The problem of extensions is dealt with in greatest detail on the Hand-Size/Cello-Size page. Here below we will compare the differences between extensions in the three different fingerboard regions.
As we go higher up the strings, the distances between the notes become smaller and thus it becomes theoretically easier to do extensions. In the higher Thumb Region, the 1-3 major third is no longer a strained extension. But in the lower Thumb Region and all of the Intermediate Region the fact of no longer being able to comfortably use the 4th finger more than compensates (negatively) for these smaller distances. The 2-3 extension (and likewise the 1-3 major third) in the lower Intermediate Region, is one of the most uncomfortable, strained positions that we cellists have to use . This extension is perhaps even more uncomfortable than the 1-4 major third in the low Neck Region. Compare the following three “identical” passages in each of the Neck, Intermediate and Thumb Regions:
Fingering a passage with the use of the thumb can allow us to avoid many awkward extensions, however in many passages this solution is only really practical in the Intermediate and Thumb Regions (and not in the Neck Region) because of the ergonomic difficulties of using the thumb in the Neck Region (see Thumb Position in the Neck Region).
This possibility of using the thumb to eliminate extensions in the higher regions, added to the fact of the smaller distances “up high”, means that by far the most common, disturbing and unavoidable extensions occur in the lower Neck Region.
In the following pages we will look at the specific characteristics of extensions in the different fingerboard regions: