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Overtraining syndrome in horses

Published online by Cambridge University Press:  01 May 2008

C M McGowan*
Affiliation:
The University of Helsinki, PO Box 57, Helsinki00014, Finland
D J Whitworth
Affiliation:
The University of Queensland, St Lucia, Queensland4072, Australia
*
*Corresponding author: [email protected]
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Abstract

Overtraining is a significant cause of poor athletic performance in both human and equine athletes. In humans, overtraining syndrome has been defined as an imbalance between training and recovery manifesting as a syndrome of chronic fatigue and poor performance that may be accompanied by physiological and psychological changes. A similar syndrome has been described in horses using both cross-sectional observations and longitudinal studies with progressively increasing training loads until signs of overtraining were observed. The original cross-sectional studies of overtraining in horses linked the syndrome to increased red cell volume. However, more recent longitudinal studies revealed that overtraining is not always associated with increased red cell volume. Once other causes of poor performance have been ruled out, overtraining syndrome should be suspected in horses with evidence of sustained decreased performance in association with one or more physiological or psychological (behavioural) signs. While no single physiological marker is able to identify the syndrome, accompanying physiological signs in horses may include a decrease in body weight, elevated heart rates during exercise, lower plasma cortisol response to exercise, or elevated muscle enzymes or gamma glutamyl transferase concentrations. Behavioural signs were consistent and an early marker of overtraining syndrome in longitudinal studies in horses, and more research on developing behavioural scores to assist in early detection of overtraining syndrome in horses -as has been achieved for humans- is warranted. Two successful models of overtraining syndrome in horses have been developed, both of which appear to meet the criteria of overtraining syndrome rather than overreaching. Overtraining syndrome in horses is real, reproducible and future research should ensure the criteria for diagnosis of overtraining syndrome are met.

Type
Review Article
Copyright
Copyright © Cambridge University Press 2008

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References

1Kuipers, H and Keizer, HA (1988). Overtraining in elite athletes: review and directions for the future. Sports Medicine 6: 7992.CrossRefGoogle ScholarPubMed
2Persson, SGB (1967). On blood volume and working capacity of horses. Acta Veterinaria Scandinavica Supplement 19: 1189.Google Scholar
3Persson, SGB (1968). Blood volume, state of training and working capacity of race horses. Equine Veterinary Journal 1: 5262.CrossRefGoogle Scholar
4Persson, SGB, Larsson, M and Lindholm, A (1980). Effects of training on adrenal-cortical function and red-cell volume in trotters. A Zentralblatt fur Veterinarmedizin Reihe A 27: 261268.CrossRefGoogle Scholar
5Persson, SGB (1983). Analysis of fitness and state of training: evaluation of exercise tolerance and fitness in the performance horse. In: Snow, DH, Persson, SGB and Rose, RJ (eds) Equine Exercise Physiology. Cambridge: Granata editions, pp. 470486.Google Scholar
6Golland, LC, Evans, DL, Stone, GM, Tyler-McGowan, CM, Hodgson, DR and Rose, RJ (1999). Plasma cortisol and β-endorphin concentrations in trained and over-trained Standardbred racehorses. European Journal of Physiology 439: 1117.Google ScholarPubMed
7Hamlin, MJ, Shearman, JP and Hopkins, WG (2002). Changes in physiological parameters in overtrained Standardbred racehorses. Equine Veterinary Journal 34: 383388.CrossRefGoogle ScholarPubMed
8Tyler-McGowan, CM, Golland, LC, Evans, DL, Hodgson, DR and Rose, RJ (1999). Haematological and biochemical responses to training and overtraining. Equine Veterinary Journal Supplement 30: 621625.CrossRefGoogle Scholar
9Golland, LC, Evans, DL, Tyler-McGowan, CM, Hodgson, DR and Rose, RJ (2003). The effects of overtraining on blood volumes in Standardbred racehorses. The Veterinary Journal 165: 228233.CrossRefGoogle ScholarPubMed
10Tyler, CM, Golland, LC, Evans, DL, Hodgson, DR and Rose, RJ (1996). Changes in maximum oxygen uptake during prolonged training, overtraining, and detraining in horses. Journal of Applied Physiology 81(5): 22442249.CrossRefGoogle ScholarPubMed
11Kindermann, W (1986). Das uebertraining – ausdruck einer vegetativen fehlsteuerung. Deutsche Zentralblatt Sportmedizin 8: 238245.Google Scholar
12Morgan, WP, Brown, DR, Raglin, JS, O'Connor, PJ and Ellickson, KA (1987). Psychological monitoring of overtraining and staleness. British Journal of Sports Medicine 21(3): 107114.CrossRefGoogle ScholarPubMed
13Budgett, R (1990). Overtraining syndrome. British Journal of Sports Medicine 24: 231236.CrossRefGoogle ScholarPubMed
14Fry, RW, Morton, AR and Keast, D (1991). Overtraining in athletes: an update. Sports Medicine 12: 3265.CrossRefGoogle ScholarPubMed
15Lehmann, M, Dickhuth, HH, Gendrisch, G, Lazar, W, Thum, M, Kaminski, R, Aramendi, JF, Peterke, E, Wiel, W and Keul, J (1991). Training-overtraining. A prospective, experimental study with experienced middle- and long-distance runners. International Journal of Sports Medicine 12(5): 444452.CrossRefGoogle ScholarPubMed
16Stone, MH, Keith, RE, Kearney, JT, Fleck, SJ, Wilson, GD and Triplett, NT (1991). Overtraining: a review of the signs, symptoms and possible causes. Journal of Applied Sports Science and Research 5: 3550.Google Scholar
17Lehmann, M, Baumgartl, P, Wiesenack, C, Seidel, A, Baumann, H, Fischer, S, Spöri, U, Gendrisch, G, Kaminski, R and Keul, J (1992). Training-overtraining: influence of a defined increase in training volume vs. training intensity on performance, catecholamines and some metabolic parameters in experienced middle- and long-distance runners. European Journal of Applied Physiology 64(2): 169177.CrossRefGoogle ScholarPubMed
18Hooper, SL, MacKinnon, LT, Howard, A, Gordon, RD and Bachmann, AW (1995). Markers for monitoring overtraining and recovery. Medicine and Science in Sports and Exercise 27: 106112.CrossRefGoogle ScholarPubMed
19Halson, SL, Lancaster, GI, Jeukendrup, AE and Gleeson, M (2003). Immunological responses to overreaching in cyclists. Medicine and Science in Sports and Exercise 35: 854861.CrossRefGoogle ScholarPubMed
20Robson, P (2003). Elucidating the unexplained underperformance syndrome in endurance athletes: the interleukin-6 hypothesis. Sports Medicine 33: 771781.CrossRefGoogle ScholarPubMed
21Halson, SL and Jeukendrup, AE (2004). Does overtraining exist? An analysis of overreaching and overtraining research. Sports Medicine 34: 967981.CrossRefGoogle ScholarPubMed
22Meeusen, R, Piacentini, MF, Busschaert, B, Buyse, L, De Schutter, G and Stray-Gundersen, J (2004). Hormonal responses in athletes: the use of a two bout exercise protocol to detect subtle differences in (over)training status. European Journal of Applied Physiology 91(2–3): 140146.CrossRefGoogle ScholarPubMed
23Smith, LL (2004). Tissue trauma: the underlying cause of overtraining syndrome? Journal of Strength and Conditioning Research 18: 185193.Google ScholarPubMed
24Fry, AC, Schilling, BK, Weiss, LW and Chiu, LZ (2006). β-2 Adrenergic receptor down-regulation and performance decrements during high intensity resistance exercise overtraining. Journal of Applied Physiology 101(6): 16641672.CrossRefGoogle ScholarPubMed
25Mujika, I and Padilla, S (2003). Scientific bases for precompetition tapering strategies. Medicine and Science in Sports and Exercise 35(7): 11821187.CrossRefGoogle ScholarPubMed
26Coutts, A, Reaburn, P, Piva, TJ and Murphy, A (2007). Changes in selected biochemical, muscular strength, power, and endurance measures during deliberate overreaching and tapering in rugby league players. International Journal of Sports Medicine 28(2): 116124.CrossRefGoogle ScholarPubMed
27Coutts, AJ, Wallace, LK and Slattery, KM (2007). Monitoring changes in performance, physiology, biochemistry, and psychology during overreaching and recovery in triathletes. International Journal of Sports Medicine 28(2): 125134.CrossRefGoogle ScholarPubMed
28Costill, DL (1986). Peaking for performance. In: Inside Running. Indiananapolis: Benchmark Press, pp. 123134.Google Scholar
29MacKinnon, LT (2000). Special feature for the Olympics: effects of exercise on the immune system: overtraining effects on immunity and performance in athletes. Immunology and Cell Biology 78(5): 502509.CrossRefGoogle Scholar
30Kibler, WB, Chandler, TJ and Stracener, ES (1992). Musculoskeletal adaptations and injuries due to overtraining. In: Holloszy, JD (ed.) American College of Sports Medicine Series: Exercise and Sport Sciences Reviews, volume 20. Baltimore: Williams and Wilkins, pp. 99126.Google Scholar
31Fry, RW, Morton, AR, Garcia-Webb, P, Crawford, GPM and Keast, D (1992). Biological responses to overload training in endurance sports. European Journal of Applied Physiology 64: 335344.CrossRefGoogle ScholarPubMed
32Fry, AC, Kraemer, WJ, van Borselen, F, Lynch, JM, Marsit, JL, Roy, EP, Triplett, NT and Knuttgen, HG (1994). Performance decrements with high-intensity resistance exercise overtraining. Medicine and Science in Sports and Exercise 26: 11651173.CrossRefGoogle ScholarPubMed
33Nederhof, E, Zwerver, J, Brink, M, Meeusen, R and Lemmink, K (2007). Different diagnostic tools in nonfunctional overreaching. International Journal of Sports Medicine. Nov 30; [Epub ahead of print].Google ScholarPubMed
34Mackinnon, LT, Hooper, SL, Jones, S, Gordon, RD and Bachmann, AW (1997). Hormonal, immunological, and hematological responses to intensified training in elite swimmers. Medicine and Science in Sports and Exercise 29(12): 16371645.CrossRefGoogle ScholarPubMed
35Shephard, RJ (2001). Chronic fatigue syndrome: an update. Sports Medicine 31(3): 167194.CrossRefGoogle ScholarPubMed
36Smith, LL (2000). Cytokine hypothesis of overtraining: a physiological adaptation to excessive stress? Medicine and Science in Sports and Exercise 32(2): 317331.CrossRefGoogle ScholarPubMed
37Clancy, RL, Gleeson, M, Cox, A, Callister, R, Dorrington, M, D'Este, C, Pang, G, Pyne, D, Fricker, P and Henriksson, A (2006). Reversal in fatigued athletes of a defect in interferon gamma secretion after administration of Lactobacillus acidophilus. British Journal of Sports Medicine 40(4): 351354.CrossRefGoogle ScholarPubMed
38McKeever, KH (2003). Overtraining syndrome in Standardbred horses: new insights into the role of red blood cell hypervolaemia. The Veterinary Journal 165: 190192.CrossRefGoogle ScholarPubMed
39Bruin, G, Kuipers, H, Keizer, HA and Vander Vusse, GJ (1994). Adaptation and overtraining in horses subjected to increasing training load. Journal of Applied Physiology 76: 19081913.CrossRefGoogle Scholar
40Persson, SG and Osterberg, I (1999). Racing performance in red blood cell hypervolaemic Standardbred trotters. Equine Veterinary Journal Supplement 30: 617620.CrossRefGoogle Scholar
41Padalino, B, Rubino, G and Centoducati Pand Petazzi, F (2007). Training versus overtraining: evaluation of two protocols. Journal of Equine Veterinary Science 27(1): 2831.CrossRefGoogle Scholar
42McGowan, CM, Golland, LC, Evans, DL, Hodgson, DR and Rose, RJ (2002). Effects of prolonged training, overtraining and detraining on skeletal muscle metabolites and enzymes. Equine Veterinary Journal Supplement 34: 257263.CrossRefGoogle Scholar
43Bröjer, J, Holm, S, Jonasson, R, Hedenström, U and Essén-Gustavsson, B (2006). Synthesis of proglycogen and macroglycogen in skeletal muscle of Standardbred trotters after intermittent exercise. Equine Veterinary Journal Supplement 36: 335339.CrossRefGoogle Scholar
44Olsson, KE and Saltin, B (1970). Variation in total body water with muscle glycogen changes in man. Acta Physiologica Scandinavica 80(1): 1118.CrossRefGoogle ScholarPubMed
45Buchanan, BR and Andrews, FM (2003). Treatment and prevention of equine gastric ulcer syndrome. Veterinary Clinics of North America: Equine Practitioner 19: 575597.Google ScholarPubMed
46Carlson, GP (1987). Haematology and body fluids in the equine athlete: a review. In: Gillespie, JR and Robinson, NE (eds) Equine Exercise Physiology 2. Davis, California: ICEEP Publications, pp. 393425.Google Scholar
47Rose, RJ and Allen, JR (1985). Hematologic responses to exercise and training. Veterinary Clinics of North America: Equine Practice 1(3): 461476.Google ScholarPubMed
48Rose, RJ (1982). Haematological changes associated with endurance exercise. Veterinary Record 110(8): 175177.CrossRefGoogle ScholarPubMed
49Raidal, SL, Rose, RJ and Love, DN (2001). Effects of training on resting peripheral blood and BAL-derived leucocyte function in horses. Equine Veterinary Journal 33: 238243.CrossRefGoogle ScholarPubMed
50McGowan, CM, Fordham, T and Christley, RM (2002). Incidence and risk factors for exertional rhabdomyolysis in Thoroughbred racehorses in the United Kingdom. Veterinary Record 151(21): 623626.CrossRefGoogle ScholarPubMed
51Upjohn, MM, Archer, RM, Christley, RM and McGowan, CM (2005). Incidence and risk factors associated with exertional rhabdomyolysis syndrome in National Hunt racehorses in Great Britain. Veterinary Record 156(24): 763766.CrossRefGoogle ScholarPubMed
52Jeffcott, LB, Rossdale, PD, Freestone, J, Frank, CJ and Towers-Clark, PF (1982). An assessment of wastage in Thoroughbred racing from conception to 4 years of age. Equine Veterinary Journal 14(3): 185198.CrossRefGoogle ScholarPubMed
53Snow, DH, Gash, S and Rice, D (1987). Field observations on selenium status, whole blood glutathione peroxidise and plasma gamma-glutamyl transferase activities in Thoroughbred racehorses. In: Gillespie, JR and Robinson, NE (eds) Equine Exercise Physiology 2. Davis, California: ICEPP Publications, pp. 494505.Google Scholar
54Snow, DH and Harris, P (1988). Enzymes as markers of physical fitness and training of racing horses. Advances in Clinical Enzymology 6: 251258.Google Scholar
55Tyler-McGowan, CM (1997). Training, overtraining and detraining in Standardbred racehorses. PhD Thesis, The University of Sydney, Australia.Google Scholar
56Golland, LC, Evans, DL, Stone, GM, Tyler-McGowan, CM, Hodgson, DR and Rose, RJ (1999). Maximal exercise transiently disrupts hormonal secretory patterns in Standardbred geldings. Equine Veterinary Journal Supplement 30: 581585.CrossRefGoogle Scholar
57Henderson, AJ (2007). Don't fence me in: managing psychological well being for elite performance horses. Journal of Applied Animal Welfare Science 10(4): 309329.CrossRefGoogle ScholarPubMed