Picking offers great possibilities for tight attack and fast play, for example by sweep picking. Yet players who use picking as main technique should pay much attention to combine accuracy with relaxation. Very often, the need for accuracy leads to lots of strain in hand, arm and shoulder, all the way up to the neck.
Best is to keep the arm almost free from the instrument. Challenging, but rewarding, because:
Many famous players, both on bass guitar and guitar apply this technique. Watch the video below for a great example.
If it is too much for you, keep your arm flat on the bass without really pressing it. The further away from the wrist you rest the arm, the better. You may for example use a bridge cover and rest your arm there and pick close to the neck. Unfortunately, the sound you will get there is not what pick players are after. They will want the agressive attack they get from playing close to the bridge. In that case, by far the best way to go, again, is to keep the arm free from the instrument.
Hold the pick between the pad of the straight thumb and the side of the curved index finger, allowing the other fingers to spread a little and relax and to keep the palm open. Closing the hand and holding the pick with thumb, index and middle finger is also good as long as you do not strain the hand. Holding the pick between the thumb pad and the side of the index finger will prevent pick rotation and reduce the risk of dropping. Try to adopt a comfortable and relaxed grip. Practice slowly to combine relaxation with accuracy.
The picking movement up and down the strings seems to originate from the wrist, but a relaxed forearm will allow the bones of the forearm to transplant part of the force of that movement to the elbow. The best way is to make wrist and hand rotate from there. Do not squeeze the pick and do not press the bass with the forearm. With a tense forearm, all force will come down on the wrist, at the risk of wrist tendonitis.
Some less advisable ways of picking and their disadvantages:
Special ergonomic picks are on the market, reducing strain and the risk of dropping them. Lower tension strings, a softer pick and picking further away from the bridge will also reduce strain . Bridge and pickup covers may provide comfortable spots to gently rest the forearm.
Picking may lead to strap the bass higher. This will benefit the left arm.
Thumbing, moving the side of the thumb up and down across the string. requires more contraction of the hand and forearm muscles compared to slapping. Like when picking, keeping the forearm fully free from the bass is by far the best option.
Keep the palm of the hand relaxed. If, maybe later, you start to study triple and quadruple thumbing, a somewhat open palm will be needed to make it work, allowing the thumb strokes up and down to be followed by plucks of the index finger (for triplets) and index & middle finger (for quadruplets). If you use double thumbing as main technique, rest the thumb on the side of the curved index finger without squeezing, much like if you were picking.
Once mastered, these techniques will be no issue, since they will only be used incidentally. The point is to not overdo it while learning them.Tapping with the plucking hand is no problem. Rest your thumb gently on the side of the neck and relax your arm.
Tapping with the fretting hand, which is pretty much the same as the more incidental hammer-on, should be performed with the standard left hand position as is shown perfectly in this video. Some players might want to create some room to move for the fingers, making it necessary to put the thumb opposite the middle finger and move the wrist out underneath the neck and bend it inward sharply. The bent wrist, together with forceful tapping will be at the very serious risk of carpal tunnel syndrome.
Learning to tap might cause strain in the left hand. Practice this beautiful technique for short periods only, alternating with other techniques. Do some stretches before and after. Put the palms of the hands together in front of your nose, fingers up and turned towards the nose a little. Keep the elbows up. Do not press. Relax hands and forearms, allowing them to move down slowly between the elbows. Let the hands dangle at your side for a few seconds. Repeat four times.