Regardless of whether you carry a formal leadership title or not, a key aspect of achieving excellence is one's ability to play any of the roles necessary to win.  If you are unwilling to play a particular role because you believe that it is not your job or that it is beneath you, excellence will ultimately escape you.  Team work and commitment are not just words, but critical activities necessary to be taken on in order to "win."  As a leader you cannot simply speak louder, or even yell, to make sure your point is heard, when what your team member really needs is to be shown how to do a task.  And you cannot simply bark out orders when what a team member really needs is encouragement and coaching.  A leader must be willing to take on whatever role the team needs to win at the task at hand.  And if that means cleaning the bathrooms and taking out the garbage, a leader must be willing to do that too.  And through your leadership example, others will see and learn that they too need to take on the roles and tasks necessary to win, and not just the ones contained within their job descriptions.  It is this willingness to do what is necessary for the team's success that defines the members of the team and the team as a whole.

Talent wins games, but teamwork and intelligence win championships. Michael Jordan

Individual commitment to a group effort - that is what makes a team work, a company work, a society work, a civilization work. Vince Lombardi

If you want to lift yourself up, lift up someone else. Booker T. Washington