Let me share with you an exercise that helps you strengthen and coordinating your left hand fingers. These permutations put you through every possible four-finger combination you encounter in bass playing.

You can start this exercise on any fret and play it across all the strings of the bass.

The numbers correspond to the fingers:

1 = Index Finger

2 = Middle Finger

3 = Ring Finger

4 = Pinkie

The permutations are:

Column 1

1234

1243

1324

1342

1423

1432

Column 2

2134

2143

2314

2341

2413

2431

Column 3

3124

3142

3214

3241

3412

3421

Column 4

4123

4132

4213

4231

4312

4321

This is what Column 1 sounds like:

1-2-3-4

1-2-4-3

1-3-2-4

1-3-4-2

1-4-2-3

1-4-3-2