Wall Street shouldn't rule your workout. But marketing fitness products is a big business—$5 billion in 2007—so the industry is full of gear meant to deliver fiscal dividends first and physical results second, says Fabio Comana, C.S.C.S., an educational curriculum developer for the American Council on Exercise. "There are a ton of bad fad products out there that are either ineffective, unnecessary, or dangerous," he says. His fail-safe rule for filtering out the duds? Seek out simplicity. "Recent research into how the body's muscles and joints move has given us a better idea of what type of equipment is actually effective," says Comana. Read on for our favorite low-tech, high-intensity power tools.
Best Home Gym
FreeMotion EXT Dual Cable Cross
Most home gym machines lock your limbs into one range of motion, limiting potential strength gains. The arms on this machine swivel like shipyard cranes into 108 different positions, recruiting stabilizer muscles and increasing the time muscles stay under tension. The net benefit is a superior workout, according to a 2008 study published in the Journal of Strength and Conditioning Research. Scientists found that compared with users of fixed-form equipment, men who work out on free-form machines saw a 58 percent greater improvement in strength and a 196 percent greater improvement in balance, and they felt 30 percent less pain.
"The repetitive motions on fixed-form equipment probably cause muscular imbalances that lead to structural changes and the increase of skeletal-frame stress," says study author Keith Spennewyn, M.S., president of the National Institute of Health Science. "Free-form exercise reduces these factors by training muscles and joints together, the same way they function out in the real world." The FreeMotion machine isn't cheap, but free delivery and in-home setup sweeten the deal. ($4,000, freemotionfitness.com)
Best Lo-Fi Fitness Tool
Iron Woody Woody Bag
The rugged PVC shell of this amped-up sandbag allows you to perform dynamic moves, such as snatches, jerks, and throws, without creating a dust storm in the process. "We have about 400 athletes a week using them," says Tracy Sibley, director of strength and conditioning at Gardner-Webb University in Boiling Springs, North Carolina. "Even with all that punishment, the bags are nearly indestructible." ($60 to $120, ironwoodyfitness.com)
Best Total-Body Tool
Fitness Anywhere TRX Suspension Trainer Force Kit
Designed by a Navy SEAL as a go-anywhere workout, this set of nylon straps creates resistance from two sources always at your disposal: body weight and gravity. Lock the straps onto any elevated fixture—a pullup bar, door, or tree branch—and you'll unlock new dimensions in your training. "Traditional isolation exercises, such as the biceps curl and side lunge, primarily occur in only one of the three planes of motion," says Todd Durkin, C.S.C.S., owner of Fitness Quest 10 in San Diego.
"But with multiplanar training on the TRX, we're able to strengthen muscles and joints as a group, ironing out any muscular imbalances. That makes the moves more effective, realistic, and challenging." Resistance can be adjusted from 5 percent to 100 percent of body weight by changing the incline of your body. ($210, fitnessanywhere.com)