Like some players here, I have recurring problem with my left elbow that started in the mid-1990s. The problem has caused me to have to give up playing bass or guitar several times over the years. The problem seems to be coming back. It is the typical tennis elbow, golf elbow, tendinitis problem. I am cautiously experimenting with playing guitar and bass again and I have been observing my physical responses for the past 6 months trying to identify the cause of this problem. Here's what I think is happening, anecdotally. When I play Bass Guitar or Classical Guitar, my left hand is supinated completely so the left elbow is at its maximum travel (like having the steering wheel at one lock point). The palm is held completely parallel to the neck. This causes burning and discomfort in the outside of the left elbow; really the entire elbow. Bass demands playing sequential series of notes. Playing Classical Guitar is very similar in that melody lines are played on the bass and treble strings, which are also a sequential series of notes. When I play a steel string guitar, my left hand palm is not perpendicular to the neck. My left hand is about midpoint between full supination and pronation, I'm thinking this is because with steel string guitar I play mainly 4-note chords and this places my left hand and elbow is completely different positions away from the extremes. At this time I haven't found a solution other than to attempt to modify how I play and fret the bass. A solution to play similar to steel string guitar may not be workable. Here is an interesting YouTube video explaining pronation and supination. pronation and supination of the forearm - YouTube Does this sound accurate or familiar to anyone? I even went to the Rothman Institute but thry couldn't find a cause, or a solution. They mostly do sports medicine, maybe some arts medicine for dancers, but nothing for players of guitar-type instruments. Ed T.