Exercise Physiology Final Lab

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Comparison of Caloric Expenditure Between Rower Ergometer and Cycle Ergometer Ryan Cormier, Lee Maniff, David Ciampittiello, Colin McFadden Exercise Science Department May 11th 2012

Introduction Obesity is defined as having too much body fat.i Ten years ago, according to the body mass index (BMI), there were no states reported with an obesity prevalence of 30% or more. Today more than one-third of U.S. adults (35.7%) are obese.ii One of the largest concerns with obesity is that it is directly linked with multiple health risks. Some of the health risks associated with obesity are coronary heart disease, Type 2 diabetes, hypertension, cancer, stroke, respiratory problems and in females infertility.iii Studies have shown a decreased risk of mortality from complications of obesity with an increase of physical activity.iv

There are many factors correlated with obesity in adults. A few factors include caloric intake, caloric storage, and caloric expenditure.v Caloric intake refers to the amount of Calories that an individual consumes. Caloric storage refers to the amount of Calories that are stored in the human body. Caloric expenditure refers to how many Calories an individual uses. There are three factors that affect caloric expenditure: Basal/Resting metabolic rate, thermogenesis, and work/exercise metabolism.vi All three elements are influenced by genetic and environmental factors. Although genetic factors contribute to weight gain and potentially obesity, environmental factors are thought to be the biggest and most controllable contributor. The sedentary lifestyle is one of the biggest factors linked to obesity. This is why aerobic exercise is such an important aspect of fighting obesity. Increasing aerobic exercise is a great way to increase daily caloric expenditure and over time promote weight loss. Some common aerobic exercises that overweight

populations can perform are walking, swimming, cycling and rowing. In this study, two forms of exercise were chosen to investigate, cycling and indoor rowing. Both exercises are non-weight bearing, easily accessible in most gyms, and require little experience to perform.

The rower ergometer is an exercise machine that replicates outdoor rowing. This exercise utilizes a large amount of the muscle in the human body. Some of these muscle groups include legs, gluteals, back, arms and your core.vii The cycle ergometer is an exercise machine used to simulate the act of cycling. It isolates the lower extremity, legs and gluteals, during exercise.viii

Rowing and cycling performance has been researched extensively in the past. One main area of research regarding rowing and cycling is the topic of efficiency and energy expenditure. In general, researchers have looked for ways to increase cycling and rowing performance by finding ways to decrease energy expenditure and increase efficiency.

Many factors have been researched regarding ways to increase rowing efficiency. One 2009 study showed that some of the biggest aspects involved in rowing efficiently are setup and technique.ix Strength and power production as well as body structure have been shown to play a big factor in performance in rowing and cycling. Being taller and leaner can be a big advantage when it comes to rowing.x A factor researched that may be highly involved in cycling efficiency is the

prevalence of type 1 muscle fibers in the legs.xi It is assumed that increasing efficiency would allow for more work to be done with lesser amount of energy expenditured. Several studies have been done on rowing where elite rowers were compared to non-rowers to see differences between the groups. There seems to be adaptations coming from sport specific training that allow proficient rowers to become more efficient with the same statement being true for cyclists as well.xii xiii xiv

Although much of the research involving rower and cycle ergometers are geared towards performance, there is some research investigating the differences between rowing and cycling. One study on the subject looked at female masters level recreational level rowers and the physiological responses they experienced during maximal cycling and rowing. The results of this study showed that cycling and rowing produce very similar max VO2, minute ventilation, max heart rate, and blood lactate under maximal exercise conditions in this population xv. Since this was done under maximal conditions to exhaustion, it still leaves the question of what different physiological responses cycling and rowing might produce under submaximal conditions. One such study was done in which many physiological measurements were taken during submaximal cycling and rowing with the main focus of the study being on energy expenditure. The test showed VO2 and heart rate were significantly higher at all power increments during the rowing graded exercise test. This lead those researchers to believe that energy costs for rowing ergometry were significantly higher than cycle ergometry at all comparative power outputs including maximal levels.xvi

These studies demonstrate certain areas in the relevant research that are very strong as well as areas that are lacking. Since the topic of performance in rowing and cycling, in regards to efficiency, have been investigated so thoroughly it may be more beneficial to focus on unanswered questions. Other than a study performed energy expenditure in 1988, the research is limited in regards to comparing the rower and cycle ergometers. It may be beneficial to do a study where energy expenditure was given the operational definition, “amount of Calories burned during exercise”, since in this day and age energy is usually thought of in terms of Calories. A possible limitation that has been brought up through a review of relevant literature could be that studying a population of highly experienced rowers and cyclers with increased performance efficiency coming from training could alter their specific energy expenditures.

This particular study was conducted to determine which modality would expend more Calories at the same workload, the rower ergometer or a cycle ergometer. The study also examined which exercise was perceived to be easier and elicited a higher heart rate. If the study determined that one exercise burned more Calories than the other, and was perceived to be easier, it would be more likely that an individual would utilize the exercise for weight loss. The hypothesis for this study was that the rower ergometer would elicit higher energy expenditure at any given workload when compared to the cycle ergometer. Our reasoning behind the hypothesis regarding a higher caloric expenditure being elicited in the rower during

equal workloads was that the rower activates more muscle groups.xvii It was also hypothesized that heart rate would be higher on the rower at any given workload compared to the cycle ergometer. It was believed the heart rate response might be higher in the rower because of the upper-body exercises may be caused by increased sympathetic nervous system stimulation.xviii

Methods

Concept2 Rower First the subject was fitted with a heart rate monitor and a corresponding heart rate watch. The metabolic cart was calibrated according to laboratory standards. Headgear and mouth apparatus were secured to the subject. The subject was given a brief tutorial on how to properly perform the rowing machine. The subject then adjusted the foot placement and straps. The damper was set to five to keep tests consistent across subjects. The rower ergometer was set with a timer of two minutes and at the end of the test, the machine calculated the subject’s average wattage. The subject was asked to perform the exercise at a submaximal pace that if asked to, could be maintained for five to ten minutes. Before the test commenced, the subject did not perform a warm-up period. The data collected in the test included VO2 (L/min), VCO2 (L/min), RER and heart rate (bpm) at each thirtysecond interval by the metabolic cart.

Wattage Bike The subject was given at least fifteen minutes of recovery. Before exercise commenced, the subject returned to resting heart rate. The subject was again equipped with the heart rate monitor and the corresponding heart rate watch. The metabolic cart was recalibrated according to laboratory standards. Headgear and mouth apparatus were secured to the subject. The seat of the cycle ergometer was adjusted to the height of the subject, so that the subject’s leg was almost fully extended at the bottom of the revolution. The average wattage performed on the rower ergometer was used for the wattage on the cycle ergometer. The subject was informed to cycle between 40-80 rpms at the given wattage for two minutes. Before the test was performed, there was no warm-up period. The data collected in the test included VO2 (L/min), VCO2 (L/min), RER and heart rate (bpm) at each thirtysecond interval by the metabolic cart.

Calculations Caloric Expenditure per thirty-second interval was calculated based on the following formula: (VO2 * Caloric Equivalent)/2 = Caloric Equivalent was acquired from a RER Caloric Equivalent chart. RER was obtained from the metabolic cart. Data was calculated in thirty-second intervals to determine how many Calories were burned in two minutes. The total Calories of the rower ergometer and the cycle ergometer were compared against each other to conclude which exercise burned the most Calories.

Results:
Rower Ergometer Cycle Ergometer Mean Total Calories Expended * 21.63583333 18.52833333 Mean VO2 2.22 1.93 Mean RER 0.88 0.79 Mean Heart Rate 141.75 133.38

*Total Calories expended for each subject across two minutes Table 1: The above data is comprised of the mean of all thirty-second intervals for the entire two-minute trial for all subjects. The rower produced higher results in all areas tested compared to the cycle.

Figure 1: All six subjects expended more Calories on the rower as opposed to the cycle at the same workload.

Figure 2: Mean Calories expended at each thirty-second interval are higher using the rower compared to using the watt bike.

Figure 3: Mean oxygen consumption at each thirty-second interval was greater using the rower than cycle.

Figure 4: Mean RER at each thirty-second interval was higher during the rower than the cycle.

Figure 5: Mean heart rate at each thirty-second interval was higher during the rower than cycle.

Discussion The purpose of this study was to determine which modality would yield a higher caloric expenditure at the same workload, the rower ergometer or the cycle ergometer. It was hypothesized that at the given workload, each subject would yield a higher caloric expenditure using the rower ergometer. Figure 1 represents all subject after two minutes on both exercise modalities. The data shows that all subjects expended, on average, 21.6 Calories using the rower ergometer. However, at the same workload, all subjects expended on average 18.5 Calories using the cycle ergometer. At this rate if the subject maintained the same pace for an extended period of time, the difference would be much larger. For example after an hour of exercise, there would be a difference of 93 Calories. In regards to weight loss, the caloric balance equation (CBE) is used to calculate caloric expenditure against caloric intake. The CBE states that if more Calories are expended than Calories ingested, the body will use stored Calories to fuel the energy requirements. One pound of stored fat is equivalent to 3500 Calories. Although each thirty-seconds of exercise between the two modalities yielded only a difference 0.775 Calories, Figure 2 shows the linear increase at each interval. Figure 2 and Figure 3 show a positive correlation that oxygen consumption is closely related to caloric expenditure. Caloric expenditure is calculated using oxygen consumed (L*min-1) multiplied by the caloric equivalent (Calorie*L-1O2) pertaining to the individuals Respiratory Exchange Rate (RER). RER is the ratio of carbon dioxide (VCO2) produced divided by oxygen consumed (VO2). The amount of oxygen consumed and carbon dioxide produced depends on the fuel source being utilized, either fats or carbohydrates, due to the different chemical compositions of the fuels. An RER value of 0.70

indicates a reliance of 100% fat utilization, while an RER value of 1.0 indicates 100% reliance of carbohydrates. As RER shifts between 0.70 and 1.0, a mixture of fat and carbohydrates are utilized.xix As Figure 4 shows, at each thirty-seconds of exercise on the rower ergometer, each subject relied more on carbohydrates, RER of 0.88 which implies 59.2% carbs; 40.8% fats, as the fuel source because they are more readily available. The cycle ergometer remained using fat as the primary source of fuel with an average RER of 0.79, which implies 28.6% carbs and 71.45 fats. Figure 5 represents the mean heart rate at each thirty-second interval. It was hypothesized that at the same workload the rower ergometer would cause heart rate to be higher. Table 1 shows the rower ergometer yielded, on average, a heart rate of 141.75 beats per minute. The mean heart rate while on the cycle ergometer for the test was 133.38 beats per minute. The physiological response to heart rate is thought to reflect a greater sympathetic stimulation.

One study was done in which many physiological measurements were taken during submaximal cycling and rowing with the main focus of the study being on energy expenditure. The study performed in 1988 closely resembled this particular study right down to the results. The test showed VO2 and heart rate were significantly higher at all power increments during the rowing graded exercise test. This lead those researchers to believe that energy costs for rowing ergometry were significantly higher than cycle ergometry at all comparative power outputs including maximal levels.xx This previous study used a sample population of 60 men

and 47 women ranging from age 20-74. Our study used five men and one female between the ages of 19 and 22. Both studies used the cycle ergometer as well as the rower ergometer, however the test from 1988 used graded exercise when our study focused on submaximal two minutes of exercise. Although there was variation between sample sizes, the same results occurred regarding energy expenditure, that the rower ergometer had higher energy expenditure. Some potential limitations regarding this study included sample size and time frame in which data was needed to be collected. A source of error regarding the rower ergometer was that wattage was an average across two minutes whereas on the cycle ergometer the wattage was maintained. The subject’s were not monitored in their prior meal, which could have caused an increased heart rate before testing. Inadequate sleep before testing can cause an error in the data as well. Possible future studies should examine caloric expenditure regarding cycle and rower ergometers in a larger and more diverse sample size, over different time durations, at different workload intensities, and possibly comparing other modalities.

Following results of the study performed, it is confirmed that the rower ergometer not only expends more Calories at a given workload but also yields a higher oxygen consumption, RER and heart rate. From these findings, the general public would be able to apply the benefits of the rower ergometer and also cycle ergometer. As stated, this study was designed to determine which modality would expend more Calories at the same workload, but be perceived to be easier. Therefore the rower ergometer was determined to be the choice exercise

i

Board, A.D.A.M. Editorial. "Causes, Incidence, and Risk Factors." Obesity. U.S. National Library of Medicine, 18 Nov. 0000. Web. ii "Adult Obesity Facts." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 27 Apr. 2012. Web. iii "The Health Effects of Overweight and Obesity." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 17 Aug. 2011. Web. iv Xiao Jun, W ., & Balluz, L. S. (2011). Physical Activity Level and Ischemic Heart Disease Prevalence Among Individuals Aged 45 Years and Older With Normal Weight, BRFSS, 2007. Journal Of Physical Activity & Health, 8(4), 475-480 v Lee M. Kaplan. Weigh Less, Live Longer (Harvard Special Health Report). Sept 2006 p10. vi Swain, D. P. (2000). Energy cost calculations for exercise prescription: an update. / Calcul du cout energetique pour la prescription d’exercice: une mise a jour. Sports Medicine, 30(1), 17-22 vii Kinesiology of the rowing stroke, NSCA Journal, Volume 10, Number 2, 1988, Thomas Mazzone, M.D. Wyoming County Community Hospital, Warsaw, New York viii Bini, R., Diefenthaeler, F., & Carpes, F. P. (2011). Lower limb muscle activation during a 40km cycling time trial: Co-activation and pedaling technique. International Sportmed Journal. 12(1). 7-16 ix Hofmijster, M. J., van Soest, A. J., & de Roning, J. J. (2009). Gross Efficiency during Rowing is Not Affected by Stroke Rate. Medicine & Science In Sports & Exercise, 41(5), 1088-1095 x Lawton, T. W., Cronin, J. B., & McGuigan, M. R. (2011). Strength Testing and Training of Rowers. Sports Medicine, 41(5), 413-432 xi Coyle, E. F., Sidossis, L. S., Horowitz, J. F., & Beltz, J. D. (1992). Cycling efficiency is related to the percentage of Type I muscle fibers. / L’ efficacite lors de I’ exercise est en rapport avec le pourcentage def fibres musculaires de type I. Medicine & Science In Sports & Exercise, 24(7), 782-788 xii Petrykowski, A., & Lutoslawska, G. (2011). THE RELATIONSHIP BETWEEN 500 M AND 2000 M SIMULATED ROWING TIMES FOR SCHOOLBOY ROWERS OVER A TRAINING PERIOD OF THREE YEARS. Human Movement, 12(2), 147-152 xiii MAHLER, D., ANDREA, B., & WARD, J. (1987). Comparison of exercise performance on rowing and cycle ergometers (Comparaison de la performance d’ exercice sur ergometra d’ aviron etbicyclette ergometrique. Research Quarterly For Exercise & Sport, 58(1), 41-46 xiv Bouckaert, J. J. Pannier, J., & Vrijens, J. J. (1983). Cardiorespiratory response to bicycle and rowing ergometer exercise in oarsmen. European Journal Of Applied Physiology & Occupational Physiology, 51(1), 51-59 xv Wiener, S.P., Ewing Garber, C. C., & Manfredi, T.G. (1995). A comparison of exercise performance on bicycle and rowing ergometers in female Master recreational rowers. /Comparaison de la performance d’ effort sur bicyclette ergometrique et sur ergometer d’ aviron chez des rameuses veterans de loisir. Journal Of Sports Medicine & Physical Fitness, 35(3), 176-180 xvi Hagerman, F.C., Lawrence, R. A., & Mansfield, M. C. (1988). A comparison of energy expenditure during rowing and cycling ergometry. / Comparaison de la depense energetique lors d’ un exercice ergometrique en aviron et a bicyclette. Medecine & Science In Sports & Exercise, 20(5), 479-488 xvii Kinesiology of the rowing stroke, NSCA Journal, Volume 10, Number 2, 1988, Thomas Mazzone, M.D. Wyoming County Community Hospital, Warsaw, New York xviii Plower SA, Smith DL. Exercise Physiology for Health, Fitness, and Performance. 3 rd Edition. 2011. 101-106, 220-221 xix Plower SA, Smith DL. Exercise Physiology for Health, Fitness, and Performance. 3 rd Edition. 2011. 101-106, 220-221 xx Hagerman, F.C., Lawrence, R. A., & Mansfield, M. C. (1988). A comparison of energy expenditure during rowing and cycling ergometry. / Comparaison de la depense energetique lors d’ un exercice ergometrique en aviron et a bicyclette. Medecine & Science In Sports & Exercise, 20(5), 479-488

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