So when it comes to training, I want to get my work done,” James said. ”I want to get the most out of it, and I want to be very efficient.” Tonal gives him exactly that kind of workout productivity. “The efficiency of Tonal is second to none when it comes to strength training,” he said.

LeBron James. Powered by Tonal. Video of LeBron James completing a full body workout using Tonal.

Williams, one of Tonal's early investors, leads a growing list of over 30 athlete investors and brand ambassadors that includes LeBron James, Stephen Curry, Klay Thompson, Tony Gonzalez, Drew Brees, Maria Sharapova, Michelle Wie, Paul George, Sue Bird, Larry Fitzgerald, and Bobby Wagner.

Does Tonal really work? Just like any other piece of home fitness equipment, you get out of it what you put into it. If you use the Tonal machine regularly and consistently, then, yes, you can reap a number of benefits. I found that for strength-building and high-intensity exercise, Tonal is extremely effective.

Since Tonal uses an electromagnetic motor instead of metal to create resistance, you can't rely on momentum like you would with dumbbells and traditional weights to help you through each rep.

Your gym. And your motivation. Right there on your wall. An all-in-one design can change change and change again to replace every machine in a weight.

Still, Tonal is on to something, and has a laundry list of all-star investors including Amazon, LeBron James and Serena Williams. It's easy to see why they love it, but the real challenge will be getting the price to a place where it doesn't feel so heavy for the average person to lift.

That price starts at $3,995, plus tax; plus delivery and professional installation ($295); plus the “Smart Accessories” - the bar, handles, rope, bench, foam roller and workout mat that you need to do a lot of the exercises - ($495); plus a monthly membership fee ($49), which adds up to a (very) grand total of about $4,900 ...

$59.95 per month You'll also need an active Tonal membership, which costs $59.95 per month. However, you can share the membership with others in your household. Without the membership, though, most of the features - like the classes, dynamic weight adjustments, form feedback and workout reporting - are inaccessible.

The purpose of Tonal is to replace all types of strength training equipment -- you'll just need the one machine to get a full-body workout. Tonal has 17 different sensors to assess your form, technique and speed, and it gives you feedback based on this to help you self-correct.

Does Tonal really work? Just like any other piece of home fitness equipment, you get out of it what you put into it. If you use the Tonal machine regularly and consistently, then, yes, you can reap a number of benefits. I found that for strength-building and high-intensity exercise, Tonal is extremely effective.

Does Tonal really work? Just like any other piece of home fitness equipment, you get out of it what you put into it. If you use the Tonal machine regularly and consistently, then, yes, you can reap a number of benefits. I found that for strength-building and high-intensity exercise, Tonal is extremely effective.