Virginia defensive back Maurice Canady runs the 40-yard dash at the 2016 NFL football scouting combine in Indianapolis. (Michael Conroy/AP)

A dozen years ago, when Jeff Foster first came to National Football Scouting, the company that runs the NFL combine, he surveyed all 32 teams. The sport’s biggest job fair has four components — an on-field workout, medical testing, player interviews and psychological testing — and Foster wanted to know what teams valued the most.

“All 32 teams said medical was No. 1,” Foster explained recently. “All 32 teams said interviews were No. 2.”

Over the past decade, the combine, which begins Tuesday, has exploded into one of the NFL’s premier events, with activities for football-starved fans on-site and nearly round-the-clock television coverage for everyone else. But the part of the event that matters most to NFL personnel executives takes place far from any fan’s line of sight.

Two months before the NFL draft, 330 prospects will travel this week to Indianapolis, where they will get poked, prodded, measured and examined, a job interview unlike any other. While the players’ 40-yard-dash times might get the most attention from fans and analysts, it’s what’s discovered by doctors and trainers behind closed doors that teams find most valuable — and that some find most problematic.

“Do we have a problem with that? Yes,” said DeMaurice Smith, the executive director of the NFL Players Association. “I mean, can you imagine after you’ve applied for this great job . . . they say to you, ‘Hey, your résumé looks great. Tomorrow you have to go through a full day of medical screening before we offer you a job.’ It would make everybody’s head explode.

(Thomas Johnson/The Washington Post)

“To the public, they make it look like it is a measurement of their physical ability. What happens outside the view of the public is that they are taking evaluations of players medically and psychologically that very few professionals in any other business would put up with.”

While NFL teams find this information critical to understanding a prospect’s fitness and capabilities, others suggest the whole exercise could unwittingly violate federal law. The University of Pennsylvania Law Review published a study last month that recommended the NFL reconsider the way it conducts its annual job fair. Researchers at the University of Houston Law Center and Harvard Law School say asking players to submit to invasive medical exams appears to violate both the Americans With Disabilities Act — which despite its name provides protections to all prospective employees, disabled or not — and the Genetic Information Nondiscrimination Act, which prohibits employers from asking about family history or using that information when making hiring decisions.

“Employers are not supposed to make disability-related inquiries,” explained Jessica Roberts from the Houston Law Center, “or examine prospective employees before there’s some kind of offer of employment. . . . You can ask the prospective employees whether they can perform job-related functions, but it has to be job-related.”

While there could be a gray area between tests that measure performance and those that examine health, Glenn Cohen, a Harvard law professor who co-authored the study, says the list of questionable exams the NFL requires of draft prospects is long: heart tests, blood tests, X-rays and MRI exams, psychological tests, even exams measuring eyesight or range of motion. (The NBA and NHL similarly conduct annual pre-draft combines in which prospects also undergo various medical exams and athletic tests.)

So what exactly are football prospects asked to go through at the combine? Foster explained that the players arrive in Indianapolis this week in waves. After getting checked in, they’re quickly ushered to a hospital for a “pre-exam,” which includes lab work, X-rays, an electrocardiogram (EKG) and, for many players, MRIs. These tests are designed not simply to test their fitness in the NFL but to make sure they’re healthy enough to participate in the combine’s on-field workout.

That night, they will start the interview process. Each team is allowed to conduct private, 15-minute interviews with up to 60 players during the combine.

(Thomas Johnson/The Washington Post)

“The league and each team has conducted their own training for what’s appropriate and what’s legal to ask in a job interview-type setting,” Foster said.

The next morning, players first undergo drug testing and baseline neurological testing, then will be examined closer by each team. At Lucas Oil Stadium, seven rooms are set aside for medical exams. Five or six teams share a room, and the players will be looked at by each doctor in each room.

The player then could be asked to undergo additional MRIs either at the stadium or at a hospital. The entire process could take two or more hours.

While each team takes its own notes and makes its medical grades, much of the information collected at the combine is shared using electronic medical records, almost in real time. Foster said that 30 seconds after an MRI is complete, trainers and doctors across the league can view the images on their laptops.

That afternoon players start psychological testing, which could measure intelligence, cognitive ability or personality profile. While every prospect undergoes a pair of tests — the Wonderlic Cognitive Ability Test and one the league created called a “player assessment test” — Foster said about two dozen teams conduct some form of additional psychological testing.

By the time players tackle the on-field drills or meet with reporters for the first time, they already have been through more than two days of medical exams, psychological tests and team interviews. The remainder of the combine — the part that garners the most attention on television — consists of drills and on-field workouts.

Legal researchers point out that prospects have little choice but to submit to the elaborate medical obstacle course. Foster, too, says that while everything at the combine is optional, it is in many ways compulsory.

“We can’t force them to do anything,” he said. “But if you’re not going to participate, there’s no reason to be here.” He said skipping a medical test could serve as a “red flag” to NFL teams “and would not be good for the player.”

Smith says prospects have little leverage and the NFLPA can’t help or advise them through the process because they aren’t yet union members.

“That magical moment happens at the draft when they’re walking across the stage,” he said. “Literally, on one side of the steps they’re not union members, and when they climb to the top of the steps, they are.”

Smith doesn’t particularly like the function of the combine — “I have a personal animus towards a system that reminds me of all sorts of bad things that used to happen in our country” — but NFL teams find it essential. They study players for two years or more, watch film, visit campuses, talk to college coaches. But the combine provides access to bones, joints, muscles and organs that they feel are essential to making informed draft-day decisions.

“This is the first place to do that,” Foster said.