Oscar García-García

Differences in the Contractile Properties of the Knee Extensor and Flexor Muscles in Professional Road Cyclists During the Season

Abstract García-García, O, Cancela-Carral, JM, Martínez-Trigo, R, and Serrano-Gómez, V. Differences in the contractile properties of the knee extensor and flexor muscles in professional road cyclists during the season. J Strength Cond Res 27(10): 2760–2767, 2013—The purpose of this study was to establish reference values of tensiomyography (TMG) in professional road cyclists and to examine how the planned periods of the Season produce differences in the muscles: vastus medialis (VM), vastus lateralis (VL), rectus femoris (RF), and biceps femoris (BF), and to determine how these differences may depend on each cyclist, the assessed muscle, and the side of the body. Ten professional road cyclists (27.5 ± 5.5 years; 178.2 ± 7.8 cm; 65.6 ± 5.46 kg; 72.1 ± 3.7 ml·kg−1·min−1 V[Combining Dot Above]O2; 6 ± 0.4 W·kg−1) were assessed by TMG, in microcycle recovery, at 2 moments of periods during the season: preparation period (PP) and competition period (CP). Students t contrast for paired groups, Cohens d effect sizes, and a repeated measures analysis of variance (ANOVA) was applied. We did not find significant differences (p < 0.01) between the lower limbs. The results showed a significantly large increment between the time contraction (TC) values of the PP and CP in the muscles VM (28.7 ± 5.5 vs. 40.6 ± 14.4 milliseconds; 41.4%, p < 0.05, d = 1.1), VL (28.3 ± 4.9 vs. 40.6 ± 10.2 milliseconds; 43.4%, p < 0.05, d = 1.53), and RF (35.9 ± 6.9 vs. 45.9 ± 16.2 milliseconds; 27.8%, p < 0.05, d = 0.8). Nevertheless, TC of the BF presents a significantly large decrease in the CP (35.9 ± 9.9 vs. 28.2 ± 5.2 milliseconds; −21.4%, p < 0.05, d = 0.97). Radial muscle displacement (DM) values are slightly lower during the CP, but the difference is not significant. ANOVA confirmed that these differences depend on the evaluated muscles (TC p = 0.02; DM p = 0.001) and on the cyclists (TC p = 0.001; DM p = 0.001) and does not depend on the side of the body. In conclusion, the TC values during the Season show marked differences between the knee extensors (large increased) and the knee flexor (large decreased). The DM has not changed significantly, keeping the muscular and tendon stiffness.

NEUROMUSCULAR PROFILE OF TOP LEVEL WOMEN KAYAKERS, ASSESSED THROUGH TENSIOMYOGRAPHY.

Abstract García-García, O, Cancela-Carral, JM, and Huelin-Trillo, F. Neuromuscular profile of top-level women kayakers assessed through tensiomyography. J Strength Cond Res 29(3): 844–853, 2015—The aim of this study is to assess the contractile properties and the lateral symmetry percentages of trapezius, deltoideus, and latissimus dorsi muscles of top-level female kayakers [FKs]) and to determine the gender influence and the specific training in the assessed parameters. Twenty-one volunteers participated in this study, who were stratified into 3 groups: 7 top-level FKs, 4 top-level men kayakers (MKs), and 10 physically active female non-kayakers (FNKs), and they have been assessed through tensiomyography (TMG). Reliability of the TMG assessment was tested by calculating intraclass correlation coefficient reliabilities, and all the values obtained were over 0.8. A t-test (p ⩽ 0.05), a 1-factor analysis of variance (p ⩽ 0.01), and Cohens d effect sizes were implemented, and we used the algorithm of TMG-BMC tensiomyography to determine the lateral symmetry percentages. The results show that FKs and MKs differ only in the lower reaction time that FKs obtain when contracting their trapezius muscle (19.5%; p = 0.008; d = 2.13). However, FKs present >34.4% of time contraction (p = 0.003; d = 1.8) in their latissimus dorsi muscle than FNKs. Also, FKs have >123.7% of time contraction (p = 0.009; d = 1.5), >11.3% of time reaction (p = 0.01; d = 1.5), >34.8% of maximum radial displacement (p = 0.01; d = 1.35), and <20.4% of lateral symmetry (p = 0.006; d = 1.6) in their trapezius than FNKs. In conclusion, the specific training seems to have a significant influence on the FKs neuromuscular profile compared with FNKs.

Baseline Mechanical and Neuromuscular Profile of Knee Extensor and Flexor Muscles in Professional Soccer Players at the Start of the Pre-Season

Abstract The aim of the study was to determine the mechanical and neuromuscular profile of knee extensor and flexor muscles in professional soccer players at the start of the pre-season, and to calculate percentages for symmetry, as well as examine differences according to the player’s positional role. The vastus medialis (VM), vastus lateralis (VL), rectus femoris (RF) and biceps femoris (BF) of 16 professional soccer players were evaluated by means of tensiomyography (TMG) on the first day of the pre-season. A paired-samples t test (p < .05) was used to compare the dominant and non-dominant lower limb. One-way ANOVA was applied, with the positional role as an independent factor. No differences were observed between the dominant and non-dominant leg. The highest degree of symmetry corresponded to the VM (92.5 ± 2.7%), and the lowest to the BF (80.7 ± 10.9%). The positional role was associated with significant differences in some of the variables for the BF, RF and VM, although only the half-relaxation time in the BF and the time to sustain force in the VM differed across all the playing positions considered. TMG was shown to be a useful way of evaluating the neuromuscular characteristics of soccer players at the start of the pre-season, and of establishing baseline values for individual players.

Neuromuscular Parameters Predict the Performance in an Incremental Cycling Test

The aim was to determine the predictive capacity of neuromuscular parameters on physiological predictors of performance related to pedaling power. The sample comprised fifty elite cyclists. On the same day, they were given a neuromuscular evaluation with tensiomyography (TMG) and then performed an effort test on a cycle ergometer until exhaustion. The TMG recorded the maximum radial muscle belly displacement, contraction time, delay time, derivative normalized response speed, and lateral symmetry. Peak power output (Wpeak·kg-1), effort time, maximum lactate concentration, power in the first lactate threshold, and power in the second lactate threshold were recorded in the effort test. Linear regression analysis was used to determine the explanatory capacity of neuromuscular parameters on potential cycling performance indicators. A higher Wpeak·kg-1 during a maximal incremental test on the cycle ergometer can be predicted moderately (R2=0.683; R2a=0.615; R=0.826; Std. Error=0.26017; p<0.001) by a longer rectus femoris contraction time and a greater radial muscle belly displacement of the vastus lateralis and vastus medialis as well as a slower normalized response speed of the biceps femoris. In conclusion, neuromuscular parameters can partially explain performance in a specific cycling test until exhaustion.

The influence of situational variables on defensive positioning in professional soccer

Abstract The aim of this study was to examine the effects of match conditions on the defensive positioning in professional soccer. One hundred and ten ball recovery situations from an elite soccer team were analysed using a tracking system (Amisco Pro). Three team performance variables (ball recovery location (BRL), position of the defensive line (PDL) and position of the offensive line (POL), and three situational variables (match location, quality of opposition and match status) were considered. The results suggest that teams alter their style of play as a consequence of the match conditions. BRL was advanced by 4.87 and 1.80 m (p < 0.05) when the teams were losing and winning, respectively, and POL by 3.67 m (p < 0.05) when losing, than when the scores were even. Playing away decreased the BRL, the PDL and the POL by 4.62, 3.41 and 3.48 m compared with playing at home (p < 0.01). Playing against strong opposition decreased the BRL and the PDL by 5.32 and 3.51 m (p < 0.01) respectively, compared with playing against similar opponents. A combination of these variables can be used to develop a model to predict future performances. The findings emphasise the need for match analysts and coaches to consider the impact of match conditions during assessments of technical and tactical components of football performance.

Intrasession Reliability of the Tests to Determine Lateral Asymmetry and Performance in Volleyball Players

The development of lateral asymmetries in athletes could have an influence on performance or injuries. The aim of this study was to determine the within-day reliability of the symmetry tests and the performance tests, and explore the relationship between them. Eighteen male volleyball players (18.1 ± 2.1 years) participated in this study. Seven lateral symmetry assessments were used, namely: lateral symmetry through tensiomyography (LS), active knee extension (AKE), Y-balance test (YBT), muscular electrical activity in attack jump (MEA-AJ), single-leg squat jump (SLSJ), triple hop test for distance (THTD), and bilateral maximum repetition in leg press (1RMSL); and three volleyball performance tests, namely: the T-test, counter-movement jump (CMJ), and attack jump (AJ). Three in-day measurements were taken from each volleyball player after the recovery was completed. The reliability was calculated through the intraclass correlation coefficient and the coefficient of variation, and the relationship was calculated through Pearson’s bivariate correlation coefficient (p < 0.05). The results indicate that AKE, YBT, and LS are the symmetry tests with increased reproducibility. THTD correlates positively with the AKE test and 1RMSL test, and a greater symmetry in the YBT correlates with a greater performance in the CMJ and AJ performance tests. In conclusion, AKE, LS, and YBT are the best tests to determine, with reliability, the asymmetries in volleyball players, and a greater symmetry in the YBT seems to influence the height of bilateral vertical jump.

Análisis de la capacidad explicativa de las pruebas de detección de talento en el rendimiento en competición de jóvenes triatletas

El objetivo es establecer la relacion entre las pruebas de deteccion de talentos de la federacion espanola de triatlon (FETRI) y los resultados obtenidos en el campeonato de Espana del mismo ano. La muestra fue formada por 489 triatletas federados (342 hombres, 147 mujeres, 271 junior y 218 cadetes). Las variables independientes han sido las pruebas que conforman el proceso de deteccion de talentos de la FETRI: 100m de natacion estilo libre, 1000m de natacion estilo libre, 400m lisos, 1000m lisos, y se ha utilizado como variable dependiente el puesto obtenido en el Campeonato de Espana de triatlon. Se implemento un analisis de componentes de varianza (p<0,05), usando procedimientos de minimos cuadrados (Varcomp) y de maxima verosimilitud (GLM) y un analisis de generalizabilidad. Los resultados indican que el modelo es significativo (p=0,0251) y que tres variables resultan significativas para explicar el puesto obtenido en el campeonato de Espana de triatlon (natacion de 100 y 1000 metros y carrera de 1000 metros), sin embargo ninguna de sus interacciones resulta significativa, asi como tampoco la carrera de 400 metros. El modelo presenta un excelente nivel de fiabilidad (e2 = 1) y de generalizabilidad (Φ = 1). En conclusion, el resultado en el Campeonato de Espana no encuentra una explicacion satisfactoria a traves de las pruebas de deteccion de talentos marcadas por la FETRI por lo que una posible solucion seria mantener las pruebas que han mostrado una alta capacidad explicativa, y sustituir a aquellas otras que no tienen esa capacidad por la realizacion de otras mas cercanas al modelo de rendimiento del triatlon.