RELATIONSHIP BETWEEN VERTICAL JUMPS AND STARTING ACCELERATION IN SPRINT

The purpose of this study was to relate standardized vertical jumps with acceleration phase in sprint. Since vertical jumps employ typical kinetic chains and provide insight into basic movement strategies of the athlete, they may provide additional information about the nature of sprint acceleration phase

Selective effect of static stretching, concentric contractions, and a balance task on ankle force sense

Proper ankle motor control is critical for balance in the human body during functional activities such as standing, walking, and running. Different exercise modalities are often performed during the same training session where earlier activities may influence later ones. The purpose of the current study was to determine the acute effects of different exercise modalities on ankle force sense. Seventeen subjects performed four different intervention protocols (static stretching, balance task, concentric contractions, and control) in random order. Each session comprised measurements before and after the intervention protocol of the force sense of the ankle plantar flexors (PF) and dorsal flexors (DF) at 10% and 30% of maximal voluntary isometric contraction (MVC). Absolute errors (AE) were calculated separately for each force level and muscle group. An overall PF error (PF-SUM = PF at 10% MVC + PF at 30%MVC), DF error (DF-SUM = DF at 10%MVC + DF at 30%MVC) and ankle error (PF-DF-SUM = PF-SUM + DF-SUM) were also calculated. The main effect of time generally revealed that ankle force sense was significantly reduced after static stretching (PF-DF-SUM: Pre: 6.11±2.17 Nm, Post: 8.03±3.28 Nm; p < 0.05), but no significant differences were observed for the concentric contractions (PF-DF-SUM: Pre: 6.01±1.97 Nm, Post: 6.50±2.28 Nm) and the balance task (PF-DF-SUM: Pre: 5.25±1.97 Nm, Post: 5.50 ±1.26 Nm). The only significant interaction was observed for the PF-DF-SUM (F = 4.48, p = 0.008) due to greater error scores after stretching (+31.4%) compared to the concentric (+8.2%), balance (+4.8%), and control (-3.5%) conditions. Based on these results, static stretching should not be performed before activities that require a high ankle force sense such as balance, coordination, and precision tasks.This work was supported by Javna Agencija za Raziskovalno Dejavnost RS (SI) (P5- 0142 to DS)

Terminologija v poklicnem vsakdanu: stanje in potrebe

Terminologija v poklicnem vsakdanu: stanje in potreb

Etiology of Neuromuscular Fatigue After Repeated Sprints Depends on Exercise Modality

International audienc

Effect of fatigue on force production and force application technique during repeated sprints

International audienc

Effects of creeping exercise on upper limb strength

This study determined the influence of creeping exercise on the strength and endurance of the upper body. A total of 32 young football players were divided into an experimental (EXP) and a control group (CON). The EXP group included 17 boys&nbsp; (11.6±0.6years), while the CON group included 15 boys (10.5±1.1years). Upper body strength and endurance were measured by five motor performance tests: push-ups, pull-ups, pulling and pushing on a bench and a complex creeping exercise ("driving a wheelbarrow"). Strength training consisted of a creeping exercise (6 weeks, 2-3 sets, 2-3 times a week, 10-15 minutes). The EXP group improved their performance in push-ups and pull-ups by ~90% (p&lt;0.05) and ~26% (p&lt;0.05), respectively. No significant differences were observed when pulling or pushing on the bench, while the EXP group improved performance scores in "driving a wheelbarrow" by ~13% (p&lt;0.01). For the CON group, motor tests either remained unchanged or decreased. A significantly lower number of repetitions (~20%; p&lt;0.05) was achieved only for pull-ups. Creeping exercises improved the results in the selected upper body strength and motor performance tests. This improvement could be attributed to changes in the neural mechanisms of muscular force generation in the shoulder girdle and trunk

High-intensity sprint fatigue does not alter constant-submaximal velocity running mechanics and spring-mass behavior

International audienc

Neuromuscular Adaptations after an Altitude Training Camp in Elite Judo Athletes

The aim of this study was to investigate neuromuscular adaptations in elite judo athletes after three weeks of power-oriented strength training at terrestrial altitude (2320 m). Nineteen men were assigned to altitude training (AL) (22.1 ± 2.3 years) and sea level training (SL) (22.6 ± 4.1 years). Neuromuscular assessment consisted of: (1) maximal isometric knee extensor (KE) torque, (2) KE rate of torque development (RTD), (3) quadriceps activity and voluntary activation, (4) soleus Hreflex, (5) quadriceps single (TTW) and double twitch torque (TDB100) and contraction time (CTTW). There were no significant differences between groups at baseline for any of the observed parameters. Significant differences were found between groups in terms of change in RTD (p = 0.04). Cohen’s d showed a positive significant effect (0.43) in the SL group and a negative significant effect (−0.58) in the AL group. The difference between groups in changes in CTTW as a function of altitude was on the edge of significance (p = 0.077). CTTW increased by 8.1 ± 9.0% in the AL group (p = 0.036) and remained statistically unchanged in the SL group. Only the AL group showed a relationship between changes in TTW and TDB100 and changes in RTD at posttest (p = 0.022 and p = 0.016, respectively). Altitude induced differences in muscular adaptations likely due to greater peripheral fatigue.Spanish Ministry of Economy, Industry and Competitiveness under grant DEP2015-64350-P MINECO/FEDERSlovenian Research Agency (P5-0142)FPI pre-doctoral grant under grant BES -2016-07803