Wheelchair basketball players are no strangers to physical barriers. So it was that when the 33rd annual National Wheelchair Basketball Tournament ended Saturday there was the small matter of cutting down the net, the way all very happy winners do.

Ten feet is up there if you're in a wheelchair, of course, but nothing is impossible when you've just scored 29 points and led your team to its second straight national championship. Curtis Bell, tournament most valuable player, was too high to hold down. He rolled his chair under the basket, bounded out onto his one leg, climbed onto the seat of the chair, stood up, hauled out a huge hunting knife and chopped free a strand

"Who's next?" cried out the big center of the Casa Colina Condors of Pomona, Calif., the team that had just completed a 61-49 thrashing of the North Florida Renegades.

The Condors swarmed under the basket. One by one they climbed the shoulders and backs of their teammates and slashed at the cords. When the net came down they cheered. They rolled their chairs into a line for photos. Dave Kiley, a paraplegic, plunked his blond son Justin into his lap. They shouted. They laughed. They boogied in their wheelchairs. They sang.

"Cel-e-brate good times COME ON!"

"It's funny," the able-bodied coach of the Condors, Frank Burns, had said the day before the championship game. "People think they're so different. We're playing the game by NCAArules with only a few minor alterations. It's a cruel pun but the best play in wheelchair basketball is the pick and roll, just like stand-up ball.

"At first you notice the differences, but after awhile you find yourself watching a good give and go and you forget these guys are in chairs.You're just looking at good basketball."

There are other things you notice about wheelchair basketball: surprises. Like the dirt. Somehow you don't expect wheelchair ballplayers to get dirty and sweaty and scratched up. But when they come out in their warmup suits the legs of the trousers are torn and dirty.

"Think about it," said Ed Owens, a 6-foot-10 polio victim who has played the chair game for 20 years. "All those bearings and wheels, the grease, the leg braces. It's all machinery. One of the hardest things we have to get people used to is the fact that they're going to get dirty in a wheelchair."

Then there's the silence. No thud-thud-thudding of giant feet pounding the hardwood. Just the hiss of grey pneumatic tires, the occasional crash of steel and aluminum as two chairs collide.

And the crashes themselves. It is a fact that the fastest time ever recorded for the Boston Marathon was by a wheelchair racer who finished in less than two hours. These things fly . And when they collide they send their riders sprawling.

All part of the game. In the gym of John Glenn High School in Westland, Mich., last weekend wheelchair basketball players were flying everywhere in pursuit of the national championship, sometimes in their chairs and sometimes out. In this game, when rough turns to tumble it's up to the driver to regain his seat.

There is no quarter given, no quarter expected.

There are those, in fact, who think this game finally has grown too competitive for its own good.

Wheelchair basketball started 35 years ago, when disabled U.S. veterans came home from World War II and wondered what to do with themselves.Some started fooling around with basketballs and wheelchairs and by 1948 the National Wheelchair Basketball Association had been organized by Dr. Tim Nugent of the University of Illinois. The idea then was to provide some organized recreation to help with rehabilitation.

The next year was the first national tournament. There were six teams in the country. Today there are 156 in the association and winning the national title has become a very big deal.

Says Nugent, still active in the wheelchair sports scene: "We've got wheelchair basketball, baseball, football, track for the blind. You name it and we do it. But they're all worthless without the competition. We believe it's the competition that fosters health and growth."

Nugent's view is shared by the hundreds of people who gathered in Westland last weekend to crown the 1981 champion in basketball, the most competitive wheelchair sport. "The thing we have to do is to separate this from the image of the Special Olympics," said Kent Anderson, who has refused to let the brutal crippling effects of cerebral palsy interrupt his quest for a normal life.

"We're not mentally disabled," said Anderson, who throws the discus from a wheelchair for Central Michigan University. "We have to go out and compete for jobs in the real world. We need competition in our sports, too."

Basketball is the grandfather of the wheelchair sports. In its 3 1/2 decades the national crown has grown so precious that there is today a creeping professionalism in this game. The Chicago Sidewinders, fourth in the 1981 tournament and veterans of national ranking, have a full-time professional promoter who raises funds for the team. They travel around the country for their 40-game regular season, motoring in the team Winnebago or flying to some games.

Competition for the best players in the land extends to job offers and even, some say, offers of money if a certain player relocates to play with a certain team.

Said Owens, who is in the process of moving from Kentucky to the West Coast, "I made up my mind where I wanted to go and what I wanted to do first. That way I'm not balancing offers against each other. I know I can get a job wherever I go. It's like a big family if you play basketball. I know people all across the country."

There are those who think this big, competitive family is slashing at the foundations of the wheelchair game; who say it's not fun anymore.

One such person sat in the stands during the semifinal contest last weekend between the Renegades of North Florida and the Sidewinders of Chicago. He had polio and he had played this game for 24 years. What he saw he found distressing.

"When I started," he said, "we had people who were really disabled. But then you started getting the ringers (outstanding players who bounced from team to team). Nobody wants players that have to be taught, that have to be upgraded physically.

"No, no, no. We want guys who can play. Wheelchair basketball isn't what it's supposed to be, where you see people who are physically handicapped. People aren't going to pay to see a bunch of gimpies who can't catch the ball, who can't move.

"The national title means money. And the payoff to the guy who can help you win it is going to be in jobs, money, entertainment, excitement. It's the complete reverse of what it's meant to be."

How does money enter into it?

"You go to some organization or company," said the veteran, "and you say, 'Hey, we got the national champions.' They say, 'Come on in.'

"But you say, 'We have this bunch of crippled guys,' and that's when they say, 'We gave already at the office. . .'

"There's too much pressure in this game, too much emotion. It's win, win, win. It drives you bananas. It changes your whole personality."

While the veteran spoke, a spirited, see-saw game was winding down. With a little over a minute left North Florida had the ball with the score tied at 48. The Renegades stalled, looking for the last shot, but with 10 seconds left they were denied.The buzzer sounded a tie.

The first overtime period ended in a tie. The crowd of 1,500 was buzzing as the pressure built.

In the second overtime the Renegades went up by one, then Chicago went ahead on a basket by Randy Wix and six seconds to go. North Florida took the ball out with only one chance left to survive the semifinals. f

The Chicagoans swarmed on defense. The clock wound down. Somewhere between one second and none the ball went to Phil Errion, whose legs are shriveled from polio. Errion, a little-used reserve, wheeled to the top of the key and flung a blind hook over his shoulder. The buzzer sounded.

Incredibly, the ball smacked the backboard dead center and swished in.

In the delirium that followed Errion leaped from his wheelchair and took three exuberant steps before his body reminded him that he couldn't walk. His teammates buried him in a sea of affection.

Even the Chicago players smiled bittersweet smiles.

That ending somehow took the sting out of the old veteran's accusations. If competition is band, how come it makes people who can't walk forget they can't?

Wheelchair basketball is a fast and occasionally beautiful game. The unanimous choice for the best in the world at it is Dave Kiley of the Condors, who lost use of his legs when an inner tube he was riding down a snowy mountain crashed into a tree nine years ago. Like Kiley, most wheelchair players lost use of their legs either through disease or accident. Very few were born crippled.

Kiley is your standard 28-year-old California beach boy, with shaggy blond hair and a deep tan. Why is he so good?

"A good able-bodied athlete, becomes a good wheelchair athlete," said a veteran observer. "He was an athlete before he got hurt. He thinks with his chair, he understands the game, he practices. You see his shot, it's a classic basketball shot. He's a natural."

Kiley's wheelchair is a Quadra, the No. 1 sports chair in the nation. It doesn't look anything like the chair in which they take you to surgery in the hospital. It looks like a Maserati.

Quadras weigh less than 25 pounds. They are fabricated of airplane aluminum, strong and superlight. The wheels are cambered, meaning they are wider apart at the ground than at the top. That makes the chairs turn better and keeps hands from getting squashed in collisions. The backs of the chairs are as low as an inch or two from the seat, for range of motion.They look fast. They are.

"This is the Indianapolis of wheelchairs," Nugent said of the basketball championships. "This is where all the advances in machinery are made."

Wheelchair players are crippled people who find themselves moving with grace and speed and self-esteem. They pilot stripped-down racing machines and they play to win.

For most of them, the game shapes their lives.

Bruce Karr, player-coach of the Chicago Sidewinders, veteran of wheelchair Olympics in Rome, Tokyo, Israel, Heidelbert, Toronto; of Pan American Games in Jamaica, Lima, Argentina, Mexico: "I got polio in 1953. When I went to Illinois (University) in 1955 I had no intention of ever getting into sports again. My Philosophy was, 'They'll put me in a dorm with a bunch of cripples.'"

Tom Osburn of the Indiana Olympians wheelchair team lost both legs in Vietnam when he stopped on a land mine: "I'm 32. If I had'nt been hurt, I bet I wouldn't be playing ball right now. Let's face it, in traditional sports you're only good until your legs give out.

"At least that's one problem we don't have."