You have probably seen the colorful rubber bracelets with a magnet, which are supposed to improve your balance, strength and flexibility. They cost around $30.
The American Council of Exercise (ACE) sponsored a study to help determine if wearing a Power Balance bracelet will indeed enhance your performance. John Porcari, Ph.D. and his research team at the University of Wisconsin tested a college athletes, where each athlete performed two sets of four exercises: balance, strength, vertical jump and trunk flexibility. For one set of exercises, they wore a Power Balance bracelet, and for another set they wore a placebo rubber bracelet for $0.30. The order of wearing the bracelets was randomized and double-blinded, i.e. neither the athletes or the researches knew which bracelet was being worn for each trial. The results of the trial showed no significant difference in strength, vertical jump, balance, or flexibility between the $30 Power Balance bracelet and the $0.30 rubber bracelet. All subjects did better in the second round of tests – a phenomenon called the “order effect” – the athletes were either more warmed up, or got used to the task.
This explains why the public sales demonstrations of Power Balance appear to have an effect on balance, strength or flexibility. In reality, these demonstrations are just a trick. The sales people can easily change the outcome by the way how they apply the force to the body. They can push in certain direction, change the angle a little bit, or push or pull slightly differently.
Power Balance sold over three millions bracelets 2008-2011. If you bought the bracelet and feel cheated, the company promised to offer refunds to the customers who feel they have been misled. If you like how the Power Balance bracelet looks, you can find the cheaper, yet colorful versions anywhere online.
The complete ACE study can be found at www.acefitness.org.
Books and e-books on strengthening, stretching, myofascial release and improved performance are available here, in the tennis fitness love store.