The exercise classes were perceived to be quite strenuous, with RPE greater than 5 (i.e., hard) at all measured time points (Table 2). Despite the high intensity of exercise, spontaneous comments from the subjects suggested that even with the video recording to guide the exercise pattern, the effort was less than typically experienced in a live class with the instructor and other class members present. Thus, the observed responses plausibly represent a conservative estimate of the exercise intensity during typical indoor cycling classes.
The main finding from this study was that although the average intensity of indoor cycling classes was comparatively moderate (i.e., 65-75% o2max), there was an appreciable percentage of the exercise bout when the intensity was greater than VT, based on both o2 (approximately 35%) and HR (35-50%) criteria, and the highest o2 observed during the indoor cycling classes was frequently (10 of 40 exercise bouts) greater than o2max observed during incremental cycle exercise, which itself satisfied accepted criteria for achieving o2max (21). Five of the 10 exercise sessions, in which greater than o2max values were observed, occurred in subjects who demonstrated a plateau during the incremental test. The responses of the subjects were quite variable, particularly with the constant cueing provided by the videotape. Since there was no exercise prescription (e.g., target HR) per se, the variability of response potentially represents spontaneous down-regulation of exercise intensity despite cueing that might suggest increasing power output. This would be consistent with the concept that exercise intensity may be intrinsically regulated in a way designed to prevent overexertion injuries (29).
Although the subjects in this study were not athletes systematically training every day, the percentage of the exercise bout with exercise intensities greater than VT was much higher than routinely observed in athletes during spontaneous training (4,12-14,33-35), although it is within the range of individual high intensity training bouts in athletes (35). On this basis, if indoor cycling were used as an everyday training activity, it is possible that the overall intensity would be too high and possibly contribute to developing nonfunctional overreaching (27,28). However, as an episodic training activity, the comparatively high intensity may be associated with an effective training response. In particular, recent results by Helgerud et al. (20), Laursen et al. (23), and Septo et al. (37) have suggested that in order for already trained athletes to improve o2max, training intensities approximating the intensity of o2max are required.
The current data are consistent with the authors, previous observations of higher than incremental o2max values during cycle time trials in both athletes (15) and well-trained nonathletes (16). However, since running time trials have not been shown to produce higher than incremental o2max responses (9), it may be argued that local muscle fatigue during cycling limits exercise prior to achieving a limitation of central oxygen transport capacity. A wide variety of studies have shown that Vo2max is systematically lower during cycle ergometry than during running. Thus, cycling may be a somewhat limited model for testing the conceptual underpinnings of o2max, in that for the majority of individuals, cycling exercise is more likely to be limited by local muscular factors, potentially the amount of muscle engaged in exercise, than by the ability of the central circulation to offer oxygen to the exercising musculature.
Regardless of this limitation, the current results reinforce other studies that have demonstrated that o2 values greater than the o2max achieved during incremental exercise can be observed during both submaximal (8) and maximal (3,5,32) exercise. The difference between the current results and those of Rozenek et al. (32) and Billat et al. (3,5) is that the training sessions designed by these investigators were intended to induce o2max. The indoor cycling exercise bouts studied in this study and the study by Caria et al. (8) were anticipated to be submaximal. Thus, the frequent observations of o2 values greater than o2max was unanticipated. This may have unintended consequences in that the risk of serious health consequences (e.g., myocardial infarction) during exercise training is linked to unaccustomed heavy exercise (38), particularly in beginning exercisers. This may be a meaningful concern given that indoor cycling classes are often targeted toward middle-aged fitness participants, a population in whom there may be a significant incidence of subclinical cardiovascular disease and in whom the adequacy of preliminary medical screening may be suboptimal (38). Accordingly, in cases in which less athletic individuals are performing indoor cycling classes, it may be especially prudent to consider both the choreography of the exercise session and the adequacy of pre-exercise screening.
From the standpoint of using indoor cycling classes to contribute to the off-season conditioning of athletes, it is reasonably well-established that higher-intensity training is necessary to provoke adaptations to the cardiorespiratory system. Thus, in addition to the low impact nature of this mode of exercise, it may be that this would be an effective method of nonspecific conditioning that would be very effective on a result-per-time basis. The current data were collected from university-aged female nonathletes. As such, the generalizability of the response is limited. Future studies in competitive athletes would be productive. On the other hand, there is good evidence that unaccustomed high-intensity exercise may contribute to the triggering of acute myocardial infarction in individuals with underlying cardiovascular disease. Given that indoor cycling is widely used in the fitness industry and targeted at middle-aged individuals, those wishing to lead indoor cycling classes should make sure that they have conducted appropriate pre-exercise screening.
This study was funded by a grant from the Office of University Graduate Studies at the University of Wisconsin-La Crosse. There was no extramural funding. None of the authors has conflicts of interest or relationships that require disclosure. The results do not constitute endorsement of any product by the authors or by the National Strength and Conditioning Association.
1. Bassett, DR and Howley, ET. Maximal oxygen uptake: ‘classical’ versus ‘contemporary’ viewpoints. Med Sci Sports Exerc
29: 591-603, 1997.
2. Bergh, U, Ekblom, B, and Astrand, PO. Maximal oxygen uptake: ‘classical’ versus ‘contemporary’ viewpoints. Med Sci Sports Exerc
32: 85-88, 2000.
3. Billat, VL, Slawinski, J, Bocquet, V, Chasing, P, Demarle, A, Lappitte, L, and Koralsztein, JP. Intermittent runs at the velocity associated with maximal oxygen uptake enables subjects to remain at maximal oxygen uptake for a longer time than intense but submaximal runs. Eur J Appl Physiol
81: 188-196, 2000.
4. Billat, VL, Demarle, A, Slawinski, J, Paiva, M, and Koralsztein, JP. Physical and training characteristics of top-class marathon runners. Med Sci Sports Exerc
33: 2089-2097, 2001.
5. Billat, VL, Slawinski, V, Bocquet, P, Chasaing, P, Demarle, A, and Koralsztein, JP. Very short interval training around critical velocity allows middle-aged runners to maintain o2
max for 14 minutes. Int J Sports Med
22: 201-208, 2001.
6. Borg, GA. Borg,s Perceived Exertion and Pain Scales
. Champaign, IL: Human Kinetics, 1998. pp. 1-120.
7. Cannon, C, Foster, C, Porcari, JP, Skemp-Arlt, KM, Fater, DCW, and Backes, R. The Talk Test as a measure of exertional ischemia. Am J Med Sport
6: 52-57, 2004.
8. Caria, MA, Tangianu, F, Concu, A, Crisafulli, A, and Mameli, O. Quantification of spinning
bike performance during a standard 50-minute class. J Sports Sci
9. Crouter, S, Foster, C, Esten, P, Brice, G, and Porcari JP. Comparison of incremental treadmill exercise and free range running. Med Sci Sports Exerc
33: 644-647, 2001.
10. Daniels, JT, Yarbrough, RA, and Foster, C. Changes in o2
max and running performance with training. Eur J Appl Physiol
39: 249-254, 1978.
11. Day, JR, Rossiter, HB, Coats, EM, Skasick, A, and Whipp, BJ. The maximally attainable o2
during exercise in humans: the peak vs. maximum issue. J Appl Physiol
95: 1901-1907, 2003.
12. Esteve-Lanao, J, San Juan, AF, Earnest, CP, Foster, C, and Lucia, A. How do endurance runners actually train? Relationship with competitive performance. Med Sci Sports Exerc
37: 496-504, 2005.
13. Esteve-Lanao, J, Lucia, A, Foster, C, and Seiler, S. Impact of training intensity distribution on performance in endurance athletes. J Strength Cond Res
21: 943-949, 2007.
14. Fiskestand, A and Seiler, KS. Training and performance characteristics among Norwegian international elite rowers 1970-2001. Scand J Med Sci Sports
14: 303-310, 2004
15. Foster, C, Green, MA, Snyder, AC, and Thompson, NN. Physiological responses during simulated competition. Med Sci Sports Exerc
25: 877-882, 1993.
16. Foster, C, Coyne, RB, Crowe, A, Dumit, M, Lettau, S, Teske, HM, and Volkert, P. Comparison of free range and graded exercise testing. Med Sci Sports Exerc
29: 1521-1526, 1997.
17. Foster, C and Cotter, H. Blood lactate, respiratory and heart rate markers of the capacity for sustained exercise. In: Physiological Assessment of Human Fitness
(2nd ed.). Maud, PJ, and Foster, C, eds. Champaign, IL: Human Kinetics, 2005. pp. 63-76.
18. Foster, C, Kuffel, E, Bradley, N, Battista, RA, Wright, G, Porcari, JP, Lucia, A, and deKoning, JJ. o2
max during successive maximal efforts. Eur J Appl Physiol
102: 67-72, 2007.
19. Francis, P, Stavig-Witucki, A, and Buono, MJ. Physiological response to a typical studio cycling session. Am Coll Sports Med Heath Fitness J
3: 30-36, 1999.
20. Helgerud, J, Hoydal, K, and Want, E. Aerobic high-intensity intervals improve o2
max more than moderate training. Med Sci Sports Exerc
39: 665-671, 2007.
21. Howley, ET and Bassett, DR. Criteria for maximal oxygen uptake: review and commentary. Med Sci Sports Exerc
27: 1292-1301, 1995.
22. Kang, J, Chaloupka, EC, Mastrangelo, MA, Hoffman, JR, Ratamess, NA, and O'Connor, E. Metabolic and perceptual responses during spinning
cycle exercise. Med Sci Sports Exerc
37: 853-859, 2005.
23. Laursen, PB, Shing, CM, Peak, JM, Coombes, JS, and Jenkins, DG. Interval training program optimization in highly trained endurance cyclists. Med Sci Sports Exerc
24. Lucia, A, Mabadan, M, Hoyos, J, Hernandez-Capilla, M, Perez, M, San Juan, AF, Earnest CP, and Chicharro, JL. Frequency of the o2
max plateau phenomenon in world class cyclists. Int J Sports Med
27: 1-9, 2006.
25. Lucia, A, Hoyos, J, Carvajal, A, and Chicharo, JL. Heart rate response to professional road cycling: the Tour de France. Int J Sports Med
20: 167-172, 1999.
26. Meyer, K, Samek, L, Pinchas, A, Baier, M, Betz, P, and Roskamm, H. Relationship between ventilatory threshold and onset of ischemic during stress testing. Eur Heart J
16: 623-630, 1995.
27. Meeusen, R, Duclos, M, Gleeson, M, Rietjens, G, Steinacker, J, and Urhausen, A. Prevention, diagnosis and treatment of the overtraining syndrome. Eur J Sport Sci
6: 1-14, 2006.
28. Moore, CA and Fry, AC. Nonfunctional overreaching during off-season training for skill position players in collegiate American football. J Strength Cond Res
21: 793-800, 2007.
29. Noakes, TD. Challenging beliefs: ex Africa simper aliquid novi. Med Sci Sports Exerc
29: 571-590, 1997.
30. Noakes, TD. Maximal oxygen uptake: ‘classical’ versus ‘contemporary’ viewpoints: a rebuttal. Med Sci Sports Exerc
30: 1381-1398, 1998.
31. Rossiter, HB, Kowalchk, JM, and Whipp, BJ. A test to establish maximal O2
uptake despite no plateau in the O2
uptake response to ramp incremental exercise. J Appl Physiol
100: 764-770, 2006.
32. Rozenek, R, Funato, K, Kubo, J, Hoshikawa, M, and Matsuo, A. Physiological responses to interval training sessions at velocities associated with o2
max. J Strength Cond Res
21: 188-192, 2007.
33. Schumacker, YO and Mueller, P. The 4000-m team pursuit cycling world record: theoretical and practical aspects. Med Sci Sports Exerc
34: 1029-1036, 2002.
34. Seiler, KS and Kjerland, GO. Quantifying training intensity distribution in elite endurance athletes. Scand J Med Sci Sports
16: 49-56, 2006.
35. Seiler, KS, Haugen, O, and Kuffel, E. Autonomic recovery after exercise in trained athletes: intensity and duration effects. Med Sci Sports Exerc
39: 1366-1373, 2007.
36. Snell, PG, Stray-Gunderson, J, Levine, B, Hawkins, MN, and Raven, PB. Maximal oxygen uptake as a parametric measure of cardiorespiratory capacity. Med Sci Sports Exerc
39: 103-107, 2007.
37. Stepto, NK, Hawley, JA, Dennis, SC, and Hopkins, WG. Effect of different interval training programs on cycling time trial performance. Med Sci Sports Exerc
31: 736-741, 1998.
38. Thompson, PD, Franklin, BA, Balady, GJ, Blair, SN, Convado, D, Estes, M, Fulton, JE, Gordon, NF, Haskell, WL, Link, MT, Maron, B, Mittleman, MA, Pelliccia, A, Wenger, NK, Willich, S, and Costa, F. Exercise and acute cardiovascular events: placing the risks into perspective. Circulation
115: 2358-2368, 2007.