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Comparison of the electromyographic activity of the abdominal and rectus femoris muscles during traditional crunch and Rock Gym® device

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Abdominal exercises are performed with the purpose of preventing or rehabilitating low back pain, improving sports performance, and increasing strength and endurance during activities of daily living, and for aesthetic reasons. The objective of this study is to analyze and compare the electromyographic activity of the rectus abdominis (RA), external oblique abdominis (EO), and rectus femoris (RF) muscles during traditional crunch and exercise with Rock Gym® device.


A convenience sample of 15 healthy men (mean ± standard deviation, age 22.47 ± 2.26 years, body fat percentage 13.44 ± 4.37%) was selected. All men regularly participated in physical activity. Electromyographic recordings were performed using simple differential surface electrodes during five repetitions of each abdominal exercise (traditional and Rock Gym® at levels RG1, RG2, RG3, and RG4) in a randomized and counterbalanced manner. Electromyographic signals were quantified by root mean square and normalized using the maximum voluntary isometric contraction. Data were analyzed using repeated measures analysis of variance (p < 0.05).


Electromyographic activity of the abdominal muscles RA and EO in the crunch exercise was significantly higher (RA) or similar (EO) compared with the Rock Gym® device; however, the activity of the RF muscle in the device was significantly greater in relation to the traditional exercise.


Traditional crunch produced greater or similar EMG activity in the abdominal muscles and minimized RF activity compared with the Rock Gym® device; hence, traditional crunch is preferred for training, especially for people with weak abdominal musculature and/or problems in the lower back.

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  1. Aguiar AP. Análise eletromiográfica e do lactato sanguíneo em exercício resistido incremental. Dissertação [Mestrado em Fisioterapia]. Faculdade de Ciências da Saúde: Universidade Metodista de Piracicaba, 2006.

  2. Brown LE. Treinamento de força/National Strength and Conditioning Association. Manole: São Paulo; 2008.

  3. Cadore EL, Pinto RS, Lhullier FL, Correa CS, Alberton CL, Pinto SS, et al. Physiological effects of concurrent training in elderly men. Int J Sports Med. 2010;31(10):689–97.

  4. Calamita SAP, Biasotto-Gonzalez DA, De Melo NC, Fumagalli MA, Amorim CF, Paula Gomes CAF, et al. Immediate effect of acupuncture on electromyographic activity of the upper trapezius muscle and pain in patients with nonspecific neck pain: a randomized, single-blinded, sham-controlled, Crossover Study. J Manipulative Physiol Ther. 2018;41(3):208–17.

  5. Correa CS, Costa R, Pinto RS. Utilização de diferentes técnicas para o controle do posicionamento dos eletrodos de superfície na coleta do sinal eletromiográfico. Rev Acta Brasileira do Movimento Humano. 2012;2(2):5–13.

  6. Di dio LJA. Tratado de Anatomia Sistêmica Aplicada. (Vol. 1). São Paulo: Atheneu; 2002.

  7. Escamilla RF, Mctaggart MS, Fricklas EJ, Dewitt R, Kelleher P, Taylor MK, et al. An electromyographic analysis of commercial and common abdominal exercises: implications for rehabilitation and training. J Orthop Sports Phys Ther. 2006;36(2):45–57.

  8. Escamilla RF, Lewis C, Bell D, Bramblet G, Daffron J, Lambert S, et al. Core muscle activation during Swiss ball and traditional abdominal exercises. J Orthop Sports Phys Ther. 2010;40(5):265–76.

  9. Escamilla RF, Lewis C, Pecson A, Imamura R, Andrews JR. Muscle activation among supine, prone, and side position exercises with and without a Swiss ball. Sports Health. 2016;8(4):372–9.

  10. Evangelista AL, Macedo J. Treinamento funcional e core training: exercícios práticos aplicados. Phorte: São Paulo; 2011.

  11. Faul F, Erdfelder E, Lang AG, Buchner A. G*Power 3: a flexible statistical power analysis program for the social, behavioral, and biomedical sciences. Behav Res Methods. 2007;39(2):175–91.

  12. Fleiss JL. The design and analysis of clinical experiments. New York: Wiley; 1986.

  13. Furtado RNV, Ribeiro LH, Abdo BA, Descio FJ, Martucci Júnior CE, Serruya DC. Dor lombar inespecífica em adultos jovens: fatores de risco associados. Rev Bras Reumatol. 2014;54(5):371–7.

  14. García-Vaquero MP, Moreside JM, Brontons-Gil E, Peco-González N, Vera-Garcia FJ. Trunk muscle activation during stabilization exercises with single and double leg support. J Electromyogr Kinesiol. 2012;22(3):398–406.

  15. Hall SJ. Biomecânica Básica. 6th ed. Rio de Janeiro: Guanabara Koogan; 2013.

  16. Hermens HJ, Freriks B. The SENIAM CD-ROM: European recommendations for surface electromyography (CD-ROM). Enschede: Roessingh Research and Development, Enschede, the Netherlands; 1999.

  17. Kang H, Jung J, Yu J. Comparison of trunk muscle activity during bridging exercises using a sling in patients with low back pain. J Sports Sci Med. 2012;11(3):510–5.

  18. Kim MH, Oh JS. Effects of performing an abdominal hollowing exercise on trunk muscle activity during curl-up exercise on an unstable surface. J Phys Ther Sci. 2015;27(2):501–3.

  19. Konrad P. The ABC of EMG: a practical introduction to kinesiological electromyography. Noraxon INC: USA; 2005.

  20. Lima CS, Pinto RS. Cinesiologia e musculação. Artmed: Porto Alegre; 2006.

  21. Lizardo FB, Sousa GC, Facury Neto MA, Marques KV, Bernardino Júnior R, Silva DCO, et al. Análise eletromiográfica comparativa dos músculos reto do abdome e reto femoral em exercícios abdominais com e sem a utilização do aparelho ab swing. Biosci J. 2009;25(3):92–103.

  22. Maeo S, Takahashi T, Takai Y, Kanehisa H. Trunk muscle activities during abdominal bracing: comparison among muscles and exercises. J Sports Sci Med. 2013;12(3):467–74.

  23. Martuscello JM, Nuzzo JL, Ashley CD, Campbell BL, Orriola JJ, Mayer JM. Systematic review of core muscle activity during physical fitness exercises. J Strength Cond Res. 2013;27(6):1684–98.

  24. Moore KL, Dalley AF, Agur AMR. Anatomia Orientada Para a Clínica. Rio de Janeiro: Guanabara Koogan; 2014.

  25. Narici MV, Roi GS, Landoni L, Minetti AE, Cerretelli P. Changes in force, cross-sectional area and neural activation during strength training and detraining of the human quadriceps. Eur J Appl Physiol Occup Physiol. 1989;59(4):310–9.

  26. Nelson GA, Bent-Forsythe DA, Roopchand-Martin SC. Electromyographic activity of the rectus abdominis during a traditional crunch and the basic jackknife exercise with the Ab Lounge. J Strength Cond Res. 2012;26(6):1584–8.

  27. Parfrey KC, Docherty D, Workman RC, Behm DG. The effects of different sit-and curl-up positions on activation of abdominal and hip flexor musculature. Appl Physiol Nutr Metab. 2008;33(5):888–95.

  28. Rhea MR. Determining the magnitude of treatment effects in strength training research through the use of effect size. J Strength Cond Res. 2004;18(4):918–20.

  29. Snarr RL, Hallmark AV, Nickerson BS, Esco MR. Electromyographical comparison of pike variations performed with and without instability devices. J Strength Cond Res. 2016;30(12):3436–42.

  30. Solnik S, Rider P, Steinweg K, DeVita P, Hortobágyi T. Teager–Kaiser energy operator signal conditioning improves EMG onset detection. Eur J Appl Physiol. 2010;110(3):489–98.

  31. Sternlicht E, Rugg SG, Bernstein MD, Armstrong SD. Electromyographical analysis and comparison of selected abdominal training devices with a traditional crunch. J Strength Cond Res. 2005;19(1):157–62.

  32. Sundstrup E, Jakobsen MD, Andersen CH, Jay K, Andersen LL. Swiss ball abdominal crunch with added elastic resistance is an effective alternative to training machines. Int J Sports Phys Ther. 2012;7(4):372–80.

  33. Vasseljen O, Dahl HH, Mork PJ, Torp HG. Muscle activity onset in the lumbar multifidus muscle recorded simultaneously by ultrasound imaging and intramuscular electromyography. Clin Biomech. 2006;21(9):905–13.

  34. Vera-Garcia FJ, Moreside JM, McGill SM. MVC techniques to normalize trunk muscle EMG in healthy women. J Electromyogr Kinesiol. 2010;20(1):10–6.

  35. Vinstrup J, Sundstrup E, Brandt M, Jakobsen MD, Calatayud J, Andersen LL. Core muscle activity, exercise preference, and perceived exertion during core exercise with elastic resistance versus machine. Scientifica. 2015;403068:1–6.

  36. Weineck J. Anatomia Aplicada ao Esporte. Manole: São Paulo; 2013.

  37. Willardson JM, Behm DG, Huang SY, Rehg MD, Kattenbraker MS, Fontana FE. A comparison of trunk muscle activation: Ab Circle vs. traditional modalities. J Strength Cond Res. 2010;24(12):3415–21.

  38. Youdas JW, Guck BR, Hebrink RC, Rugotzke JD, Madson TJ, Hollman JH. An electromyographic analysis of the Ab-Slide exercise, abdominal crunch, supine double leg thrust, and side bridge in healthy young adults: implications for rehabilitation professionals. J Strength Cond Res. 2008;22(6):1939–46.

  39. Youdas JW, Coleman KC, Holstad EE, Long SD, Veldkamp NL, Hollman JH. Magnitudes of muscle activation of spine stabilizers in healthy adults during prone on elbow planking exercises with and without a fitness ball. Physiother Theory Pract. 2017;34:212–22.

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Correspondence to Frederico Balbino Lizardo.

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Gregorio, F.C., Lizardo, F.B., Santos, F.R.A. et al. Comparison of the electromyographic activity of the abdominal and rectus femoris muscles during traditional crunch and Rock Gym® device. Res. Biomed. Eng. 36, 39–48 (2020).

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  • Biomechanics
  • Electromyography
  • Rectus abdominis