Updated dumbbells to reshape your workout

The traditional cast-iron dumbbell has some competition. As an ever-wider swath of the population seeks the numerous health benefits of weight training in the comfort of home, the old gym staple is being reshaped, re-teched and reinvented -- to the point where some models hardly seem like dumbbells. The four here offer unique connective-tissue strengthening, enhanced convenience, improved safety or greater efficiency.

-- Roy M. Wallack

Unconventional

Xco Trainer: A granulate-filled tube made to strengthen joints and connective tissue as well as muscles.

Likes: Works a large area through “reactive impact,” a phenomenon caused by unexpected change in direction. For example, although you may stop the lifting portion of a biceps curl, the granulate continues flowing upward for a second, forcing your joints to work harder to slow the weight and reverse direction. By subjecting muscles and joints to stresses they don’t expect, connective tissue and joint stability become stronger. Also, the Xco sounds cool -- like a big saltshaker. Three weights available.

Dislikes: May be too different for people wanting a conventional strength workout.

Price: $50 for the 1-pound weight; $55, 1.3 pounds; $60, 2 pounds; $65, 2.6 pounds. (800) 348-8371 or www.fitter1.com.

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Color-coded

Hampton Jelly Bells: Colorful, conventional-style dumbbells covered in urethane with extra-soft handles.

Likes: A comfortable grip that, when sweaty, is safer than that of traditional weights. Does less damage to your floor. Weight choices range from 5 pounds to 130 pounds.

Dislikes: Expensive compared with traditional all-metal dumbbells.

Price: $35 (one pair of 2.5 pounders); $51 (5 pounds); $70 (7.5 pounds); $80 (10 pounds); $100 (12.5 pounds); $120 (15 pounds). (877) 339-9733 or www.hamptonfit.com.

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Quick-change artist

ProBell: User-friendly adjustable-weight dumbbell system.

Likes: Extremely space-, time- and cost-efficient. A turn of the dial causes an internal cam system on the bar to pick up only the weight selected; the others stay in the tray. Economical compared with a series of stand-alone dumbbells.

Dislikes: None.

Price: 3 pounds to 18 pounds (in 3-pound increments, chrome finish), $229; 5 to 30 pounds (in 5-pound increments; black finish) $279. (877) 777-6235 or www.probell.com.

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Learning curve

Smart Bells: Curved, sculpted two-handled weight used in a full-body, integrated workout.

Likes: Efficient workout combines strength, flexibility, cardio and core training with a yoga-like flow. Available in 3-, 6- and 13.7-pound versions.

Dislikes: May be too different for those looking for a conventional strength workout.

Price: $74.95 (includes DVD workout). (800) 500-2030 or www.smartbells.com.