Are There Any Benefits/Drawbacks to the Different Movement Types Besides Speed?

Once you research the necessary Science and train your soldiers with the correct military skills, they gain the ability to perform a variety of different stances, both while moving and while stationary. The new abilities are as follows:

Stationary Abilities

• Lie Prone
• Crouch
• Stand (Default)

Movement Abilities (Slowest to Fastest)

• Crawl
• Walk (Default)
• Run

Aside from the obvious changes in movement speed when running or crawling, are they any other bonuses/detriments given by using these abilities? If not, it seems like 'walk' is a pretty useless form of movement.