First off, ankle or wrist weights are weights that one can wear around the ankle or the wrist. They come in either a band or pouches filled with weights, sand, or water. Some of these come with multiple weights that you can add or subtract to change the amount of weight you are using each time.
These are designed to increase resistance during certain cardio exercises however, one has to be very careful when using them. If you use them while walking, you should use light weights of no more than three pounds because ankle weights tend to make you the fronts of your thighs (quadriceps) rather than the backs of the thighs (hamstrings) thus causing an imbalance.
In addition, ankle weights tend to pull on the ankle joint which could result in injuries to the knees, hips, or back. It is much better to use ankle weights when doing exercises that target the hip and leg muscles such as leg lifts. Since ankle weights rely on gravity to provide resistance, when used with leg lifts, the muscles end up working harder leading to increased strength.
Furthermore, wrist weights can have the same issues of muscle imbalance due to swinging your arms back and forth. This movement can also cause injuries in the neck, shoulders, elbows and wrists. But as with ankle weights, there is a time and place to use wrist weights effectively. They can easily be used instead of dumbbells if you cannot use regular weights. They work well with targeted exercises such as bicep curls or rows.
If you want to use these, consider contacting an experienced personal trainer to learn the best way to use them so you don't hurt yourself. If you have joint or back problems, talk to your doctor. Like any weight, you do not want to use these every day and you only want to use them when doing exercises containing up and down movements.
Just because they fasten around the ankle or wrist does not mean you want to use heavier weights, consider what you would normally use and stick with that amount. Let me know what you think, I'd love to hear. Have a great day.