Electromyographic and kinetic comparison of a flexible and steel barbell
Purpose: This research design compares mean peak integrated electromyography (I-EMG) and mean peak ground reaction forces (GRFs) between a standard steel Olympic barbell (SB) and flexible barbell (FB) during the squat (SQ) exercise for human subjects, as well as GRFs for a similar machine-driven lift. Methods: A lifting machine set atop a force plate and lifted either a SB or FB with a total loaded weight of 47.6 kg at a rate of 52 repetitions per minute for a minimum of 12 repetitions. Next, ten NCAA Division I football players familiarized with both bars were randomly assigned the SB and FB loaded at 30% one repetition maximum (1RM) and performed 7-10 repetitions at the same rate as the machine. I-EMG data was collected from surface electrodes placed on the legs and trunk according to the SENIAM protocol where appropriate. Results: Paired t-tests between the SB and FB revealed significant increases (p<0.05) in GRFs for the FB during the machine-driven lift and the SQ exercise. I-EMG was significantly higher for the FB when compared to the SB for the vastus lateralis (VL), rectus abdominis (RA), rectus femoris (RF) and external oblique (EO). Results show increases in some leg and trunk muscle activity and increases in GRFs when using a FB loaded at 30% 1RM for the SQ exercise when compared to a SB. Conclusions: A FB, when used under certain conditions, may illicit increased muscle activity for the SQ exercise for some leg and trunk muscle groups compared to a SB.
Abernethy, D., & Brown, G. (February 2014). Tsunami bar. Retrieved from http://www.tsunamibarbell.com
Anderson, K., & Behm, D. G. (2005). Trunk muscle activity increases with unstable squat movements. Canadian Journal of Applied Physiology, 30(1), 33-45.
Brandon, R., Howatson, G., Strachan, F., & Hunter, A. M. (2015). Neuromuscular response differences to power vs strength back squat exercise in elite athletes. Scandinavian Journal of Medicine & Science in Sports, 25(5), 630-639.
Ebben, W. P., & Jensen, R. L. (2002). Electromyographic and kinetic analysis of traditional, chain, and elastic band squats. Journal of Strength and Conditioning Research / National Strength & Conditioning Association, 16(4), 547-550.
Ellenbecker, T. S., Sueyoshi, T., & Bailie, D. S. (2014). Muscular activation during plyometric exercises in 90° of glenohumeral joint abduction. Sports Health: A Multidisciplinary Approach, 7(1), 75-79.
Hermens, H. J., Freriks, B., Merletti, R., Stegeman, D., Blok, J., Rau, G., . . . Hägg, G. (1999). European recommendations for surface electromyography. Roessingh Research and Development, 8(2), 13-54.
Kraemer, W., & Ratamess, N. (2004). Fundamentals of resistance training: Progression and exercise prescription. Medicine and Science in Sports and Exercise, 36(4), 674-688.
Martorelli, A., Bottaro, M., Vieira, A., Rocha-Júnior, V., Cadore, E., Prestes, J., . . . Martorelli, S. (2015). Neuromuscular and blood lactate responses to squat power training with different rest intervals between sets. Journal of Sports Science & Medicine, 14(2), 269.
McGill, S. M., & Marshall, L. W. (2012). Kettlebell swing, snatch, and bottoms-up carry: Back and hip muscle activation, motion, and low back loads. Journal of Strength and Conditioning Research / National Strength & Conditioning Association, 26(1), 16-27. doi:10.1519/JSC.0b013e31823a4063 [doi]
Newton, R. U., Kraemer, W. J., Häkkinen, K., Humphries, B. J., & Murphy, A. J. (1996). Kinematics, kinetics, and muscle activation during explosive upper body movements. Journal of Applied Biomechanics, 12, 31-43.
Walker, S., Peltonen, H., Avela, J., & Häkkinen, K. (2011). Kinetic and electromyographic analysis of single repetition constant and variable resistance leg press actions. Journal of Electromyography and Kinesiology, 21(2), 262-269.
Wallace, B. J., Winchester, J. B., & McGuigan, M. R. (2006). Effects of elastic bands on force and power characteristics during the back squat exercise. Journal of Strength and Conditioning Research / National Strength & Conditioning Association, 20(2), 268-272. doi:R-16854 [pii]
Winter, D. A. (2009). Biomechanics and motor control of human movement. Hoboken, NJ: John Wiley & Sons.
Zatsiorsky, V. M., & Kraemer, W. J. (2006). Science and practice of strength training. Champaign, IL: Human Kinetics.