Effect of acute exposure to moderate altitude on kinematic variables of the ippon-seoi-nage and its relationship with the countermovement jump in elite judokas.

Filipa Almeida,Juan Bonitch-Góngora,Paulino Padial,Antonio J Morales-Artacho,Belén Feriche,Blanca De La Fuente,Qun Chen

doi:10.1371/journal.pone.0206297

Abstract

This study aimed to assess the effect of acute exposure to moderate altitude on kinematic variables of the ippon-seoi-nage and on the mechanical outputs of the countermovement jump (CMJ). Thirteen elite male judokas from the Spanish Judo Training Centre in Valencia (age: 21.54 ± 2.15 years) participated in the study. All of them performed an incremental CMJ test and an ippon-seoi-nage technique test before (N) and after the ascent to a moderate altitude of 2320 m above the sea level (H). A linear velocity transducer was attached to the bar to assess the mechanical outputs of each loaded CMJ at different percentages of their own body weight (25, 50, 75 and 100%). A wearable sensor was used to assess the kinematic variables (times, accelerations and angular velocities) transferred to a dummy during the technique test. The kinematic variables showed great individual reliability (CV = 8.46% in N; CV = 8.37% in H), which contrasted with low reliability observed when the whole group was considered. The smallest important CV ratio (>1.15) showed that H caused changes in the reliability of the kinematic variables, with some variables becoming more reliable and others losing the reliability they had in N. H also caused small increments in peak velocity across all loads tested in the CMJ (+3.67%; P<0.05). In contrast, no changes in the kinematic variables were verified. In addition, there was no association between leg extension capability and the acceleration (r = -0.16 ± 0.19 in N; r = -0.24 ± 0.19 in H) or angular velocity (r = -0.19 ± 0.24 in N; r = -0.30 ± 0.26 in H) of the ippon-seoi-nage, nor was acute exposure to H found to affect this association (P>0.05). Differences between individual and within-groups CV confirm the individual adaptations that each judoka makes during this technique. Additionally, the CV ratio shows a change in the space-time pattern of the technique in H. Therefore, it would be necessary to include an adaptation period to adapt the technique after the ascent in altitude. Further studies are needed to confirm the relationship and transference from the velocity gains in CMJ during altitude training.

Highlights

IntroductionThere is increasing evidence that acute exposure to moderate altitude improves explosive actions in basic strength exercises (bench-press, back squat and squat jump exercises) [1,2,3] and in sports activities such as sprints, jumps and throws [4,5,6]
There is increasing evidence that acute exposure to moderate altitude improves explosive actions in basic strength exercises [1,2,3] and in sports activities such as sprints, jumps and throws [4,5,6]
The main aim of this study was to verify if the acute exposure to a moderate altitude affected the times, angular velocities and accelerations transferred to the uke during the performance of the ippon-seoi-nage in elite judokas and its relationship with their leg extension capacity

Summary

Introduction

There is increasing evidence that acute exposure to moderate altitude improves explosive actions in basic strength exercises (bench-press, back squat and squat jump exercises) [1,2,3] and in sports activities such as sprints, jumps and throws [4,5,6]. An increase in spinal excitability has been related to acute simulated hypoxia [11] and a greater increase in the Hoffmann’s reflex amplitude of the soleus muscle has been described at acute moderate altitude when compared with sea level [12], which can be related to a direct effect of hypoxemia on the supraspinal structures [10] All these findings seem to indicate a possible additive effect between air pressure and composition that could positively affect explosive actions performed in moderate altitude, while simulated hypoxia does not display changes of interest [2,13] and may reproduce different responses [14]. There is no studies on the effect of acute exposure to moderate altitude on the quality of the technical performance, which is crucial when training in altitude condition is used

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