The weekend death of 96-year-old fitness icon Jack LaLanne, who used little more than a chair and a towel to create exercise programs that spurred television viewers to get off the couch, is a reminder of how much he shaped the industry.

LaLanne, known as the godfather of modern fitness, continued to work out two hours each morning and eat at least 10 raw vegetables and five fresh fruits a day well into his 90s.

He died of respiratory failure due to pneumonia on Jan. 23, 2011, at his home in Morro Bay on California's central coast.

LaLanne credited exercise with changing his life as a teen, and spent the next eight decades encouraging physical activity and healthy living with the mindset that "inactivity is the killer and, remember, it's never too late."

LaLanne's television show, which began in 1951 and spanned three decades, reached out to the masses. Despite his propensity for vigorous exercise — which included heavy weight training long before it became popular — his training consisted of simple exercises that could be done in the living room, the backyard or anywhere you could fit your body.

LaLanne's just-move-it approach to exercise gained popularity in the 1950s and fitness evolved from the simple, do-it-anywhere, low-cost concept, to a multibillion-dollar industry that pushed hardcore, high-impact workouts. Given the aging population and the epidemic of inactivity and obesity in the past decade or so, the fitness movement is once again advocating simple, daily physical activity.

Here's a look at other famous fitness leaders, and the messages they have preached.

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Caption: Richard Simmons's videos include Dance Your Pants Off! and the Sweatin' to the Oldies series. ((Tina Fineberg/Associated Press))

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Montrealers Ben and Joe Weider are credited with moving body-building from cult status in the 1950s to the mainstream. The brothers started their body-building mecca and magazine empire in the early 1950s in New York with the publication Your Physique. After running into some business troubles, the Weiders developed the Mr. Olympia contest and created the International Federation of Bodybuilders. The Weiders also backed Austrian body-building superstar Arnold Schwarzenegger, who catapulted to fame following the 1977 film Pumping Iron. The Weiders built their empire by selling weight training to men and women as an important aspect of fitness, with mass circulations of magazines including Muscle and Fitness, and Shape. Ben Weider died in 2008 at age 85. Joe Weider, now 90, continues in the family fitness business.

Texas beauty Debbie Drake was considered a fitness trailblazer as the first woman to star in her own daily exercise show, which debuted in 1960 across North America. She remained on the air, with Debbie Drake's Dancercize, until 1978. She also branched out into books, like Debbie Drake's Easy Way to a Perfect Figure and Glowing Health, and record albums, including Look Good! Feel Great! and How to Keep Your Husband Happy. Drake is still active in promoting exercise and positive lifestyles.

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Caption: Jane Fonda's Workout Book sold 17 million copies. ((Associated Press))

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Known for his uber-enthusiastic approach, as well as his wild tight shorts and muscle shirts, Richard Simmons opened his first exercise studio in 1975 in Beverly Hills, Calif. Using his childhood struggles with weight to motivate others to battle the bulge, Simmons has encouraged hundreds of thousands of people to sweat along with him for more than three decades.

Who could forget American actor-turned political activist-turned fitness guru Jane Fonda, with her lean and lithe body in those slouchy workout socks and body-hugging tights? Inspired by her bestselling book, Jane Fonda's Workout Book, she released her first exercise video, Jane Fonda's Workout, in 1982. The video sold 17 million copies.

Fonda subsequently released 23 workout videos, five workout books and 13 audio programs. Now in her 70s, Fonda has relaunched her Jane Fonda Workout brand with a new team of young trainers, with walking and strength-training videos aimed at older people.

Bess Motta, Arlaine Wright and other divas in Flashdance -inspired exercise gear led North Americans in sexy aerobic sweat-fests known as 20 Minute Workout. Hailed at the time as the first aerobic workout TV show featuring a group of physically fit exercisers, the provocative Canadian-produced show was first broadcast in the early 1980s and in rerun syndication until the mid- to late 1980s (and as recently as the early '90s in countries like Canada). Each program had a designated group leader who was wired for sound and gave the exercise instructions. The series advocated a high-impact form of exercise that has now pretty much gone by the wayside.

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Caption: Bob Harper, centre, Jillian Michaels, right, and host Alison Sweeney form the hardcare team on the U.S. reality show The Biggest Loser. ((Mitchell Haaseth/NBC/Associated Press))

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For more than two decades, Hal Johnson and Joanne McLeod have been encouraging people to live a healthier, more active lifestyle. Through their short Body Break television spots and public appearances, the duo's motto has always been: "Keep fit and have fun." Their official website says: "Our goal for BodyBreak remains the same as it was back in 1988: To encourage Canadians to live healthy, active lifestyles. … no matter what your race, gender or physical limitation, we can all live, work and play together."

Jillian Michaels and Bob Harper are the drill sergeants who put obese contestants on the U.S. reality show The Biggest Loser through gruelling workouts meant to turn them from fat to fab in a matter of weeks.

Launched in the early 2000s, the show has been a ratings hit, but has also been criticized for setting unrealistic expectations for the average person.