1) For larger muscle groups, select a larger pulse width than for smaller muscle groups.

2) A larger pulse width should be used for larger muscle groups than for smaller muscle groups.

Yes, a larger muscle group would be something like the thigh area.

Is this text from an instruction manual for one of those muscle toning devices? (=1) More context would be helpful, but the "Impulsbreite" is the pulse width – which describes the timing of the electrical charge.

Option (2) is in case these are not instructions...