ENERGY EXPENDITURE AND RELATIVE EXERCISE INTENSITY WHEN EXERCISING ON THE FREEBOUNDER®

Submitted by:

John P. Porcari, Ph.D,. Jared Hartung, B.S., & Abigail Ryskey, M.S.

University of Wisconsin-La Crosse

March 13, 2018

INTRODUCTION

Have you ever wondered if you could have the cardiorespiratory benefits of running with the low impact forces of walking? John Louis, the creator of the FREEBOUNDER® (John Louis, Northfield, IL), has invented an exercise device that purportedly does just that. The FREEBOUNDER® is a spring-loaded platform and frame that incorporates upper and lower body movements to provide a total body aerobic workout (Figure 1). Although there is no current research on the FREEBOUNDER®, there have been numerous studies published on the physiological effects of trampoline exercise, a similar mode of exercise.

Figure 1. Image of the FREEBOUNDER®

Over the years, trampolines have been used for recreational activity, exercise,

competition, and rehabilitation. Training on a trampoline has been shown to improve balance and gait in stroke patients (Hahn, Shin, & Lee, 2015). They have also been used to help with spatial awareness and decrease muscle strain in fighter pilot’s necks (Sovelius et al., 2006). The use of trampolines, especially mini-trampolines, have been used in the fitness industry for many years. Bhattacharya et al. (1980) found trampoline exercise was just as effective as running for improving cardiorespiratory fitness. Burandt, Porcari, Cress, Doberstein, and Foster (2016) and McGlone, Kravitz, and Janot (2002) found that subjects who exercising on mini-trampolines met American College of SportsMedicine’s (ASCM) guidelines for improving cardiorespiratory fitness. ACSM (2016) recommends exercising at an intensity of 64-95% of maximal heart rate (HR) or 46-90% of maximal oxygen consumption (VO2max) in order to improve cardiorespiratory fitness. Subjects in the study by Burandt et al. (2016) exercised at 79% of HRmax and 59% of VO2max, while subjects from McGlone et al. (2002) exercised at 81% of HRmax and 63% of VO2max on a mini-trampoline.

Even though several studies found that trampoline exercise provides the same cardiorespiratory effects as running, other studies found conflicting results. Gerberich et al. (1990) found that HR and VO2 were significantly lower while jumping on a trampoline compared to running, especially at higher exercise intensities. Similarly, Weston, Khan, and Mars (2001) found the VO2 response when running was significantly greater than when exercising on a mini-trampoline at any given HR.

Most studies done on a mini-trampoline do not involve the upper body, but the FREEBOUNDER® incorporates both the upper and lower body to achieve a full body aerobic workout. Thus, the current study was designed to examine the intensity of exercising on the FREEBOUNDER® and determine if it meets ACSM’s guidelines for improving cardiorespiratory fitness and body composition.

METHODS

Subjects

The subjects for this study were 14 apparently healthy college-aged volunteers recruited from the University of Wisconsin - La Crosse campus. The subjects were recreationally active, exercising at least 3 times per week. Each subject completed a PAR-Q to screen for cardiovascular and orthopedic contraindications to exercise and provided written informed consent prior to participating in this study. The study was approved by the University of Wisconsin-La Crosse Institutional Review Board.

Procedures

Initially, each subject completed an incremental maximal exercise test on a treadmill. Subjects ran at a self-selected pace, which was kept constant throughout the test. The incline began at 0% grade and increased 2.5% every 2 minutes until the subject reached volitional exhaustion. During the test, HR was monitored continuously and recorded every minute using a Polar HR monitor. VO2 was measured continuously and recorded every minute using an AEI metabolic cart. Ratings of perceived exertion (RPE) were recorded at the end of each 2-minute stage and at maximal exertion using the 6-20 Borg Scale (Borg, 1998).

Following completion of the treadmill test, subjects completed 2-3 practice trials on the FREEBOUNDER®, following along with a 12-minute DVD-based workout in order to

become familiar with the exercise movements to be performed. Once proficient at the

routine and movements, subjects then completed an exercise session on the FREEBOUNDER®, following along with the same 12-minute DVD as was used during practice. The specific exercises and the order of exercises included in the workout are presented in Appendix A. Throughout this session, HR and VO2 were monitored continuously and recorded every 30 seconds, while RPE was recorded every 2 minutes using the 6-20 Borg Scale.

RESULTS

Descriptive characteristics of the 14 subjects who participated in the study are presented in Table 1. Responses to the 12-minute FREEBOUNDER® workout are presented in Table 2 and Figures 2-6, respectively.

Figure 6. Average RPE during the FREEBOUNDER® exercise session.

DISCUSSION

The purpose of this study was to examine the relative exercise intensity and energy expenditure while exercising on the FREEBOUNDER® and determine if it meets ACSM’s guidelines for improving cardiorespiratory fitness and body composition. To achieve this goal, ACSM (2016) recommends exercising between 64-95% of HRmax or 46-90% of VO2max. We found the overall relative exercise intensity of the FREEBOUNDER® exercise session to be 75% of HRmax and 48% of VO2max, which are within ACSM guidelines for improving cardiorespiratory fitness. These intensities would classify the overall workout on the FREEBOUNDER® as moderate-intensity exercise. Another way to quantify exercise intensity is by using RPE. ACSM (2016) recommends individuals exercise in the range of 12-17 on the 6-20 Borg scale. In the current study, subjects exercised at an average RPE of 12.3, which corresponds to moderate or “somewhat hard”exercise based upon the verbal cues on the Borg scale (Borg, 1998).

The results of the present study are in general agreement with the findings of McGlone et al. (2002) and Burandt et al., (2016). McGlone et al. found that when subjects exercised on a mini-trampoline at the same RPE as running on a treadmill, they averaged 81% of HRmax and 63% of VO2max. Burandt et al. (2016) found that subjects exercised at an average of 79% of HRmax, 59% of VO2max, and an RPE of 11.7 when completing a Jumping Fitness mini-trampoline routine. As can be seen, exercising on the FREEBOUNDER® resulted in almost identical relative HR values (%HRmax), but somewhat lower relative VO2 values (%VO2max). This would indicate that gripping onto the frame of the FREEBOUNDER® during some of the exercises results in a pressor response, where HR is elevated disproportionately relative to oxygen consumption. During many of the exercises on the FREEBOUNDER®, the user specifically targets the upper body to perform the different movement (e.g., military presses and dips). Because the upper body muscles are smaller than the lower extremities, they require less energy, resulting in a lower relative oxygen cost.

Many individuals start exercising or continue to exercise in order to lose or maintain body weight. ACSM recommends individuals expend 240 – 400 Kcals per session (~8 – 13 Kcals/min) in order to meet this goal (Donnelly et al., 2009). In the current study, the average energy expenditure was 9.2 Kcal/min. These values are within the range of what would be recommended. Similarly, Burandt et al. (2016) found the average energy expenditure during a 19-minute mini-trampoline fitness workout to be 10.9 Kcals/min.

In conclusion, the current study found the relative exercise intensity of the FREEBOUNDER® exercise session to be 75% of HRmax and 48% of VO2max. Additionally, subjects expended an average of 9.2 Kcal/min. Collectively, these data suggest that exercising on the FreebounderTM would be considered “moderate-intensity” exercise and should results in significant improvements in aerobic capacity and body composition if the product is used regularly.

REFERENCES

American College of Sports Medicine. (2016). Guidelines for Exercise Testing and

Prescription. 10th edition. Philadelphia, PA: Wolters Kluwer.

Bhattacharya, A., McCutcheon, E. P., Shvartz, E., & Greenleaf, J. E. (1980). Body acceleration distribution and O2 uptake in humans during running and jumping. Journal of Applied Physiology: Respiratory, Environmental, and Exercise Physiology, 49(5), 881-887.

Borg, G. (1998). Perceived exertion and pain scales. Champaign, IL: Human Kinetics.

Burandt, P., Porcari, J. P., Cress, M., Doberstein, S., & Foster, C. (2016). Putting mini-

trampolines to the test. ACE ProSource.

Donnelly, J. E., Blair, S. N., Jakicic, J. M., Manore, M. M., Rankin, J. W., & Smith, B. K. (2009). American College and Sports Medicine position stand. Appropriate physical activity intervention strategies for weight loss and prevention of weight regain for adults. Medicine & Science in Sports & Exercise, 41(2), 459-471.

Gerberich, S. G., Leon, A. S., McNally, C., Serfass, R., & Edin, J. B. (1990). Analysis of the acute physiologic effects of minitrampoline rebounding exercise. Journal of Cardiopulmonary Rehabilitation, 10(11), 395-400.

Hahn, J., Shin, S., & Lee, W. (2015). The effect of modified trampoline training on balance, gait, and falls efficacy of stroke patients. Journal of Physical Therapy

Science, 27(11), 3351–3354 http://doi.org/10.1589/jpts.27.3351

McGlone, C., Kravtiz, L., & Janot, J. M. (2002). Rebounding: a low-impact exercise alternative. ACSM’s Health and Fitness Journal, 6(2), 11-15.

Sovelius, R., Oksa, J., Rintala, H., Huhtala, H., Ylinen, J., & Sitonen, S. (2006). Trampoline exercise vs. strength training to reduce neck strain in fighter pilots. Aviation, Space, and Environmental Medicine, 77(1), 20-25.

Weston, A. R., Khan, A., & Mars, M. (2001). Does heart rate adequately reflect exercise intensity during mini-trampoline exercise. South African Journal of Sports Medicine, 8(1), 9-13.

Appendix A

12-minute FREEBOUNDER® Workout

Active Recovery. 90s
Squat. 30s
Alpine Ski 15s
Burst. 30s
Lateral Core Glide. 15s
Squat. 30s
Active Recovery 15s
Burst. 30s
Dip/Row. 15s
Squat. 30s
Military Press. 15s
Burst. 30s
Active Recovery 15s
Squat 30s
Lateral Core Glide 15s
Burst 30s
Crunch 15s
Squat 30s
Military Press 15s
Burst 30s
Dip/Row. 15s
Squat 30s
Active Recovery 15s
Burst 30s
Lateral Core Glide. 15s
Squat. 30s
Active Recovery 60s