Are your best employees suffering from collaborative overload?

That's the question posed by the Harvard Business Review's latest cover story. The short answer is a resounding yes.

For their research, the authors of the HBR article--Wharton's Adam Grant and Reb Rebele and the University of Virginia's Rob Cross--studied collaborative interactions at more than 300 organizations. Their conclusion is that the most valuable collaborators--those considered by their colleagues as the top teammates and best sources of information--also happened to have the lowest engagement and career satisfaction scores. 

While this could be the result of a variety of factors, the researchers conclude that collaborative overload is the main culprit. So how do you prevent your top teammates from feeling overused to the point of burnout? Inc. recently spoke to Rebele and Cross to learn more. Here are their answers, organized into three takeaways from their article. 

1. You rely too much on "extra milers."

An extra-miler is exactly what it sounds like: a kickass employee who often goes above and beyond her role. (The authors borrowed the term from the University of Iowa's Ning Li, whose research highlights how important extra-milers are to team performance.) 

You want extra-milers on your top teams. You need them on your top teams. But when it comes to collaboration, they simply shoulder too much of the burden: "In most cases, 20 percent to 35 percent of value-added collaborations come from only 3 percent to 5 percent of employees," note the authors. That 3 percent to 5 percent are your extra-milers. 

How does this happen? "What I tend to see in the analyses we do is, in most organizations, if you do a good job on a big project, your reputation grows, and you're part of the next three, four, or five big projects," says Cross. "But there's very little thought around what needs to be taken off this person's plate."

Cross suggests remaining cognizant of the intense demands that a small, crucial set of your employees are shouldering. If you don't want to overburden that crucial group, here's what you should do. First, redefine their roles to relieve them of (some of) their draining tasks. Second, hire or reassign others to handle those less essential duties.

Might these superstars chafe at being relieved of some of their duties? Perhaps at first, they'll resist. After all, they like handling the burden. They're extra-milers for a reason. But if they're at all like the dissatisfied superstars the authors encountered in their research, they'll eventually be happier that you've taken the strain away from their sharing. Being all things to all people is not sustainable path to employee happiness.

2. You're allowing your star collaborators to hoard too much crucial information.

One reason collaboration can drain star employees is because they get asked the same questions--time and again. Some star employees are the only ones in the organization with certain forms of know-how, whether it's a particular high-tech task or the contact info for certain service providers. 

The authors call this sort of collaborative resource "informational." As a leader, you need to make sure your company's informational resources are never the sole domain of certain employees. They should be recorded and shared in documents or videos that anyone in the organization can access. Doing this will relieve some of the collaborative burden your star employees feel. 

3. You're spending too much time on introductions. 

Sometimes, your star collaborators are the employees who are exceptionally networked in your organization; they're the people who know everyone in every department. The authors call this a "social" resource.

As a leader, you need to make sure your company's social resources are also easily shareable. Your organization should be one where intros to new colleagues are brief, requiring one--and only one--message or exchange.

Above all else, leaders need to grasp that burning out your best collaborators is an organizational problem. It's not the fault of your strongest individuals. It's the fault of leadership, for putting too much on their plates. But too often, the top brass just doesn't see it that way. "Leaders don't see these failures as systemic," says Rebele. "They see them as independent." 

But the sooner you recognize that strain is an organizational problem, the sooner you'll solve the problem--and your best employees will become more engaged.