are constantly searching for something that will give them a competitive
edge. Performance jewelry is one of the latest products on the market
designed to improve athletic performance. The most common claims are that
wearing this performance jewelry will improve flexibility, balance, and
strength. There is considerable marketing of these products, including
testimonial evidence by high profile athletes, in support of the purported
benefits. In demonstrations designed to validate the performance enhancing
benefits of these products, however, companies typically conduct the testing
in the following sequence: The first trial is done without the bracelet
on and the second trial is performed with the bracelet on. Invariably,
subjects perform better on the second trial. This brings into questions
whether the improvement on the second trial is due to 1) a benefit of
the bracelet, 2) the fact the subjects were warmed-up (Maud et al., 2006a;
3) subjects being habituated to the task (Benson and Friedman, 1996; Wright
et al., 2009),
or 4) a placebo effect (Beedie and Foad, 2009).
One of the most popular performance enhancing bracelets currently on the
market is sold by Power Balance® (www.powerbalance.com). The
Power Balance® bracelet has two dime-sized holograms; one on
either side of the bracelet. The holograms within the Power Balance®
bracelet are designed to "resonate with and respond to the natural
energy field of the body". This purportedly improves flexibility,
balance, and strength. To our knowledge, no randomized, double- blind,
placebo trials have ever been conducted evaluating the validity of these
claims. Thus, the purpose of this study was to evaluate whether wearing
of the Power Balance® bracelet can improve trunk flexibility, balance,
strength, and lower body power.
Forty-two NCAA Division III athletes (22M: 20.1 ± 1.4 years, 1.82 ± 6.4
m, 82.0 ± 12.6 kg; 20F: 19.5 ± 1.3 years, 1.66 ± 6. 8 m, 63.2 ± 8.1 kg)
completed four tests: trunk flexibility, balance, strength, and vertical
jump. The trunk flexibility, balance, and strength tests were the same
tests that are presented on the Power Balance® website (www.powerbalance.com/test-video).
The vertical jump test was added as a test of lower body power. Subjects
performed two trials of each test, without warm-up: During one trial subjects
wore a Power Balance® bracelet and for the other trial subjects
wore a placebo bracelet. The order of bracelets was randomized and the
testing was conducted in a double-blind fashion. Neither the subject nor
the examiner knew which bracelet the subject had on for each trial.
Comparisons between the Power Balance® and placebo bracelet
are presented in Table 1. There was no significant difference
in flexibility, balance, strength, or vertical jump height between the
Power Balance® and placebo conditions. Comparisons between Trial 1 and
Trial 2 scores are presented in Table 2. Flexibility, balance, strength, and vertical jump
height were all significantly greater for Trial 2 compared to Trial 1,
regardless of which bracelet was worn for the second trial.
study found that under the testing conditions used in the current study,
there were no significant performance benefits when wearing the Power
Balance® bracelet compared to the placebo bracelet. Trial 2
scores were significantly greater than Trial 1 scores for all of the testing
measures. Because the order of bracelets was randomized and balanced,
these improvements were attributed to the fact that subjects were either:
1) more warmed-up (Maud et al., 2006a;
or 2) habituated to the task (Benson and Friedman, 1996; Wright
et al., 2009).
In either case, these findings help to explain why the public demonstrations
of this type of product appear to have a beneficial effect on flexibility,
balance, and strength.
There are many ways to design a study such as this. This study was specifically
conducted in the fashion it was, in order to mimic the way the tests are
conducted by companies who try to show that their products enhance athletic
performance (i.e., Trial 1 without the bracelet and Trial 2 with the bracelet).
Thus, this study demonstrates that t the holographic bracelets do not
work as advertised. It should be noted that while this study investigated
the Power Balance® bracelet, it is presumed that results inves-tigating
other performance enhancing jewelry would be similar, under similar testing
circumstances. To fully evaluate any potential benefit of thes products,
future studies, in addition to being conducted in a randomized, double-blind,
placebo fashion, should incorporate a warm-up prior to all tests, as well
as a sufficient number of trials so the learning effect is removed from
all testing measurements. Additionally, even though most manufac-tures
claim that the improvement in performance when using holograms is instantaneous,
future studies may want to have subjects wear the bracelet for a longer
period of time to see if there is any effect under those circum-stances.