It's the start of another afternoon of practice for the women's swim team at Pomona-Pitzer College in Claremont, and Coach Penny Dean is stressing the importance of the rigorous workout routine.
A few swimmers grumble before they dive into the pool again to continue the endless laps.
Dean knows the workouts are not easy but "that's the only way they're going to become successful in swimming."
The 30-year-old coach, who has led Pomona-Pitzer to eight consecutive Southern California Intercollegiate Athletic Conference swimming championships, should know.
She has written the book on rigorous swim training.
"How to Swim a Marathon" was published in April, and Dean has the unquestioned firsthand experience.
She is the record holder for swimming the English Channel (from England to France), negotiating the treacherous 24 miles in 7 hours and 40 minutes on July 29, 1978.
She also holds three world records for swimming the 21-mile Santa Catalina Channel in 1976 and 1977, including a time of 20 hours and 3 minutes for going from the island to San Pedro and back in 1977.
Why would anyone want to become a marathon swimmer?
Dean admits you have to be a little different.
"I had a really good background in swimming," said Dean, who started at age 1. "I was not a great swimmer (at Pomona College), and the chances of getting to the Olympics were not really great.
"I always enjoyed channel swimming, even more than being in a pool, so it was a natural thing for me."
Dean's career as marathon swimmer actually started long before college. She was only 10 when she attempted her first marathon. But it didn't exactly turn out as well as she had hoped.
She swam for a club where the coaches asked her and an 8-year-old boy to try to swim the length of the Golden Gate Bridge (about a mile).
With the icy water and strong currents, Dean decided to quit swimming with about 400 yards to go. She would soon regret it.
"I had this feeling that what I had done was wrong," she recalled. "I had only 400 yards to go. I looked on shore and saw my mom walk away, and I thought it was because of me failing. After that I decided that I would set a goal of swimming the English Channel."
Easier set than done.
By the time Dean was ready to challenge the English Channel at age 23, she had been a successful pool swimmer for clubs and was a six-time small college All-American at Pomona College in the mid-1970s.
She said it was her swims of the Catalina Channel the previous two years that helped her prepare for the England-to-France swim that is considered the toughest challenge for a marathon swimmer.
"It's similar in distance to swimming Catalina," Dean said. "The real difference is it's cold water, and the currents are stronger."
Dean said the water temperature around Catalina varied from 64 to 70 degrees while it ranged from 54 to 65 in the English Channel. "You also swim one (Catalina) at night and the other during the day."
She trained in England for about a year, thanks to a grant from the Watson Foundation, before challenging the channel.
Conditions of the grant required Dean to study swimming programs in Europe, swim the channel and write a book about her experience.
Her rigorous four-hour-a-day training schedule was progressing nicely until three months before her challenge when "my arm started turning blue. I found out that I had an artery missing from my left arm."
That might stop a lot of swimmers--not Dean.
Despite considerable pain, she went ahead.
When she needed inspiration, she looked back to her failure at the Golden Gate.
"Every time I was feeling sorry for myself, I could look back to that. When you have a goal inside of you for 13 years, your body and your mind can do amazing things."
She trained for the English Channel with a goal of maintaining 80 to 88 strokes a minute. That would give her momentum to fight the cold and currents for 24 miles.
"I wanted to have the speed of a 200-meter race and be able to hold it. But when I started swimming, it was more like 93 strokes a minute, and I went a lot faster than I had expected."
The fact that Dean had competed despite a circulation problem in her left arm made her record time even more impressive. She had surpassed the previous record by 1 hour and 5 minutes.
Dean continued competing in various distance events until she developed mononucleosis in the summer of 1979. By the time she had attempted to resume training again in November of that year, the pain in her arm had become unbearable.
"It got to the point where I couldn't even pick up a glass with my left arm," she said.
So Dean had an operation to clear her posterior artery and allow more blood to enter her arm. But the operation left her feeling the same as before.
The artery problem has all but put an end to Dean's career as a distance swimmer. She said she could swim only about 50 yards before last year.
Then she decided to swim again, at least for enjoyment. "I like to exercise because it makes me feel alive, and swimming relaxes me more than anything else."