Roy L. answered • 06/21/20
Ivy League College-App Writing Guide and Dedicated Hebrew tutor
The difference between the two comes to light as we unpack the form, or binyan, of each word by itself.
Letargel / לתרגל comes from the active binyan Pa-el, which connotes an active, dominant process. Pa-el form verbs exist in reference to themselves, instead of framing the action as a process of becoming, or attaining, a certain character or state of being. In this case, Letargel / לתרגל is an active derivative of the root ר.ג.ל, or r.g.l, which, when used in an adjective form connotes regularity, normality, or something one has grown accustomed to, and in noun form - routine, habit, etc.
Hence, Letargel, in its active binyan / form, connotes the active process of practicing, drilling, 'grinding'.
This is as opposed to a passive binyan / form such as Hitpa-el, which would combine with our root ר.ג.ל / r.g.l to create Lehitragel, a verb describing the process of becoming accustomed to, savvy at something.
Hitpa-el is the binyan used in our second word, להתאמן / Lehitamen, which, when derived from the root a.m.n / א.מ.נ (connoting art, or craft) is framed in reference to the root as a process of attaining the qualities of the root.
Hence, Lehitamen, in its passive binyan / form, connotes the more passive process of practicing a craft / skill / ability, or attaining a certain quality / state of being. The latter sense is where this word is most commonly used in casual speech - exercising - in the context of physical fitness.
**This is similar to when, in English, we tend to assume exercise to mean physical exercise even when this is not explicitly stated.**
