From the Chronicle.com:
To what extent can coaches use negative tactics to motivate athletes? And what impact does that approach have on coaches’ credibility?
[…]
The main takeaway: Verbally aggressive language doesn’t work, even in an environment where athletes have been conditioned to expect it, the researchers found.
According to the study, which focused on feedback from 130 Division I college athletes, players who were exposed to a verbally aggressive coach reported significantly less motivation to perform, and viewed such coaches as significantly less competent, than did athletes who played for coaches with a more affirming style.