Research and News
Top 10 Myths of Elastic Resistance
by Phil Page, PT, ATC
1. There is very little scientific evidence on elastic resistance. FALSE!
There are over 100 published randomized, clinical trials (the highest level of evidence) that have used elastic resistance. In addition, there are over 60 basic and applied studies that have been published to describe the scientific foundation for elastic resistance, including electromyographic (EMG) evidence and biomechanical analysis. The most comprehensive and updated list of these references is available at www.Thera-BandAcademy.com.
2. Isotonic or machine-based resistance is more safe & effective than elastic resistance. FALSE!
The injuries and rates reported with using elastic resistance in the literature are as small if not smaller than using isotonic resistance. Scientific evidence proves that the resistance provided by elastics is very similar to isotonic resistance in physiologic response, strength outcomes, and patterns of muscle activation.
Thera-Band Torque, compared to isotonic weights
3. In contrast to isotonic resistance, the strength curve (torque at the joint) of elastic resistance is linear & ascending. FALSE!
Many people confuse FORCE (resistance) with TORQUE (force x distance). This has led to the misperception that isotonic resistance is more “functional” to the strength capacity of muscles than elastic resistance. The FORCE produced by elastic resistance is linear and ascending, meaning that resistance increases proportional to amount the band is stretched (percent elongation). This increasing force curve is relatively flat within the clinical elongations (25-300%), and increases exponentially at elongations beyond 500%. The TORQUE (strength curve) of elastic resistance is actually bell-shaped (ascending-descending), similar to human strength curves and isotonic resistance
4. The resistance of bands increases with range of motion, making it difficult to complete the end of the exercise. FALSE!
Even though the resistance of the band increases with range of motion during elongation, the torque produced by the bands at the joint is “bell-shaped”, meaning that at the beginning and end ranges, the strength curve profile accommodates the strength curve profile of human strength curves. The change in torque occurs as a result of the changing angle between the band and lever arm, known as the “force angle.” As the range of motion increases, the force angle decreases, thus changing torque production.
5. The band must be perpendicular to the arm for maximum torque production. FALSE!
The torque (strength curve) of an exercise is determined using the formula, Torque = Force x Distance perpendicular to the Lever arm). This takes the vertical direction of gravity into account in addition to the resistance. The distance perpendicular to the lever arm changes as range of motion increases, and the maximum torque is generally produced where the lever arm is perpendicular to the resistance (as in isotonic resistance). However, unlike isotonic resistance, elastic resistance is not reliant on gravity. Therefore, instead of the distance perpendicular, the sine of the “force angle” (angle between the band and the lever arm) is used to quantify torque in the formula, Torque = Force x Distance x sine (Force Angle). Since the resistance of the band increases and the force angle decreases with increasing range of motion, the maximum torque is often noted at mid-range with proper positioning.
6. The resistance of bands and tubing is not predictable or quantifiable. FALSE!
The force production of Thera-Band resistance is consistent and quantifiable. The force can be determined by knowing the percent elongation. For example, Thera-Band® bands stretched to 100% (double resting length) provide the following resistances: Yellow= 3#; Red= 4#; Green= 5#; Blue= 7#; Black= 9.5#. It’s important to note that different colors from different manufacturers may not be as consistent as Thera-Band® resistive bands. Properly positioning the patient will ensure that the strength curve of an isotonic exercise will be similar to the strength curve of the same exercise performed with elastic resistance.
7. Elastic bands stretch out over time with repeated use, thus decreasing the force. FALSE!
Elastic bands and tubing only increase their resting length after the first few pulls with normal use. Once the material has been “pre-stretched” to about 200%, the length of the material is “set”. Therefore, bands experience a small decrease in force after the few pulls, but do not stretch out after the initial setting of the resting length. Patterson et al. (2001), after pre-stretching bands, noted no significant difference in pull force after over 5000 repetitions.
8. The initial length of the band determines the force produced. FALSE!
The force of the band depends directly on the percent change from the resting length (elongation), regardless of the resting length of the band. For example, a 1 foot length of red Thera-Band resistance band that is stretched to 2 feet (100% elongation) will have the same force (4 pounds) as a 2 foot length of band stretched to 4 feet (100% elongation = 4 pounds of force for red bands).
9. Elastic resistance doesn’t offer enough stimulus to increase strength. FALSE!
In nearly every clinical trial in the literature, elastic resistance has been shown to increase strength. This increase ranges from 10 to 130%, and occurs in a variety of populations, from athletes to older adults. They key is to dose the appropriate resistance levels with the individual, rather than prescribing the same resistance for everyone, since everyone’s strength capacity is different. In addition, elastic resistance training has been reported to increase gait and mobility, balance, function, and reduced pain.
10. The best way to progress an exercise resistance is by “shortening-up” on the band. FALSE!
While “shortening-up” on the band does increase the resistance of the exercise, it will also change the overall strength curve of the exercise. Simoneau (2001) demonstrated that grasping the band closer to it’s attachment in order to increase the resistance changed the torque of the movement, thus creating a different strength curve for the exercise. In order to maintain the appropriate biomechanics of an exercise, we should retain the same position of the patient while simply using the next color level of resistance band or tubing.
For complete references or more information on elastic resistance, including Frequently-Asked Questions, visit the most comprehensive resource for research and education on elastic resistance in the world: www.Thera-BandAcademy.com
The Scientific and Clinical Application of Elastic Resistance
More detail is available in the text, The Scientific and Clinical Application of Elastic Resistance, edited by Phil Page PT & Todd Ellenbecker PT from Human Kinetics.
Related posts:
| Print article | This entry was posted by Dr. Phil Page on May 7, 2009 at 11:41 pm, and is filed under Thera-Band Elastic Resistance. Follow any responses to this post through RSS 2.0. You can leave a response or trackback from your own site. |
Abduction exercise after hip replacement: is there an optimal progression?
about 1 week ago - No comments
Patients undergoing total hip replacement often have weak hip abductor muscles before and after surgery. One of the most common hip exercises is sidelying hip abduction using an ankle weight. While this may be an effective exercise to activate the gluteus medius muscle, open-chain, non-weight bearing hip abduction is not specific to the function of
Young women can gain as much strength using the Thera-Band® Exercise Station as training with free weights
about 2 weeks ago - No comments
Dr. Juan Carlos Colado of the University of Valencia in Spain has published several excellent research papers on the effectiveness of Thera-Band® elastic resistance for fitness. In particular, he and his colleagues have shown that elastic resistance is as effective as isotonic machines for increasing strength in middle-aged women (Colado & Triplett 2008). In addition,
Thera-Band® resistance vital part of older adult home exercise study
about 3 weeks ago - No comments
Thera-Band® Academy has been supporting clinical research projects around the world for over a decade. The research helps validate the use of Thera-Band products and provides clinicians with evidence to support practice. Several years ago, the First Step to Active Health® program was developed in response to a “call to action” by the National Blueprint
Thera-Band® resistance helps female cancer survivors keep fit after chemotherapy
about 3 weeks ago - No comments
Breast cancer survivors often experience weight gain after chemotherapy, particularly pre-menopausal women. This weight gain has been associated with an increased recurrence and death from breast cancer (Chlebowski et al. 2006). Researchers at the University of Washington and Oregon Health Sciences University suggested that exercise may be a low-cost, non-pharmacologic strategy to prevent or reverse
Thera-Band® exercises reduce pain and improve muscle function in Air Force helicopter pilots
about 3 weeks ago - No comments
It’s been estimated that 50% of military helicopter pilots experience neck pain in the previous year, likely due to the postural demands and helmet-mounted technology. Physical therapist researchers in Sweden investigated the effectiveness of a neck exercise program for Swedish Air Force helicopter pilots and reported their findings in Spine. They measured the incidence of
Thera-Band® exercises improve kyphotic posture in women
about 1 month ago - No comments
It’s generally accepted that our posture declines as we age. Researchers at the University of Kansas Department of Physical Therapy examined the natural progression of thoracic kyphosis in healthy women. They found that kyphosis increases in females with age, particularly between 50 and 59 years of age. The researchers then established an exercise program for
Thera-Band® exercises safe and effective for patients with hemophilia and bleeding disorders
about 2 months ago - No comments
Bleeding disorders such as hemophilia may cause bleeding in the joints, known as ‘hemarthrosis.’ This may lead to arthritis and subsequent joint replacement surgery. Exercise is an important component in managing hemarthrosis; however, many patients are hesitant to exercise for fear of injury and resulting bleeding. Few studies have examined the effectiveness of exercise in
Elastic resistance exercise program effective in high school-based exercises for teens
about 2 months ago - No comments
Elastic tubing has been proven as effective as free weights again; this time, in teenagers. Several studies have shown that Thera-Band® elastic resistance has similar effects on muscle activation and strength as isotonic resistance (Andersen et al. 2010; Colado & Triplett 2008). Current physical activity guidelines recommend resistance training to improve muscular fitness in youths.
Thera-Band exercises effective for acute ankle sprains
about 4 months ago - No comments
Ankle sprains are the most common injury in sports. Rehabilitation exercise after ankle sprains include active and resisted exercises, often performed with a Thera-Band® elastic band. Reduced ankle dorsiflexion range of motion (ROM) is considered to be a sign of significant injury and can affect gait and function. Researchers at the Mayo clinic in Rochester,
Study published in Physical Therapy journal on Thera-Band resistance vs. dumbbells
about 5 months ago - 1 comment
In an Academy blog post in February, Thera-Band® resistance or dumbbells? New research supports both in the clinic, we reviewed a new research article published online in the Physical Therapy journal. The article is now available in print at the journal’s website. The landmark study showed that Thera-Band elastic resistance was as effective as dummbells at
about 8 months ago
I’m always trying to convince the guys at the gym that bands should be taken seriously. This article has given me the empirical ammunition I needed to try and bring the knuckle dragging aforementioned into the twenty first century!
about 8 months ago
For a while, I’ve been trying to incorporate some sort of Isotonic exercise into my strength training. I’d had a bad taste in my mouth when it came to resistance bands due to the ‘silly consumer product’ status I’d given them because of their convenience and simplicity. But the more I thought about the physical properties of the elasticity found in resistance bands, the more I realised how perfect they were for Isotonic movement in every way. Especially if you know how to quantify the force they have at any given elongation.
The only problem I see with resistance bands for certain free weight exercises is that the place where the band will attach to the ground is static, whereas natural gravity pulls directly down at any given location a free weight exists in. For the squat, for example, near lock-out, you may have 200 lbs with an additional 50 lbs from resistance bands. The 200 lbs is pulled straight down by gravity, while depending on the location of the barbell the bands are connected to and the place on the ground where the bands are connected, the force acting upon the bar may not be directly down through the duration of the repetition. In fact, the force cannot be directly down for the entire rep, because the bar moves back and forth slightly as your body positions itself under it to push it upwards. The path of the bar will never be in a perfect vertical line. If the contrary were true, the use of stabilizing muscles would be null as we would be able to simply push up with no balance and not fall over. Earths gravity is not comparable to a smith machine. Therefore this particular use of resistance bands have an unnatural stimulation of the stabilizing muscles [or a lack of stimulation] which would in turn produce less functional strength than that which would be produced through the use of only free-weights.
Is there a way to counteract or defy this characteristic?