Four that go the distance

Somewhere between the $70,000 anti-gravity treadmill that uses an air vacuum to lower your body weight by 50% or more and the $369 department-store rattletrap with a tread belt about as burly as toilet paper is the sweet spot: a moderately priced treadmill that's tough enough for years of serious running and walking. The four below offer heart-rate readouts, good reputations, solid feel and a nice array of high-performance programs.

-- Roy M. Wallack

Lightweight champ

Lifespan TR 2000 fold-up: Compact treadmill, great for small spaces and small runners, with nice safety and performance features, including a rare 5% decline.

Likes: Very small footprint (63.5 inches long) due to unique under-the-belt motor (rather than in front); 32 inches when folded up. Includes 2.5-horsepower engine with maximum speed and elevation of 10 mph and 10 degrees, with a 1% to 5% downslope. Convenient handlebar speed and incline control toggle buttons let you adjust at full stride. Despite small size, the deck is a passable running length (56 inches). Child-safe belt pauses after 20 seconds of nonuse. Feels firm compared to other treads in this price range.

Dislikes: On the descents, I felt some belt slippage at 9 to 10 mph. I weigh 180 pounds; the salesman told me he recommends this one for runners 165 or less (the recommended maximum user weight for walkers is 350 pounds). Also, none of the programs include descents. Heart-rate chest strap is optional. Price: $1,599 (on sale at $1,399). (877) 654-3837; www.lifespanfitness.com.

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A solid fold-up

Spirit XT 675 fold-up: Solid-feeling tread for enthusiast runners has a load of good features.

Likes: Very solid and quiet. Although built like a tank at 264 pounds, it folds up easily. Nice features abound: 3.5-horsepower motor; 60-inch belt; instant-response elevation and mph buttons (with a maximum slope of 15 degrees -- great for hiking workouts), with easy-access remote controls on the handles; quality three-ply deck; six wheels for fast rollaway storage; iPod input jack with speakers; dual fans; nine programs, including heart-rate control; a knee-level storage bin.

Dislikes: Heart-rate chest strap is extra.

Price: $2,399. (Note: The 675 is an upgrade of the still-available 600 model, which has similar features and feel, $2,099). (866) 697-6531; www.spiritfitness.com.

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Up and down the hills