Complex sentence: In finger vibrato, the performer only moves his/her fingers; in full-arm, the performer pulls his/her arm back and forth on the violin but only minimally changes his/her finger's position, creating a change of tone.
Split into simpler sentences: In finger vibrato, the performer only moves his/her fingers. In full-arm, the performer pulls his/her arm back and forth on the violin but only minimally changes his/her finger's position, creating a change of tone.