2017, Volume 13, Issue 1
Effect of mechanical vibration applied in the direction of the resultant muscle forces’ vector addition on maximal isometric force production in judo athletes
Mariana Oliveira1, Bruno Teobaldo1, Maicon Albuquerque1, Luciano Prado1, Leszek Szmuchrowski1, Sara Andrade1, Marcos Drummond1, Eduardo Pena1, Reginaldo Gonçalves1, Diego Campos1, Bruno Pena1
Author for correspondence: Mariana Oliveira; UFMG, Brazil; email: maripaulinoliveira[at]gmail.com
Background and Study Aim: Judo can be characterised as an intermittent and high-intensity sport, which demands motor actions like pushing, pulling, dominating and throwing the opponent. The combat requires a combination of different expressions of muscle strength, such as maximal and submaximal strength efforts in the upper limbs during the gripping combat (kumi-kata), to control the distance between the opponent and preparation of the throws. The aim of the present study was the effects of mechanical vibrations applied in the direction of the resultant muscle forces produced on the maximal isometric strength of the upper limbs muscles in judo athletes.
Material and Methods: The sample consisted of 10 male national-level judo athletes (20.0 ±1.5 years old,1.7 ±0.6 m body height, 55.4 ±7.6 kg total body mass). The intervention session consisted of three steps: pre-test; kumi-kata maximal volunteer contraction MVC with local vibration (LV); post-test. Pre-test (all the volunteers performed three kumi-kata MVCs with a duration of 6 seconds and 5-minute intervals between the repetitions). Kumi-kata MVC with LV (after 30 minutes recovery from the pre-test, athletes performed three MVCs with LV exposure during 6 seconds, and a 3-minutes rest interval between MVCs was adopted; the flexion angle of the knees was set at 10° and elbow flexion at 90°; the LV was only applied after the volunteers reached the peak strength). Post-test (was performed in three different moments: immediately, 5-minutes and 10-minutes after; all the procedures of pre-test were repeated).
Results: A significant increase in maximal strength during vibration was found compared to pre-test (p = 0.006) and post-test in all moments: immediately (p = 0.021), 5-minutes (p = 0.005) and 10-minutes (p = 0.008) values. Regarding intra-repeated measures, immediately after was higher than 5-minutes (p = 0.018) and 10-minutes (p = 0.008). Impulse did not differ between situations (with and without vibration).
Conclusions: The application of mechanical vibration in the direction of the resultant muscle forces of upper limbs superimposed during maximal isometric actions could generate acute and residual increases in the maximal strength of judo athletes.
Key words: tonic vibration reflex, maximal volunteer contraction, kumi kata, whole body vibration