Justin Tuck the Giants’ defensive end

In the Giants' equipment room here, there are more than a half-dozen styles of the newfangled shorts. It is easy to pick out the ones that are most likely to be embraced by players. Some shorts have large, inflexible pads sewn onto the hip and thigh area, making them look like something a ninja turtle might wear. But others have small foam, plastic or puttylike nodules sewn into the fabric, allowing the shorts and the padding to bend more than traditional pads around the target area, which is more likely to appeal to players who worry about a negative impact on their range of motion. (The players will still wear regular knee pads underneath their pants).

Skiba anticipates that if the pads are made mandatory, companies will make position-specific shorts. Defensive backs, for instance, want padding only in the front of the thigh. Offensive linemen usually wear the biggest pads because they get the most blunt force hits. But most running backs and linebackers, who are hit often in the legs, do not usually wear large pads, making some of the new shorts an intriguing option for them. And Justin Tuck, the Giants' defensive end, wears thigh and knee pads but no hip pads, on the theory that he is seldom hit in the hip.

"A pound here or there goes a long way," said Tuck, who is unsure if he will wear the new girdles in the preseason. "I feel a lot better if I play at 260 than at 263. Athletes are very superstitious. Guys have certain routines they follow for years and they want to keep it that way."

Giants Coach Tom Coughlin requires players to wear thigh pads, although they Justin Tuck offer much less protection now than they used to. Traditional thigh pads were half-inch foam, but at the behest of players they have been winnowed to a piece of inflexible plastic barely the width of a bicep. They crack often; Skiba said the Giants go through at least 100 of them each season. Players dislike them so much that they leave them in their lockers.

"So how much protection is it?" Skiba said.

The good news: the padding is so light and flexible on some of the designs being tested that players who are used to wearing compression tights under their uniforms are unlikely to feel weighed down. The bad news: the padding is so light that it is unlikely to prevent a serious injury caused by a direct blow from a helmet. But for skill position players who receive mostly glancing blows, the new shorts may alleviate some of the lacerations and contusions they get when wearing no pads.

The N.F.L. has no statistics indicating that wearing lower-body padding prevents injuries. But Ray Anderson, the N.F.L.'s executive vice president for football operations, said data showed that bruises to the hip, thigh and knee cost players workdays — vital practice time, if not games. There is urgency to limiting lost time: with an 18-game regular season almost certain to be a part of a new collective bargaining agreement, the N.F.L. is exploring things like equipment and expanded rosters to insulate players from bruises and broken bones.

"You mitigate any excuses," Anderson said in a telephone interview. "They think it makes them lighter and they feel faster and therefore they don't want to wear them. Then players say, 'I would wear them but I look across the field and I think they have a speed advantage.' "

Parcells considered not wearing full pads as conduct detrimental to the team because it created an unnecessary injury risk. But even one of the game's most influential coaches lost out to a more ingrained part of the N.F.L. culture: speed kills.

With players and collisions bigger and more devastating than ever, it may seem counterintuitive to eschew anything that offers protection. But professional football players — mainly receivers and defensive backs who rely on quickness, but some linemen, too — have a finely tuned sense of their bodies and are convinced that even plastic shells less than a quarter-inch thick and a few inches wide encumber them.

The days of fully armored players — with bulky thigh and hip pads rippling from beneath uniforms — are long gone, especially at the skill positions. Many leave everything except shoulder pads in the locker room, preferring the risk of injury — and in the case of Johnson, who played for Parcells with the Jets and the Cowboys, multiple team fines — over allowing an opponent to have an edge.