and shake. It can be troubling, but there are ways to deal with it. First, here's what's happening when you shake.
When you move a part of your body, there's an entire symphony of muscles working together. Some muscles are being told to contract and shorten, while others are signaled to relax and lengthen. All the motor units work together, handing off movements from one to the next. Each of those small movements combine, making it appear as if you're moving in a smooth, controlled fashion.
As the muscles you're moving get fatigued, the individual motor units controlling them shut down. Now your body can no longer make smooth handoffs from one position to the next. There are gaps where muscles don't work and sudden stops, jerking or trembling is the result. The more tired muscles you have, the greater the gaps and the more dramatic the shaking will be.
That's the technical explanation or HOW things happen, but it doesn't explain WHY. So the next time you start quivering, consider these causes and ways to deal with the problem.
Not enough sleep. During sleep is when your muscles rebuild and repair. When you don't get enough rest, your body simply doesn't have the energy it needs to properly activate all the muscle units. If you haven't gotten a good nights sleep, consider changing your schedule so you can start your workout refreshed and ready to go.
Lack of stabilizing strength. There are several points during an exercise movement that can tax muscles. For example, when you first attempt a bench press, your chest muscles will be much stronger than the balancing muscles used to stabilize the load. You might be able to press the weight, but you'll shake as you do it. Only over time, as your balancing muscles get stronger and catch up to the bigger muscle groups, will the shaking subside. Use lighter weights until the smaller muscles are strong enough to do more.
Attempting too much weight. When shaking begins early in the workout, it may be a sign that you're starting out too heavy. The muscles simply don't have the strength to move in a controlled manner. Attempting to lift without maintaining proper form (or while shaking) puts you at risk of injury. Scale back how heavy you're lifting until you grow stronger.
Pushing yourself too long. Extreme workouts have gotten much more popular the last few years. But being popular doesn't mean they're more effective. You can't go from sitting on the couch all night to 90 minute workouts, seven days a week. Even with light weights, if you're exercising longer than is appropriate for your body, shaking will begin as your muscles get fatigued. For exercise beginners, start with 30 minutes a day.
Too little water. When you body gets low on fluids, it short circuits the signals going to your muscle fibers. Make sure to have plenty of water before, during and after the workout. Invest in a couple reusable, dishwasher safe water bottles. Then carry a full bottle with you, so water is always close by.
Low blood sugar. Your body needs fuel (food) to function properly. If you don't eat enough before a workout, your muscles won't have anything to draw from when you move them. Make sure to eat something like a little oatmeal before a workout. If you start shaking while exercising, consider eating something like a banana to give you simple sugars and potassium for energy.
Working out until you feel yourself shaking has never been proven to be an effective exercise strategy. The best option is to take steps to avoid it from happening at all. Get enough sleep, drink plenty of water, eat enough food and choose weights and routines that are challenging, but that you can control.
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