Effect of different pushing speeds on bench press.

Int J Sports Med. 2012 May;33(5):376-80. doi: 10.1055/s-0031-1299702. Epub 2012 Feb 8.

Padulo J, Mignogna P, Mignardi S, Tonni F, D’Ottavio S.

Source

Faculty of Medicine and Surgery, University of Rome, Italy. sportcinetic@yahoo.it

Abstract

The purpose of this study was to investigate the effect on muscular strength after a 3-week training with the bench-press at a fixed pushing of 80-100% maximal speed (FPS) and self-selected pushing speed (SPS). 20 resistance-trained subjects were divided at random in 2 groups differing only regarding the pushing speed: in the FPS group (n=10) it was equal to 80-100% of the maximal speed while in the SPS group (n=10) the pushing speed was self-selected. Both groups were trained twice a week for 3 weeks with a load equal to 85% of 1RM and monitored with the encoder. Before and after the training we measured pushing speed and maximum load. Significant differences between and within the 2 groups were pointed out using a 2-way ANOVA for repeated measures. After 3 weeks a significant improvement was shown especially in the FPS group: the maximum load improved by 10.20% and the maximal speed by 2.22%, while in the SPS group the effect was <1%. This study shows that a high velocity training is required to increase the muscle strength further in subjects with a long training experience and this is possible by measuring the individual performance speed for each load.

© Georg Thieme Verlag KG Stuttgart · New York.

PMID: 22318559 [PubMed - indexed for MEDLINE]

Eur J Appl Physiol. 2012 Mar;112(3):1015-25. doi: 10.1007/s00421-011-2059-0. Epub 2011 Jul 7.

Muscle activations under varying lifting speeds and intensities during bench press.

Sakamoto A, Sinclair PJ.

Source

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

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.

Electromyographic Activity of the Hamstrings During Performance of the Leg Curl, Stiff-Leg Deadlift, and Back Squat Movements

WRIGHT, GLENN A.; DELONG, THOMAS H.; GEHLSEN, GALE

Abstract

To compare the effectiveness of 3 weight-training movements for the hamstrings, 11 weight-trained men performed 3 repetitions at 75% of 1 repetition maximum of the leg curl (LC), stiff-leg deadlift (SLDL), and back squat. Integrated electromyography (EMG) and peak EMG were analyzed in the biceps femoris and semitendinosus independantly during the concentric (CON) and eccentric (ECC) phase of each exercise. Results were as follows: CON-LC and CON-SLDL elicited the greatest integrated EMG activity, with no significant difference between exercises. The CON-squat showed approximately half as much integrated EMG activity as CON-LC and CON-SLDL. Highest peak EMG was found in the CON-LC and CON-SLDL, with no significant difference in these exercises. The CON-squat produced a peak EMG that was approximately 70% of LC and SLDL. We conclude that LC and SLDL involve the hamstrings to a similar degree; however, the back squat involves only about half as much hamstring integrated EMG activity as LC and SLDL.