Are isokinetic leg torques and kick velocity reliable predictors of competitive level in taekwondo athletes? PLOS ONE 16(6):e0235582.https://doi.org/10.1371/journal.pone.0235582
Pedro Vieira Sarmet Moreira, Coral Falco, Luciano Luporini Menegaldo, Márcio Fagundes Goethel, Leandro Vinhas de Paula, Mauro Gon´çalves
ABSTRACT:
The aim of this study is to analyze how isokinetic knee and hip peak torques and roundhouse kick velocities are related to expertise level (elite vs. sub-elite) in taekwondo athletes. Seven elite and seven sub-elite athletes were tested for kick-specific variables (KSV, composed of kinematic variables and power of impact) and for concentric isokinetic peak torque (PT) at 60°/s and 240°/s. First, KSVs and PTs were compared between groups, then PTs were correlated with KSVs. Parametric variables with larger effect sizes (Cohen’s d) were entered in a stepwise linear discriminant analysis (LDA), generating an equation to estimate competitive level. Between-group differences were found in hip flexors (p = 0.04, d = 0.92) and extensors (p = 0.04, d = 0.96) with PT at 240°/s. Hip flexion PT at 60°/s and 240°/s correlated negatively with kick time (R = –0.46, p = 0.0499 and R = –0.62, p = 0.01 respectively). Hip flexion torque at 60°/s correlated positively (R = 0.52, p = 0.03) with peak linear velocity of the foot (LVF) and power of impact (R = 0.51, p = 0.03). Peak torque of hip extension at 60°/s and hip abduction at 240°/s also correlated with LVF (R = 0.56, p = 0.02 and R = 0.46, p = 0.0499). Hip extension at 60°/s correlated positively with peak linear velocity of the knee (R = 0.48, p = 0.04). The LDA showed an accuracy of 85.7% (p = 0.003) in predicting expertise level based on hip flexion and extension torques at 240°/s and on knee extension velocity during the kick. The study demonstrates that hip muscle strength is probably the dominant muscular factor for determining kick performance. Knee angular velocity combined with hip torques is the best discriminator for competitive level in taekwondo athletes.
Acute and residual neuromuscular effects of displacement in indirect vibratory stimulation. Journal of Electromyography and Kinesiology 58 (2021) 102551
Leandro V. de Paula, Pedro V.S. Moreira, Lucas A.A. de Oliveira, Leszek A. Szmuchorwski, Andr´e G.P. Andrade
ABSTRACT:
The aim of this study was to evaluate the effect of indirect vibratory stimulation on different magnitudes of
displacement on acute and residual neuromuscular responses. Fifteen healthy volunteers were randomly submitted
to 3 experimental sessions, with intervals of 5 to 7 days (5 maximal voluntary contractions - MVC, 12 s of
duration each and 5 min of recovery) between sessions. To determine the residual responses, the volunteers
performed a MVC before and after each treatment for 12 s, with a 5-minute recovery. The experimental sessions
were composed of isometric actions without vibrations (CONTROL) and two sessions of isometric actions with
the addition of vibrations at 20 Hz and 3 mm (Sinusoidal Vibration A) and 5 mm (Sinusoidal Vibration B). Before
and after each of the experimental sessions, an isometric evaluation without vibrations was performed. For the
acute effect, it was verified that the addition of vibrations induced a facilitatory effect on the explosive strength
variables (p < .05), independent of the type of studied displacement in relation to the control treatment. In short,
it was verified that the addition of vibration induced an acute facilitating effect on the explosive strength.
However, the induced effect was not persistent (residual effect) for the explosive strength.
