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PHYSIOLOGICAL RESEARCH

Conducted by the University of Lausanne Switzerland
CASS (Centre Analyse Sport et Sante)
With the collaboration of Dr. Gremion
Orthopedic Hospital in Lausanne

July 1997

INTRODUCTION
Recently, an Australian university study concluded that using Kangoo Jumps while running, jogging, or working out in an aerobic class, reduced the potential for joint and spine aggravation or injury. The results, researchers concluded, were due to Kangoo Jumps' unique leaf spring design which softens the impact of each step.

The manufacturer wanted to investigate the calorie burn rate of Kangoo Jumps compared to an aerobic activity such as jogging. The aim was to gauge the proper intensity of an optimized workout relative to calorie burn and the consumption of oxygen.

Initially, this product was created to reduce the impact on the joints and tendons of the knees and ankles while jogging. Since that time, it has been further modified and improved for use in fitness centers for aerobic courses.

AIM
The overall aim of this study was to measure the difference, if any, of caloric and oxygen consumption that is created by using Kangoo Jumps instead of conventional running shoes. The physical differences between them are obvious as Kangoo Jumps have a rigid shell, known as the outer boot, that is fixed on two semi-spherical lamellas, or "clam shells", that act as a "rebounding" spring.

A laboratory test was conducted to measure the exchange of oxygen and to also calculate the caloric burn rate at each speed of the exercise.

Subjects:
Eight (8) test subjects, four (4) male and four (4) females, participated in the study. All of them are very fit and workout often, while participating in one or more sports activities each week. All of them had already used Kangoo Jumps a number of times and were familiar with them prior to this experience.

Protocol:
The subjects participated in a progressive exercise that was designed to determine the rate of oxygen consumption. The test was conducted on a fitness center treadmill. The selection of the speed was determined by a control console, set and moderated by scientific methods.

The exercises were executed on a slope of zero percent (0%) and consisted of in running at different speeds on a treadmill, specifically, eight (8), ten (10), and twelve (12) kilometers per hour. Each stage lasted three (3) minutes, allowing a state of equilibrium to be reached. There was no pause between the succession of the stages.

The first half of the group began the session with Kangoo Jumps and the other half with conventional running shoes. Forty-fine (45) minutes later, the test is repeated after the participants exchanged shoes.

The cardiac frequency was continuously measured by a Baumann's belt (BHL 6000) and was monitored and processed by the software program AncarElite 2.0 (Baumann). Ventilation is obtained by integrating the measure of the flow. Oxygen consumption, or the breathing rate, was also calculated. All factors were calculated within a mean of thirty (30) seconds, while also taking into account the subject's temperature and blood pressure.

RESULTS
The results of caloric burn rate, ventilation, breathing rate, oxygen consumption and cardiac frequency for each subject are available upon request. Researchers concluded that half of the subjects reached or exceeded their anaerobic limit while using Kangoo Jumps at 12 km/h. The mean caloric burn rate obtained by the eight subjects, at 8, 10 and 12 km/h with Kangoo Jumps is, respectively, 154, 165 and 206 Cal/min/kg.

With absolute or relative value (/kg), the oxygen consumption is significantly higher (p<0,05) with Kangoo Jumps compared to jogging while using conventional running shoes.

This difference is greater at lower speeds than at higher speeds. In fact, at 8 and 10 km/h, the difference varies between twenty (20%) and thirteen (13%) percent, respectively, while at 12 km/h, the variation is only seven (7%) percent.

This diminution is also valid for the values of energetic expense using the equation kcal/min. In fact, the subjects using Kangoo Jumps, obtained values that were superior to the use of conventional running shoes, ie: nineteen (19%) percent at 8 kilometers per hour and seven (7%) percent at 12 km/h.

DISCUSSION
The results that were obtained confirm the previous hypothesis:

The energetic expense is higher, at a same speed, using Kangoo Jumps compared to the use of conventional running shoes while jogging.

Yet, it is interesting to notice that the more the speed increases, the more the difference diminishes. This could be due to the fact that many subjects, at a speed of 12 km/h have reached or exceeded their anaerobic limit (QR>1), showing the anaerobic phase and the values of oxygen consumption (with or without Kangoo Jumps) come up to a common level. Furthermore, for these same subjects, no significant difference concerning cardiac frequency is observed at 12 km/h, which would confirm the hypothesis that these subjects are very close to their "limit".

Bio-mechanical factors should also be taken into account. At low speeds, it is possible to better utilize the elasticity of the Kangoo Jumps' T-spring band. Yet, the more the speed increases, the more the rate increases, the time of contact decreases, so the use of elasticity of the Kangoo Jumps is very much diminished or even non-existent.

The movement of the Kangoo Jumps imitates more and more the movement of jogging, which would diminish the energetic expense per kilometer and consequently the oxygen consumption. Furthermore, with the increase of the speed, the subject tends to bend forward, which prevents him to make the best use of Kangoo Jumps.

In fact, Kangoo Jumps are built so that the maximum elasticity is obtained when the subject presses vertically on the shoes. The research concludes that it would be better to work at low speed or at low rate.

It is also worth noticing that with the subjects that use Kangoo Jumps on a regular basis (subjects 2,4 and 6), the difference of their oxygen consumption is nine (9%) percent at 8 km/h and is negligible at 12 km/h. So, part of the difference obtained in average results can be explained by lower performances on behalf of the subjects that are not used to using Kangoo Jumps.

CONCLUSION
Kangoo Jumps, for adults, are best suited for those who wish to experience a significant energetic expense while reducing the negative impact on the joints and spine . We notice that at a same speed, the energetic expense with Kangoo Jumps is the same as jogging while running at a speed of two (2) km/h slower. Kangoo Jumps greatly lessen the injurious impact on the ankles, knees, and spine for two reasons: 1) The unique spring design decreases the normal pounding effect of running, and 2) The runner obtains more "air time" resulting in less actual impacts with the running surface. Finally, the use of the Kangoo Jumps can be useful in the rehabilitation of both athletes and "normal" active people that are recovering from "sports related" injuries.

We are very thankful for Dr. Gremion's valuable collaboration on this project