Hostname: page-component-78c5997874-m6dg7 Total loading time: 0 Render date: 2024-11-04T19:44:26.221Z Has data issue: false hasContentIssue false

The limitations of the constant load and self-paced exercise models of exercise physiology

Published online by Cambridge University Press:  03 February 2012

Frank E. Marino*
Affiliation:
School of Human Movement Studies, Faculty of Education, Charles Sturt University, Bathurst, NSW2795, Australia
*
*Corresponding author: [email protected]
Get access

Abstract

The fundamental tenets of exercise physiology are to describe energy transformations during physical work and make predictions about physical performance under different conditions. Historically, the most popular method to observe such responses during exercise has been the constant load or fixed-intensity protocol, based largely on the assumption that there is a certain threshold response of the organism under a given condition. However, constant load exercise does not fully allow for randomness or variability, as the biological system is overridden by a predetermined externally imposed load that cannot be altered. Conversely, in self-regulated (paced) exercise, there is almost an immediate reduction in power output and muscle recruitment upon commencing exercise. This observation suggests the existence of neural inhibitory command processes. This difference in regulation demonstrates the inherent importance of variability in the biological system; for in tightly controlled energy expenditure, as is the case during constant load exercise, sensory cues cannot be fully integrated to provide a more appropriate response to the given task. The collective evidence from conventional constant load versus self-regulated exercise studies suggests that energy transformations are indeed different, so that the inherent biological variability accounts for the different results achieved by the two experimental paradigms.

Type
Review Article
Copyright
Copyright © Cambridge University Press 2012

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1Hill, AV and Lupton, H (1923). Muscular exercise, lactic acid, and the supply and utilization of oxygen. Quarterly Journal of Medicine 16: 135171.CrossRefGoogle Scholar
2Taylor, HL, Buskirk, E and Henschel, A (1955). Maximal oxygen intake as an objective measure of cardio-respiratory performance. Journal of Applied Physiology 8(1): 7380.CrossRefGoogle ScholarPubMed
3Edwards, RHT (1983). Biochemical bases of fatigue in exercise performance: catastrophe theory of muscular fatigue. In: Knuttgen, HG, Vogel, JA and Poortmans, J (eds) Biochemistry of Exercise. Champagne, IL: Human Kinetics Publishers, pp. 327.Google Scholar
4Noakes, TD and St Clair Gibson, A (2004). Logical limitations to the “catastrophe” models of fatigue during exercise in humans. British Journal of Sports Medicine 38(5): 648649.CrossRefGoogle Scholar
5Schmidt, RA (1988). Motor Control and Learning: A Behavioral Emphasis. Champaign, IL: Human Kinetics Publishers.Google Scholar
6Palmer, GS, Hawley, JA, Dennis, SC and Noakes, TD (1994). Heart rate responses during a 4-d cycle stage race. Medicine and Science in Sports and Exercise 26: 12781283.CrossRefGoogle ScholarPubMed
7Ulmer, HV (1996). Concept of extracellular regulation of muscular metabolic rate during heavy exercise in humans by psychophysiological feedback. Experentia 52: 416420.CrossRefGoogle ScholarPubMed
8Noakes, TD (2008). Testing for maximum oxygen consumption has produced a brainless model of human exercise performance. British Journal of Sports Medicine 42: 551555.CrossRefGoogle ScholarPubMed
9Guyton, AC and Hall, JE (2006). Textbook of Medical Physiology. Philadelphia, PA: Elsevier Saunders.Google Scholar
10Noakes, TD (2011). The VO2 max and the central Governor: a different understanding. In: Marino, FE (ed.) Regulation of Fatigue in Exercise. New York, NY: Nova Science Publishers, Inc., pp. 79100.Google Scholar
11Brooks, GA, Fahey, TD and Baldwin, KM (2005). Exercise Physiology: Human Bioenergetics and its Applications. 4th edn.Dubuque, IA: McGraw-Hill.Google Scholar
12Eddington, AS (1928). The Nature of the Physical World. Cambridge: Cambridge University Press.Google Scholar
13Koch, LG and Britton, SL (2008). Aerobic metabolism underlies complexity and capacity. Journal of Physiology 586(1): 8395.CrossRefGoogle ScholarPubMed
14Noakes, TD, St Clair Gibson, A and Lambert, VA (2004). From catastrophe to complexity: a novel model of integrative central neural regulation of effort and fatigue during exercise in humans. British Journal of Sports Medicine 38(4): 511514.CrossRefGoogle ScholarPubMed
15Pandolf, KB and Noble, BJ (1973). The effect of pedalling speed and resistance changes on perceived exertion for equivalent power outputs on the bicycle ergometer. Medicine and Science in Sports 5(2): 132136.Google ScholarPubMed
16St Clair Gibson, A and Noakes, TD (2004). Evidence for complex system integration and dynamic neural regulation of skeletal muscle recruitment during exercise in humans. British Journal of Sports Medicine 38: 797806.CrossRefGoogle ScholarPubMed
17Amann, M, Eldridge, MW, Lovering, AT, Stickland, MK, Pegelow, DF and Dempsey, JA (2006). Arterial oxygenation influences central motor output and exercise performance via effects on peripheral locomotor muscle fatigue in humans. Journal of Physiology 575(3): 937952.CrossRefGoogle ScholarPubMed
18Kay, D, Marino, FE, Cannon, J, St Clair Gibson, A, Lambert, MI and Noakes, TD (2001). Evidence for neuromusclur fatigue during high-intensity cycling in warm, humid conditions. European Journal of Applied Physiology 84(1–2): 115121.CrossRefGoogle ScholarPubMed
19Katch, VL, Sady, SS and Freedson, P (1982). Biological variability in maximum aerobic power. Medicine and Science in Sports and Exercise 14: 2125.CrossRefGoogle ScholarPubMed
20McLellan, TM, Cheung, SS and Jacobs, I (1995). Variability of time to exhaustion during submaximal exercise. Canadian Journal of Applied Physiology 20(1): 3951.CrossRefGoogle ScholarPubMed
21Hickey, MS, Costill, DL, McConell, GK, Widrick, JJ and Tanaka, H (1992). Day to day variation in time trial cycling performance. International Journal of Sports Medicine 13: 467470.CrossRefGoogle ScholarPubMed
22Schabort, EJ, Hawley, JA, Hopkins, WG, Mujika, I and Noakes, TD (1998). A new reliable laboratory test of endurance performance for road cyclists. Medicine and Science in Sports and Exercise 30(12): 17441750.CrossRefGoogle ScholarPubMed
23Marino, FE, Lambert, MI and Noakes, TD (2004). Superior performance of African runners in warm humid but not in cool environmental conditions. Journal of Applied Physiology 96: 124130.CrossRefGoogle ScholarPubMed
24Tucker, R, Rauch, L, Harley, YXR and Noakes, TD (2004). Impaired exercise performance in the heat associated with an anticipatory reduction in skeletal muscle recruitment. Pflügers Archives 448: 422430.CrossRefGoogle ScholarPubMed
25Marino, FE, Cannon, J and Kay, D (2010). Neuromuscular responses to hydration in moderate to warm ambient conditions during self-paced high intensity exercise. British Journal of Sports Medicine 44: 961967.CrossRefGoogle ScholarPubMed
26Périard, J, Cramer, M, Chapman, P, Caillaud, C and Thompson, M (2011). Cardiovascular strain impairs prolonged self-paced exercise in the heat. Experimental Physiology 96(2): 134144.CrossRefGoogle ScholarPubMed
27Maughan, R, Otani, H and Watson, P (2011). Influence of relative humidity on prolonged exercise capacity in a warm environment. European Journal of Applied Physiology doi:10.1007/s00421-011-2206-7.Google Scholar
28Amann, M and Dempsey, JA (2008). Locomotor muscle fatigue modifies central motor drive in healthy humans and imposes a limitation to exercise performance. Journal of Physiology 586: 161173.CrossRefGoogle ScholarPubMed
29Amann, M, Romer, LM, Subudhi, AW, Pegelow, DF and Dempsey, JA (2007). Severity of arterial hypoxaemia affects the relative contributions of peripheral muscle fatigue to exercise performance in healthy humans. Journal of Physiology 581(1): 389403.CrossRefGoogle ScholarPubMed
30Noakes, TD and Marino, FE (2007). Arterial oxygenation, central motor output and exercise performance in humans. Journal of Physiology 585: 919921.CrossRefGoogle ScholarPubMed
31Nielsen, B, Hales, JRS, Strange, S, Christensen, NJ, Warberg, J and Saltin, B (1993). Human circulatory and thermoregulatory adaptations with heat acclimation and exercise in a hot, dry environment. Journal of Physiology 460: 467485.CrossRefGoogle Scholar
32Parkin, JM, Carey, MF, Zhao, S and Febbraio, MA (1999). Effect of ambient temperature on human skeletal muscle metabolism during fatiguing submaximal exercise. Journal of Applied Physiology 86: 902908.CrossRefGoogle ScholarPubMed
33González-Alonso, J, Teller, C, Anderson, SL, Jensen, FB, Hyldig, T and Nielsen, B (1999). Influence of body temperature on the development of fatigue during prolonged exercise in the heat. Journal of Applied Physiology 86(3): 10321039.CrossRefGoogle ScholarPubMed
34González-Alonso, J, Calbert, JAL and Nielsen, B (1999). Metabolic and thermodynamic responses to dehydration-induced reductions in muscle blood flow in exercising humans. Journal of Physiology 520(2): 577589.CrossRefGoogle ScholarPubMed
35González-Alonso, J, Calbert, JAL and Nielsen, B (1998). Muscle blood flow is reduced with dehydration during prolonged exercise in humans. Journal of Physiology 513(3): 895905.CrossRefGoogle ScholarPubMed
36Febbraio, MA, Snow, RJ, Stathis, CG, Hargreaves, M and Carey, MF (1994). Effect of heat stress on muscle energy metabolism during exercise. Journal of Applied Physiology 77: 28272831.CrossRefGoogle ScholarPubMed
37Febbraio, MA, Snow, RJ, Stathis, CG, Hargreaves, M and Carey, MF (1996). Blunting the rise in body temperature reduces muscle glycogenolysis during exercise in humans. Expermental Physiology 81: 685693.Google ScholarPubMed
38MacDougall, JD, Reddan, WG, Layton, CR and Dempsey, JA (1974). Effects of metabolic hyperthermia on performance during heavy prolonged exercise. Journal of Applied Physiology 36(5): 538544.CrossRefGoogle ScholarPubMed
39Marino, FE, Mbambo, Z, Kortekaas, E, Wilson, G, Lambert, MI and Noakes, TD (2001). Influence of ambient temperature on plasma ammonia and lactate accumulation during prolonged submaximal and self-paced running. European Journal of Applied Physiology 86: 7178.CrossRefGoogle ScholarPubMed
40Kay, D and Marino, FE (2003). Failure of fluid ingestion to improve self-paced exercise performance in moderate-to-warm humid environments. Journal of Thermal Biology 28: 2934.CrossRefGoogle Scholar
41Burke, LM, Hawley, JA, Schabort, EJ, St Clair Gibson, A, Mujika, I and Noakes, TD (2000). Carbohydrate loading failed to improve 100-km cycling performance in a placebo trial. Journal of Applied Physiology 88: 12841290.CrossRefGoogle Scholar
42Tatterson, AJ, Hahn, AG, Martin, DT and Febbraio, MA (2003). Effects of heat stress on physiological responses and exercise performance in elite cyclists. Journal of Science and Medicine in Sport 3: 186193.CrossRefGoogle Scholar
43Marino, F, Kay, D and Serwach, N (2004). Exercise time to fatigue and the critical limiting temperature: effect of hydration. Journal of Thermal Biology 29: 2129.CrossRefGoogle Scholar