There were not enough data to compare the effects of concurrent training on immediate and mean power. Therefore, we pooled these data. The mean overall ES for power development of the lower body (Figure 1 and Table 3) for strength training only was 0.91 (95% CI: 0.65, 1.30; n: 15); for endurance training, it was 0.11 (95% CI: −0.15, 0.38; n: 14); and for concurrent training, it was 0.55 (95% CI: 0.31, 0.79; n: 17). Significant differences for lower body (Figure 1 and Table 3) were found between strength, endurance, and concurrent training (p < 0.05). Insufficient data were obtained for an analysis of the upper body.
Skeletal muscle demonstrates remarkable plasticity to various loading patterns, and it is becoming increasingly evident that muscle tissue can distinguish between specific signals imposed by variations in the duration, modality, and type of exercise. Endurance athletes demonstrate an increase in mitochondrial density (35), and no change or a small selective hypertrophy of type 1 fibers, with maintenance or a decrease in type 2 fiber size (15). Elite weightlifters and power lifters train at relatively high percentages of their 1RM, express preferential hypertrophy of type 2 fibers (17), and have a decrease in mitochondrial density relative to that of the general population (34).
Volume is typically defined as the total amount of work done during a given exercise session. For endurance exercise, this is at least partly dependent on the duration and frequency of training. We found primarily low (r = −0.26 to −0.35) to moderate (r = −0.75) significant negative correlations for frequency and duration of endurance exercise for hypertrophy, strength, and power outcomes. As indicated by the theoretical Venn diagram in Figure 6, commonality between long duration endurance and resistance exercise may be low. However, commonality between short duration high-intensity sprinting with resistance exercise may be high. As an explanation, the neuromuscular system is required to exert their lowest forces over long sustained periods of time, which likely results in adaptations with the lowest possible commonality to strength training. These results coincide with past research from Balabinis et al. (4) who found that shorter duration, high-intensity sprinting exercise did not result in decrements in strength or power and significantly increased V[Combining Dot Above]O2max in college level basketball players. More recently, Rhea et al. (43) found that short duration sprinting in National Collegiate Athletic Association baseball players resulted in greater increases in power than did low-intensity long duration exercise. It is also possible that greater total volumes of endurance training lead to a greater susceptibility for overreaching and under recovery. One limitation of our study is that we did not specifically analyze the total frequency of muscle groups trained (endurance + strength).
Perhaps the most intriguing finding of this study was that body fatness decreased with increasing endurance training intensities (Figure 5). In fact, the most dramatic loss in fat mass occurred from moderately high to very high intensities. These results seem paradoxical; research on the acute response of endurance exercise has found that maximal total fat calories are metabolized at moderate intensity endurance exercise (44). However, maximizing intensities, which are ideal for fat metabolism during an exercise, may not be ideal for maximizing fat metabolism in the long term. Research indicates that increases in metabolic rate after exercise increases exponentially with increasing intensity (8). Moreover, although traditional endurance exercise may decrease muscle mass relative to strength training alone, very high-intensity exercise does not appear to have this effect (4). Finally, research comparing very high-intensity to low-intensity exercise demonstrates that the former results in greater increases in the activity of muscle 3-hydroxyacycl coenzyme A dehydrogenase, an enzyme critical to the rate of beta oxidation (51).
This research received no funding from any organization or grants.
1. Aagaard P, Andersen JL. Effects of strength training
on endurance capacity in top-level endurance athletes. Scand J Med Sci Sports 20(Suppl. 2): 39–47, 2010.
2. Abernethy P, Quigley B. Concurrent strength and endurance training
of the elbow extensors. J Strength Cond Res 7: 234–240, 1993.
3. Ahtiainen JP, Hulmi JJ, Kraemer WJ, Lehti M, Pakarinen A, Mero AA, Karavirta L, Sillanpaa E, Selanne H, Alen M, Komulainen J, Kovanen V, Nyman K, Häkkinen K. Strength, endurance or combined training elicit diverse skeletal muscle myosin heavy chain isoform proportion but unaltered androgen receptor concentration in men. Int J Sports Med 30: 879–887, 2009.
4. Balabinis CP, Psarakis CH, Moukas M, Vassiliou MP, Behrakis PK. Early phase changes by concurrent endurance and strength training
. J Strength Cond Res 17: 393–401, 2003.
5. Bell G, Syrotuik D, Socha T. Effect of strength training
and concurrent strength and endurance training
on strength, testosterone, and cortisol. J Strength Cond Res 11: 57–64, 1997.
6. Bell GJ, Petersen SR, Wessel J, Bagnall K, Quinney HA. Physiological adaptations to concurrent endurance training
and low velocity resistance training. Int J Sports Med 12: 384–390, 1991.
7. Bell GJ, Syrotuik D, Martin TP, Burnham R, Quinney HA. Effect of concurrent strength and endurance training
on skeletal muscle properties and hormone concentrations in humans. Eur J Appl Physiol 81: 418–427, 2000.
8. Borsheim E, Bahr R. Effect of exercise intensity, duration and mode on post-exercise oxygen consumption. Sports Med 33: 1037–1060, 2003.
9. Burd NA, Tang JE, Moore DR, Phillips SM. Exercise training and protein metabolism: Influences of contraction, protein intake, and sex-based differences. J Appl Physiol 106: 1692–1701, 2009.
10. Chtara M, Chaouachi A, Levin GT, Chaouachi M, Chamari K, Amri M, Laursen PB. Effect of concurrent endurance and circuit resistance training sequence on muscular strength and power
development. J Strength Cond Res 22: 1037–1045, 2008.
11. Craig B, Lucas J, Pohlman R. Effects of running, weightlifting and a combination of both on growth hormone release. J Appl Sport Sci Res 5: 198–203, 1991.
12. Creer A, Gallagher P, Slivka D, Jemiolo B, Fink W, Trappe S. Influence of muscle glycogen availability on ERK1/2 and Akt signaling after resistance exercise in human skeletal muscle. J Appl Physiol 99: 950–956, 2005.
13. Dolezal BA, Potteiger JA. Concurrent resistance and endurance training
influence basal metabolic rate in nondieting individuals. J Appl Physiol 85: 695–700, 1998.
14. Dudley GA, Djamil R. Incompatibility of endurance- and strength-training modes of exercise. J Appl Physiol 59: 1446–1451, 1985.
15. Edstrom L, Ekblom B. Differences in sizes of red and white muscle fibres in vastus lateralis of musculus quadriceps femoris of normal individuals and athletes. Relation to physical performance. Scand J Clin Lab Invest 30: 175–181, 1972.
16. Escamilla RF. Knee biomechanics of the dynamic squat exercise. Med Sci Sports Exerc 33: 127–141, 2001.
17. Fry AC. The role of resistance exercise intensity on muscle fibre adaptations. Sports Med 34: 663–679, 2004.
18. Glowacki SP, Martin SE, Maurer A, Baek W, Green JS, Crouse SF. Effects of resistance, endurance, and concurrent exercise on training outcomes in men. Med Sci Sports Exerc 36: 2119–2127, 2004.
19. Gregor RJ, Broker JP, Ryan MM. The biomechanics of cycling. Exerc Sport Sci Rev 19: 127–169, 1991.
20. Häkkinen A, Hannonen P, Nyman K, Lyyski T, Häkkinen K. Effects of concurrent strength and endurance training
in women with early or longstanding rheumatoid arthritis: Comparison with healthy subjects. Arthr Rheum 49: 789–797, 2003.
21. Häkkinen K, Alen M, Kraemer WJ, Gorostiaga E, Izquierdo M, Rusko H, Mikkola J, Häkkinen A, Valkeinen H, Kaarakainen E, Romu S, Erola V, Ahtiainen J, Paavolainen L. Neuromuscular adaptations during concurrent strength and endurance training
versus strength training
. Eur J Appl Physiol 89: 42–52, 2003.
22. Halson SL, Jeukendrup AE. Does overtraining exist? An analysis of overreaching and overtraining research. Sports Med 34: 967–981, 2004.
23. Hawley JA. Molecular responses to strength and endurance training
: Are they incompatible? Appl Physiol Nutr Metab 34: 355–361, 2009.
24. Hennessy L, Watson A. The interference effects of training for strength and endurance simultaneously. J Strength Cond Res 12: 9–12, 1994.
25. Hickson RC. Interference of strength development by simultaneously training for strength and endurance. Eur J Appl Physiol Occup Physiol 45: 255–263, 1980.
26. Hunter G, Demment R, Miller D. Development of strength and maximum oxygen uptake during simultaneous training for strength and endurance. J Sports Med Phys Fitness 27: 269–275, 1987.
27. Karavirta L, Häkkinen K, Kauhanen A, Arija-Blazquez A, Sillanpaa E, Rinkinen N, Häkkinen A. Individual responses to combined endurance and strength training
in older adults. Med Sci Sports Exerc 43: 484–490, 2011.
28. Koller A, Mair J, Schobersberger W, Wohlfarter T, Haid C, Mayr M, Villiger B, Frey W, Puschendorf B. Effects of prolonged strenuous endurance exercise on plasma myosin heavy chain fragments and other muscular proteins. Cycling vs. running. J Sports Med Phys Fitness 38: 10–17, 1998.
29. Kraemer W, Patton J, Gordon S, Harman E, Deschenes M, Reynolds K, Newton R, Triplett N, Dziados J. Compatibility of high-intensity strength and endurance training
on hormonal and skeletal muscle adaptations. J Appl Physiol 78: 976–989, 1995.
30. Kraemer WJ, Vescovi JD, Volek JS, Nindl BC, Newton RU, Patton JF, Dziados JE, French DN, Häkkinen K. Effects of concurrent resistance and aerobic training on load-bearing performance and the Army physical fitness test. Mil Med 169: 994–999, 2004.
31. Leveritt M, Abernethy P. Acute effects of high-intensity endurance exercise on subsequent resistance activity. J Strength Cond Res 13: 47–51, 1999.
32. Leveritt M, Abernethy PJ, Barry B, Logan PA. Concurrent strength and endurance training
: The influence of dependent variable selection. J Strength Cond Res 17: 503–508, 2003.
33. Leveritt M, Abernethy PJ, Barry BK, Logan PA. Concurrent strength and endurance training
. A review. Sports Med 28: 413–427, 1999.
34. MacDougall JD, Sale DG, Moroz JR, Elder GC, Sutton JR, Howald H. Mitochondrial volume density in human skeletal muscle following heavy resistance training. Med Sci Sports Exerc 11: 164–166, 1979.
35. MacLean DA, Graham TE, Saltin B. Branched-chain amino acids augment ammonia metabolism while attenuating protein breakdown during exercise. Am J Physiol 267: E1010–E1022, 1994.
36. Mann RA, Hagy J. Biomechanics of walking, running, and sprinting. Am J Sports Med 8: 345–350, 1980.
37. Martinez ML, Ibanez Santos J, Grijalba A, Santesteban MD, Gorostiaga EM. Physiological comparison of roller skating, treadmill running and ergometer cycling. Int J Sports Med 14: 72–77, 1993.
38. McCarthy JP, Agre JC, Graf BK, Pozniak MA, Vailas AC. Compatibility of adaptive responses with combining strength and endurance training
. Med Sci Sports Exerc 27: 429–436, 1995.
39. McCarthy JP, Pozniak MA, Agre JC. Neuromuscular adaptations to concurrent strength and endurance training
. Med Sci Sports Exerc 34: 511–519, 2002.
40. Nelson AG, Arnall DA, Loy SF, Silvester LJ, Conlee RK. Consequences of combining strength and endurance training
regimens. Phys Ther 70: 287–294, 1990.
41. Rhea MR. Determining the magnitude of treatment effects in strength training
research through the use of the effect size. J Strength Cond Res 18: 918–920, 2004.
42. Rhea MR, Alvar BA, Burkett LN, Ball SD. A Meta-analysis to determine the dose response for strength development. Med Sci Sports Exerc 35: 456–464, 2003.
43. Rhea MR, Oliverson JR, Marshall G, Peterson MD, Kenn JG, Ayllon FN. Noncompatibility of power
and endurance training
among college baseball players. J Strength Cond Res 22: 230–234, 2008.
44. Romijn JA, Coyle EF, Sidossis LS, Gastaldelli A, Horowitz JF, Endert E, Wolfe RR. Regulation of endogenous fat and carbohydrate metabolism in relation to exercise intensity and duration. Am J Physiol 265: E380–E391, 1993.
45. Rose AJ, Broholm C, Kiillerich K, Finn SG, Proud CG, Rider MH, Richter EA, Kiens B. Exercise rapidly increases eukaryotic elongation factor 2 phosphorylation in skeletal muscle of men. J Physiol 569: 223–228, 2005.
46. Sale DG, Jacobs I, MacDougall JD, Garner S. Comparison of two regimens of concurrent strength and endurance training
. Med Sci Sports Exerc 22: 348–356, 1990.
47. Sale DG, MacDougall JD, Jacobs I, Garner S. Interaction between concurrent strength and endurance training
. J Appl Physiol 68: 260–270, 1990.
48. Sillanpaa E, Häkkinen A, Nyman K, Mattila M, Cheng S, Karavirta L, Laaksonen DE, Huuhka N, Kraemer WJ, Häkkinen K. Body composition and fitness during strength and/or endurance training
in older men. Med Sci Sports Exerc 40: 950–958, 2008.
49. Sillanpaa E, Laaksonen DE, Häkkinen A, Karavirta L, Jensen B, Kraemer WJ, Nyman K, Häkkinen K. Body composition, fitness, and metabolic health during strength and endurance training
and their combination in middle-aged and older women. Eur J Appl Physiol 106: 285–296, 2009.
50. Tang JE, Perco JG, Moore DR, Wilkinson SB, Phillips SM. Resistance training alters the response of fed state mixed muscle protein synthesis in young men. Am J Physiol Regul Integr Comp Physiol 294: R172–R178, 2008.
51. Tremblay A, Simoneau JA, Bouchard C. Impact of exercise intensity on body fatness and skeletal muscle metabolism. Metabolism 43: 814–818, 1994.