For years infomercials have played off the elusive dream of one-stop fitness -- a contraption or exercise routine that provides a total body workout to those big and small, young and old.
This one-size-fits-all approach is misguided, according to exercise experts. We should be exercising according to the kind of life we lead -- each person is going to bring different exercise needs to the table according to their personal preference and physical capabilities.
ABC News asked leading fitness experts and kinethseiologists to weigh in on which exercises are a best fit for people of various ages, stages of life and level of fitness. As always, experts recommend consulting with a physician before starting any exercise program.
The Couch Potato -- aka, the Exercise Newbie:
Expert Favorite: Walking plus weight lifting
They haven't been friendly with the gym for years, or maybe they were just never the exercise-type, but they're turning over a new leaf. Former couch potatoes should resist the temptation to jump on the treadmill, fitness experts warn. Exercise tolerance -- the amount of exertion one's body can handle -- "is not something to be messed with," says Jason West, clinical assistant professor in the exercise and sports medicine department at the University of Tulsa.
For people who haven't been active in a long time, "they're almost like a kid in their training age. Their room for gain is huge, but they're going to have muscle soreness or injuries if they don't start slow," he says.
West recommends starting with a walking program, supplemented with some weight training on machines. Because lifting free weights requires balancing the body while lifting, weight lifting machines are a good place to start because people can "just sit in a comfortable position and focus on one muscle group," he says.
"A lot of times people are sitting at their job ten hours a day and then think they can go and work out," says Wendy Dolen, exercise physiologist and wellness coordinator at M-Healthy at the University of Michigan. She agrees with walking as a starting point for those new to working out, but also emphasizes moving throughout the day so that the workouts are such a shock to the body. "Answer the telephone standing, hand-deliver a message, anything to incorporate movement into your day as well," she says.
With those who are new to working out, there's always a high risk of falling back onto their sedentary ways, says Peter Walters, associate professor in the Applied Health Science Department, Wheaton College. "Half of people who begin an exercise program aren't continuing after two months. My thought is, 'What is an activity that someone cannot just do, but enjoy?'," he says. "For the elderly that's often walking, for younger people that tends to be some kind of group exercise class or activity."
The Single Parent on a Tight Schedule
Expert Favorite: Housework Training
For parents who don't feel that they can dedicate a chunk of time to a workout, Davis suggests embracing household chores and playtime with kids as a way to amp up activity levels. Taking the stairs two at a time with a basket of laundry is like a lunge with added weight for resistance. Pushing a child on the swing is like a low-intensity chest press. Using a manual push lawn mower is both cardiovascular and resistance training.
For parents who feel they can squeeze a trip to the gym into their busy schedules, West suggests circuit training using the weight machines. Rotating around exercises that use different muscle groups cuts down on the recovery time between sets.
Though people often prefer to wait until later in the day to go to the gym, Walters urges parents to get up a bit earlier and do their exercise routine, whether at home or at the gym, before the day starts. People who slot it into their day in the morning are more likely to stick to it than those who push it off until the evening, he says.
The Mommy-to-Be -- Baby-Bump Friendly Fitness
Expert Favorite: Prenatal Yoga
A pregnant woman's body has to change in a number of ways to accommodate the baby. These changes can have serious consequences for the types of exercise she can do and the type of injury she is at risk for. The extra weight in her stomach and breasts will change her center of gravity and put extra strain on her lower back; her joints will become more elastic which will increase the risk of injury if she tries to do high-impact exercise; her blood pressure is more susceptible to spiking if she's not careful about keeping her head higher than her heart.
As a result, pregnant women should never try to work out harder than they did before becoming pregnant and in general should look to low-impact, low-intensity forms of exercise such as walking, pregnant yoga, and swimming.
"Prenatal yoga is something I refer people to often because it rolls in breathing techniques that they will use during labor with stretching and flexibility," says Dolen.
Into the second and third trimesters, women should choose exercises that support the abdomen and lower back because there will be a shift in her posture due to the extra weight, says Billy Davis, director of personal training at Complete Body and Spa in New York City. "Seated and lying exercises, no heavy squats, and more walking, less running."
The Ex-Jock/Weekend Warrior
Expert Favorite: Lower-Intensity Weight Lifting
They were the quarterbacks, the volleyball captains, or the cross country runners back in high school and college, but out in the real world, their office jobs leave them sedentary. These "ex-jocks" tend to be weekend warriors when it comes to exercise: they go for high-intensity exercises or community sports leagues on Sunday but are sedentary the rest of the week. This puts them at high risk for muscle strain, joint pain, and other kinds of injuries, as their attempts to recapture their glory days leads them to overreach their body's abilities.
"They do too much too soon and you see a lot of immediate injuries," says Dolen, of University of Michigan. "You can't leave it all to the weekend. You have to make time in the week to exercise as well or you're going to keep hurting yourself," she says.
Former athletes, even those who have been "on the bench" for a decade, do have an advantage over those who were always sedentary, says West, of University of Tulsa. There will be some carry-over of their former fitness, but they're still going to have to start with the basics if they want to excel at sports again, he says: flexibility, cardiovascular training and resistance training.
"You can go back and lift again, but you're going to be working with less weight than you remember and you're going to need more recovery time than before," says Davis. As long as they build up in intensity slowly, the sky's the limit in terms of the kinds of exercise they can pursue.
The Generic Jogger in Need of a Boost
Expert Favorite: Weight Training
When the weather is nice, they take to the streets and parks: they run because they like it, or because it's simple and free. Those who jog quasi-regularly are usually in good cardiovascular shape, but they can be surprisingly low in muscle strength or flexibility, experts say.
This makes casual runners a prime candidate for a little weight training to build up the muscles that support their running, such as those in the back and stomach. Especially after age 40, injuries from running will be muscular and skeletal, Walters says, so building up the muscles with strength training will make someone less likely to injure themselves during their weekly jog.
For casual runners who want a jumpstart, West recommends high-intensity interval training (HIT). It's running, only amped up: "sprint for 30 seconds and rest for 30-90 seconds and then repeat," he says. The same principle can be applied to biking or other kinds of aerobic exercise. Studies show that people who do this kind of high-intensity interval training boost their aerobic capacity more than those who exercise five times as long at a slower, steady pace.
The Retiree With Arthritis
Expert Favorite: Aqua-Aerobics in a Heated Pool
Expert Favorite: Aqua-Aerobics in a Heated Pool
One in five adults has arthritis in one form or another. For some it can hinder exercise, for others, the pain can make daily activities like bathing seem impossible. Though it was long thought that those with severe arthritis should avoid exercise so as not to aggravate their joints, doctors now know that regular activity and strength training can help restore joint function, according to the Arthritis Foundation.
Low-intensity, low-impact exercises that don't require a lot of balance are key for those suffering from arthritis. This is why hands down the best exercise is working out in a heated pool with styrofoam dumbbells . On land, lifting weights can lead to strain or injury if they are dropped, and only work the muscles in one direction. Moving a Styrofoam dumbbell underwater provides resistance in every direction, while the warmth of a heated pool keeps the muscles and joints loose and less prone to injury, says West of University of Tulsa.
"Even walking in a shallow pool is good. You get all the resistance without all the weight bearing down on their joints. Not to mention, it's fun. People like pools," says Complete Body and Spa's Davis.