What does the fortune teller mean by "lack of muscle"?

What does it mean to say that a person lacks tendons? Better give a few more examples.

One-track-minded people have poor flexibility, that is, poor logical thinking, so they can't generalize and draw inferences from others. Flexibility is an important evaluation basis of IQ.

Insufficient attention means that the amount of knowledge and information obtained per unit time is less than that of ordinary people, or the ability to analyze and process information per unit time is slow or the flexibility of logical reasoning is poor, and things can be done but not considered comprehensively.

One-track-minded people have low IQ, and simplicity is a typical manifestation of low IQ.