Why Your Untargeted Muscles Shrink During Workout
Evidence for Simultaneous Muscle Atrophy and Hypertrophy in Response to Resistance Training in Humans
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
A 10-week study tracked how muscles change when people do targeted resistance training. It found that while the worked muscles grew, some unworked muscles actually shrank. Eating more protein and calories helped prevent this shrinkage and supported overall muscle growth.
Practical Takeaways
Prioritize adequate daily protein and calorie intake during targeted resistance training programs to support overall muscle growth and minimize shrinkage in unworked areas.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
A 10-week study tracked how muscles change when people do targeted resistance training. It found that while the worked muscles grew, some unworked muscles actually shrank. Eating more protein and calories helped prevent this shrinkage and supported overall muscle growth.
Practical Takeaways
Prioritize adequate daily protein and calorie intake during targeted resistance training programs to support overall muscle growth and minimize shrinkage in unworked areas.
Publication
Journal
Medicine & Science in Sports & Exercise
Year
2024
Authors
K. Van Vossel, Julie Hardeel, Thibaux Van der Stede, Tom Cools, Jonas Vandecauter, Lynn Vanhaecke, Jan Boone, Silvia S. Blemker, E. Lievens, W. Derave
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Claims (5)
If you do targeted strength training for a few weeks, the muscles you work will grow bigger, but the muscles you don't use during those exercises might actually shrink a little bit. This happens because your body adapts specifically to the exact movements you're doing.
Eating more protein while lifting weights for 10 weeks is linked to bigger muscles and less muscle loss, specifically in the thigh muscle.
When you do strength training while not eating enough calories or protein, your body might build muscle in the areas you're working while actually shrinking muscle in the areas you're not. It's like your body is shifting resources from one place to another to cope with the stress and low fuel.
When people new to weightlifting don't eat enough calories, they actually lose muscle in body parts they aren't even working out. But if they eat enough food, their muscles stay the same size even in those untrained areas.
Eating more calories helps keep your leg muscles from shrinking, even the ones you aren't directly working out during strength training.