Why do they claim that masturbation slows muscle growth?

Cultural taboo: Studies reveal this to be a natural part of emerging sexuality for the majority of males and females worldwide. Cultural taboos limit the discussion of the topic to a variable degree.Taboos will permit or encourage a variety of myths that discourage it.Most experts would agree it is an innocuous practice.

They?: They who know, don't claim such things. They who do not know, well... can claim anything they want to, because this is the internet age. Anybody can post anything online. Exercise (moving muscles in a repetitive manner) increases muscle strength, muscle endurance, and muscle growth. Using the powers of deduction, one might argue that masturbation could even exercise and improve certain muscles.