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Muscle activations under varying lifting speeds and intensities during bench press.
Eur J Appl Physiol. 2012 Mar; 112(3):1015-25.EJ

Abstract

During a set of resistance exercise performed until exhaustion, the relationship between intensity and the number of repetitions can be affected by lifting speed, with faster speeds producing higher numbers. The hypothesized mechanisms include enhanced utilization of the stretch-shortening cycle. This study investigated muscle activations under varying speeds and intensities during bench press using surface electromyography (EMG) to suggest further mechanisms for the above finding. Thirteen weight-trained men (21.7 ± 3.6-year-old) performed bench press until fatigue under five intensities (40-80% 1RM), and four speeds (slow 5.6-s/repetition, medium 2.8-s/repetition, fast 1.9-s/repetition, and ballistic maximum speed). Surface EMG was recorded from the pectoralis, deltoid, and triceps for root-mean-square amplitude and median frequency. EMG amplitudes were greater for faster and heavier conditions before fatigue. Faster conditions, however, produced a significant fall in amplitude during the final concentric phase compared to slower movements. After fatigue, EMG amplitude increased, with the speed effect being maintained. The intensity effect on amplitude either disappeared or remained similar, depending on the muscles. Median frequencies before fatigue were similar among speeds and intensities. The fall in frequency after fatigue was similar across speeds, but greater for lighter intensities. It was concluded that reduced muscle activation during the final concentric phase in faster conditions allowed a better muscle pump, explaining the increased repetition numbers. Fatigue levels are likely to have been similar across speeds, but greater for lower intensities. An incomplete rise in EMG amplitude after fatigue for lower intensities could imply an increased contribution of central fatigue or neuromuscular transmission failure.

Authors+Show Affiliations

Discipline of Exercise and Sport Science, Faculty of Health Sciences, The University of Sydney, 75 East Street, Lidcombe, NSW 2141, Australia. s_akihiro@hotmail.comNo affiliation info available

Pub Type(s)

Journal Article
Randomized Controlled Trial

Language

eng

PubMed ID

21735215

Citation

Sakamoto, Akihiro, and Peter James Sinclair. "Muscle Activations Under Varying Lifting Speeds and Intensities During Bench Press." European Journal of Applied Physiology, vol. 112, no. 3, 2012, pp. 1015-25.
Sakamoto A, Sinclair PJ. Muscle activations under varying lifting speeds and intensities during bench press. Eur J Appl Physiol. 2012;112(3):1015-25.
Sakamoto, A., & Sinclair, P. J. (2012). Muscle activations under varying lifting speeds and intensities during bench press. European Journal of Applied Physiology, 112(3), 1015-25. https://doi.org/10.1007/s00421-011-2059-0
Sakamoto A, Sinclair PJ. Muscle Activations Under Varying Lifting Speeds and Intensities During Bench Press. Eur J Appl Physiol. 2012;112(3):1015-25. PubMed PMID: 21735215.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Muscle activations under varying lifting speeds and intensities during bench press. AU - Sakamoto,Akihiro, AU - Sinclair,Peter James, Y1 - 2011/07/07/ PY - 2010/11/24/received PY - 2011/06/22/accepted PY - 2011/7/8/entrez PY - 2011/7/8/pubmed PY - 2012/6/20/medline SP - 1015 EP - 25 JF - European journal of applied physiology JO - Eur. J. Appl. Physiol. VL - 112 IS - 3 N2 - During a set of resistance exercise performed until exhaustion, the relationship between intensity and the number of repetitions can be affected by lifting speed, with faster speeds producing higher numbers. The hypothesized mechanisms include enhanced utilization of the stretch-shortening cycle. This study investigated muscle activations under varying speeds and intensities during bench press using surface electromyography (EMG) to suggest further mechanisms for the above finding. Thirteen weight-trained men (21.7 ± 3.6-year-old) performed bench press until fatigue under five intensities (40-80% 1RM), and four speeds (slow 5.6-s/repetition, medium 2.8-s/repetition, fast 1.9-s/repetition, and ballistic maximum speed). Surface EMG was recorded from the pectoralis, deltoid, and triceps for root-mean-square amplitude and median frequency. EMG amplitudes were greater for faster and heavier conditions before fatigue. Faster conditions, however, produced a significant fall in amplitude during the final concentric phase compared to slower movements. After fatigue, EMG amplitude increased, with the speed effect being maintained. The intensity effect on amplitude either disappeared or remained similar, depending on the muscles. Median frequencies before fatigue were similar among speeds and intensities. The fall in frequency after fatigue was similar across speeds, but greater for lighter intensities. It was concluded that reduced muscle activation during the final concentric phase in faster conditions allowed a better muscle pump, explaining the increased repetition numbers. Fatigue levels are likely to have been similar across speeds, but greater for lower intensities. An incomplete rise in EMG amplitude after fatigue for lower intensities could imply an increased contribution of central fatigue or neuromuscular transmission failure. SN - 1439-6327 UR - https://www.unboundmedicine.com/medline/citation/21735215/Muscle_activations_under_varying_lifting_speeds_and_intensities_during_bench_press_ L2 - https://dx.doi.org/10.1007/s00421-011-2059-0 DB - PRIME DP - Unbound Medicine ER -