The Shake Weight is a dumbbell in which the weights on either end are attached to the handle by a spring. It is sold by a company called Fitness IQ. It can be purchased online, in some retail stores, and from television infomercials.
There are two versions of the Shake Weight: one for men and one for women. The women’s Shake Weight weighs 5 lbs and costs $19.99 before shipping and handling. The men’s Shake Weight weighs 10 lbs and costs $29.99 before shipping and handling. The package is shipped directly to your door and includes one Shake Weight, a workout DVD, and instructions.
How It Works
According to the Shake Weight’s advertisements, it works by a method called "dynamic inertia."
The weight bounces off the ends of the handle by the spring as it is shaken back and forth. The user performs this shaking motion in various positions to target the major muscles of the upper body, such as those in the chest, shoulders, and arms. The movement of the device is generated by the user and is not battery powered.
Basically, it moves only when you shake it.
The Shake Weight Workout
The Shake Weight includes a 6-minute workout DVD that focuses only on upper-body exercises.
During the workout, the instructor on the DVD guides you through a series of exercises that involve shaking the weight in various positions.
For example, to target the shoulders, the instructor grips the handle in both hands with one hand being placed on top of the other. The arms are held in front of the body and the Shake Weight is rapidly shaken toward and away from the body. To target the triceps, the weight is held by both hands behind the head while quickly shaking it up and down. The biceps exercise involves holding the weight with one hand at about the level of the head while continuously shaking it toward and away from the body. The shaking exercises lasts approximately 20 to 30 seconds each.
In between the shaking sets, you do active recovery, which involves either some type of stretch or a movement that is similar to traditional dumbbell training (such as doing a standing chest fly or bent-over triceps kickback) while holding the Shake Weight.
There are no instructions about how often the workout should be performed.
The Shake Weight is affordable. The exercises can be easily performed. You can carry the device almost anywhere. The exercise plan offers a quick workout. The company claims that there is a 100% money back guarantee for unsatisfied customers. The weight is very light, so almost anyone can perform the exercises.
For a muscle to be fully stimulated, resistance must be applied through a full range of motion. The Shake Weight does not deliver this and will not result in the same muscular activity as traditional dumbbell exercise, despite what the company claims.
Also, you cannot add additional weight to the device and it offers limited exercises. A muscle improves when it is continually challenged with increased resistance and targeted with a variety of exercises. Therefore, very little (if any) results should be expected with the Shake Weight.
The company claims that the Shake Weight for women will result in lean muscle, which implies fat loss, while it claims that men will experience an increase in muscle mass. However, the workout program of only 6 minutes is not enough exercise to actually burn a significant amount of fat, nor is there enough weight to increase muscle mass.
In addition, the Dynamic Inertia concept may sound unique and complex, but it is neither. “Dynamic” and “inertia” are two terms used to describe movement. Based on this concept, all forms of resistance training involve dynamic inertia.
As a matter of fact, you will get a greater amount of movement with traditional weight training, in which you can target your muscles through a full range of motion. The shaking motion of the device is unnatural and may cause muscle spasms that could lead to injury.
The company also claims that the Shake Weight has been validated by a well-documented scientific study from a prestigious university. However, the actual study is not published in any peer-reviewed scientific journal. A reference to the study cannot be found on the Shake Weight web site, in any advertisement, or with the product package. An attempt to search for the specific study online also yielded no results.
Save your money and do not buy this exercise device. You can probably get the same type of workout by using a regular 5-lb. dumbbell and shaking it back and forth.
Of course, that would not be recommended as an effective way to work your muscles very well, either. The best way to sculpt your arms, tone your upper body, and decrease body fat is to perform a well-designed workout routine that offers a variety of aerobic and traditional resistance training exercises.
The American College of Sports Medicine (ACSM) recommends at least 2-3 days per week of total-body resistance exercise for most people who want to increase or maintain muscular fitness. The ACSM also recommends a minimum of 30 minutes of moderate-intensity physical activity on most days of the week to improve overall health.
Although it may be better than doing no exercise at all, the Shake Weight does not come close to meeting the published and well-respected scientifically based exercise guidelines.
(Michael R. Esco, PhD, CSCS, HFS, is an assistant professor in the department of physical education and exercise science at Auburn University Montgomery in Montgomery, Ala. His opinions and conclusions are his own.)