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A STUDY OF IMPACT SHOCK DURING JOGGING
comparison between conventional running shoes and Kangoo Jumps. (This
is only a summary of the whole study)
Federation Institute of Technology
Department of Orthopedic & Traumatology, Division of Sports
G. Gremion, P.F. Leyvraz, E. Mercier, K. Aminian.
Impact force experienced during running has been recognized as a source
of injury. Much less is known about impact injury during the use of
Kangoo Jumps, a revolution in shoe design, which includes a leaf spring
attached to the sole of the shoe.
The purpose of this study was to investigate the
impact characteristics for Kangoo Jumps and to test the hypothesis that
there is lower impact shock while using Kangoo Jumps than running in
conventional athletic shoes. Eleven (11) athletes, six (6) males and
five (5) female subjects participated in the study. Each completed two
different trials with low-mass accelerometers attached to the proximal
tibia and to the lumbar spine (L5). Each performed three trials of
vertical jumping and a trial of running for 20 seconds at a self-pace,
wearing his or her normal training shoes and then Kangoo Jumps.
Our results showed that using Kangoo Jumps
exhibited a significant reduction of impact force during running. We
observed an acceleration of 7g at the tibia and 2.5g at the lumbar
spine with conventional training shoes. With Kangoo Jumps the
acceleration impact force was only 3.5g at the tibia and 1.9g at the
This study concluded that using Kangoo Jumps while
running results in less impact shock to the body with each foot contact
and may be a useful exercise modality for rehabilitation of sports
related injuries due to the reduced impact shock.
Walking and running are well known exercises that can improve
cardiovascular endurance, strengthen muscles and reduce body fat. Under
normal circumstances of running or jumping, the elastic compliance of
the internal structure of the foot, such as the internal arch and
tendons, reduce impact forces and provide only about 40% to 60% energy
One aspect of running which has been
well-documented is the impact shock transmitted through the body when
the foot makes contact with the ground. This event occurs about 6,000
times in a race of 10 km. The shock wave is transmitted across the
structures of the lower extremity and upward through the spine to the
One positive aspect of the shock is to stimulate
the bone mass density of the lower extremities. However repetitive
landings and impacts have also been implicated in degenerative diseases
for the knees and the hips.
With injuries, it seems to be important to restore
the full ability to compete using different methods which diminish
joint loading without diminishing the capacity to improve the
Recently, there has been a fitness shoe system
developed, providing an enjoyable method of highly effective exercise
that would appear to significantly reduce the impact of high
acceleration forces. The shoe, Kangoo Jumps, is constructed in a
similar fashion to that of an inline roller skate with the exception of
wheels. Under the shoe is an elliptical arch stretching from the toe to
the heel of the shoe that is bisected with a removable band. At each
step, we observe a depression of the arch that works like a leaf
spring, returning to its previous form.
The purpose of this study was to examine impact
shock and the attenuation characteristics during the use of Kangoo
Jumps while running. To that end, we have measured impact force at the
tibia and lumbar spine during the use of Kangoo Jumps while running and
then we compared these results with data collected from the same
subjects while running with conventional running or training shoes.
Eleven healthy subjects (mean +/- SD age 31 +/- 7 yr; height 176+/- 11
cm; mass: 64.6 =/- 9 kg.), 6 males and 5 females volunteered to take
part in the study. They were sport teachers in fitness centers and none
reported any significant musculo-skeletal disorder. All subjects were
previously trained in the correct use of Kangoo Jumps.
The time domain variables output for statistical
analysis were PA tibia and PA lumbar spine. The main effect of
condition for these dependent variables was tested using a subject,
During running we observed a significantly lower peak impact for Kangoo
Jumps (P=0.001). Mean PA tibia value for the Kangoo running condition
was 4 G, the mean spine value, 2.5 G whereas running with normal
training shoes showed higher values of force acceleration: 7.8 G PA
tibial and 2.3 PA spine.
The length of the step measured by the time in air
is greater with Kangoo Jumps: 143 cm with Kangoo Jumps, 123 with
Exemplar timer series of tibial and lumbar spine
acceleration signals during stance phase of running and Kangoo jumping.
PA indicates peak acceleration just after foot contact.
The purpose of this study was to investigate the peak acceleration
force characteristics when jogging in a pair of Kangoo Jumps compared
to normal training shoes. The results clearly show that the Kangoo
Jumps result in considerably less impact forces being transferred to
the lower limbs compared to normal training shoes. In particular, the
impulse during first initial contact with the ground is reduced some
50% . Furthermore, the length of the step measured by the time in the
air is greater with Kangoo jumps than with training shoes. This is a
valuable contribution to attenuate the frequencies of impacts of the
lower limb with the ground for the same intensity of the physical work.
The frequency analysis of tibial and lumbar spine
acceleration showed that using Kangoo Jumps demonstrated less impact
acceleration, with lower values than running with training shoes for
peak and median frequency.
The frequency range is associated with the
collision of the foot to the ground and this frequency band may be
implicated in musculo-skeletal injuries. Some have suggested that
removal of higher frequencies may reduce the likelihood of degenerative
joint diseases. Kangoo Jumps may, therefore, prove to be an aerobic
exercise workout that is less harmful to the joints in terms of
repetitive impacts of the foot and ground.
The results of the frequency analysis for the
running trials agree with other studies. The running condition with
training shoes displayed peaks between 6 and 10 g at the tibia level as
found in previous studies. With Kangoo Jumps acceleration is 50% lower.
The reduction of the force impact is significant.
The curves below demonstrate the
force of impact on the legs, hips and spine while running, as measured
with a piezoresistive accelerometer.