The purpose of this study was to evaluate the acute immune responses to an upper body tri-set resistance training (RT) session in RT trained individuals. Eighteen young trained men (22·0 ± 1·8 years) were randomly assigned to an exercise group (EG; n = 9) or control group (CG; n = 9). The EG completed an acute tri-set RT protocol using two combinations of three exercises for the same muscle group with six to eight repetitions at 75% of one repetition maximum (1RM) for each exercise. Blood samples were collected before (Pre), and 15 min (Post) and 24 h (P24h) after the acute RT protocol to determine basal and acute total leucocytes and leucocyte subsets counting, interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α) and cortisol. There were significant increases in total leucocytes, monocytes and neutrophils at Post as compared with Pre (P<0·05). Additionally, total leucocytes and monocytes were reduced even at P24h when compared to Pre (P<0·05). There were no significant changes in plasma concentrations of TNF-α, IL-6 and cortisol throughout the measured moments. As compared to CG, EG demonstrated very large effect sizes for total leucocytes, neutrophils and monocytes 15 min postprotocol and a reduction (trivial and small effect sizes) P24h. These results suggest that the tri-set RT session did not exacerbate the acute inflammatory response and might be a good option for variations in RT methods for trained individuals. © 2014 Scandinavian Society of Clinical Physiology and Nuclear Medicine 341 January 2014 10.1111/cpf.12066 Original Article Original Articles © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.3416471Ahtiainen, J.P., Pakarinen, A., Alen, M., Kraemer, W.J., Hakkinen, K., Muscle hypertrophy, hormonal adaptations and strength development during strength training in strength-trained and untrained men (2003) Eur J Appl Physiol, 89, pp. 555-563Ahtiainen, J.P., Pakarinen, A., Kraemer, W.J., Hakkinen, K., Acute hormonal responses to heavy resistance exercise in strength athletes versus nonathletes (2004) Can J Appl Physiol, 29, pp. 527-543Baechle, T.R., Earle, R.W., (2008) Essentials of Strength Training and Conditioning, , Human Kinetics Publishers, Champaign, ILBrown, L.E., Weir, J.P., Procedures recommendation I: accurate assessment of muscular strength and power (2001) J Exerc Physiol, 4, pp. 1-21Buford, T.W., Cooke, M.B., Willoughby, D.S., Resistance exercise-induced changes of inflammatory gene expression within human skeletal muscle (2009) Eur J Appl Physiol, 107, pp. 463-471Cadore, E.L., Lhullier, F.L., Brentano, M.A., da Silva, E.M., Ambrosini, M.B., Spinelli, R., Silva, R.F., Kruel, L.F., Hormonal responses to resistance exercise in long-term trained and untrained middle-aged men (2008) J Strength Cond Res, 22, pp. 1617-1624Cupps, T.R., Fauci, A.S., Corticosteroid-mediated immunoregulation in man (1982) Immunol Rev, 65, pp. 133-155Dornfest, B.S., Lapin, D.M., Naughton, B.A., Adu, S., Korn, L., Gordon, A.S., Phenylhydrazine-induced leukocytosis in the rat (1986) J Leukoc Biol, 39, pp. 37-48Ferreira, F.C., de Medeiros, A.I., Nicioli, C., Nunes, J.E., Shiguemoto, G.E., Prestes, J., Verzola, R.M., Perez, S.E., Circuit resistance training in sedentary women: body composition and serum cytokine levels (2009) Appl Physiol Nutr Metab, 35, pp. 163-171Ghanbari-Niaki, A., Saghebjoo, M., Rashid-Lamir, A., Fathi, R., Kraemer, R.R., Acute circuit-resistance exercise increases expression of lymphocyte agouti-related protein in young women (2010) Exp Biol Med (Maywood), 235, pp. 326-334Gleeson, M., Immune function in sport and exercise (2007) J Appl Physiol, 103, pp. 693-699Gleeson, M., Bishop, N.C., Stensel, D.J., Lindley, M.R., Mastana, S.S., Nimmo, M.A., The anti-inflammatory effects of exercise: mechanisms and implications for the prevention and treatment of disease (2011) Nat Rev Immunol, 11, pp. 607-615Hakkinen, K., Pakarinen, A., Acute hormonal responses to two different fatiguing heavy-resistance protocols in male athletes (1993) J Appl Physiol, 74, pp. 882-887Hakkinen, K., Pakarinen, A., Alen, M., Kauhanen, H., Komi, P.V., Neuromuscular and hormonal adaptations in athletes to strength training in two years (1988) J Appl Physiol, 65, pp. 2406-2412Hiscock, N., Pedersen, B.K., Exercise-induced immunodepression- plasma glutamine is not the link (2002) J Appl Physiol, 93, pp. 813-822Jackson, A.S., Pollock, M.L., Generalized equations for predicting body density of men (1978) Br J Nutr, 40, pp. 497-504Johnnidis, J.B., Harris, M.H., Wheeler, R.T., Stehling-Sun, S., Lam, M.H., Kirak, O., Brummelkamp, T.R., Camargo, F.D., Regulation of progenitor cell proliferation and granulocyte function by microRNA-223 (2008) Nature, 451, pp. 1125-1129Koch, A.J., Immune response to resistance exercise (2010) Am J Lifestyle Med, 4, pp. 244-252Kraemer, W.J., Ratamess, N.A., Hormonal responses and adaptations to resistance exercise and training (2005) Sports Med, 35, pp. 339-361Kraemer, W.J., Noble, B.J., Clark, M.J., Culver, B.W., Physiologic responses to heavy-resistance exercise with very short rest periods (1987) Int J Sports Med, 8, pp. 247-252Kraemer, W.J., Marchitelli, L., Gordon, S.E., Harman, E., Dziados, J.E., Mello, R., Frykman, P., Fleck, S.J., Hormonal and growth factor responses to heavy resistance exercise protocols (1990) J Appl Physiol, 69, pp. 1442-1450Kraemer, W.J., Fleck, S.J., Dziados, J.E., Harman, E.A., Marchitelli, L.J., Gordon, S.E., Mello, R., Triplett, N.T., Changes in hormonal concentrations after different heavy-resistance exercise protocols in women (1993) J Appl Physiol, 75, pp. 594-604Kraemer, W.J., Clemson, A., Triplett, N.T., Bush, J.A., Newton, R.U., Lynch, J.M., The effects of plasma cortisol elevation on total and differential leukocyte counts in response to heavy-resistance exercise (1996) Eur J Appl Physiol Occup Physiol, 73, pp. 93-97Kraemer, W.J., Hakkinen, K., Newton, R.U., Nindl, B.C., Volek, J.S., McCormick, M., Gotshalk, L.A., Evans, W.J., Effects of heavy-resistance training on hormonal response patterns in younger vs. older men (1999) J Appl Physiol, 87, pp. 982-992Kruger, K., Agnischock, S., Lechtermann, A., Tiwari, S., Mishra, M., Pilat, C., Wagner, A., Mooren, F.C., Intensive resistance exercise induces lymphocyte apoptosis via cortisol and glucocorticoid receptor-dependent pathways (2011) J Appl Physiol, 110, pp. 1226-1232Marx, J.O., Ratamess, N.A., Nindl, B.C., Gotshalk, L.A., Volek, J.S., Dohi, K., Bush, J.A., Kraemer, W.J., Low-volume circuit versus high-volume periodized resistance training in women (2001) Med Sci Sports Exerc, 33, pp. 635-643Mayhew, D.L., Thyfault, J.P., Koch, A.J., Rest-interval length affects leukocyte levels during heavy resistance exercise (2005) J Strength Cond Res, 19, pp. 16-22Nieman, D.C., Immune response to heavy exertion (1997) J Appl Physiol, 82, pp. 1385-1394Nieman, D.C., Davis, J.M., Brown, V.A., Henson, D.A., Dumke, C.L., Utter, A.C., Vinci, D.M., McAnulty, L.S., Influence of carbohydrate ingestion on immune changes after 2 h of intensive resistance training (2004) J Appl Physiol, 96, pp. 1292-1298Paulsen, G., Crameri, R., Benestad, H.B., Fjeld, J.G., Morkrid, L., Hallen, J., Raastad, T., Time course of leukocyte accumulation in human muscle after eccentric exercise (2010) Med Sci Sports Exerc, 42, pp. 75-85Peake, J.M., Nosaka, K., Muthalib, M., Suzuki, K., Systemic inflammatory responses to maximal versus submaximal lengthening contractions of the elbow flexors (2006) Exerc Immunol Rev, 12, pp. 72-85Pizza, F.X., Baylies, H., Mitchell, J.B., Adaptation to eccentric exercise: neutrophils and E-selectin during early recovery (2001) Can J Appl Physiol, 26, pp. 245-253Prestes, J., De Lima, C., Frollini, A.B., Donatto, F.F., Conte, M., Comparison of linear and reverse linear periodization effects on maximal strength and body composition (2009) J Strength Cond Res, 23, pp. 266-274Ratamess, N.A., Alvar, B.A., Evetoch, T.K., Housh, T.J., Kibler, W.B., Kraemer, W.J., Triplett, N.T., American College of Sports Medicine position stand. Progression models in resistance training for healthy adults (2009) Med Sci Sports Exerc, 41, pp. 687-708Shinkai, S., Watanabe, S., Asai, H., Shek, P.N., Cortisol response to exercise and post-exercise suppression of blood lymphocyte subset counts (1996) Int J Sports Med, 17, pp. 597-603Simonson, S.R., Jackson, C.G., Leukocytosis occurs in response to resistance exercise in men (2004) J Strength Cond Res, 18, pp. 266-271Siri, W.E., Body composition from fluid spaces and density: analysis of methods. 1961 (1993) Nutrition, 9, pp. 480-491. , discussion 480, 492Smilios, L., Pilianidis, T., Karamouzis, M., Tokmakidis, S.P., Hormonal responses after various resistance exercise protocols (2003) Med Sci Sports Exerc, 35, pp. 644-654Steensberg, A., Fischer, C.P., Keller, C., Moller, K., Pedersen, B.K., IL-6 enhances plasma IL-1ra, IL-10, and cortisol in humans (2003) Am J Physiol Endocrinol Metab, 285, pp. E433-E437Uchida, M.C., Nosaka, K., Ugrinowitsch, C., Yamashita, A., Martins Jr., E., Moriscot, A.S., Aoki, M.S., Effect of bench press exercise intensity on muscle soreness and inflammatory mediators (2009) J Sports Sci, 27, pp. 499-507Voight, M.L., Hoogenboom, B.J., Prentice, W.E., (2007) Musculoskeletal Interventions: Techniques for Therapeutic Exercise, , The MaGraw-Hill Companies, Inc., New York, NY