Sky King Calf Isolator Review

The Sky King Calf Isolator is a cleverly designed device that promises to train your calves like nothing else. Well, as the home of vertical jump training we had to check that out. Read on for our findings.

What Exactly is the Sky King Calf Isolator?

The Sky King is a device consisting of a support belt, some straps, two heavy duty springs, and two heavy duty foot stirrups. Essentially you wrap the belt around your waist behind you and each foot into a stirrup.

Then you pull the straps tight to create the tension in the springs. Once you have strapped yourself in you contract your toes and calves into a planter flexion motion which is resisted by the springs. Pretty simple stuff really.

Sky King Calf IsolatorSky King Calf Isolator

Our Training Experiences

The Sky King Calf Isolator is a unique take on lower leg training. We found using the device fun and convenient. It is also very portable so you can take it with you if you go somewhere that doesn't have access to a gym..

The calf isolator as the name suggests is designed to train your calves. In this regard it works very well. In less than 10 minutes every second day you can have your lower legs thoroughly fried. Another bonus that we weren't expecting is that it also effectively helps trains the muscles in your feet.

This is an often under-trained area when it comes to increasing your vertical jump. Your foot is the last bit of your body to touch the ground before you jump. In essence it is your last opportunity to apply force for maximum jump height. Powerful feet muscles are therefore obviously advantageous to your hops.

Interestingly, when I first started using it, it was always their feet muscles that gave out before the calves. After a few weeks they soon adapted but it certainly showed how under developed they were.

One interesting way we found to use the Sky-King was to sit down about 45 minutes before going to bed, train the calves for 10-15 minutes, and then do 30 minutes of stretching. Whilst strapped into it, the springs provide a fantastic hamstring and calf stretch. So you do your calf work, then start stretching those muscle groups.

Sky King Calf IsolatorCalf Isolator in action!

Does the Sky King Calf Isolator Work?

As with all training aids this is the important question. Unless a thorough scientific study is conducted isolating the various training variables it is difficult to tell if the training aid is helping, or if the training itself is doing the work. However, acknowledging those limitations, it is our belief that it does indeed strengthen your calves.

Value For Money - The BIG Let Down

So far all our feedback has been pretty positive. We liked using it. We found it easy to use. It was fun. It was convenient. It worked to a certain extent. However, it is also VERY EXPENSIVE for what it is.

As is mentioned on this site a number of times, the majority of your jumping power is generated from above your knees. That said, it is still important to develop those lower leg muscles.

The Sky King Calf Isolator promotes itself as getting a calf workout unlike any other. We disagree. As good as the device is, we feel you could just as easily get the same benefits from doing just about any weighted calf exercise. It does give you a great hamstring and calf stretch but there are many stretches that you can do using no equipment that also give you the same feeling.

Finally the real kicker. The Sky King costs $99.95, which quite frankly is a lot of money to pay for what boils down to convenience.


The Sky King Calf Isolator ultimately fails our value for money test because it is just too expensive given the same results can be achieved using just about any weighted object and step.

If you like the idea of sitting at home in front of the TV whilst simultaneously improving your vertical jump, and are happy to pay $99.95 for the privilege than this device might.

However for the majority of athletes looking to increase their vertical jump, you will be just as happy to save your money and do your calf work at the gym. And to that end, we couldn't disagree.

Look, if you really are serious about increasing your vertical jump don't mess about with gimmicky things such as this device. For less than half the price you can grab a copy of our Game Changers book which has a number of insane vertical jump training methods that you can use to EASILY ADD 6-12 INCHES TO YOUR VERTICAL.


Download our FREE REPORT and gain 4 inches on your vertical in 4 weeks!