The presidents of the eight Ivy League colleges voted on Tuesday to increase their academic requirements for students recruited as athletes, to cap the total number of athletes admitted to each institution each year, and to relax much-protested requirements about mandatory time off for athletes during the academic year.

The Ivy League has always had more-stringent academic standards for athletes than other conferences or the National Collegiate Athletic Association. During the admissions process, each student is given an "academic index" number based on a complicated formula involving high-school class rankings and standardized test scores. At any Ivy institution, the mean of the academic indices for football players cannot be more than one standard deviation below the mean for the student body as a whole.

Similar standards have existed less formally for other sports, as Ivy League admissions offices share admissions data on all their sports teams annually. The new rules will extend the model to athletes in all 33 sports sponsored by the league. Individual teams will not be required to meet the one-standard-deviation rule, but all athletes taken as a group will.

The league also has a minimum standard for the academic index that all athletes must meet to be recruited. On Tuesday, the presidents voted to raise that standard slightly but "significantly," according to one league official.

The "proposal was based on extended consideration of how best to reflect our schools' many similarities as well as their many important differences," said the presidents of Cornell University and Dartmouth College, Hunter R. Rawlings III and James S. Wright, in a written statement. "It will enhance adherence to our admissions principles, while at the same time providing for equitable athletic competition among our institutions."

The changes come in a climate of increased scrutiny of intercollegiate sports in the Ivy League. Last year, the presidents voted to require all teams to take a minimum of seven weeks' worth of breaks over the course of the academic year, despite the protests of coaches and athletes. The league also voted to reduce the number of football players admitted each year from 35 per institution to 25.

On Tuesday, the league voted to change the seven-weeks-off rule to 49 days off. Coaches will be able to schedule the breaks whenever they wish, but they do not have to be a solid week, as they were last year.