ARATANI Yurie

HAMADA Hiroki

HAYASHI Sotaro

ONODERA Sho

SAITO Tatsuya

TAMARI Yutaro

TSUTIDA Yasukiyo

WADA Takuma

WAKIMOTO Toshihiro

YAMAGUCHI Hidetaka

YOSHIDA Noboru

YOSHIOKA Akira

Kawasaki University of Medical Welfare Institutional Repository

85Kawasaki Journal of Medical Welfare Vol. 24,  No. 2,  2019 85-89Changes in Physiological Stress of Tandem-bicycle Cyclists and a Single-bicycle Cyclist during a Three Hour Endurance RaceSho ONODERA＊1, Noboru YOSHIDA＊2, Hiroki HAMADA＊3, Yutaro TAMARI＊4, Sotaro HAYASHI＊5, Takuma WADA＊1, Akira YOSHIOKA＊6, Yasukiyo TSUTIDA＊7, Toshihiro WAKIMOTO＊1, Tatsuya SAITO＊1, Yurie ARATANI＊3 and Hidetaka YAMAGUCHI＊8(Accepted December 26, 2018)Key words: relative exercise intensity, heart rate, blood pressure, RPEAbstract　This study aimed to clarify the changes in physiological stress of a tandem bicycle (front and rear cyclist) and a single bicycle (single cyclist) during a 3-h endurance bicycle race. Three healthy Japanese adult males participated in a 3-h endurance race held at Okayama International Circuit (3.7 km around). The tandem-bicycle cyclists were keeping the same pace with the single-bicycle cyclist for 3-h. During the race, heart rate, rating of perceived exertion (RPE), blood pressure and urinary catecholamine were measured. Relative exercise intensity was calculated using the V4O2peak and average heart rate values were obtained during each lap. The exercise intensity of the tandem-bicycle cyclists was higher for uphill than downhill riding. In contrast, the exercise intensity of the single-bicycle cyclist was higher for downhill than uphill riding. Going uphill, the tandem bicycle has a load of two people while the single bicycle has a load of one person. Conversely, going downhill, the weight of the two cyclists on the tandem bicycle increases the speed, whereas the single-bicycle cyclist must pedal to catch up with that speed. Urinary catecholamine levels tended to increase after the race. Exercise intensity shows force results in the opposite directions for tandem and single-bicycle cycling both uphill and downhill.Material＊1 Department of Health and Sports Science, Faculty of Medical Technology,     Kawasaki University of Medical Welfare, Kurashiki, 701-0193, Japan    E-Mail: shote@mw.kawasaki-m.ac.jp＊2 Doctoral Program in Health Science, Graduate School of Health Science and Technology,     Kawasaki University of Medical Welfare＊3 Master’s Program in Health and Sports Science, Graduate School of Health Science and Technology,     Kawasaki University of Medical Welfare＊4 Faculty of Life Science, Department of Clinical Engineering, Hiroshima Institute of Technology＊5 Faculty of Education, Fukuyama City University ＊6 Department of Health Educations, Faculty of Education, Kansai University of Social Welfare＊7 SANIN-CHUO College＊8 Department of Sports Social Management, Kibi International University86 Sho Onodera et al.1. Introduction　A tandem bicycle is a two-saddle bicycle in which the front and rear cyclists work together to propel the bicycle1). In our previous study, we found that the relative exercise intensity between the front and rear cyclists appeared to differ during the latter half of a 2-h race, such that the intensity was higher in the front cyclist than in the rear cyclist2,3). We speculated that the physiological stress of a single-bicycle cyclist during uphill riding is higher than that during downhill riding when compared with a tandem bicycle. We thus aimed to clarify the changes in physiological stress of a tandem bicycle (front and rear cyclist) and a single bicycle (single cyclist) during a 3-h endurance bicycle race.　2. Methods　Three healthy Japanese adult males (tandem bicycle: front saddle cyclist: age, 27 years; height, 172 cm; body weight, 63 kg; and peak oxygen uptake (V4O2peak), 39.4 ml/kg/min; rear saddle cyclist: age, 26 years; height, 174 cm; body weight, 91 kg; and V4O2peak, 33.4 ml/kg/min; and single-bicycle cyclist: age, 23 years; height, 174 cm; body weight, 59 kg; and V4O2peak, 44.6 ml/kg/min) participated in a 3-h endurance race held at Okayama International Circuit (3.7 km around). All procedures were approved by the Ethics Committee of the Kawasaki University of Medical Welfare and conformed to the Declaration of Helsinki (#306). The tandem-bicycle cyclists were keeping the same pace with the single-bicycle cyclist for 3-h. During the race, heart rate was recorded from start to finish using a heart rate monitor (M400; POLAR, Sweden). Additionally, heart rate, rating of perceived exertion (RPE)4) and blood pressure (501; KENZMEDICO, Japan) were measured every three laps. The participants were allowed a short rest (10 min) after every three laps. Urinary catecholamine (adrenaline, noradrenaline and dopamine; creatinine correction) levels were measured before and after the race. The V4O2peak was measured using the Douglas bag method with a bicycle ergometer four months before the race at a laboratory at Kawasaki University of Medical Welfare. Relative exercise intensity was calculated using the V4O2peak and average heart rate values were obtained during each lap. The racetrack was approximately 3.7 km in length (Cycle Endurance Race 2017 in Okayama International Circuit) (Figure 1, Okayama International Circuit Japan5)) and the temperature and humidity were 26.6°C and 58.4%, respectively. A global positioning system was used to track the cyclists’ locations during the race.Figure 1　OKAYAMA International Circuit (3.7km)5)87Changes in Physiological Stress of Tandem-bicycle Cyclists　3. Results & Discussion　Table 1 summarizes the average speed of both bicycles for each lap. The average speeds of the tandem and single bicycle were 20.9 ± 1.7 km/h and 20.6 ± 1.7 km/h for each lap, respectively. Figure 2 (A: X-Y, uphill road), Figure 3 (B: Y-Z, downhill to uphill) and Figure 4 (C: Z-X, long downhill to long uphill) show the Table 1　Lap time and average speed of tandem bicycle and single bicycle for each lap/ Lap 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 12th 13th 14th 15thTimeTandem 8'32 9'38 10'00 9'56 9'59 9'41 10'24 10'29 10'37 10'45 10'47 10'59 11'01 11'50 10'55Single 8'32 9'39 10'00 10'02 9'59 9'41 10'26 10'29 10'38 10'44 10'46 11'04 11'06 11'50 10'55SpeedTandem 25.6 22.4 21.6 21.9 21.6 22.2 20.7 20.8 20.2 20.1 20.2 19.5 19.5 18.3 19.7Single 25.3 22.1 21.3 21.3 21.4 22.1 20.4 20.4 20.0 19.2 20.0 19.3 19.2 18.0 19.6(Time : min.’sec., Speed : km/h)Figure 2　Changes in relative oxygen uptake (%V4O2peak) between each cyclist during A: X-Y (an uphill road)◯：Front saddle cyclist, ●：Rear saddle cyclist, ◆：Single cyclistFigure 3　 Changes in relative oxygen uptake (%V4O2peak) between each cyclist during B: Y-Z (from downhill to uphill)◯：Front saddle cyclist, ●：Rear saddle cyclist, ◆：Single cyclistFigure 4　 Changes in relative oxygen uptake (%V4O2peak) between each cyclist during C: Z-X (from long downhill to long uphill)◯：Front saddle cyclist, ●：Rear saddle cyclist, ◆：Single cyclist88 Sho Onodera et al.Figure 5　 Changes in the blood pressure of each cyclist■：Front saddle cyclist SBP, ●：Rear saddle cyclist SBP, ◆：Single cyclist SBP□：Front saddle cyclist DBP, ◯：Rear saddle cyclist DBP, ◇：Single cyclist DBPFigure 6　Changes in the RPE of each cyclist◯：Front saddle cyclist, ●：Rear saddle cyclist, ◆：Single cyclistaverage relative oxygen uptake (%V4O2peak) in the trials between the cyclists. The average %V4O2peak at A was 63.7% for the front cyclist, 69.9% for the rear cyclist and 58.1% for the single cyclist; at B the average %V4O2peak was 64.9% for the front cyclist, 72.3% for the rear cyclist and 68.1% for the single cyclist; at C the average %V4O2peak was 63.8% for the front cyclist, 68.8% for the rear cyclist and 64.3% for the single cyclist. The value tended to be higher for the rear cyclist relative to the other cyclists. 　The exercise intensity of the tandem-bicycle cyclists was higher for uphill than downhill riding6,7). In contrast, the exercise intensity of the single-bicycle cyclist was higher for downhill than uphill riding. Going uphill, the tandem bicycle has a load of two people while the single bicycle has a load of one person. Conversely, going downhill, the weight of the two cyclists on the tandem bicycle increases the speed, whereas the single-bicycle cyclist must pedal to catch up with that speed. This is considered to be a burden on the single-bicycle cyclist.　Figure 5 presents the changes in blood pressure. Diastolic blood pressure tended to decrease with each lap. This result speculates that the diastolic blood pressure during the race was influenced by exercise intensity exercise for each lap. Figure 6 shows the changes in RPE. RPE tended to increase with each lap. Table 2 shows the comparison of urinary adrenaline, noradrenaline and dopamine concentrations before and after the race. Adrenaline and noradrenaline tended to increase after the race. Urinary catecholamine is a stress hormone that is metabolized from dopamine to noradrenalin and then to adrenaline. Urinary noradrenaline is associated with psychological stress, and adrenaline is associated with physical stress6). Urinary adrenaline and noradrenaline levels increased in all cyclists, indicating similar levels of physiological and psychological stress. It is thought that this supports the increase of psychological stress after racing, Table 2　 Changes in urinary adrenalin, noradrenalin and dopamine concentrations between the before and after of the raceAdrenaline Noradrenalin Dopaminepre post pre post pre postFront saddle cyclist 9.86 19.68 69.83 139.43 453.09 276.51Rear saddle cyclist 10.11 30.32 89.92 218.01 411.41 416.20Single cyclist 28.03 22.08 88.75 147.34 439.37 380.72(ng/mgCr)89Changes in Physiological Stress of Tandem-bicycle Cyclistsbecause the increase of urinary noradrenaline levels is in agreement with the increase of RPE. Further study will require at least 7 to 8 samples for each group of cyclists in order to demonstrate statistically that there is no difference.　4. Conclusion　Exercise intensity shows force results in the opposite directions for tandem and single-bicycle cycling both uphill and downhill.　Conflicts of Interest　The authors declare that there are no conflicts of interest regarding the publication of this article. Acknowledgement　This study was supported by the Japan Society for the Promotion of Science KAKENHI (Grant Number: 15K01509).References 1. Japan Cycling Association : https://www.j-cycling.or.jp/about/pdf/PDF_research_13.pdf, 2010. (September 27, 2018) 2. Onodera S, Saito T, Wada T, Murata M, Hayashi S, Watanabe Y, Fujiwara Y and Wakimoto T : Changes of heart rate during tandem bicycle cycling in a 2-hour endurance race. Kawasaki Medical Welfare Journal, 24(1), 89-94, 2014. (In Japanese) 3. Onodera S, Wada T, Tamari Y, Yoshida N, Hayashi S and Yoshioka A : Changes in relative intensity during a two hour endurance race using a tandem-bicycle for exercise. Kawasaki Journal of Medical Welfare, 22(1), 47-52, 2016. 4. Borg GA : Perceived exertion: a note on "history" and methods. Medicine and Science in Sports, 5(2), 90-93, 1973. 5. OKAYAMA International Circuit : http://www.okayama-international-circuit.jp/guide/pdf/course.pdf, 2016. (September 27, 2018) 6. Onodera S, Yoshida N, Wada T, Tamari Y, Hayashi S, Matsumoto N, Yoshioka A, Yamaguchi H, Katayama K and Ogita F : Changes in relative exercise intensity during a three hours endurance race using a tandem-bicycle for exercise. Advances in Exercise and Sports Physiology, 22(4), 93, 2016. 7. Onodera S, Wada T, Tamari Y, Yoshida N, Hayashi S, Yamaguchi H, Wakimoto T, Hamada H and Yoshioka A : Changes in physiological responses to tandem bicycle exercise during the 5 hour endurance race in Okayama International Circuit. Kawasaki Journal of Medical Welfare, 23(2), 65-70, 2018. 8. Wilmore JH and Costill DL : Physiology of sport and exercise. 3rd ed, Human Kinetics, United States, Champaign IL, 2004.

Changes in Physiological Stress of Tandem-bicycle Cyclists and a Single-bicycle Cyclist during a Three Hour Endurance Race

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Changes in Physiological Stress of Tandem-bicycle Cyclists and a Single-bicycle Cyclist during a Three Hour Endurance Race

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