Shirtless men, women in sports bras - not at this gym.

At the Lord's Gym, a franchise chain with locations across the US, women are not allowed to wear spaghetti-strap tank tops or short shorts. In fact, female gym-goers must make sure their tops are long enough to cover their bottoms.

The rules are meant to offer members a fitness environment that focuses on health whilst leaving out the sexual temptations and vanity often associated with secular gyms.

"Many people want to have a quality atmosphere that's not involved in the meat-market setting and that's serious about workouts," explained Dr Paul Sorchy, a chiropractor who has bought several Lord's Gyms including one in Clermont, Florida, according to the New York Times. "People want something truly family-friendly, and want to have a team of folks they can trust."

The unique Christian gym is drawing all kinds of people - from gym buffs to those who confess they would not normally join a gym.

Jason Russell, a former manager of a secular gym, had planned to open his own Christian-friendly gym when he discovered the Lord's Gym in Clermont. He is now its manager.

"Me being a single guy and trying to walk the Christian line, it was difficult," said Russell, 30. "I needed not only to protect myself, but as a leader, to help others with their spiritual journey."

The 10,000-square foot Lord's Gym in Clermont offers "Yogod", its version of yoga, a "Chariots of Fire" spinning class, and combines prayer and push-ups. The smoothie bar serves a drink called "The Land of Milk and Honey", and Christian rock music is also plays encouragingly throughout the 1,800-member gym.

Member Merri Bush, 42, said she would not normally have joined a gym. But the Lord's Gym allows her and her daughter Christyna Askey, 21, to walk on the treadmill each morning as they read and discuss the Bible.

The first Lord's Gym opened in 1994 in Roseville, California, as a nonprofit community centre for teens. Its founder, Doug Bird, is a former drug dealer who is now the pastor of Abundant Life Fellowship Church in Roseville, a town near Sacramento.

At first, the gym expanded across the nation mostly as non-profit community centres, but then for-profit gyms also began to appear, including the Clermont gym.

"These are places where fitness is important, not sex or vanity," said R Marie Griffith, a professor of religion at Princeton University who has written about Christian diet and fitness programmes, according to the New York Times. "It's supposed to be that we're not going to forget we're Christian here. There's a sense of comfort around people with the same moral values as you have; no one's going to 'rock your world'."

Gym member Per Heistad, who said he frequently travels for business and is a self-described gym buff, said he is no longer comfortable at other gyms.

"I don't need anything to lead me into temptation," Heistad said. "I can get there on my own."

"It's a Christian business, a Christian environment," he added. "It's a better feel. You stand a little taller, don't grunt, don't get pumped and yell, 'Daddy's got a new set of pipes.'"

Although the company logo depicts Jesus and the Cross, Lord's Gym welcomes all people to enjoy its facilities and does not require doctrinal or religious views to be shared as criteria for membership.

Lord's Gym contributes 10 per cent of its income to Lord's Gym Youth Outreach Centers around the US, James and Betty Robison with LIFE Outreach International, and several other non-profit organisations.