of literature out there that suggests that penalties are more effective than rewards. Look at Kahneman and Tversky's prospect theory and "loss aversion." Researchers have found that humans will work harder to avoid a penalty than they will to obtain the same value of gain. I just ran an experiment looking in part at penalties vs rewards. We replicated prior research finding that individuals are willing to exert more effort to avoid a loss than to obtain an equally valued gain.
The intriguing question to me is whether or not a rewards focused lens would lead to more wins for a coach (though the coach would probably be a basket case mentally: i.e., neurotic). I think it very well might in the short run, but probably isn't sustainable.