Sports Medicine

, Volume 48, Issue 11, pp 2517–2548 | Cite as

Biomarkers of Physiological Responses to Periods of Intensified, Non-Resistance-Based Exercise Training in Well-Trained Male Athletes: A Systematic Review and Meta-Analysis

  • Grace GreenhamEmail author
  • Jonathan D. Buckley
  • Joel Garrett
  • Roger Eston
  • Kevin Norton
Systematic Review



Intensified training is important for inducing adaptations to improve athletic performance, but detrimental performance effects can occur if prescribed inappropriately. Monitoring biomarker responses to training may inform changes in training load to optimize performance.


This systematic review and meta-analysis aimed to identify biomarkers associated with altered exercise performance following intensified training.


Embase, MEDLINE, CINAHL, Scopus and SPORTDiscus were searched up until September 2017. Included articles were peer reviewed and reported on biomarkers collected at rest in well-trained male athletes before and after periods of intensified training.


The full text of 161 articles was reviewed, with 59 included (708 participants) and 42 (550 participants) meta-analysed. In total, 118 biomarkers were evaluated, with most being cellular communication and immunity markers (n = 54). Studies most frequently measured cortisol (n = 34), creatine kinase (n = 25) and testosterone (n = 20). Many studies reported decreased immune cell counts following intensified training, irrespective of performance. Moreover, reduced performance was associated with a decrease in neutrophils (d = − 0.57; 95% confidence interval (CI) − 1.07 to − 0.07) and glutamine (d = − 0.37; 95% CI − 0.43 to − 0.31) and an increase in urea concentration (d = 0.80; 95% CI 0.30 to 1.30). In contrast, increased performance was associated with an increased testosterone:cortisol ratio (d = 0.89; 95% CI 0.54 to 1.24). All remaining biomarkers showed no consistent patterns of change with performance.


Many biomarkers were altered with intensified training but not in a manner related to changes in exercise performance. Neutrophils, glutamine, urea and the testosterone:cortisol ratio exhibited some evidence of directional changes that corresponded with performance changes therefore indicating potential to track performance. Additional investigations of the potential for these markers to track altered performance are warranted.



Grace Greenham was supported by an Australian Government Research Training Program Scholarship and a research scholarship from the Adelaide Football Club. Joel Garrett was supported by an Australian Government Research Training Program Scholarship and a research scholarship from the Port Adelaide Football Club.

Compliance with Ethical Standards


No sources of funding were used to assist in the preparation of this article.

Conflict of interest

Grace Greenham, Jonathan D Buckley, Joel Garrett, Roger Eston, and Kevin Norton have no conflicts of interest.

Supplementary material

40279_2018_969_MOESM1_ESM.docx (7.1 mb)
Supplementary material 1 (DOCX 7274 kb)


  1. 1.
    Halson S, Jeukendrup A. Does overtraining exist? An analysis of overreaching and overtraining research. Sports Med. 2004;34(14):967–81.PubMedCrossRefGoogle Scholar
  2. 2.
    Armstrong L, VanHeest J. The unknown mechanism of the overtraining syndrome: clues from depression and psychoneuroimmunology. Sports Med. 2002;32(3):185–209.PubMedPubMedCentralCrossRefGoogle Scholar
  3. 3.
    Meeusen R, Duclos M, Foster C, Fry A, Gleeson M, Nieman D, et al. Prevention, diagnosis and treatment of the overtraining syndrome: joint consensus statement of the European College of Sport Science (ECSS) and the American College of Sports Medicine (ACSM). Eur J Sport Sci. 2013;13(1):1–24.CrossRefGoogle Scholar
  4. 4.
    Lewis E, Howard T, OConnor F. Overtraining. In: Madden G, Putukain M, McCarty E, Young C, editors. Netters sports medicine. The Team Physician’s Handbook. Philadelphia: Elsevier Publishing; 2009.Google Scholar
  5. 5.
    Kirkendall DT. Mechanisms of peripheral fatigue. Med Sci Sports Exerc. 1990;22(4):444–9.PubMedPubMedCentralCrossRefGoogle Scholar
  6. 6.
    Enoka RM, Stuart DG. Neurobiology of muscle fatigue. J Appl Physiol. 1992;72(5):1631–48.PubMedPubMedCentralCrossRefGoogle Scholar
  7. 7.
    Carfagno D, Hendrix J. Overtraining syndrome in the athlete: current clinical practice. Curr Sports Med Rep. 2014;13(1):45–51.PubMedPubMedCentralCrossRefGoogle Scholar
  8. 8.
    Urhausen A, Kindermann W. Diagnosis of overtraining: what tools do we have? Sports Med. 2002;32(2):95–102.PubMedCrossRefGoogle Scholar
  9. 9.
    Smith L. Cytokine hypothesis of overtraining: a physiological adaptation to excessive stress. Med Sci Sports Exerc. 2000;32(2):317–31.PubMedCrossRefGoogle Scholar
  10. 10.
    Hooper S, MacKinnon L, Hanrahan S. Mood states as an indication of staleness and recovery. Int J Sport Psychol. 1997;28(1):1–12.Google Scholar
  11. 11.
    Saw AE, Main LC, Gastin PB. Monitoring the athlete training response: subjective self-reported measures trump commonly used objective measures: a systematic review. Br J Sports Med. 2016;50:281–91.PubMedPubMedCentralCrossRefGoogle Scholar
  12. 12.
    Hooper S, Mackinnon L, Gordon R, Bachmann A. Hormonal responses of elite swimmers to overtraining. Med Sci Sports Exerc. 1993;25(6):741–7.PubMedPubMedCentralCrossRefGoogle Scholar
  13. 13.
    Hooper S, Mackinnon L, Howard A, Gordon R, Bachmann A. Markers for monitoring overtraining and recovery. Med Sci Sports Exerc. 1995;27(1):106–12.PubMedPubMedCentralCrossRefGoogle Scholar
  14. 14.
    Mackinnon L, Hooper S, Jones S, Gordon R, Bachmann A. Hormonal, immunological, and hematological responses to intensified training in elite swimmers. Med Sci Sports Exerc. 1997;29(12):1637–45.PubMedPubMedCentralCrossRefGoogle Scholar
  15. 15.
    Parry-Billings M, Budgett R, Koutedakis Y, Blomstrand E, Brooks S, Williams C, et al. Plasma amino acid concentrations in the overtraining syndrome: possible effects on the immune system. Med Sci Sports Exerc. 1992;24(12):1353–8.PubMedPubMedCentralCrossRefGoogle Scholar
  16. 16.
    Moher D, Liberati A, Tetzlaff J, Altman D. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med. 2009;6(7):e1000097. Scholar
  17. 17.
    Pauw KD, Roelands B, Cheung SS, De Geus B, Rietjens G, Meeusen R. Guidelines to classify subject groups in sport-science research. Int J Sports Physiol Perform. 2013;8(2):111–22.PubMedPubMedCentralCrossRefGoogle Scholar
  18. 18.
    Higgins J, Altman D, Gøtzsche P, Jüni P, Moher D, Oxman A, et al. The Cochrane Collaboration’s tool for assessing risk of bias in randomised trials. Br Med J. 2011;343:5928. Scholar
  19. 19.
    Cohen J. Statistical power analysis for the behavioral sciences. London: Routledge; 1988.Google Scholar
  20. 20.
    Sawilowsky S. New effect size rules of thumb. J Mod Appl Stat Methods. 2009;8(2):597–9.CrossRefGoogle Scholar
  21. 21.
    Borenstein M, Hedges LV, Higgins J, Rothstein HR. When does it make sense to perform a meta-analysis? Introduction to meta-analysis. Chichester: Wiley; 2009.Google Scholar
  22. 22.
    Purvis D, Gonsalves S, Deuster PA. Physiological and psychological fatigue in extreme conditions: overtraining and elite athletes. PM R. 2010;2(5):442–50. Scholar
  23. 23.
    Balslov P, Bagger M, Pedersen P. Blood urea and tryptophan/BCAA ratio after 4 weeks with markedly increased training volume. J Sports Sci. 2000;18(7):523–4.CrossRefGoogle Scholar
  24. 24.
    Faude O, Meyer T, Urhausen A, Kindermann W. Recovery training in cyclists: ergometric, hormonal and psychometric findings. Scand J Med Sci Sports. 2009;19(3):433–41.PubMedPubMedCentralCrossRefGoogle Scholar
  25. 25.
    Flynn M, Pizza F, Brolinson P. Hormonal responses to excessive training: influence of cross training. Int J Sports Med. 1997;18(3):191–6.PubMedPubMedCentralCrossRefGoogle Scholar
  26. 26.
    Bosquet L, Montpetit J, Arvisais D, Mujika I. Effects of tapering on performance: a meta-analysis. Med Sci Sports Exerc. 2007;39(8):1358–65.PubMedPubMedCentralCrossRefGoogle Scholar
  27. 27.
    Apple F. The creatine kinase system in the serum of runners following a doubling of training mileage. Clin Physiol. 1992;12(4):419–24.PubMedPubMedCentralCrossRefGoogle Scholar
  28. 28.
    Arakawa K, Hosono A, Shibata K, Ghadimi R, Fuku M, Goto C, et al. Changes in blood biochemical markers before, during, and after a 2-day ultramarathon. Open Access J Sports Med. 2016;7:43–50.PubMedPubMedCentralCrossRefGoogle Scholar
  29. 29.
    Atlaoui D, Duclos M, Gouarne C, Lacoste L, Barale F, Chatard J. The 24-h urinary cortisol/cortisone ratio for monitoring training in elite swimmers. Med Sci Sports Exerc. 2004;36(2):218–224 7p.PubMedPubMedCentralCrossRefGoogle Scholar
  30. 30.
    Atlaoui D, Duclos M, Gouarne C, Lacoste L, Barale F, Chatard JC. 24-hr urinary catecholamine excretion, training and performance in elite swimmers. Int J Sports Med. 2006;27(4):314–21.PubMedPubMedCentralCrossRefGoogle Scholar
  31. 31.
    Aubry A, Hausswirth C, Louis J, Coutts AJ, Buchheit M, Le Meur Y. The development of functional overreaching is associated with a faster heart rate recovery in endurance athletes. PLoS One [Electronic Resource]. 2015;10(10):e0139754.CrossRefGoogle Scholar
  32. 32.
    Bagger M, Balslov P, Pedersen PK. Changes in resting metabolic variables and running economy after 4 weeks of increased training duration. J Sports Sci. 2000;18(7):523.CrossRefGoogle Scholar
  33. 33.
    Billat VL, Flechet B, Petit B, Muriaux G, Koralsztein JP. Interval training at VO2max: effects on aerobic performance and overtraining markers. Med Sci Sports Exerc. 1999;31(1):156–63.PubMedPubMedCentralCrossRefGoogle Scholar
  34. 34.
    Bonifazi M, Sardella F, Lupo C. Preparatory versus main competitions: differences in performances, lactate responses and pre-competition plasma cortisol concentrations in elite male swimmers. Eur J Appl Physiol. 2000;82(5–6):368–73.PubMedPubMedCentralCrossRefGoogle Scholar
  35. 35.
    Bouaziz T, Makni E, Passelergue P, Tabka Z, Lac G, Moalla W, et al. Multifactorial monitoring of training load in elite rugby sevens players: cortisol/cortisone ratio as a valid tool of training load monitoring. Biol Sport. 2016;33(3):231.PubMedPubMedCentralCrossRefGoogle Scholar
  36. 36.
    Buchheit M, Racinais S, Bilsborough JC, Bourdon PC, Voss SC, Hocking J, et al. Monitoring fitness, fatigue and running performance during a pre-season training camp in elite football players. J Sci Med Sport. 2013;16(6):550–5.PubMedPubMedCentralCrossRefGoogle Scholar
  37. 37.
    Chennaoui M, Gomez-Marino D, Drogou C, Bourrilhon C, Sautivet S, Guezennec CY. Hormonal and metabolic adaptation in professional cyclists during training. Can J Appl Physiol. 2004;29(6):714–30.PubMedPubMedCentralCrossRefGoogle Scholar
  38. 38.
    Coutts AJ, Reaburn P, Piva TJ, Rowsell GJ. Monitoring for overreaching in rugby league players. Eur J Appl Physiol. 2007;99(3):313–24.PubMedPubMedCentralCrossRefGoogle Scholar
  39. 39.
    Coutts AJ, Wallace LK, Slattery KM. Monitoring changes in performance, physiology, biochemistry, and psychology during overreaching and recovery in triathletes. Int J Sports Med. 2007;28(2):125–34.PubMedPubMedCentralCrossRefGoogle Scholar
  40. 40.
    Cunniffe B, Griffiths H, Proctor W, Davies B, Baker JS, Jones KP. Mucosal immunity and illness incidence in elite rugby union players across a season. Med Sci Sports Exerc. 2011;43(3):388–97.PubMedPubMedCentralCrossRefGoogle Scholar
  41. 41.
    Dressendorfer RH, Petersen SR, Lovshin SEM, Hannon JL, Lee SF, Bell GJ. Performance enhancement with maintenance of resting immune status after intensified cycle training. Clin J Sport Med. 2002;12(5):301–7.PubMedPubMedCentralCrossRefGoogle Scholar
  42. 42.
    Dressendorfer RH, Wade CE. Effects of a 15-d race on plasma steroid levels and leg muscle fitness in runners. Med Sci Sports Exerc. 1991;23(8):954–8.PubMedPubMedCentralCrossRefGoogle Scholar
  43. 43.
    Dressendorfer RH, Wade CE. The muscular overuse syndrome in long-distance runners. Phys Sports Med. 1983;11(11):116–30.CrossRefGoogle Scholar
  44. 44.
    Flynn M, Pizza F, Boone J Jr, Andres F, Michaud T, Rodriguez-Zayas J. Indices of training stress during competitive running and swimming seasons. Int J Sports Med. 1994;15(1):21–6.PubMedPubMedCentralCrossRefGoogle Scholar
  45. 45.
    Freitas VH, Nakamura FY, Miloski B, Samulski D, Bara-Filho MG. Sensitivity of physiological and psychological markers to training load intensification in volleyball players. J Sports Sci Med. 2014;13(3):571–9.PubMedPubMedCentralGoogle Scholar
  46. 46.
    Fry RW, Morton AR, Garcia-Webb P, Crawford GPM, Keast D. Biological responses to overload training in endurance sports. Eur J Appl Physiol Occup Physiol. 1992;64(4):335–44. Scholar
  47. 47.
    Gomes RV, Moreira A, Lodo L, Nosaka K, Coutts AJ, Aoki MS. Monitoring training loads, stress, immune-endocrine responses and performance in tennis players. Biol Sport. 2013;30(3):173–80. Scholar
  48. 48.
    Hedelin R, Kentta G, Wiklund U, Bjerle P, Henriksson-Larsen K. Short-term overtraining: effects on performance, circulatory responses, and heart rate variability/Surentrainement a court terme: effets sur les performances, le systeme circulatoire et la variabilite de la frequence cardiaque. Med Sci Sports Exerc. 2000;32(8):1480–4.PubMedPubMedCentralCrossRefGoogle Scholar
  49. 49.
    Halson SL, Lancaster GI, Jeukendrup AE, Gleeson M. Immunological responses to overreaching in cyclists. Med Sci Sports Exerc. 2003;35(5):854–61.PubMedPubMedCentralCrossRefGoogle Scholar
  50. 50.
    Hoffman JR, Kang J, Ratamess NA, Faigenbaum AD. Biochemical and hormonal responses during an intercollegiate football season. Med Sci Sports Exerc. 2005;37(7):1237–41.PubMedPubMedCentralCrossRefGoogle Scholar
  51. 51.
    Hoffman JR, Cooper J, Wendell M, Im J, Kang J. Effects of β-hydroxy β-methylbutyrate on power performance and indices of muscle damage and stress during high-intensity training. J Strength Cond Res. 2004;18(4):747–752 6p.PubMedPubMedCentralGoogle Scholar
  52. 52.
    Hough J, Robertson C, Gleeson M. Blunting of exercise-induced salivary testosterone in elite-level triathletes with a 10-day training camp. Int J Sports Physiol Perform. 2015;10(7):935–8.PubMedPubMedCentralCrossRefGoogle Scholar
  53. 53.
    Ishigaki T, Koyama K, Tsujita J, Tanaka N, Hori S, Oku Y. Plasma leptin levels of elite endurance runners after heavy endurance training. J Physiol Anthropol Appl Hum Sci. 2005;24(6):573–8. Scholar
  54. 54.
    Kirwan JP, Costill DL, Houmard JA, Mitchell B, Flynn MG, Fink WJ. Changes in selected blood measures during repeated days of intense training and carbohydrate control. Int J Sports Med. 1990;11(5):362–6.PubMedPubMedCentralCrossRefGoogle Scholar
  55. 55.
    Kirwan JP, Costill DL, Flynn MG, Mitchell JB, Fink WJ, Neufer PD, et al. Physiological responses to successive days of intense training in competitive swimmers. Med Sci Sports Exerc. 1988;20(3):255–9.PubMedPubMedCentralCrossRefGoogle Scholar
  56. 56.
    Kizaki K, Terada T, Arikawa H, Tajima T, Imai H, Takahashi T, et al. Effect of reduced coenzyme Q10 (ubiquinol) supplementation on blood pressure and muscle damage during kendo training camp: a double-blind, randomized controlled study. J Sports Med Phys Fitness. 2015;55(7–8):797–804.PubMedPubMedCentralGoogle Scholar
  57. 57.
    Lancaster G, Halson S, Khan Q, Drysdale P, Jeukendrup A, Drayson M, et al. The effects of acute exhaustive exercise and intensified training on type 1/type 2 T cell distribution and cytokine production. Exerc Immunol Rev. 2004;10:91–106.PubMedPubMedCentralGoogle Scholar
  58. 58.
    Le Meur Y, Hausswirth C, Natta F, Couturier A, Bignet F, Vidal PP. A multidisciplinary approach to overreaching detection in endurance trained athletes. J Appl Physiol. 2013;114(2):411–20.PubMedPubMedCentralCrossRefGoogle Scholar
  59. 59.
    Le Meur Y, Louis J, Aubry A, Guéneron J, Pichon A, Schaal K, et al. Maximal exercise limitation in functionally overreached triathletes: role of cardiac adrenergic stimulation. J Appl Physiol. 2014;117(3):214–22.PubMedPubMedCentralCrossRefGoogle Scholar
  60. 60.
    Malczewska J, Stupnicki R, Blach W, Turek-Lepa E. The effects of physical exercise on the concentrations of ferritin and transferrin receptor in plasma of male judoists. Int J Sports Med. 2004;25(7):516–521 6p.PubMedPubMedCentralCrossRefGoogle Scholar
  61. 61.
    Manetta J, Brun JF, Maimoun L, Fedou C, Prefaut C, Mercier J. The effects of intensive training on insulin-like growth factor I (IGF-I) and IGF binding proteins 1 and 3 in competitive cyclists: relationships with glucose disposal. J Sports Sci. 2003;21(3):147–54.PubMedPubMedCentralCrossRefGoogle Scholar
  62. 62.
    Meyer T, Faude O, Urhausen A, Scharhag J, Kindermann W. Different effects of two regeneration regimens on immunological parameters in cyclists. Med Sci Sports Exerc. 2004;36(10):1743–1749 7p.PubMedPubMedCentralCrossRefGoogle Scholar
  63. 63.
    Miloski B, de Freitas VH, Nakamura FY, de A Nogueira FC, Bara-Filho MG. Seasonal training load distribution of professional futsal players: effects on physical fitness, muscle damage and hormonal status. J Strength Cond Res. 2016;30(6):1525–33.PubMedPubMedCentralCrossRefGoogle Scholar
  64. 64.
    Ndon JA, Snyder AC, Foster C, Wehrenberg WB. Effects of chronic intense exercise training on the leukocyte response to acute exercise. Int J Sports Med. 1992;13(2):176–82.PubMedPubMedCentralCrossRefGoogle Scholar
  65. 65.
    O’Connor PJ, Morgan WP, Raglin JS. Psychobiologic effects of 3 d of increased training in female and male swimmers. Med Sci Sports Exerc. 1991;23(9):1055–61.PubMedPubMedCentralGoogle Scholar
  66. 66.
    Pacini S, Branca JJV, Culisano M, Levi Micheli M, Ceroti M, Ruggiero M, et al. Salivary testosterone and cortisol levels to assess conditioning training program in rugby union players. Med Sport. 2014;67(3):449–63.Google Scholar
  67. 67.
    Palazzetti S, Richard MJ, Favier A, Margaritis I. Overloaded training increases exercise-induced oxidative stress and damage. Can J Appl Physiol. 2003;28(4):588–604.PubMedPubMedCentralCrossRefGoogle Scholar
  68. 68.
    Peake JM, Gerrard DF, Griffin JF. Plasma zinc and immune markers in runners in response to a moderate increase in training volume. Int J Sports Med. 2003;24(3):212–6.PubMedPubMedCentralCrossRefGoogle Scholar
  69. 69.
    Piacentini MF, Witard OC, Tonoli C, Jackman SR, Turner JE, Kies AK, et al. Effect of intensive training on mood with no effect on brain-derived neurotrophic factor. Int J Sports Physiol Perform. 2016;11(6):824–30.PubMedPubMedCentralCrossRefGoogle Scholar
  70. 70.
    Pimenta E, Barbosa Coelho D, Capettini L, Gomes T, Pussieldi G, Ribeiro J, et al. Analysis of creatine kinase and alpha-actin concentrations in soccer pre-season. Revista Brasileira de Ciência e Movimento. 2015;23(4):5–14.CrossRefGoogle Scholar
  71. 71.
    Pizza FX, Flynn MG, Sawyer T, Brolinson P, Starling RD, Andres FF. Run training versus cross-training: effect of increased training on circulating leukocyte subsets. Med Sci Sports Exerc. 1995;27(3):355–62.PubMedPubMedCentralGoogle Scholar
  72. 72.
    Proia P, Bianco A, Schiera G, Saladino P, Pomara F, Petrucci M, et al. The effects of a 3-week training on basal biomarkers in professional soccer players during the preseason preparation period. J Sports Med Phys Fitness. 2012;52(1):102–106 5p.PubMedPubMedCentralGoogle Scholar
  73. 73.
    Rietjens GJ, Kuipers H, Adam JJ, Saris WH, van Breda E, van Hamont D, et al. Physiological, biochemical and psychological markers of strenuous training-induced fatigue. Int J Sports Med. 2005;26(1):16–26.PubMedPubMedCentralCrossRefGoogle Scholar
  74. 74.
    Robson-Ansley PJ, Blannin A, Gleeson M. Elevated plasma interleukin-6 levels in trained male triathletes following an acute period of intense interval training. Eur J Appl Physiol. 2007;99(4):353–60.PubMedPubMedCentralCrossRefGoogle Scholar
  75. 75.
    Shing CM, Ogawa K, Zhang X, Nagatomi R, Peake JM, Suzuki K, et al. Reduction in resting plasma granulysin as a marker of increased training load. Exerc Immunol Rev. 2007;13:89–99.PubMedPubMedCentralGoogle Scholar
  76. 76.
    Slivka DR, Hailes WS, Cuddy JS, Ruby BC. Effects of 21 days of intensified training on markers of overtraining. J Strength Cond Res. 2010;24(10):2604–2612 9p. Scholar
  77. 77.
    Smith DJ, Norris SR. Changes in glutamine and glutamate concentrations for tracking training tolerance. Med Sci Sports Exerc. 2000;32(3):684–9.PubMedPubMedCentralCrossRefGoogle Scholar
  78. 78.
    Smith TB, Hopkins WG, Lowe TE. Are there useful physiological or psychological markers for monitoring overload training in elite rowers? Int J Sports Physiol Perform. 2011;6(4):469–84.PubMedPubMedCentralCrossRefGoogle Scholar
  79. 79.
    Tanaka H, West KA, Duncan GE, Bassett DR Jr. Changes in plasma tryptophan/branched chain amino acid ratio in responses to training volume variation. Int J Sports Med. 1997;18(4):270–5.PubMedPubMedCentralCrossRefGoogle Scholar
  80. 80.
    Thiel C, Vogt L, Burklein M, Rosenhagen A, Hubscher M, Banzer W. Functional overreaching during preparation training of elite tennis professionals. J Hum Kinet. 2011;28:79–89.PubMedPubMedCentralCrossRefGoogle Scholar
  81. 81.
    Verde T, Thomas S, Shephard R. Potential markers of heavy training in highly trained distance runners. Br J Sports Med. 1992;26(3):167–75.PubMedPubMedCentralCrossRefGoogle Scholar
  82. 82.
    Witard OC, Turner JE, Jackman SR, Tipton KD, Jeukendrup AE, Kies AK, et al. High-intensity training reduces CD8+ T-cell redistribution in response to exercise. Med Sci Sports Exerc. 2012;44(9):1689–97. Scholar
  83. 83.
    Acharya K, Ackerman S. Eosinophil granule proteins: form and function. J Biol Chem. 2014;289(25):17406–15.PubMedPubMedCentralCrossRefGoogle Scholar
  84. 84.
    Billett HH. Hemoglobin and hematocrit. Clinical methods: the history, physical, and laboratory examinations. Boston: Butterworths; 1990.Google Scholar
  85. 85.
    Gabay C. Interleukin-6 and chronic inflammation. Arthritis Res Ther. 2006;8(2):S3.PubMedPubMedCentralCrossRefGoogle Scholar
  86. 86.
    Maton A, Hopkins R, McLaughlin C, Johnson S, Warner M, LaHart D, et al. Human biology and health. Englewood Cliffs: Prentice Hall; 1993.Google Scholar
  87. 87.
    Shetty N. Immunology: introductory textbook. 2nd ed. New Delhi: New Age International; 2005.Google Scholar
  88. 88.
    Gleeson M, Bishop NC. The T cell and NK cell immune response to exercise. Ann Transplant. 2005;10(4):43–8.PubMedPubMedCentralGoogle Scholar
  89. 89.
    Mackinnon L. Advances in exercise immunology. Champaign: Human Kinetics; 1999.Google Scholar
  90. 90.
    Mairbäurl H. Red blood cells in sports: effects of exercise and training on oxygen supply by red blood cells. Front Physiol. 2007;4(1):332.Google Scholar
  91. 91.
    Pyne D. Regulation of neutrophil function during exercise. Sports Med. 1994;17(4):245–58.PubMedCrossRefGoogle Scholar
  92. 92.
    Virella G. Medical immunology. Boca Raton: CRC Press; 2001.Google Scholar
  93. 93.
    Johnson SA, Horn DL, Pederson HJ, Marr J. The function of platelets. Transfusion. 1966;6(1):3–17.CrossRefGoogle Scholar
  94. 94.
    Neville V, Gleeson M, Folland JP. Salivary IgA as a risk factor for upper respiratory infections in elite professional athletes. Med Sci Sports Exerc. 2008;40(7):1228–1236 9p.PubMedPubMedCentralCrossRefGoogle Scholar
  95. 95.
    Sullivan G, Carper H, Novick W, Mandell G. Inhibition of the inflammatory action of interleukin-1 and tumor necrosis factor (alpha) on neutrophil function by pentoxifylline. Infect Immun. 1988;56(7):1722–9.PubMedPubMedCentralGoogle Scholar
  96. 96.
    Lehmann M, Foster C, Dickhuth H-H, Gastmann U. Autonomic imbalance hypothesis and overtraining syndrome. Med Sci Sports Exerc. 1998;30(7):1140–5.PubMedPubMedCentralCrossRefGoogle Scholar
  97. 97.
    Brownlee K, Moore A, Hackney A. Relationship between circulating cortisol and testosterone: influence of physical exercise. J Sports Sci Med. 2005;4(1):76–83.PubMedPubMedCentralGoogle Scholar
  98. 98.
    Tee J, Bosch A, Lambert M. Metabolic consequences of exercise-induced muscle damage. Sports Med. 2007;37(10):827–36.PubMedPubMedCentralCrossRefGoogle Scholar
  99. 99.
    Aoi W, Naito Y, Tokuda H, Tanimura Y, Oya-Ito T, Yoshikawa T. Exercise-induced muscle damage impairs insulin signaling pathway associated with IRS-1 oxidative modification. Physiol Res. 2012;61(1):81.PubMedPubMedCentralGoogle Scholar
  100. 100.
    Rivier C, Rivier J, Vale W. Stress-induced inhibition of reproductive functions: role of endogenous corticotropin-releasing factor. Science. 1986;231(1):607–10.PubMedPubMedCentralCrossRefGoogle Scholar
  101. 101.
    Freeman M, Kanyicska B, Lerant A, Nagy G. Prolactin: structure, function, and regulation of secretion. Physiol Rev. 2000;80(4):1523–631.CrossRefPubMedGoogle Scholar
  102. 102.
    Berg J, Tymoczko J, Stryer L. Important derivatives of cholesterol include bile salts and steroid hormones. Biochemistry. 5th ed. New York: WH Freeman; 2002.Google Scholar
  103. 103.
    Heymsfield SB, Arteaga C, McManus C, Smith J, Moffitt S. Measurement of muscle mass in humans: validity of the 24-hour urinary creatinine method. Am J Clin Nutr. 1983;37(3):478–94.PubMedCrossRefGoogle Scholar
  104. 104.
    Bouget M, Rouveix M, Michaux O, Pequignot J-M, Filaire E. Relationships among training stress, mood and dehydroepiandrosterone sulphate/cortisol ratio in female cyclists. J Sports Sci. 2006;24(12):1297–302.PubMedPubMedCentralCrossRefGoogle Scholar
  105. 105.
    Binienda Z, Sarkar S, Silva-Ramirez S, Gonzalez C. Role of free fatty acids in physiological conditions and mitochondrial dysfunction. Food Nutr Sci. 2013;4(9):6.Google Scholar
  106. 106.
    Venkatraman JT, Pendergast DR. Effect of dietary intake on immune function in athletes. Sports Med. 2002;32(5):323–37.PubMedPubMedCentralCrossRefGoogle Scholar
  107. 107.
    Antonio J, Street C. Glutamine: a potentially useful supplement for athletes. Can J Appl Physiol. 1999;24(1):1–14.PubMedPubMedCentralCrossRefGoogle Scholar
  108. 108.
    Brooks GA. The lactate shuttle during exercise and recovery. Med Sci Sports Exerc. 1986;18(3):360–8.PubMedPubMedCentralCrossRefGoogle Scholar
  109. 109.
    Blomstrand E. A role for branched-chain amino acids in reducing central fatigue. J Nutr. 2006;136(2):544S–7S.PubMedPubMedCentralCrossRefGoogle Scholar
  110. 110.
    Hübner-Wozniak E, Stupnicki R, Hackney A. Changes in plasma creatine kinase activity and urea concentration monitored daily during training of elite wrestlers. Res Sports Med. 1997;7(3–4):207–14.Google Scholar
  111. 111.
    Zouhal H, Jacob C, Delamarche P, Gratas-Delamarche A. Catecholamines and the effects of exercise, training and gender. Sports Med. 2008;38(5):401–23.PubMedPubMedCentralCrossRefGoogle Scholar
  112. 112.
    Meldrum BS. Glutamate as a neurotransmitter in the brain: review of physiology and pathology. J Nutr. 2000;130(4):1007S–15S.PubMedPubMedCentralCrossRefGoogle Scholar
  113. 113.
    Nikolaidis M, Michailidis Y, Mougios V. Variation of soluble transferrin receptor and ferritin concentrations in human serum during recovery from exercise. Eur J Appl Physiol. 2003;89(5):500–2.PubMedPubMedCentralCrossRefGoogle Scholar
  114. 114.
    Ishibashi A, Maeda N, Kamei A, Goto K. Iron supplementation during three consecutive days of endurance training augmented hepcidin levels. Nutrients. 2017;9(8):820.CrossRefPubMedCentralGoogle Scholar
  115. 115.
    Nieman DC, Mitmesser SH. Potential impact of nutrition on immune system recovery from heavy exertion: a metabolomics perspective. Nutrients. 2017;9(5):513.CrossRefPubMedCentralGoogle Scholar
  116. 116.
    Clarke A, Anson J, Dziedzic C, McDonald W, Pyne D. Iron monitoring of male and female rugby sevens players over an international season. J Sports Med Phys Fitness. 2017. Scholar
  117. 117.
    Clénin G, Cordes M, Huber A, Schumacher YO, Noack P, Scales J, et al. Iron deficiency in sports—definition, influence on performance and therapy. Swiss Med Wkly. 2015;145:w14196.PubMedPubMedCentralGoogle Scholar
  118. 118.
    Pate R. Sports anemia: a review of the current research literature. Physician Sportsmed. 1983;11(2):115–31. Scholar
  119. 119.
    Sharif K, Vieira Borba V, Zandman-Goddard G, Shoenfeld Y. Eppur Si Muove: ferritin is essential in modulating inflammation. Clin Exp Immunol. 2018;191(2):149–50.PubMedPubMedCentralCrossRefGoogle Scholar
  120. 120.
    Ganz T, Nemeth E. Iron homeostasis in host defence and inflammation. Nat Rev Immunol. 2015;15(8):500.PubMedPubMedCentralCrossRefGoogle Scholar
  121. 121.
    Shephard R, Shek P. Potential impact of physical activity and sport on the immune system—a brief review. Br J Sports Med. 1994;28(4):247–55.PubMedPubMedCentralCrossRefGoogle Scholar
  122. 122.
    Gleeson M. Immune function in sport and exercise. J Appl Physiol. 2007;103(2):693–9.PubMedPubMedCentralCrossRefGoogle Scholar
  123. 123.
    Fulkerson PC, Rothenberg ME. Targeting eosinophils in allergy, inflammation and beyond. Nat Rev Drug Discov. 2013;12(2):117.PubMedPubMedCentralCrossRefGoogle Scholar
  124. 124.
    Castell LM, Newsholme EA. Glutamine and the effects of exhaustive exercise upon the immune response. Can J Physiol Pharmacol. 1998;76(5):524–32.PubMedPubMedCentralCrossRefGoogle Scholar
  125. 125.
    Brodan V, Kuhn E, Pechar J, Tomkova D. Changes of free amino acids in plasma of healthy subjects induced by physical exercise. Eur J Appl Physiol Occup Physiol. 1976;35(1):69–77.PubMedPubMedCentralCrossRefGoogle Scholar
  126. 126.
    Graham TE, Turcotte LP, Kiens B, Richter EA. Effect of endurance training on ammonia and amino acid metabolism in humans. Med Sci Sports Exerc. 1997;29(5):646–53.PubMedPubMedCentralCrossRefGoogle Scholar
  127. 127.
    Julian R, Meyer T, Fullagar HH, Skorski S, Pfeiffer M, Kellmann M, et al. Individual patterns in blood-borne indicators of fatigue—trait or chance. J Strength Cond Res. 2017;31(3):608–19.PubMedPubMedCentralCrossRefGoogle Scholar
  128. 128.
    Hecksteden A, Kraushaar J, Scharhag-Rosenberger F, Theisen D, Senn S, Meyer T. Individual response to exercise training-a statistical perspective. J Appl Physiol. 2015;118(12):1450–9.PubMedPubMedCentralCrossRefGoogle Scholar
  129. 129.
    Hopkins WG. Individual responses made easy. J Appl Physiol. 2015;118(1):1444–6.PubMedPubMedCentralCrossRefGoogle Scholar
  130. 130.
    Hopkins W, Marshall S, Batterham A, Hanin J. Progressive statistics for studies in sports medicine and exercise science. Med Sci Sports Exerc. 2009;41(1):3.PubMedCrossRefGoogle Scholar
  131. 131.
    Hecksteden A, Pitsch W, Rosenberger F, Meyer T. Repeated testing for the assessment of individual response to exercise training. J Appl Physiol. 2018;124:1567–79.PubMedPubMedCentralCrossRefGoogle Scholar
  132. 132.
    Hecksteden A, Pitsch W, Julian R, Pfeiffer M, Kellmann M, Ferrauti A, et al. A new method to individualize monitoring of muscle recovery in athletes. Int J Sports Physiol Perform. 2017;12(9):1137–42.PubMedPubMedCentralCrossRefGoogle Scholar
  133. 133.
    Kitano H. Systems biology: a brief overview. Science. 2002;295(5560):1662–4.CrossRefGoogle Scholar
  134. 134.
    Weaving D, Dalton NE, Black C, Darrall-Jones J, Phibbs PJ, Gray M, et al. The same story or a unique novel? Within-participant principle component analysis of training load measures in professional rugby union skills training. Int J Sports Physiol Perform. 2018;27:1–21.CrossRefGoogle Scholar
  135. 135.
    Brereton RG, Lloyd GR. Partial least squares discriminant analysis: taking the magic away. J Chemom. 2014;28(4):213–25.CrossRefGoogle Scholar
  136. 136.
    Hojat M, Xu G. A visitor’s guide to effect sizes–statistical significance versus practical (clinical) importance of research findings. Adv Health Sci Educ. 2004;9(3):241–9.CrossRefGoogle Scholar

Copyright information

© Springer Nature Switzerland AG 2018

Authors and Affiliations

  • Grace Greenham
    • 1
    • 2
    Email author
  • Jonathan D. Buckley
    • 1
  • Joel Garrett
    • 1
    • 3
  • Roger Eston
    • 1
  • Kevin Norton
    • 1
  1. 1.Alliance for Research in Exercise, Nutrition and Activity (ARENA), Sansom Institute for Health Research and School of Health SciencesUniversity of South AustraliaAdelaideAustralia
  2. 2.Adelaide Football ClubAdelaideAustralia
  3. 3.Port Adelaide Football ClubPort AdelaideAustralia

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