In full transparency I only skimmed the paper so I’m not sure if this is addressed, but it seems to me that the relationship between motor control and stuttering would be better explained in the other direction. As in, people with poor motor control/development are more likely to present with a stutter. With this being said, poor motor control/development is only one of many underlying factors that can result in a stutter. To add even more nuance, this presentation of poor motor control isn’t always systemic, so even if it is producing a stutter it may not have any affect on strength, balance, etc. I grew up with a severe stutter (very mild now in my mid 20’s) but was a pretty heavily acknowledged (not to toot my own horn) football player throughout high school and still train pretty successfully for a variety of athletic endeavors (weightlifting and trail running), so I personally don’t think I’d fall into the category of those affected by this.