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of a 12-Week Aerobic Training Program
J.E. Taunton, FACSM, N.S. Miller, E.C. Rhodes,
FACSM, B.D. Zumbo, S. Fraser University of British Columbia, Vancouver,
B.C. Canada December 11th 2002
Kangoo Jumps are a hard boot with a soft inner
liner and flexible ankle cuff, similar appearance to in-line skate
boots, with two horizontally opposed leaf springs underneath, as
opposed to wheels. Kangoo Jumps are designed to dissipate the impact
forces experienced through the ankles, knees, hips and back during
running or exercise.
To investigate whether the use of Kangoo Jumps provides a greater
cardiovascular improvement, with fewer injuries, when compared to
conventional runners in a walk/run program over a twelve weeks period.
Thirteen subjects completed a 12-week, 3
sessions per week training program using normal running shoes (NG)
(age: 28.8 ? 4.7; 75.1? 25.2kg), and twelve participants used Kangoo
Jumps (KG) (age: 25.4? 5.3; 67.4? 18.0kg), also for a 12 week period.
Peak oxygen uptake (VO2 peak) and ventilatory threshold (Vt) were
measured pre and post training program, using a continuous treadmill
protocol. All data were analyzed using ANCOVA (= 0.05), using age as a
covariant; injury rates were analyzed with Chi-square 2X2 table (=
RESULTS: VO2 peak significantly increased in the KG (7.8 ? 3.5
mL/kg/min) compared with NG (1.3 ? 2.8 mL/kg/min) (p< 0.05). Vt
was not significantly different between groups. NG had a significantly
greater incidence of lower leg injuries when compared to KG ( (1)= 6.7,
p<0.05). A criterion of 1-week missed training was required for
all of the 42.8% lower leg injuries.
Training with Kangoo Jumps provides an effective means of improving
aerobic capacity, and reducing the rate of injury when compared to
training with normal running shoes.
unrestricted support through Jump Canada Inc. -
Running is one of the earliest and simplest types of aerobic activity.
The combination of science and technology has lead to the evolution of
new forms of running. Kangoo Jumps boots are an example of a new
technology that is continuing the evolution of this age-old activity.
These boots have a similar appearance to in-line skate boots but differ
in that they have a horizontally opposed, two-shell leaf spring system
underneath, as opposed to wheels. They are designed to dissipate the
impact forces experienced through the ankles, knees, hips and back
(Newton et al, 1995). There has not been any literature published which
has investigated the use of Kangoo Jumps for improving aerobic
It is hypothesized that subjects using Kangoo Jumps will have a greater
improvement in cardiovascular fitness (VO2 peak) and ventilatory
threshold (Vt), compared with subjects wearing normal running shoes,
after completion of a 12-week training program.
Due to the reduced impact of running with use of the Kangoo Jumps, it
is also hypothesized that subjects wearing running shoes will have a
greater incidence of injury than those wearing Kangoo Jumps. All
participants will complete the same walk-run training program as set
out by the In Training Sun Run Clinics. The purpose of this study is to
determine the efficacy and safety of using Kangoo Jumps as an exercise
Twenty-five novice runners volunteered to participate in a 12-week
cardiovascular exercise program, which was based on the well-developed
Vancouver Sun Run "In Training" clinics. None of the subjects had
previously participated in a regimented aerobic program for a minimum
of 6 months prior to the study. The Kangoo Jumps group (KG) (n= 13;
age: 25.4? 5.3; 67.4? 18.0kg), and the group using conventional running
shoes (NG) (n=12; age: 28.8 ? 4.7; 75.1? 25.2kg) completed the same
training program, both being led by a certified leader.
All participants had their peak oxygen uptake (VO2 peak) measured
during week 1 and at the end of week 12. The continuous treadmill
protocol started at 4 mph then increased 0.5 mph every minute up to 8
mph, at which point the grade increased 2 % per minute. The subjects
stopped the test when they felt they reached their volitional fatigue.
All expired gases were collected and analyzed using the Vmax metabolic
cart (V6200, SensorMedics Corp, Yorba Linda, CA). Heart rates were
measured using Polar Vantage HR monitor (Polar Electro, Finland).
All of the subjects committed to three training sessions per week for a
total of 12 weeks; the leader led one session and two other sessions
were completed independently. The training program consisted of
walk/run intervals, increasing in total duration from 20 to 65 minutes
per session. The first session began with a short jog (30 sec) and a
4:30 minute walk, repeated 12 times. The participants' running time and
distance gradually increased each week for the entire 12-week program.
All subjects kept a training log for the duration of the 12-week
program, which provided a monitor of their program adherence and
intensity. Recorded in the training log were their heart rate and their
rating of perceived exertion (RPE) (Borg, 1975). The data received from
the subjects was limited by their honesty and knowledge to self-monitor
their performance during their independent sessions.
The data from the treadmill tests were analysed using the SPSS software
package. Analysis of covariance was used to determine if there was a
significant change in VO2 peak over the span of the training program,
co-varying age. A two-way mixed ANCOVA was used to analyse the
ventilatory threshold data. ? 2X2 contingency tables were used to
determine frequency of injuries between the two groups. These data are
reported as mean ? standard error analyzed with significance set at
p<0.05, unless otherwise indicated.
On average, the age of the volunteer, novice subjects were not
significantly different between the two groups: t (23) = 1.71,
p> 0.05. However, to ensure age had no effect on the results, it
was used as a covariant with ANCOVA. The mean weight change over the
span of the training program was not significant, NG ?1.08 kg? 0.585,
KG ?0.79kg?0.594 between the groups (p>0.05).
The mean pre-intervention VO2 peak was not significantly different
between groups (NG 41.06 ?1.22 ml ? kg ? min-1 vs. KG 43.22 ? 2.14 ml ?
kg ? min-1). However, the mean (?SE) KG VO2 peak significantly
increased (+7.8 ? 0.97 ml-1? kg-1? min-1) compared with NG (+1.3 ? 0.93
ml-1? kg-1 ? min-1) (p< 0.05) after completion of the training
program. Figures 1 and 2 graphically represent the change in VO2 peak
over the training program for the two groups.
Ventilatory Threshold (Vt)
The thresholds were calculated using the excess CO2 (ExCO2) elimination
curve (Frangiolas & Rhodes 1996) and determined by two external
reviewers to identify the percent of VO2 peak where CO2 demonstrated a
sudden and sustained increase (Vt). Age correlated with
pre-intervention Vt (r=0.40, p=0.046), and was entered as a covariate
into a 2-way mixed ANCOVA. Both groups saw an increase in V02 at Vt,
with KG increasing to a larger degree than NG (7 .9%?10.47compared with
2.59% ? 6.41 respectively, t (17.97)=1.51, p=0.15). ANCOVA showed no
main effects of time (F (1,22)=0.28, p=0.60), or group (F (1,22)=0.07,
p=0.79) or an interaction of time by group (F (1,22)=2.61, p=0.12). Fig
3 shows the VO2 (ml.kg.min-1) at which Vt was reached. Figure 3 shows
the mean improvement of VO2 at Vt over time by group.
NG had a significantly greater incidence of lower leg injuries when
compared to KG (? (1)= 6.7, p<0.05). Table 1 shown the
tabulation of injury rate of the two groups.
A subject was classified as injured if they fulfilled at least one of
the criteria below (Taunton, 2002; Johnston 2002):
a. Pain or symptoms during or immediately after a run;
b. Had pain or symptoms within approximate time span of start of
c. Injury was felt to be related to running;
d. Injury was significant enough to force them to stop running or
significantly reduce their running mileage and seek medical attention;
e. Required to stop running for min of 1 week.
According to the chi-squared analysis (see Table 1), 42.8% of the
subjects in NG were forced to reduce or end their training due to lower
leg injuries, whereas no injuries caused interruption to subjects in
KG. Figure 4 graphically represents the breakdown of injured subjects
Max VO2 Improvement
These data have shown that KG had a statistically significant
improvement in VO2 peak compared to NG. No research has been conducted
to investigate the effectiveness of the In-Training running program;
therefore there was no literature available to determine the extent of
VO2 peak change. The American College of Sports Medicine (1990) stated
that a minimum of 50% of VO2 peak must be maintained in order to gain
cardiovascular benefits. There is usually an improvement in VO2 peak of
5-10% after a 12-week training program. However, NG only had a 3.7%
improvement in VO2 peak, whereas KG improved 18.3%. From these results,
we may presume that NG did not complete their training sessions at an
intensity level near 50% of their VO2 peak. All of the subjects had
been properly educated to record their RPE and Heart Rate in order to
ensure maintenance of a minimum level of intensity. Although, it
appears that NG lacked the ability to self-monitor their exertion level
during their sessions.
An additional explanation for the difference in post training VO2 peak
is perhaps that the Kangoo Jumps mechanism required more energy to
propel the body forward, due to the requirement to compress the tension
band, whereas a conventional runner does not demand the same energy.
Therefore, when comparing the two types of footwear, there is more
energy expended when using Kangoo Jumps; thus requiring greater oxygen
consumption, with a greater demand on the cardiovascular system in the
body. Figure 1 and 2 provide a visual diagram of the extent of aerobic
capacity that increased over the training period (all figures in ml ?
kg ? min-1).
Ventilatory Threshold (Vt)
Ventilatory threshold is thought to be a measure of the body's
inability to maintain exercise using aerobic metabolism, which
therefore an increased utilisation of the anaerobic system. As a
result, an increase in VO2 at Vt would indicate a greater efficiency of
the aerobic system of the subject.
Both groups did show an increase inVO2 at Vt post intervention, with
the KG group (2.28 ml.kg.min-1 increase) demonstrating a greater
increase than the NG group (0.71 ml.kg.min-1 increase). However,
results of a two way mixed ANCOVA show no main effect for time or
group, or an interaction effect p>0.05.
The lack of a significant change in VO2 at Vt between and within groups
may in part be due to the relatively large standard deviation. A larger
sample size may have resulted in a statistically significant change, as
the few subjects with very large changes in VO2 at Vt may be distorting
Despite the increases in VO2 peak, the intensity of the training may
not have been sufficiently high to result in an increase in VO2 at Vt.
The intensity of the exercise needs to be high enough to recruit the
anaerobic metabolism and so needs to be near the lactate or ventilatory
threshold in sedentary subjects. The training level needs to be
slightly above the lactate or ventilatory threshold in trained
subjects, so the amount of change may have been dependant on initial
Of the NG subjects, 42.8% suffered lower leg injuries; compared with no
injuries in the KG, refer to Table 1, and graphically represented in
Figure 4. None of the subjects had previous injuries directly related
to an aerobic training program. The injuries that plagued the subjects
1. Iliotibial Band Friction Syndrome
2. Shin Splints
3. Ankle sprain
4. Plantar Fascitis
Of the injuries, which occurred during the training
program, 3 were unable to complete their goal of running the Vancouver
Sun Run; in addition, 1 subject was not able to complete the post
treadmill test due to severe injury.
The training program was developed in a manor to minimize the number of
injuries incurred from running, if the program is followed carefully.
The subjects who were injured during the study may have not followed
the program to detail, which may have made them more prone to a lower
leg injury. There are also other extrinsic factors that may have caused
circumstances for injuries such as worn out shoes, muscular imbalances,
or improper biomechanics.
The KG group suffered minor problems associated with the Kangoo Jumps
boots. When introducing the Kangoo Jumps to a new user it is
recommended by the manufacturer to wear long socks that will protect
your skin, above the top of the boot, from abrasion. They also comment
that there may be an adjustment period for the arches of your feet to
familiarize with the new sensation of using the Kangoo Jumps.
In this study subjects were spending from 30 minutes to 65 minutes in
the boots, and there were some minor problems that the subjects
experienced. These problems required a decrease in training for maximum
1 session; however, had the problems been identified earlier subjects
would not have missed any training. One of the problems included
bruising and swelling around the lateral and medial maleolus. This was
remedied by wearing a gel sock to provide more padding to subjects with
bony ankles. If the problem persisted with the subject, it was
recommended to cut out a large foam donut and tape in into place around
the maleolus. Kangoo Jumps are currently developing a more improved
boot that may reduce the bruising and swelling by using a softer shell
Blisters are a problem with new running shoes and they are also a
problem with the Kangoo Jumps particularly with less breathability of
the boots. If the blisters are left alone, they may worsen. The best
option to resolve the blisters is to purchase long wicking socks that
will help remove the moisture away from the skin on your foot, making
it less prone to abrasion. Any lubricating cream may also help to
reduce the friction when the subject is getting used to the boots.
Kangoo Jumps are able to fit most body types, however people with
larger calves may not be able to get a snug fit around the foot and
ankle with the boot. If the boot does not fit properly the subject will
not be able to maintain long periods of walking or running in the
boots, as problems will arise, such as those mentioned above.
The program used for the aerobic training program was developed by
sports medicine physicians to safely introduce participants of all
levels to the sport of running in preparation for a popular 10 Km road
race in Vancouver, BC. The particular level chosen for this study
begins with a short jog, followed by a lengthy walk, for a total of
5:00 minutes. As the program progresses week, the run time increases by
30 seconds, and gradually increases the length of the running time once
it surpasses 5:00 minutes. In order to gain full benefit from this
program it is necessary to maintain movement during the walk segments
of each session. While wearing Kangoo Jumps walking is a little more
difficult than wearing running shoes, therefore, the walk is more of a
walk with a bounce; which may require more energy than using running
shoes ? which may add to the amount of work performed per session. This
may be another reason for an improved VO2 peak in the post-test.
There is no literature published that investigates the use of Kangoo
Jumps as an effective exercise tool. This study has concluded that
Kangoo Jumps, when compared with a group wearing normal running shoes,
can have a greater effect on cardiovascular improvement, while reducing
the risk of injuries. Kangoo Jumps could also be an effective tool for
intervention in rehabilitative circumstances for lower leg injuries.
However, more research is needed to investigate the use of Kangoo Jumps
for rehabilitation purposes. There is also a need for further research
into the effectiveness of the In Training running program with a larger
number of subjects.