Are fitness gadgets on TV fit to use?

>>> moment. first, this is "today" on nbc.

>>> this morning on "today's" consumer, those as-seen-on-tv fitness products, we've all seen those commercials. they promise firm bodies and many of us have been enticed to buy. our consumer correspondent janice lieberman takes a closer look at some of those products. that's why we have our workoutoworkout out fits on.

>> we do. you did your tennis. we decided to give us the popular ones, as you've seen on tv, a real run for their money. we've all been enticed by those late-night infomercials.

>> are you ready to have sizzling hot abs?

>> now you can steal away the pounds.

>> they might have even persuaded you to buy. among the most popular, fitness products. but before they show up on late-night tv, a lot of products are showcased at the expo in san diego .

>> we did $6.2 billion in immediate wra purchase last year and were worth collectively $300 billion.

>> wow! so people like to watch infomercials.

>> people like to watch but more importantly, people like to buy infomercial products.

>> strutting his stuff.

>> look at this. i can do a lot of fun exercises to really work everything. and people ask me, does it work?

>> reporter: yeah, does it work?

>> i'll show you.

>> reporter: whoo, baby! with abs like that, i absolutely had to give it a try. this elliptical bike was a blast as well. not so easy, but it's fun. whoo! we were so intrigued by these products we decided to try some of them in new york. we enlisted professional trainers from chelsea pierce sports center in new york city to give them a real workout.

>> you need to read the instructions completely. sound good?

>> sounds great.

>> reporter: a week later, they were ready to give us their verdict on each product. on a scale of one to five, with five being the highest score --

>> get the sexy abs you've always wanted.

>> reporter: the torso ball for $80. what do you give it?

>> one of my favorites.

>> i thought it was a very effective way to get a positive workout.

>> it does what it says it's going to do.

>> reporter: then the wave.

>> we give this a five. total body workout.

>> combine it with dumbbells?

>> yes. great for balance for our senior population.

>> reporter: the third product they checked out trims your arms and shapes your shoulders at the same time.

>> reporter: the shame weight for $15. what do you think?

>> two for 15, we would give it a three. it's a little limiting, one arm.

>> puts in the gym as a hard core boxer, i don't know. i can't see using the shake weight.

>> the shaking and jie ration of the weight actually worked the muscles and tone and sculpt.

>> reporter: then the ab doer twist.

>> transform from flabby to fabulous.

>> reporter: for $139.

>> we're giving it a two. yep. pretty expensive compared to other ab exercise equipment .

>> better than sitting on the couch. not a great abdominal workout.

>> imagine getting sexy abs.

>> reporter: and last, but not least at $99, the rhythm rocker. what do you give it?

>> a four thanks to the video. i like the instability and versatility.

>> lots of fun. you could do both cardio and floor on it. i like that combination.

>> and great video.

>> reporter: but in the end, each trainer agreed, whatever product gets you to workup a sweat just might be worth your hard-earned cash. the makers of the ab doer twist tells us it's not an abdominal machine. rather it's a total body aerobic machine. and shake weight representative disagreed with the description of limited. they say it provides a variety of exercises that is performed in one of several six-minute routines, savannah. whatever gets you up and doing something --

>> i was going to say, janice, maybe you should test this equipment for how well it holds your dry cleaning. don't we end up throwing our clothes on it?

>> people have collections of these in the basement. you know what? if it gets you moving, it's better than sitting and watching tv , eating popcorn, watching them do the exercises on tv.

>> grab the shake weight or