Thera-Band tubing is often utilized for therapeutic exercise
both in the physical therapy setting and in a patient’s home
for incorporation into a home exercise program. Therapists
utilize Thera-Band tubing because it is low cost, portable,
versatile and doesn’t rely on gravity for resistance (1).
Thera-band tubing comes in seven colors and resistive
properties are coded by color of tubing. Given its
popularity, therapists are aware of the resistive properties
of the tubing based on color but may be unaware of the exact
resistance or force which is produced by utilizing the
tubing.
Thera-Band’s website (2) states that “bands and tubing
produce similar forces between similar colors. The force
produced by bands and tubing is directly related to
elongation. Each color will provide a specific amount of
resistance at the same percent elongation, regardless of
initial resting length. For example a 1-foot piece stretched
to 2-feet (100% elongation) will have the same force as a
2-foot piece of the same color stretched to 4-feet. The
force slowly increases as the band or tube is stretched.”
Below is a chart from TheraBand’s website which charts the
average force in ponds for Thera-Band elastic bands.
Page,
et al. JOSPT 30(1):A47. 2000 also provides a similar
chart.
|
Average Force
(pounds) for Thera-Band Elastic Bands |
| % Enlongation |
Yellow |
Red |
Green |
Blue |
Black |
Silver |
Gold |
| 50% |
2 |
2.5 |
3 |
4.5 |
6.5 |
8.5 |
14 |
| 100% |
3 |
4 |
5 |
7 |
9.5 |
13 |
21.5 |
| 150% |
4 |
5 |
6.5 |
9 |
12.5 |
17 |
27.5 |
| 200% |
5 |
6 |
8 |
11 |
15 |
21 |
33.5 |
| 250% |
6 |
7 |
9.5 |
13.5 |
17.5 |
25.5 |
40 |
In a study by Hughes et al. (1), they investigated the
relationship between tubing length and tubing tension for 6
colors of Thera-Band tubing and estimated the resistive
shoulder torque provided by Thera-band tubing during
shoulder abduction exercise. Their study concluded that
there is a strong linear relationship between tubing tension
and tubing excursion during shoulder abduction but the
resistive torque pattern provided by various levels of
tubing appears to be similar to that provided by traditional
isotonic exercise for shoulder abduction.
In another study by
Patterson et al. (3), they conducted a
study to quantify the material properties of six colors of Thera-Band tubing. In their study they investigated six
aspects of force-generating potential of Thera-Band tubing:
1) the effect of the original length of the sample, 2) the
effect of prestretching, 3) the effect of the rate of
loading, 4) the repeatability, 5) the effect of cyclic
loading and 6) the loading and versus unloading properties.
Their study concluded the following 1) Length Effect- there
were no differences in resistance attributable to the length
of the tubing 2) Prestretching Effect – There were
differences in the force-generating potential when the
material was used new, directly out of the box. They
concluded that prestretching at least 20 times appeared to
stabilize the tubing so that it exhibited consistent force
generating properties. 3,4) Repeatability and Cyclic Loading
– The force-generating potential of the material was
repeatable over at least 5,700 cycles. This information
implies that a patient could use the same piece of new
tubing for at least 6 weeks (10 reps of 4 different
exercise, 3 x’s per day for 6 wks) before potentially
needing another piece of tubing 5) Loading Rate – There was
no effect attributable to the loading rate 6) Loading Versus
Unloading – There were differences in the force-generating
potential of the tubing when the material was being actively
stretched and unstretched. From this data Patterson et al.
was able to develop a cumulative resistance chart
(click here to see article with chart) which will
allow a therapist to determine which color of tubing to use
to obtain a specific force level and percentage of strain.
By having an enhanced understanding of the resistive
properties of the Thera-Band tubing, therapists will be able
to better choose the appropriate color of Thera-Band tubing
for their patient which will maximize rehabilitation
potential while minimizing the likelihood for harm (3).
Last revised: October 6, 2009
by Chai Rasavong, MPT, MBA
