Lower Limb Neuromuscular Asymmetry in Volleyball and Basketball Players.

The primary objective of the present study was to evaluate the agreement between the dominant leg (DL) (determined subjectively) and the stronger leg (SL) (determined via a functional test) in a group of basketball and volleyball players. The secondary objective was to calculate lower limb neuromuscular asymmetry when comparing the DL vs the non-dominant leg (NDL) and the SL vs the weaker (WL) leg in the whole group and when differentiating by sex. Seventy-nine male and female volleyball and basketball players (age: 23.7 ± 4.5 years) performed three single-leg vertical countermovement jumps (SLVCJ) on a contact mat. Vertical jump height and an inter-limb asymmetry index (ASI) were determined. Only 32 (40%) of the subjects had a concordance between the perception of their dominant leg and the limb reaching the highest jump height. Using the DL as the discriminating variable, significant (p<0.05) inter-limb differences were found in the total group of players. When comparing between sexes, significant differences (p<0.05) arose in the female group only. With regard to the WL vs. the SL, significant (p<0.05) differences were noted in the whole group and when stratified into males and females. The mean ASI ranged from 9.31% (males) to 12.84% (females) and from 10.49% (males) to 14.26% (females), when comparing the DL vs. the NDL and the SL vs. the WL, respectively. Subjective expression of leg dominance cannot be used as a predictor of limb jump performance. Vertical jump asymmetry of 10-15% exists and this can be considered as a reference value for male and female basketball and volleyball players.

Effects of In-Season Inertial Resistance Training With Eccentric Overload in a Sports Population at Risk for Patellar Tendinopathy.

Gual, G, Fort-Vanmeerhaeghe, A, Romero-Rodríguez, D, and Tesch, PA. Effects of in-season inertial resistance training with eccentric overload in a sports population at risk for patellar tendinopathy. J Strength Cond Res 30(7): 1834-1842, 2016-Volleyball and basketball players can be considered as a population at risk for patellar tendinopathy. Given the paradox that eccentric training elicits therapeutic benefits yet might provoke such injury, we investigated the influence of a weekly bout of inertial squat resistance exercise offering eccentric overload on lower limb muscle power and patellar tendon complaints. Players of 8 (4 basketball and 4 volleyball) teams (38 women and 43 men) were randomly assigned to either the intervention (IG) or control (CG) group. Although IG and CG maintained scheduled in-season training routines over 24 weeks, IG, in addition, performed 1 weekly session of eccentric overload by 4 sets of 8 repetitions of the squat using flywheel inertial resistance. Victorian Institute of Sports Assessment patellar tendinopathy questionnaire (VISA-p), vertical countermovement jump, and squat power, both concentric (Squat-Con) and eccentric (Squat-Ecc), tests were performed before (T1), during (T2), and after (T3) the 24 weeks of intervention. Neither group suffered from patellar tendinopathy during the study period. VISA-p displayed no differences across groups at any measurement period. Countermovement jump scores significantly (p ≤ 0.05) differed between groups in favor of the IG. Both Squat-Con and Squat-Ecc mean scores from the IG were significantly (p < 0.01) higher than the CG. Adding a weekly eccentric overload squat training bout to a regular basketball and volleyball exercise routine enhances lower limb muscle power without triggering patellar tendon complaints. Future studies, using the current exercise paradigm, aim to explore its efficacy to prevent or combat patellar tendinopathy in sports calling for frequent explosive jumps.

Aplicaciones de la electromiografía de superficie en el deporte / Surface electromyography applications

Las técnicas electrofisiológicas (neurografía y electromiografía de aguja) permiten una aproximación al conocimiento de la función neuromuscular. La electromiografía obtiene la actividad eléctrica del músculo en reposo o activo (contracción voluntaria máxima y estática). En su aplicación clínica, asiste al diagnóstico y al seguimiento de un proceso de tipo neuromuscular. Por otro lado, la electromiografía de superficie (EMGS) o cinesiológica permite estudiar la actividad muscular en acciones dinámicas, siendo aplicable al análisis biomecánico de un gesto, al análisis de la marcha, en estudios de fatiga muscular y de rendimiento deportivo y en áreas como la medicina laboral y la ergonomía. La EMGS ofrece algunas ventajas: es incruenta y permite analizar simultáneamente distintos músculos en movimiento y en acciones de duración ilimitada. El procesado de la señal electromiográfica proporciona parámetros de amplitud y frecuencia para estudios descriptivos y comparativos. No obstante, no permite valorar la musculatura profunda y aporta menos definición que los electromiogramas de aguja(AU)

The electrophysiological techniques (neurography and needle electromyography) allow us an approach to the knowledge of the neuromuscular function. Electromyography obtains the electrical activity from the muscle in rest or in contraction (maximum and static voluntary contraction). In its clinical application, electromyography helps to the diagnosis and follow-up of a process of neuromuscular type. On the other hand, kinesiological or surface electromyography (SEMG) allows the study detecof the muscular activity in dynamics, which we can apply to the biomechanical movement analysis, gait analysis, studies of muscular fatigue, sport performance and applications in work medicine and ergonomics. SEMG brings advantages like the fact that is a bloodless test, of being able to analyze varying muscles at the same time, in motion and in actions of non limited duration. The processed one brings us parameters of amplitude and frequencies, which we will use for descriptive and comparative studies. As a balancing entry, it does not allow us to study deep musculature, and some aspects of definition are lost in the obtained outlines(AU)