Heleodório Honorato dos Santos

The effects of knee extensor eccentric training on functional tests in healthy subjects

BACKGROUND It is well known that eccentric training increases muscle strength and promotes greater neural activation, and therefore has been used in the recovery of knee extensors. The hypothesis of this study was that there would be a strong correlation between knee extensor torque and functional tests. OBJECTIVES To investigate the relationship between knee extensor peak torque and functional tests of agility (runs) and propulsion (hop for distance) after short-term isokinetic eccentric training. METHODS Twenty healthy and active male undergraduate students (age 22.5 ± 2.1 years; height 1.72 ± 0.10 m; weight 67.8 ± 9.5 kg; body mass index: 22.5 ± 2.0 kg/m²), with no abnormalities or history of injury of the limbs, performed an isokinetic assessment of the knee extensors and flexors and also functional tests before and after isokinetic training, which consisted of 3 sets of 10 MVECs at 30º/s, with 3 minutes of rest between sets, twice a week for 6 weeks. RESULTS The eccentric training increased the extensor peak torque (16, 27 and 17%; P<0.01) and decreased the H/Q ratio (10, 20 and 13%; P<0.01) for the isometric and eccentric modes at 30°/s and 120°/s, respectively. It also decreased the time in two of the five agility tests (carioca and pivot diagonal; P<0.01), and increased the distance in the hop tests, for both dominant and non-dominant limbs (P<0.01). CONCLUSIONS Although the eccentric training led to an increase in extensor peak torques as well as an improvement in most of the functional tests, the hypothesis that a strong correlation would be observed between peak torques and functional tests was not confirmed. Article registered in the Australian New Zealand Clinical Trials Registry (ANZCTR) under the number 12607000590460.

Effects of High-Intensity Blood Flow Restriction Exercise on Muscle Fatigue

Abstract Strength training combined with blood flow restriction (BFR) have been used to improve the levels of muscle adaptation. The aim of this paper was to investigate the acute effect of high intensity squats with and without blood flow restriction on muscular fatigue levels. Twelve athletes (aged 25.95 ± 0.84 years) were randomized into two groups: without Blood Flow Restriction (NFR, n = 6) and With Blood Flow Restriction (WFR, n = 6) that performed a series of free weight squats with 80% 1-RM until concentric failure. The strength of the quadriceps extensors was assessed in a maximum voluntary isometric contraction integrated to signals from the surface electromyogram. The average frequency showed significant reductions in the WFR group for the vastus lateralis and vastus medialis muscles, and intergroup only for the vastus medialis. In conclusion, a set of squats at high intensity with BFR could compromise muscle strength immediately after exercise, however, differences were not significant between groups.

Static postural balance in healthy individuals: Comparisons between three age groups

The aim of the study was to compare static postural balance of healthy individuals of three age groups in different conditions of support and vision. Seventy one individuals, divided into 3 groups, were analyzed: young group (YG: 22.2 ± 2.1 years), middle aged group (MAG: 50.7 ± 5.7 years) and older individuals group (EG: 66.8 ± 5.4 years). Their balance was tested on a force platform, under 3 support and 3 visual conditions. Measures included: total (TD), anterior-posterior (APD) and mediolateral displacement (MLD) of the center of pressure (CoP). ANOVA revealed significant differences for interactions between group X support conditions and group X visual conditions for the 3 variables (p<0.01), with greater displacements for the MAG and EG groups during single-leg stance with partial and occluded vision (p<0.05). Static postural balance decreased over time in healthy individuals, and conditions of support and visual negatively affected balance with the increment of age.

Skin temperature changes during muscular static stretching exercise

This study aimed to investigate the acute effects of stretching exercise on skin temperature, flexibility, passive muscle stiffness, and pain during hamstring stretching in healthy young subjects. Thirty-one participants (n=31) were randomly divided into 2 groups: an experimental group (EG, n=15), which was submitted to hamstring stretching exercise for 180 sec, and the control group (n=16), which was not exercised. Skin temperature (TsK) was collected in subjects’ posterior thigh using a thermographic camera at 7 time points with intervals of 30 sec each: T0 (rest), T30, T60, T90, T120, T150, and T180. In addition, the knee range of motion, passive stiffness and muscle soreness (visual analogue scale) were recorded during the stretching procedure at the same times. The EG presented a small but progressive increase in TsK (30.8°C±0.6°C to 31.1°C±0.6°C, P<0.01), with an increased range of motion (P<0.01) and muscle soreness levels (P<0.01) during the gradual hamstring stretching protocol. Additionally, there was an increment of passive stiffness (P<0.01) that was partially reversed toward the end of the stretching period. This research presents evidence that constant, passive and progressive stretching of the hamstrings progressively increased the local TsK by about 0.3°C after 180 sec of stretching. These findings may help to understand the effects of repeated stress on the muscle-tendon unit and the role of muscle stretching in warm-up protocols and rehabilitation.

The influence of the external ankle support on the dynamic balance in volleyball athletes

El proposito de este estudio fue evaluar el efecto de los apoyos externos de tobillo en la propiocepcion y el equilibrio dinamico en atletas de voleibol. Diecisiete jugadores de voleibol (18,94±2,49 anos; 65,45±9,49 kg, 1,71±0,05 m, IMC=22,0±2,67 kg/m²). El equilibrio dinamico fue evaluado por el Star Excursion Balance Test(SEBT). Comparacion de los modos de estabilizacion (Si Estabilizador/SE, Ortesis/ORT y Vendaje Funcional/VF) y las lineas de cuadricula SEBT, y inter-miembros se fuera realizado. Evaluacion del SEBT mostro una diferencia significativa entre los grupos (p< 0,01), SE x ORT, SE x BF y entre lineas (p < 0,01), ademas de la interaccion linea/miembro en el MD y MND (p < 0,01). Los medios de estabilizacion externa probados (ORT x BF) se comportaron de manera similar, lo que restringe el alcance de las extremidades inferiores en la ejecucion del SEBT en algunas de las direcciones probadas.

Efeito do treino isocinético excêntrico sobre a razão I/Q do torque e EMGs em sujeitos saudáveis

OBJETIVO: Avaliar os efeitos do treino isocinetico excentrico dos extensores do joelho sobre a razao Isquiotibiais/Quadriceps (I/Q) do torque e do eletromiograma de superficie (EMGs), em sujeitos saudaveis.METODOS: Vinte homens ativos e saudaveis com idade media 22,5±2,1 anos; massa corporal 67,8±9,5 kg; estatura 1,72±0,10 m; e indice de massa corporal (IMC) de 22,5±2,0 kg/m2 foram avaliados quanto ao torque (isometrico e excentrico a 30 e 120o/s) e EMGs dos extensores e flexores do joelho, antes e apos 6 semanas de treino isocinetico excentrico (30o/s) dos extensores do joelho.RESULTADOS: O torque extensor do joelho aumentou em todos os modos e velocidades avaliados (P 0,05). As correlacoes torque/EMGs mostraram-se fracas (r 0,05) para todos os modos de contracao, no pre- e pos-treino, porem, houve diferenca (P>0,01) na comparacao entre o modo excentrico (30o e 120o/s) e isometrico, pre e pos-treino.CONCLUSOES: O treino isocinetico excentrico dos extensores do joelho aumentou a diferenca na razao I/Q do torque, porem, nao alterou a razao I/Q do EMGs, sugerindo que a adaptacao pelo aumento do torque associado ao treino excentrico nao alterou o recrutamento das unidades motoras avaliadas pelo EMGs.Objective: To evaluate the effects of isokinetic eccentric training of the knee extensors on Hamstring/Quadriceps (H/Q) torque and surface electromyogram (SEMG) ratio in healthy subjects. Methods: Twenty active, healthy men, with an average age of 22.5±2.1 years; body mass of 67.8±9.5 kg; height of 1.72±0.10 m; and body mass index (BMI) of 22.5±2.0 kg/m2, were evaluated for torque (isometric and eccentric 30o/s and 120o/s) and SEMG of the knee extensors and flexors, before and after 6 weeks of isokinetic eccentric training (30o/s) of the knee extensors. Results: Knee extensor torque increased in all modes and speeds evaluated (P<0.01), the H/Q torque ratio declined in all measurements (P<0.01), but the H/Q SEMG ratio remained at pre-training values (P>0.05). The torque/SEMG correlation was weak (r<0.3; P>0.05) for all modes of contraction, pre-and post-training. However, there were significant differences (P>0.01) in the comparison between the eccentric (30o/s and 120o/s) and isometric modes, pre-and post-training. Conclusions: Isokinetic eccentric training of the knee extensors increased the difference in torque H/Q ratio, but did not alter the SEMG H/Q ratio. This suggests that adaptation by increasing the torque, associated with eccentric training, did not alter the recruitment of motor units assessed by SEMG.

Effect of isokinetic eccentric training on H/Q torque ratio and SEMG in healthy subjects

OBJETIVO: Avaliar os efeitos do treino isocinetico excentrico dos extensores do joelho sobre a razao Isquiotibiais/Quadriceps (I/Q) do torque e do eletromiograma de superficie (EMGs), em sujeitos saudaveis.METODOS: Vinte homens ativos e saudaveis com idade media 22,5±2,1 anos; massa corporal 67,8±9,5 kg; estatura 1,72±0,10 m; e indice de massa corporal (IMC) de 22,5±2,0 kg/m2 foram avaliados quanto ao torque (isometrico e excentrico a 30 e 120o/s) e EMGs dos extensores e flexores do joelho, antes e apos 6 semanas de treino isocinetico excentrico (30o/s) dos extensores do joelho.RESULTADOS: O torque extensor do joelho aumentou em todos os modos e velocidades avaliados (P 0,05). As correlacoes torque/EMGs mostraram-se fracas (r 0,05) para todos os modos de contracao, no pre- e pos-treino, porem, houve diferenca (P>0,01) na comparacao entre o modo excentrico (30o e 120o/s) e isometrico, pre e pos-treino.CONCLUSOES: O treino isocinetico excentrico dos extensores do joelho aumentou a diferenca na razao I/Q do torque, porem, nao alterou a razao I/Q do EMGs, sugerindo que a adaptacao pelo aumento do torque associado ao treino excentrico nao alterou o recrutamento das unidades motoras avaliadas pelo EMGs.Objective: To evaluate the effects of isokinetic eccentric training of the knee extensors on Hamstring/Quadriceps (H/Q) torque and surface electromyogram (SEMG) ratio in healthy subjects. Methods: Twenty active, healthy men, with an average age of 22.5±2.1 years; body mass of 67.8±9.5 kg; height of 1.72±0.10 m; and body mass index (BMI) of 22.5±2.0 kg/m2, were evaluated for torque (isometric and eccentric 30o/s and 120o/s) and SEMG of the knee extensors and flexors, before and after 6 weeks of isokinetic eccentric training (30o/s) of the knee extensors. Results: Knee extensor torque increased in all modes and speeds evaluated (P<0.01), the H/Q torque ratio declined in all measurements (P<0.01), but the H/Q SEMG ratio remained at pre-training values (P>0.05). The torque/SEMG correlation was weak (r<0.3; P>0.05) for all modes of contraction, pre-and post-training. However, there were significant differences (P>0.01) in the comparison between the eccentric (30o/s and 120o/s) and isometric modes, pre-and post-training. Conclusions: Isokinetic eccentric training of the knee extensors increased the difference in torque H/Q ratio, but did not alter the SEMG H/Q ratio. This suggests that adaptation by increasing the torque, associated with eccentric training, did not alter the recruitment of motor units assessed by SEMG.

Efecto del entrenamiento isocinético excéntrico sobre el índice I/C de torque y EMGs en sujetos sanos

OBJETIVO: Avaliar os efeitos do treino isocinetico excentrico dos extensores do joelho sobre a razao Isquiotibiais/Quadriceps (I/Q) do torque e do eletromiograma de superficie (EMGs), em sujeitos saudaveis.METODOS: Vinte homens ativos e saudaveis com idade media 22,5±2,1 anos; massa corporal 67,8±9,5 kg; estatura 1,72±0,10 m; e indice de massa corporal (IMC) de 22,5±2,0 kg/m2 foram avaliados quanto ao torque (isometrico e excentrico a 30 e 120o/s) e EMGs dos extensores e flexores do joelho, antes e apos 6 semanas de treino isocinetico excentrico (30o/s) dos extensores do joelho.RESULTADOS: O torque extensor do joelho aumentou em todos os modos e velocidades avaliados (P 0,05). As correlacoes torque/EMGs mostraram-se fracas (r 0,05) para todos os modos de contracao, no pre- e pos-treino, porem, houve diferenca (P>0,01) na comparacao entre o modo excentrico (30o e 120o/s) e isometrico, pre e pos-treino.CONCLUSOES: O treino isocinetico excentrico dos extensores do joelho aumentou a diferenca na razao I/Q do torque, porem, nao alterou a razao I/Q do EMGs, sugerindo que a adaptacao pelo aumento do torque associado ao treino excentrico nao alterou o recrutamento das unidades motoras avaliadas pelo EMGs.Objective: To evaluate the effects of isokinetic eccentric training of the knee extensors on Hamstring/Quadriceps (H/Q) torque and surface electromyogram (SEMG) ratio in healthy subjects. Methods: Twenty active, healthy men, with an average age of 22.5±2.1 years; body mass of 67.8±9.5 kg; height of 1.72±0.10 m; and body mass index (BMI) of 22.5±2.0 kg/m2, were evaluated for torque (isometric and eccentric 30o/s and 120o/s) and SEMG of the knee extensors and flexors, before and after 6 weeks of isokinetic eccentric training (30o/s) of the knee extensors. Results: Knee extensor torque increased in all modes and speeds evaluated (P<0.01), the H/Q torque ratio declined in all measurements (P<0.01), but the H/Q SEMG ratio remained at pre-training values (P>0.05). The torque/SEMG correlation was weak (r<0.3; P>0.05) for all modes of contraction, pre-and post-training. However, there were significant differences (P>0.01) in the comparison between the eccentric (30o/s and 120o/s) and isometric modes, pre-and post-training. Conclusions: Isokinetic eccentric training of the knee extensors increased the difference in torque H/Q ratio, but did not alter the SEMG H/Q ratio. This suggests that adaptation by increasing the torque, associated with eccentric training, did not alter the recruitment of motor units assessed by SEMG.

Equilíbrio postural estático em indivíduos saudáveis: Comparações entre três grupos etários

The aim of the study was to compare static postural balance of healthy individuals of three age groups in different conditions of support and vision. Seventy one individuals, divided into 3 groups, were analyzed: young group (YG: 22.2 ± 2.1 years), middle aged group (MAG: 50.7 ± 5.7 years) and older individuals group (EG: 66.8 ± 5.4 years). Their balance was tested on a force platform, under 3 support and 3 visual conditions. Measures included: total (TD), anterior-posterior (APD) and mediolateral displacement (MLD) of the center of pressure (CoP). ANOVA revealed significant differences for interactions between group X support conditions and group X visual conditions for the 3 variables (p<0.01), with greater displacements for the MAG and EG groups during single-leg stance with partial and occluded vision (p<0.05). Static postural balance decreased over time in healthy individuals, and conditions of support and visual negatively affected balance with the increment of age.

Equilibrio postural estático en individuos sanos: Las comparaciones entre los tres grupos de edad

The aim of the study was to compare static postural balance of healthy individuals of three age groups in different conditions of support and vision. Seventy one individuals, divided into 3 groups, were analyzed: young group (YG: 22.2 ± 2.1 years), middle aged group (MAG: 50.7 ± 5.7 years) and older individuals group (EG: 66.8 ± 5.4 years). Their balance was tested on a force platform, under 3 support and 3 visual conditions. Measures included: total (TD), anterior-posterior (APD) and mediolateral displacement (MLD) of the center of pressure (CoP). ANOVA revealed significant differences for interactions between group X support conditions and group X visual conditions for the 3 variables (p<0.01), with greater displacements for the MAG and EG groups during single-leg stance with partial and occluded vision (p<0.05). Static postural balance decreased over time in healthy individuals, and conditions of support and visual negatively affected balance with the increment of age.