אימונים The sticking region in three chest-press exercises with increasing degrees of freedom

[Mike Bikov]

J Strength Cond Res. 2011 Dec 8. [Epub ahead of print]
The sticking region in three chest-press exercises with increasing degrees of freedom.
van den Tillaar R, Sætersbakken A.
Source

1 Department of Teacher Education of Nord Trøndelag University College, Norway; 2 Research Centre for Sport, Health and Human Development, Villa Real, Portugal; 3 Department of Teacher Education and Sport of Sogn and Fjrodane University College, Norway.
Abstract

The purpose was to investigate the effect of three chest-press exercises with different degrees of freedom upon the sticking region and muscle activity in maximal attempts. It was hypothesized that, with increasing degrees of freedom the sticking region (the weakest region during the lift) would be longer since the muscles need to use a part of their ability to control this increasing degrees of freedom during the exercise. Furthermore, the prime movers would have the same muscle activity, but the biceps muscle activity would increase when the degrees of freedom increases due to the enhanced control of the upwards movement. Eleven male subjects (age 22.6 ± 1.7 yrs, body mass 78.6 ± 8.0 kg, stature 1.80 ± 0.07 m) with at least one year of bench press training experience participated in this study. Every subject was tested in 1-RM in the three chest-press exercises. During the attempts kinematics and muscle activity were recorded and analyzed in four different regions (downwards, pre-, sticking and post-sticking). The participants achieved the highest 1-RM strength using the free barbell (106.4±15.5 kg), followed by the Smith machine (103.6±14.8 kg) and dumbbells (89.5±13.7 kg). Furthermore, muscle activity differences (EMG) between the three different exercises and the muscle activation between the four different regions were found. The length of the different lifting regions together with muscle activity was different between the exercises. However, the differences found did not follow the line of increasing degrees of freedom that would result in a longer sticking region. Therefore it is possible to choose to train a particular chest press exercise with the purpose of training a particular muscle more than the others.​

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