diff --git a/docs/source_docs/user_guide/inputs/model_options.rst b/docs/source_docs/user_guide/inputs/model_options.rst
index 7032d260ac8103f6bbdb447f6136a599c6b843af..6da492daec0dcbbc100794483607be34bef75b31 100644
--- a/docs/source_docs/user_guide/inputs/model_options.rst
+++ b/docs/source_docs/user_guide/inputs/model_options.rst
@@ -107,7 +107,9 @@ The following inputs are defined using the prefix ``particles``:
 |                     |                                                                           |             |           |
 |                     | Options:                                                                  |             |           |
 |                     |                                                                           |             |           |
-|                     | * ``mean_velocity``                                                       |             |           |
+|                     | * ``None`` - Particles evolve normally                                    |             |           |
+|                     | * ``mean_velocity`` - Impose a mean velocity on particles at the end of   |             |           |
+|                     |   each solids update step.                                                |             |           |
 |                     |                                                                           |             |           |
 +---------------------+---------------------------------------------------------------------------+-------------+-----------+