JIN BD Wrist Trainer Ball Auto-Start Gyroscopic Forearm Exerciser Gyro Ball for Strengthen Arms, Fingers, Bones and Muscles

It's a fun little exercise ball and it will work your forearm. The lights the ball produces when it spins are entertaining but much more so at night and/or in a dimly lit room, in a bright room the lights are barely noticeable. The instructions that came with the ball are a little vague, I ended up going to the online Google video to see how to get this ball started. Many years ago I had a Dyna-flex exerciser (I probably still do in a junk and clutter box somewhere in my house) and without reading the instructions I tried to start this ball the old Dyna-flex way, every attempt failed. I then tried reading the instructions that came with the ball, they were vague and unhelpful. I watched the video on how to start the ball which was very helpful but left out the first step. First, place the ball in the hand which you plan to exercise or to get the ball started. This will help you to get the right feel for the ball, if you wait until after the ball tries to start spinning to figure out your hand placement the inner gyroscope ball will lose all momentum as you are trying to figure it out. Second, place both thumbs on the arrows on the ball. One thumb at a time, push down and forward on the ball, alternate walking the ball in the direction of the arrows with your thumbs. In a very short time you will begin to feel tension building up on the ball, push a little further until the ball feels like it wants to spin back against you. Hold the ball in place with one thumb while you find your grip with the hand you plan to exercise. Once your working hand is in place release your thumb hold on the ball and begin working your wrist, you will know within a few seconds if the inner gyroscope ball has been activated. It took me four attempts to get this ball started the first time, it hasn't taken more than two attempts since.

Phenomenal and unique exercisor for wrist, hand, forearm. I use it several times a week. Easy to use and very effective. Strengthens grip and hand strength, and arm and shoulder too if you know how to use it. Still working great after 10 months.

I've gotten into climbing this year, so I'm always looking for exercises that can improve my forearm and grip strength. A friend recommended these gyro balls to me, and after looking up different models, I decided this one would be good to try. The device comes in simple box. Inside is a card with a QR code linking to a video for how to use it, the gyro ball, a nice case for the gyro ball, and a wrist lanyard for safety. The device itself has a labeled tacky external rubber grip going across the middle third of it. The rest of the exterior is a clear plastic that feels on the cheaper side and somewhat easy to scratch, but after a day of use I haven't actually had any functional problem with it. Shaking device it has a little bit of a plastic rattle. Having never used one of these, I followed the QR code they supplied and watched the YouTube video. To get it started, the center ball of the gyro needs to be spinning, and to do that, you basically use your thumbs to rotate the ball in the direction of the arrows on it (using the grippy strips on the ball) and wind the ball until it's difficult to move. It's important to note (and not mentioned in the video), that during wind up the device must be placed horizontal initially (flat side facing down) while starting to wind up, or the winding won't catch. This is similar to wind up toy cars from when I was a kid. Then while still holding the ball in place with one hand, you place the device in your other hand, grip the exterior, and release the wound up internal ball. At that point the ball is spinning. While keeping your palm parallel to your arm, you then rotate your wrist 90 degrees along the axis of your arm, then back again, and repeatedly keep doing this. The rotational force (centripetal) is transfered to the spinning ball speeding it up, and in return you end up feeling a force (rotational inertia) resisting your movement. The faster the ball moves, the greater the resistance becomes. It took me a few tries, but I've had no problem getting it to work every time since. I saw a lot of reviews saying it doesn't work and that they were struggling, and watching the video or other ones explaining how these work is very useful. The key is small movements along a fixed rotational axis as described. While the rotation I described kicks it in quicker, you can learn to use other wrist rotations to keep it moving as well. Once the ball hits a certain speed (I think 500 rpm according to the video), you'll see rainbow lights on it and hear at speeding up. I found that as it gets really fast it can be quite loud, and I have no idea how it compares with other ones, but it doesn't bother me too much. As for effectiveness, I was really surprised how quickly I felt fatigued in my wrist, forearm near my wrist, and back of my hand closer to my wrist. I don't feel much fatigue in my fingers or anywhere else. I rock climb twice a week at a beginner level, I'm relatively fit, and when I get the ball moving near the limit of controlling it stably, I feel a surprising amount of fatigue in less than a minute currently. After that I usually carefully switch hands (so I'm not using the safety lanyard), and I alternate. Keeping it at slower speeds I can do it for longer. Overall, I'm pretty happy with this so far. I'm sure it will improve my wrist and forearm strength a bit, although I don't know about grip strength. The device seems to be working exactly as advertised, and I'm hopeful that it will continue to perform. I would say it's worth the money. And in case you were concerned like I was at some of the reviews, it would seem a lot of these devices here have mixed reviews when you sort by most recent, but when you read the reviews, they are full of people who claim the device doesn't work or they couldn't get it to work. It's possible there's quality control issues, but considering how common the complaints are even on more popular ones, it's likely people just aren't learning how to use it (which took very little time if people watch the video). Even some of the reviews for this product have videos of people getting the ball spinning, but they're improperly rotating their wrist in a way that is inconsistent with the instructional video. It's very easy to use if directions are followed.

I liked how it was packaged and delivery was fast but the functionality of it is disappointing to me. The way the picture looks you would think that you would get colors flashing but you don't, or at least, I didn't. The only strength that I am building up is pushing down on it with my thumbs to make it have resistance. It doesn't matter how fast I move my wrists the ball doesn't keep turning.

Amazing gadget! I had surgery on my arms a couple years ago and have lost a lot of strength in my hands and arms. I felt this might help some after reading reviews. After the first use I noticed that my hands didn't feel tight anymore. Then I began to feel it loosing up my forearm and took the aches away. It's been a couple of weeks of doing about 5 minutes per hand about every other day and my strength is improving! The pain is gone and I can move my fingers with ease now. I can open jars again and it has just been wonderful. My husbands elbow pain has also improved. He says he didn't even realize he had stiffness in his hands and arm until he felt how loose and light it feels now. It definitely strengthens and works. I am all about doing anything to improve naturally. After winding the gadget, work your wrist with the rotation of the ball inside. We figured it out pretty easily.

It takes time learning to consistently get it started and the key is winding it tight enough. I use it at least 20 minutes a day, 10 minutes per hand. I can tell it is strengthening my hands, wrists and forearms.

Works wonderfully! This wrist trainer will work your muscles very well. It is well built and is great to sit and work my forearms. Worth the money and If I ever wear this one out I’ll be buying another.

Most complaints on this product are about starting. I think this is either user error or defective units. I'm glad I got the version with LEDs, because it's a good indicator of the speed that helped me learn to start it. The mechanism for starting it is simple. There is a spring that needs to engage, then you wind it and let go. The spring won't engage in all positions. For example, if you put it vertical with the arrows pointing up it never engages. Horizontal as in the instructions, or vertical with the arrows pointing down, it works fine. If when you release the wheel the LEDs don't turn on, or barely do, the winding was not enough. They have to turn on in bright multicolor and you know you got it right. Then it's a matter of learning how to move it to get it to rev faster, basically by opposing its movement. I did touch the spinning wheel multiple times, usually on purpose to stop it. It can hurt if you get your skin pinched, but I don't think it can cause an injury. This is however a downside and hence 4 stars instead of 5. I think it's safe for me, but I would not give it to my kids.