There is a common experience for those starting a new exercise routine or sport: after a workout, certain body parts may feel unsteady, like jelly. While this can happen even to experienced athletes, Andrew Jagim, an exercise physiologist at the University of Wisconsin, notes that this sensation is particularly frequent among beginners unaccustomed to physical activity. 'Even doing body-weight squats for five minutes could be enough to make their legs start shaking and quivering,' he explains.
Why Muscles Shake After Exercise
This trembling is a natural physiological reaction, but it signals that your body needs rest. According to Patrick Maloney, lead athletic trainer at Tulane Institute of Sports Medicine in New Orleans, the message from your body is: 'Hey, it's time to sit down. Don't go hurt yourself.' The shakiness occurs because your nerves are short-circuiting and struggling to communicate with your muscles due to rapid fatigue from training. As Jagim describes, your body 'can't initiate muscle contraction and relaxing like it normally does.' This temporary state of fatigue results from a disruption in communication between the nervous system and muscles.
The Role of Energy Depletion
Muscles rely on various energy stores depending on the workout. Maloney explains that shakiness arises when muscles are low on energy: 'The reason that your muscles are getting shaky and they're unable to produce that high-quality contraction is basically they're low on energy. You've exhausted all of your storages.' Some fitness programs encourage doing as many reps as possible, which can trigger this jelly-like response. While approaching maximum thresholds can lead to shaking, it is not essential for improvement. Jagim emphasizes, 'It's not something that's absolutely needed for you to get stronger or get faster or see improvement.'
When to Be Concerned
While some shakiness is normal, especially for beginners, there is a critical difference between temporary jelly muscles and prolonged soreness or pain. Warning signs that require medical attention include swollen muscles, feverish skin, or brown urine a day or two after intense exercise. These symptoms indicate rhabdomyolysis, a severe muscle damage condition where 'the muscles incurred so much damage during that workout, it's leaking ammonia and other kind of protein byproducts into the bloodstream, and it's starting to impact like liver and kidneys,' Jagim warns. This can happen when a sedentary person attempts an overly intense workout.
How to Recover Safely
If you feel weak and shaky after exercise, the best remedy is a short break. Maloney notes that shaking typically stops within about 10 minutes. You don't necessarily have to end your workout; instead, switch to a different exercise. For instance, if your legs are quivering, try pushups to engage different muscles. Jagim adds, 'Sometimes by the time you get back to a leg exercise, you'd be ready to go again.' However, caution is vital when lifting heavy weights with wobbly muscles. 'It can be dangerous,' Maloney says. 'If you're lifting weights over your head ... you can drop a weight on your head.' Always use a spotter for safety.
Building Tolerance Over Time
The more you train, the more your body adapts to high-intensity workouts. Maloney explains, 'These metabolic pathways will get more efficient and stronger to where eventually you don't experience this feeling.' Jagim agrees, stating that if you repeat the same workout after a couple of days, 'you probably wouldn't feel that sensation anymore.' Once accustomed to a routine, reaching that jelly-like state becomes rare.
