Atletas de Taekwondo apresentam desequilíbrio muscular entre os músculos flexores e extensores do joelho: achados preliminares / Taekwondo athletes have muscle imbalance between knee flexors and extensions: preliminary findings / Los atletas de Taekwondo presentan un desequilibrio muscular entre los flexores y los extensores de la rodilla: hallazgos preliminares

Durante a prática de taekwondo com movimentos repetitivos, sistematizados e com certa sobrecarga de treino, o indivíduo pode gerar possíveis adaptações orgânicas que resultam em problemas posturais com grandes chances de desencadear desequilíbrio muscular. Objetivo: Verificar a presença de desequilíbrio entre os grupos musculares agonistas e antagonistas da articulação do joelho e entre membros dominantes e não dominantes de praticantes de taekwondo por meio da dinamometria isocinética. Método: Estudo transversal, observacional e descritivo realizado com nove praticantes de taekwondo do sexo masculino. Utilizou-se um dinamômetro isocinético para investigar o pico de torque, pico de torque por peso corporal, trabalho total, potência média, relação agonista/antagonista e índice de fadiga. Os dados dos membros dominante e não dominante foram comparados por meio do teste t-student para amostras pareadas. Foram calculados o intervalo de confiança de 95% da diferença média, o tamanho de efeito e o poder das análises. Resultados: Os músculos extensores dos membros dominante e não dominante apresentaram diferença média significante de 15,49 Nm (IC95% 7,27; 23,70; p=0,002) para pico de torque e de 22,64% (IC95% 11,83; 33,46; p=0,001) para pico de torque por peso corporal a 60°/s, representando tamanho de efeito médio. Conclusão: Os atletas de taekwondo apresentaram maior pico de torque e maior pico de torque por peso corporal dos músculos extensores do joelho a 60º/s no lado dominante. A relação agonista/ antagonista foi inferior a 60% e mais da metade dos atletas apresentaram uma diferença maior que 10% no pico de torque flexor no lado não dominante.

During taekwondo practice with the repetitive motions, systematized and with certain training overload, the person can generate possible organic adaptations that result in postural problems with a great chances of triggering muscle imbalance. Objective: To verify the presence of imbalance between agonist and antagonist muscle groups of knee joint and between dominant and non-dominant limbs through isokinetic dynamometry. Methods: Cross-sectional, observational and descriptive study realized with nine male taekwondo practitioners. An isokinetic dynamometer was used to investigate the peak torque, peak torque by body weight, total work, average power, agonist/antagonist ratio and fatigue index. Data from the dominant and non-dominant limbs were compared by t-student test for pared samples. The 95% confidence interval of the mean difference, the effect size and the power of analyses power were calculated. Results: The extensor muscles of the dominant and non-dominant limbs showed mean difference of 15,49 Nm (IC95% 7,27; 23,70; p=0,002) for peak torque and of 22,64% (IC95% 11,83; 33,46; p=0,001) for peak torque by body weight at 60°/s, representing average effect size. Conclusion: The taekwondo athletes had higher peak torque and higher peak torque by body weight of the knee extensors muscles in the dominant side. The agonist/ antagonist ratio was less than 60% and more than half of the athletes showed a difference greater than 10% in the peak flexor torque on the non-dominant side.

Durante la práctica de taekwondo con los movimientos repetitivos, sistematizados y con cierta sobrecarga de entrenamiento, la persona puede generar posibles adaptaciones orgánicas que deriven en problemas posturales con grandes posibilidades de desencadenar desequilibrios musculares. Objetivo: Verificar la presencia de desequilibrio entre grupos musculares agonistas y antagonistas de la articulación de la rodilla y entre miembros dominantes y no dominantes mediante dinamometría isocinética. Métodos: Estudio transversal, observacional y descriptivo realizado con nueve practicantes masculinos de taekwondo. Se utilizó un dinamómetro isocinético para investigar el par máximo, el par máximo por peso corporal, el trabajo total, la potencia media, la relación agonista/antagonista y el índice de fatiga. Los datos de las extremidades dominantes y no dominantes se compararon mediante la prueba t- student para muestras de pared. Se calcularon el intervalo de confianza del 95% de la diferencia media, el tamaño del efecto y la potencia de los análisis. Resultados: Los músculos extensores de los miembros dominantes y no dominantes mostraron una diferencia media de 15,49 Nm (IC95% 7,27; 23,70; p=0,002) para el par máximo y de 22,64% (IC95% 11,83; 33,46; p=0,001) para el par máximo por peso corporal a 60°/s, lo que representa el tamaño medio del efecto. Conclusiones: Los atletas de taekwondo presentaron un mayor par máximo y un mayor par máximo por peso corporal de los músculos extensores de la rodilla en el lado dominante. La relación agonista/antagonista fue inferior al 60% y más de la mitad de los atletas mostraron una diferencia superior al 10% en el pico de par flexor en el lado no dominante.

Avaliação isocinética da força de contração excêntrica dos músculos isquiotibiais no período pré-operatório de pacientes com lesão de ligamento cruzado anterior / Isokinetic assessment of eccentric hamstring strength in the preoperative period of patients with anterior cruciate ligament injury

Introdução: A força de contração excêntrica é uma moderna medida para definir diferentes parâmetros no estudo da Ortopedia moderna, sendo considerada uns dos recentes temas mais discutidos no quesito ganho de força muscular. O objetivo do trabalho foi analisar o estado da musculatura flexora da coxa (isquiotibiais), através da avaliação de sua força de contração excêntrica, por meio do dinamômetro isocinético no período pré-operatório nos pacientes com lesão de ligamento cruzado anterior. Métodos: Estudo retrospectivo observacional entre agosto e dezembro de 2018 de uma clínica especializada em atendimento em Criciúma/SC. Resultados: A média do pico de torque excêntrico da musculatura posterior da coxa em flexão do membro afetado foi de 27,60 ± 10,56 kg, e do membro contralateral atingiu 27,47 ± 6,91 kg. O déficit de força entre os membros teve uma mediana de 9,14 % (0,0 - 61,45), e o tempo médio entre a lesão e o exame isocinético foi de 10,0 (1,0 - 48,0) meses. Observou-se que os maiores déficits de força foram encontrados naqueles indivíduos que tinham maior intervalo de tempo entre a lesão e a realização da avaliação isocinética. Conclusão: Nos indivíduos submetidos ao teste de dinamometria isocinética após lesão do ligamento cruzado anterior, evidenciou-se um déficit na força de contração excêntrica da musculatura isquiotibial entre o membro afetado e contralateral, o que ratifica achados da literatura a respeito da biomecânica articular do joelho. Além disso, maiores déficits foram encontrados naqueles pacientes com maior intervalo de tempo para realização do exame isocinético.

Introduction: Eccentric strength is a modern measurement for defining different parameters in the study of modern orthopaedics, being considered one of the most widely discussed topics in recent times within the subject of muscle strength gain. The aim of this work was to analyze the state of flexor muscles in the thigh (hamstring muscles) by evaluating their eccentric strength with an isokinetic dynamometer during the preoperative period of patients with anterior cruciate ligament injury. Methods: This is a retrospective observational study performed between August and December 2018 at a specialized clinic in Criciúma/SC. Results: The mean eccentric peak torque of the hamstring muscles during flexion of the affected limb was 27.60 ± 10.56 kg and that for the contralateral limb was 27.47 ± 6.91 kg. The strength deficit between limbs had a median value of 9.14% (0.0­61.45) and the mean time between the injury and isokinetic testing was 10.0 (1.0­48.0) months. Higher strength deficits were observed in individuals who had longer periods between the injury and isokinetic testing. Conclusion: In individuals who underwent isokinetic testing after an anterior cruciate ligament injury, there was a deficit between the eccentric hamstring strength of the affected limb and that of the contralateral limb, which corroborates findings in the literature regarding the biomechanics of the knee joint. Moreover, larger deficits were found in patients with longer periods between the injury and isokinetic testing.

Isokinetic Evaluation of the Shoulder After Bristow/Latarjet Surgical Procedure in Athletes / Avaliação isocinética do ombro após procedimento cirúrgico de Bristow/Latarjet em atletas

Abstract Objectives To evaluate the muscular strength of the internal (IR) and external (ER) rotators of the shoulder after Bristow/Latarjet surgery. Methods Cross-sectional study with 18 patients (36 shoulders). The isokinetic evaluation was performed using the Biodex 3 System Pro dynamometer (Biodex Medical System, Inc., Shirley, NY, USA). The athletic shoulder outcome rating scale (ASORS) and the visual analogue scale (VAS) were applied. Results The values of peak torque and maximum work in concentric and eccentric mode on the non-operated shoulder were higher than on the operated side for both the IR and ER (p< 0.01). The conventional and functional balance between the ER and IR showed no differences between the operated and the non-operated side. When comparing patients with postoperative time < 1 year or 1 year, no differences were observed in peak torque values at 60°/s and 240°/s and maximum work at 60°/s and 240°/s of the IR to the operated shoulder. However, the peak torque values of 60°/s and 240°/s and maximum work at 60°/s and 240°/s of the ER were higher in subjects with postoperative time ≥ 1 year in all variables (p< 0.05). Conclusions There was a decrease in the strength of the IR and ER in the operated shoulder compared with the healthy shoulder. However, the conventional and functional balance was maintained.

Resumo Objetivos Avaliar a força muscular dos rotadores medial (RM) e lateral (RL) do ombro após cirurgia de Bristow/Latarjet. Métodos Estudo transversal com 18 pacientes (36 ombros). A avaliação isocinética foi realizada por meio do dinamômetro Biodex 3 System Pro (Biodex Medical System, Inc., Shirley, NY, EUA). A escala de avaliação dos resultados do ombro do esportista (EROE) e a escala visual analógica (EVA) da dor foram aplicadas. Resultados Os valores do pico de torque e o trabalho máximo no modo concêntrico e excêntrico no ombro não-operado foram maiores que no lado operado, tanto para o RM e como para o RL (p< 0,01). O equilíbrio convencional e funcional entre o RL e o RM não apresentou diferenças entre o lado operado e o não operado. Na comparação entre pacientes com o tempo pós-operatório < 1 ano ou ≥ 1 ano, não se observou diferenças nos valores do pico de torque em 60°/s e 240°/s e do trabalho máximo em 60°/s e 240°/s do RM para o ombro operado. No entanto, os valores de do pico de torque em 60°/s e 240°/s e do trabalho máximo em 60°/s e 240°/s do RL foram superiores em indivíduos com tempo pós-cirúrgico ≥ 1 ano em todas as variáveis (p< 0,05). Conclusões Houve diminuição da força do RM e do RL no ombro operado em relação ao ombro saudável; porém, o equilíbrio convencional e funcional foi mantido.

A preliminary study on quantitative evaluation of thigh muscle fat content with IDEAL-IQ technique and correlation with muscle strength in the middle-aged and elderly volunteers / 中华放射学杂志

Objective:To explore the value of iterative decomposition of water and fat with asymmetry and least squares estimation-quantitative fat imaging (IDEAL-IQ) in quantitative evaluation of thigh muscle fat content and its correlation with muscle strength in middle-aged and elderly volunteers.Methods:From December 2020 to April 2021, 30 volunteers aged 45 to 70 were recruited prospectively, including 15 males and 15 females with 52.5 (49.0, 56.3) years old. All subjects were scanned at 3.0 T MR, including axial T 1WI, IDEAL-IQ and coronal T 2WI of the left thigh. The region of interest of the knee extensors (quadriceps femoris) and knee flexors (hamstrings) in the left mid-thigh were delineated, and muscle cross-sectional area (CSA), skeletal muscle index (SMI), intermuscular fat fraction (FF) and intramuscular FF were obtained. In addition, isokinetic muscle strength measurement was performed on the left knee joint of all subjects at angular speeds of 60°/s and 180°/s to obtain peak torque (PT) and total work (TW) of knee flexors and extensors. Independent sample t-test, paired t-test or Mann-Whitney U test were used to compare the differences of CSA, SMI, intermuscular FF, intramuscular FF, PT and TW between different genders and muscle groups. Pearson or Spearman correlation analysis, and multiple linear regression analysis were used to analyze the correlation between CSA, SMI, intermuscular FF, intramuscular FF and PT, TW of thigh muscles. Results:The CSA, PT and TW of thighs in males were higher than those in females ( P<0.05), while the intermuscular FF in males was lower than that in females ( P=0.005). The CSA, SMI and PT of the thigh extensors were higher than those of the flexors ( P<0.001), while the intramuscular FF and intermuscular FF were lower than those of the flexors ( P<0.001). Intramuscular FF of flexors and extensors were moderately negatively correlated with PT ( r=-0.635, P<0.001; r=-0.546, P<0.001), and highly, moderately negatively correlated with TW ( r=-0.718, P<0.001; r=-0.616, P<0.001). Intermuscular FF of flexors and extensors were moderately negatively correlated with PT ( r=-0.519, P=0.003; r=-0.443, P=0.014), and negatively correlated with TW ( r=-0.363, P=0.049; r=-0.552, P=0.002). There was no significant correlation between CSA, SMI and PT, TW in flexors and extensors of thigh ( P>0.05). Multiple linear regression analysis showed that intramuscular FF was still significantly correlated with PT and TW of flexors and extensors (flexors: R 2adj=0.505, P=0.001; R 2adj=0.540, P<0.001; extensors: R 2adj=0.351, P=0.006; R 2adj=0.470, P=0.002). Conclusion:FF based on IDEAL-IQ technology can accurately quantify the intramuscular and intermuscular fat content of thighs, and there are negative correlations between intramuscular FF, intermuscular FF and isokinetic muscle strength measurements including PT and TW. Among them, intramuscular FF is more significant.

Biomechanical Characteristics of the Knee Joint During Single-Leg Landing of Soldiers and its Relationship with Isokinetic Muscle Strength / 医用生物力学

Objective To analyze the impact of soldiers’ single-leg landing with load carriage on knee joint, and investigate its relationship with muscle strength, so as to provide references for daily load carriage training. Methods A total of 12 soldiers were required to perform single-leg landing from the 30 cm height without load carriage and with 15 kg load carriage,respectively.The kinematic and kinetic parameters were collected using Vicon motion capture system and AMTI force platform. The surface electromyography (sEMG) of anterior and posterior thigh muscles were also collected simultaneously, and the isokinetic strength during knee flexion and extension was tested. Results Compared with landing without load carriage, knee flexion angle and joint reaction force significantly increased during landing with 15 kg load carriage (P0.05). There was a significant negative correlation between peak moment of knee extension and vertical ground reaction force during single-leg landing without load carriage (P0.05). Conclusions Knee flexion angle and joint reaction force significantly increase during single-leg landing with 15 kg load carriage, the activation of anterior and posterior thigh muscles can relieved the ground reaction force during landing, and muscle strength plays some role in preventing landing injury.

Is 12 months enough to reach function after athletes' ACL reconstruction: a prospective longitudinal study

Abstract Context: Anterior Cruciate Ligament (ACL) injury is disabling in several sports because it causes knee instability and functional deficit. Usually, surgical treatments produce the best functional outcomes, however, sometimes they are not always able to fully restore stability and function. Objective: The objective of this study was to evaluate postural balance, muscle strength, and functional performance of young athletes with an ACL injury before and after ACL reconstruction. Design: This was a longitudinal observational prospective study. Method: 74 athletes, 60 men, and 14 women, aged between 16 and 45, divided into two groups: the Group-Lesion of ACL with 34 athletes (24.1 years) and the Group-Control with 40 athletes without ACL lesion (27.7 years old). All volunteers performed posturography, isokinetic dynamometry, and the Hop-Test. The ACL-Group was evaluated before and 12 months after the reconstruction and the control group was evaluated once. Results: The Postoperative ACL Group presented greater limb symmetry, 0.96 (± 0.12), than the preoperative ACL Group, 0.87 (± 0.17), p < 0.01 in the Hop-Test. In the posturography, the displacement area was smaller in the postoperative ACL Group, 19.85 (± 5.74), compared to the preoperative ACL Group, 24.20 (± 8.97), p < 0.01. In isokinetic dynamometry the torque peak was greater in the postoperative ACL Group, 0.91 (± 0.14), than in the preoperative ACL Group, 0.74 (± 0.15), p < 0.01. Conclusion: The functional outcomes increased in ACL reconstruction athletes after 12 months, but not at the same level as in the Control Group. The result indicates an incomplete functional recovery, adaptive changes in postural control after injury, reconstruction, and return to sport.

Isokinetic ankle muscle strength is reduced in recreational runners with medial tibial stress syndrome and is not associated with pain

Abstract Aim: The purpose of this study was to investigate the strength and ratios of the plantar flexors and ankle dorsiflexors in recreational runners with medial tibial stress syndrome and to assess the association between muscle strength and the level of pain in this population. Methods: Two groups (control and medial tibial stress syndrome) of eighteen runners each participated in this cross-sectional study. Isokinetic dynamometry was used to evaluate muscle strength, and for the analysis, the normalized isokinetic peak torque controlled by gender was used. Results: The medial tibial stress syndrome group showed lower normalized isokinetic peak torque in the dorsiflexors in the concentric (p = 0.008) eccentric (p = 0.011) contraction, as well as a lower plantar flexor, normalized isokinetic peak torque in the concentric (p = 0.001) and eccentric (p = 0.02) when compared to the control group. However, there was no difference in the normalized isokinetic peak torque ratio representative of the stance (p = 0.62) and swing phase (p = 0.16), and the level of pain was not correlated with the strength concentric (p = 0.32) and eccentric (p = 0.621) of plantar flexors, nor to the concentric (p = 0.21) and eccentric of dorsiflexors (p = 0.54). Conclusion: Recreational runners with MTSS showed decreased muscle strength in the sagittal plane of the ankle, no correlation with the level of pain, and no changing the ratio between plantar flexors and dorsiflexors.

The variability of isokinetic ankle strength is different in healthy older men and women

Abstract Context In the elderly, weak lower limb muscles impair functional tasks' performance. Objective To evaluate the healthy elderly's ankle dorsiflexion and plantarflexion maximum torque and its variability in two sets of 5 RM isokinetics evaluation. Method 50 women (68.0 ± 4.6 years old) and 50 men (72.7 ± 8.5 years old) did two sets of ankle plantar flexor and dorsiflexor isokinetic tests at 30°/s. Peak torque, total work, and coefficient of variation were analyzed. Results Men did the strongest plantarflexion torque (p < 0.05) and dorsiflexion torque (p < 0.05); their highest peak torque occurred at set 2 (p < 0.05), while the largest plantarflexion torque variability (p < 0.05), dorsiflexion torque variability (p < 0.05), and the largest plantarflexion torque variability occurred at set 1 (p < 0.05). Men did the highest plantarflexion and dorsiflexion total work (p < 0.05) at set 2 (p < 0.05). Conclusion Older men are stronger than older women. The torque variability, in men, was higher during the first set, suggesting an adaptation to the isokinetics evaluation. Clinicians and researchers should consider that different muscles might need different numbers of sets and trials to measure their maximal muscle strength.

Isokinetic muscle strength of knee for patients with chondromalacia patellae / 中国康复理论与实践

@#Objective To analyze the characteristics of the muscle strength around the knee joint of chondromalacia patellae patients, and to explore the difference with normal people.Methods In March, 2021, 70 knee-onset chondromalacia patellae patients (experimental group) and 35 normal people (control group) were measured isokinetic muscle strength of flexion and extension of knee in angular velocities of 60°/s and 180°/s.Results At 60°/s and 180°/s, the peak torque, the peak torque-to-weight ratio and the total work of the flexor and extensor muscles on the affected side in the experimental group were lower than that of the control group (U > 1097.0, P<0.001). The peak torque, the peak torque-to-weight ratio and the total work of the flexor and extensor muscles at 60°/s and extensor muscles at 180°/s were lower on the affected side than on the healthy side in the experimental group (|Z| > 2.121, P<0.05). The peak torque ratios at 60°/s and 180°/s were more in the affected knees than in the healthy knees of experimental group and in the control group (U > 1810.0, |Z| >3.691, P<0.01).Conclusion The explosive force and endurance of the knee flexor and extensor has weakened in patients with chondromalacia patellae, and there is imbalance in knee joint muscle strength.

Effect of fatigue on explosive strength and muscle architecture of the vastus lateralis / Efecto de la fatiga sobre la fuerza explosiva y la arquitectura muscular del vasto lateral / Efeito da fadiga na força explosiva e arquitetura muscular do vasto lateral

ABSTRACT Introduction: There has been little research on changes in rate of torque development (RTD) and muscle architecture. This study evaluated the effect of fatigue on RTD and muscle architecture of the vastus lateralis (VL). Methods: Seventeen volunteers (25.5 ± 6.2 years; 177.2 ± 12.9 cm; 76.4 ± 13.1 kg) underwent isokinetic knee extension assessment at 30°/s to obtain the peak torque (PT-ISK), before and after a set of intermittent maximal voluntary isometric contractions (MVIC) (15 reps - 3 s contraction, 3 s rest) used to promote muscle fatigue, monitored by the median frequency (MDF) of the electromyography from the VL, rectus femoris and vastus medialis muscles. Before and after the fatigue protocol, ultrasound images of the VL were obtained to measure muscle thickness (MT), fascicle length (FL), and fascicle angle (FA). The peak isometric torque (PT-ISM) and the RTDs in 50 ms windows were calculated for each MVIC. The RTDs were reported as absolute values and normalized by the PT-ISM. Results: Fatigue was confirmed due to significant reductions in MDF in all three muscles. After the fatigue protocol, the PT-ISK was reduced from 239.0±47.91 to 177.3±34.96 Nm, and the PT-MVIC was reduced from 269.5±45.63 to 220.49±46.94 Nm. All the RTD absolute values presented significant change after the fatigue protocol. However, the normalized RTD did not demonstrate any significant differences. No significant differences were found in the muscle architecture of the VL. Conclusions: The reduction in explosive strength occurred concomitantly with the reduction in maximum strength, as evidenced by the lack of changes in normalized TDT. Level of Evidence III.

RESUMEN Introducción: Los cambios en la tasa de desarrollo del torque (TDT) y la arquitectura muscular causada por la fatiga son temas poco investigados. Esta investigación evaluó el efecto de la fatiga en la TDT y la arquitectura muscular del vasto lateral (VL). Métodos: 17 voluntarios (25.5 ± 6.2 años; 177.2 ± 12.9 cm; 76.4 ± 13.1 kg) se sometieron a una evaluación isocinética de la extensión de la rodilla a 30º/s para obtener el pico de torque (PT-ISK), antes y después de una serie de contracciones voluntarias máximas intermitentes (CVIM) (15 repeticiones - contracción 3 s, intervalo 3 s) utilizadas para causar fatiga muscular, monitoreadas por la frecuencia media (FMD) de la electromiografía VL, recto femoral y vasta medial. Antes y después del protocolo de fatiga, se obtuvieron imágenes de ultrasonido VL para medir el grosor muscular, la longitud del fascículo y el ángulo del fascículo. Se calculó el par isométrico máximo (PT-ISM) y las TDT en ventanas de 50 ms para cada CVIM. Las DTT se calcularon en valores absolutos y se normalizaron mediante PT-ISM. Resultados: la fatiga se confirmó por reducciones significativas en la fiebre aftosa de los tres músculos. Después de la fatiga, el PT-ISK se redujo de 239.0 ± 47.91 a 177.3 ± 34.96 Nm, y el PT-CVIM de 269.5 ± 45.63 a 220.49 ± 46.94 Nm. Todos los valores absolutos de TDT fueron significativamente diferentes después del protocolo de fatiga. Sin embargo, las TDT normalizadas no mostraron diferencias significativas. No se observaron diferencias significativas en la arquitectura muscular de la LV. Conclusiones: La reducción en la capacidad explosiva ocurrió simultáneamente con la reducción en la fuerza máxima, evidenciada por la falta de cambios en la TDT normalizada. Nível de evidencia III.

RESUMO Introdução: Alterações na taxa de desenvolvimento de torque (TDT) e arquitetura muscular causadas pela fadiga são temas pouco investigados. Esta pesquisa avaliou o efeito da fadiga na TDT e arquitetura muscular do vasto lateral (VL). Métodos: Dezessete voluntários (25,5 ± 6,2 anos; 177,2 ± 12,9 cm; 76,4 ± 13,1 kg) realizaram avaliação isocinética de extensão do joelho em 30º/s para obtenção do pico de torque (PT-ISK) antes e após uma série de contrações voluntárias isométricas máximas (CVIM) intermitentes (15 reps - 3 s contração, 3 s intervalo) utilizadas para causar fadiga muscular, monitoradas pela frequência mediana (FMD) da eletromiografia do VL, reto femoral e vasto medial. Antes e após o protocolo de fadiga, imagens de ultrassonografia do VL foram obtidas para mensuração da espessura muscular, comprimento de fascículo e ângulo do fascículo. O pico de torque isométrico (PT-ISM) e TDTs em janelas de 50 ms foram calculados para cada CVIM. As TDTs foram calculadas em valores absolutos e normalizadas pelo PT-ISM. Resultados: A fadiga foi confirmada devido a reduções significativas da FMD dos três músculos. Após a fadiga, o PT-ISK foi reduzido de 239,0 ± 47,91 para 177,3 ± 34,96 Nm, e o PT-CVIM de 269,5 ± 45,63 para 220,49 ± 46,94 Nm. Todos os valores de TDT absolutos apresentaram-se significativamente diferentes após o protocolo de fadiga. Contudo, as TDTs normalizadas não demonstraram diferença significativa. Não foram observadas diferenças significativas na arquitetura muscular do VL. Conclusões: A redução da capacidade explosiva ocorreu de maneira concomitante com a redução da força máxima evidenciada pela falta de alterações na TDT normalizada. Nível de Evidência III.

Design and Verification of Isokinetic Muscle Strength Rehabilitation Training Equipment Based on Oil Resistance / 中国医疗器械杂志

This study designed an isokinetic muscle strength rehabilitation training equipment, based on oil resistance. The equipment detected joint angles during movement through displacement sensors to measure the angular velocity in real-time. Then it can achieve flow resistance adjustment and constant velocity movement, based on the flow area of the proportional valve calculated by PID algorithm and the deviation between the set speed and the measured speed. The equipment can also collect muscle strength during exercise through force-sensitive sensors to achieve real-time and accurate assessment of muscle strength. Moreover, the study preliminarily certificated the isokinetic motion the results showed that the mean error of peak torque test is less than 5%, and the correlation is between 0.89 and 0.92 (

Study on Overload Injuries during Periods of Intense Physical Activity Complemented by Isokinetic Dynamometry Evaluation / Estudo das lesões de sobrecarga durante período intenso de atividade física complementado com avaliação por dinamometria isocinética

Abstract Objective The present study aims to measure the incidence of overload injuries in training soldiers, who are subjected to intense physical exercise, and to compare it with a control group. Next, it intends to verify whether there is any relationship between overload injuries and some neuromuscular function parameters. Methods Analytical, prospective observational study. Both the observational and the control group consisted of soldiers from the Portuguese Army. Clinical evaluation was performed by medical interview in the week prior to the beginning of a military parachuting course and in the week immediately after its completion. The neuromuscular performance was assessed by isokinetic dynamometry during the medical interview. Results With 44 of the 57 military personnel in training complaining of pain, the observational group had significantly more injuries than the control group (p< 0.001). Five complaints had traumatic origin and 39 were overload injuries. Of the 39 military personnel with overload injuries, 21 reported limited sports performance. However, isokinetic dynamometry showed no statistically significant differences in neuromuscular performance (p = 0.223 and p = 0.229). Conclusion Military personnel in training are prone to overload injuries, with an incidence rate > 70%. The implementation of strategies for injury monitoring and prevention is critical to promote health and physical capacity.

Resumo Objetivo Os autores pretendem medir a incidência de lesões de sobrecarga em militares em formação, que são submetidos a exercício físico intenso, e compará-la com um grupo controle. Posteriormente, pretende-se verificar se existe alguma relação entre a ocorrência de lesões de sobrecarga e alguns parâmetros da função neuromuscular. Métodos Estudo observacional prospectivo analítico. Grupo de observação e grupo controle constituídos por militares do Exército Português. A avaliação clínica foi feita por entrevista médica na semana que antecede o início do curso de paraquedismo militar e na semana imediatamente após o final do curso. Em simultâneo com a entrevista médica, foi realizada a avaliação da performance neuromuscular através da dinamometria isocinética. Resultados Com 44 dos 57 militares em formação a referir queixas álgicas, o grupo de observação apresentou significativamente mais lesões que o grupo controle (p < 0.001). Cinco queixas foram de origem traumática e 39 foram lesões de sobrecarga. Dos 39 militares com lesões de sobrecarga, 21 referiram limitação do rendimento esportivo. No entanto, na avaliação por dinamometria isocinética, não se verificaram diferenças estatisticamente significativas na evolução da performance neuromuscular (p = 0.223 e p = 0.229). Conclusão Os militares em formação são indivíduos propensos a sofrerem lesões de sobrecarga, tendo-se obtido uma taxa de incidência de lesões de sobrecarga na ordem dos 70%. A implementação de estratégias de monitoração e prevenção das lesões são fundamentais na promoção da saúde e da capacidade física.

Relationship Between The Thigh Anthropometric Measurements With Isokinetic Performance Of Knee Muscles

Background: Strength measurement is an essential component of assessment in rehabilitation. However, there may be many factors that may alter muscle performance, among which anthropometric values play a significant role. Therefore, the objective of this study is to find out the correlation between thigh anthropometric measurements with the knee isokinetic muscle performance. Methods: Eighteen young, healthy male adults, whose mean age was of 21.22 ± 1.39 were included. Anthropometric measurements like height, weight, thigh girth, and femoral length were correlated with isokinetic strength of knee flexor and extensor muscles. The variables collected in isokinetic measurements; used for analysis were peak torque at three angular velocities of 60°/s, 120°/s, and 180°/s. Results: The Pearson correlation between the thigh girth and isokinetic peak torque at angular velocities of 600/s, 1200/s, and 1800/s for knee extensors were, r = 0.52, 0.69 and 0.73 whereas for knee flexors it was r = 0.53, 0.24 and 0.44 respectively which showed moderate to high correlation when the level of significance was kept at 0.05. However, the correlation between the femoral length and isokinetic peak torque at three angular velocities for knee muscles showed a weak positive correlation only. Conclusion: Study results show that there is a moderate to strong positive correlation exists between thigh girth and isokinetic peak torque of knee musculature, whereas there is only a weak correlation exists between femoral length and isokinetic peak torque of knee musculature. Therefore, it reveals that the length of the extremity does not seem to influence the outcome of isokinetic measurement values. In contrast, the girth of the muscle can influence the outcome of the isokinetic measurement values, especially for the knee joint.

Application of Convolutional Neural Network in Identifying Different Levels of Isokinetic Exercise Efforts / 法医学杂志

Objective To develop a convolutional neural network （CNN） that can identify isokinetic knee exercises moment of force-time diagrams under different levels of efforts. Methods The 200 healthy young volunteers performed concentric isokinetic right knee flexion-extension reciprocating exercises with maximal effort as well as half the effort at angular velocities of 30°/s and 60°/s twice, respectively, with an interval of 45 min. The moment of force-time diagrams were collected. The 200 subjects were randomly divided into the training set （140 subjects） and the testing set （60 subjects）. The moment of force-time diagrams from subjects in the training set were used to train CNN model, and then the fully trained model was used to predict types of curves from the testing set. Random sampling of subjects along with subsequent development of models were performed 3 times. Results Under the circumstances of isokinetic knee exercises with maximal effort and half the effort, 2 400 moment of force-time diagrams were produced, respectively. Classification accuracy rates of the CNN models after the 3 trainings were 91.11%, 90.49% and 92.08%, respectively, and the average accuracy rate was 91.23%. Conclusion The CNN models developed in this study have a good effect on differentiating isokinetic moment of force-time diagrams of maximal effort exercises from those made with half the effort, which can contribute to identifying levels of efforts exerted by subjects during isokinetic knee exercises.

Isokinetic evaluation of the trunk muscle strength in housewives with fibromyalgia: a cross-sectional study

Abstract Background: It is known that physical activity and muscular performance are reduced in fibromyalgia (FM) syndrome. This study aims to compare the performance of trunk muscles in women with FM and healthy controls and evaluate the correlation between trunk muscle strength and FM severity. Methods: Forty-six patients with FM and 42 age- and body mass index-matched healthy housewives without FM were included in the FM and control groups, respectively. The Fibromyalgia Impact Questionnaire (FIQ) was used for the assessment of FM severity. The pain intensity was evaluated using the visual analogical scale (VAS). An isokinetic dynamometer was used to measure the isokinetic trunk muscle strength. The peak torque (PT) values were recorded. The psychological status of the patients was evaluated using the Beck Depression Inventory. Results: There was no statistically significant difference in terms of age, BMI, and BDI scores in two groups (p > 0.05, for all). The isokinetic trunk extensor PT values were significantly lower in the FM group (p = 0.002 for 60°/s, and p < 0.001 for 90°/s and 120°/s) than control group. There was a statistically significant negative correlation between FIQ score and isokinetic extensor muscle parameters. Conclusion: The results indicate that trunk extensor muscles were significantly weaker in FM patients. Trunk extensor muscle strength decreased as FM severity increased in FM patients.(AU)

Effect of acupuncture combined with suspension exercise therapy on chronic low back pain / 中国针灸

OBJECTIVE@#To observe the effect of acupuncture combined with suspension exercise therapy on the clinical symptoms, lumbar proprioception and trunk isokinetic muscle strength in patients with chronic low back pain.@*METHODS@#A total of 100 patients with chronic low back pain were randomly divided into an observation group and a control group, 50 cases in each group. The patients in the control group were treated with suspension exercise therapy, and the training exercise was selected according to the patient's exercise ability, the suspension exercise therapy was given once a day, three times a week, for totally 4 weeks. Based on the treatment of the control group, the patients in the observation group were treated with acupuncture at Dachangshu (BL 25), Weizhong (BL 40), Qihaishu (BL 24), Shenshu (BL 23) and points, the acupuncture was given once a day, six times as a course of treatment, and a total of two courses of treatment were given. Before and after treatment, the scores of symptoms and signs, the pain rating index (PRI), present pain intensity (PPI) and the visual analogue scale (VAS) in the short-form of McGill pain questionnaire (SF-MPQ) in the two groups were recorded. The isokinetic feedback biomechanical test system was used to measure the lumbar proprioception and isokinetic muscle strength of the trunk, and the clinical efficacy of the two groups was evaluated.@*RESULTS@#The scores of symptoms and signs, PRI, PPI and VAS after treatment were lower than those before treatment in the two groups (<0.05), and those in the observation group were lower than those in the control group (<0.05). The absolute error angle (AE) of lumbar proprioceptive index in the flexion and extension positions after treatment was lower than that before treatment in the two groups (<0.05), and that in the observation group was lower than that in the control group (<0.05). After treatment, the peak torque (PT) of musculus flexor and musculus extensor as well as peak torque/body weight (PT/BW) of musculus extensor were increased in the two groups, and the flexor/extensor (F/E) was reduced (<0.05). The PT of musculus flexor and musculus extensor as well as PT/BW of musculus extensor in the observation group were higher than those in the control group (<0.05), and F/E was lower than that in the control group (<0.05). The total effective rate was 90.0% (45/50) in the observation group, which was higher than 76.0% (38/50) in the control group (<0.05).@*CONCLUSION@#The acupuncture combined with suspension exercise therapy could effectively improve the symptoms and signs of patients with chronic low back pain, enhance the lumbar proprioception and trunk isokinetic muscle strength.

Combined Effects of Plant-based Protein Supplementation with 8-week Resistance Training on Muscular Strength, Protein Catabolism, Immune Functions and Bone Metabolism Markers in Adult Males

@#Introduction: This study investigated the effect of combined plant-based protein supplementation and resistance training on muscular strength, blood markers of protein catabolism, immune function, and bone metabolism in sedentary adult males. Methods: In this randomised, double-blinded study, 28 healthy males aged 19 – 29 years old were equally assigned into four groups: a combined plant-based protein with resistance training (PBPEX), plant-based protein alone (PBP), resistance training alone (EX) and control (C). Mode of resistance training was flat barbell press, machine shoulder press, wide grip lateral pull-down, seated cable row, barbell back squat, leg press and leg extension. The 8-week resistance training involved three sets of 60-70% of one-repetition maximum (1-RM) at 4-6 repetition/set/mode per session, three sessions/week. Participants in PBPEX and PBP groups consumed a plant-based protein supplement consisted of 9.8 g soy and pea protein for seven days/week. Results: PBPEX showed significant increases (p<0.01) in the knee and shoulder flexion peak torque compared to EX groups, respectively. PBP showed a significantly higher level (p<0.05) of serum urea, and blood urea nitrogen (BUN) compared to other groups. There were no changes in immune function and bone metabolism markers between pre- and post-exercise in all groups. Conclusions: These findings implied that a combination of plant-based protein supplementation and resistance training elicited greater beneficial effects on muscular strength than resistance training alone and plant-based protein supplementation alone. Therefore, combined plant-based protein with resistance training may be recommended in planning exercise and nutritional programme for sedentary male adults.

Difference of Isokinetic Angle-Specific Moment Curves in Anterior Cruciate Ligament-injured Patients with or without Patellofemoral Articular Cartilage Injury / 中国康复理论与实践

Objective:To investigate the difference of isokinetic angle-specific moment curves between anterior cruciate ligament (ACL)-injured patients with and without patellofemoral cartilage injury (PFCI). Methods:A retrospective analysis was performed on patients underwent knee arthroscopy and isokinetic muscle strength testing before surgery from September, 2018 to September, 2019. Seventeen ACL-injured patients with PFCI and 17 ACL-injured patients without PFCI who matched in age, sex and meniscus injury were selected. Before arthroscopy, isometric and isokinetic strength of knee flexion and extension at velocity of 180°/s and 60°/s was tested by isokinetic dynamometer. Normalized torque-angle curves (torque/body mass) were generated in steps of 1° and the differences in angle-specific moment curves between two groups were compared. Results:At 180°/s, there was no significant difference in flexion isokinetic torque both healthy side and affected side between two groups (P >0.05); and no difference in extension torque of the healthy side (P >0.05), however, there was significant difference in extension torque of the affected side at 88° to 90° between two groups (t > 2.102, P <0.05). At 60°/s, there was significant difference in flexion torque of the healthy side at 62° to 82° between two groups (|t| >2.056, P <0.05), and no significant difference was found in flexion torque of the affected side (P >0.05), nor in extension torque of both sides between two groups (P > 0.05). A curve change was found at the beginning of the flexion and extension isokinetic moment curves at the velocity of 180°/s. The isometric knee extension torque was significantly different in the affected side between two groups (t = 2.858, P < 0.01), and no difference was found in isometric knee flexion torque in the affected side as well as both extension and flexion torques in the healthy side between two groups (t < 1.905, P > 0.05). Conclusion:The lower the isokinetic speed, the more significant the difference of strength is between ACL-injury patients with and without PFCI. High speed exercise is recommended for ACL-injured patients with PFCI.

A dominância de membros interfere no equilíbrio de força muscular do joelho de corredores recreacionais? / Does the limb dominance interfere with knee muscle strength balance in recreational runners?

Introdução: cerca de 5% da população brasileira pratica corrida de rua, e a falta de preparo físico das pessoas para esse esporte contribui para o aumento no índice de lesões, sendo o joelho uma das articulações mais acometidas. Sabendo que os parâmetros musculares interferem diretamente no desempenho e que a destreza de membros pode suscitar inferências relativas ao aumento de força no membro dominante, torna-se importante avaliar a força e a relação de equilíbrio muscular do joelho destes atletas tanto no membro dominante quanto no contralateral. Objetivo: verificar o equilíbrio muscular dos extensores e flexores de joelho dominante e não dominante em corredores recreacionais. Metodologia: foram incluídos 111 indivíduos com idade entre 18 e 65 anos, de ambos os sexos, praticantes de corrida há pelo menos 4 meses contínuos, sem histórico de lesão nos últimos 3 meses. Os participantes foram entrevistados e encaminhados para a coleta da força muscular isocinética dos grupos extensor e flexor do joelho com protocolo de 60°/s, 180°/s e 300°/s. As variáveis de interesse estudadas foram: membro dominante, tempo de prática de corrida, torque máximo, trabalho total e potência. Foram calculados os Índices de Deficiência Muscular (IDM) sendo admitido como referencial de equilíbrio até 10% na diferença entre os membros. A pesquisa foi aprovada pelo Comitê de Ética em Pesquisa do Instituto de Ciências da Saúde da Universidade Federal da Bahia, sob parecer de nº 2.621.166. Resultados: o IDM indicou que 54,1% dos extensores de joelho estavam equilibrados e que 55,9% dos flexores de joelho encontravam-se numa relação de desequilíbrio muscular. Conclusão: a dominância de membros não é um fator ligado ao desequilíbrio de forças no membro inferior. Este achado de desequilíbrio de força entre joelhos pode estar ligado à predisposição de lesão e deve orientar as equipes multiprofissionais de saúde a definir um trabalho preventivo de treinamento muscular e esportivo.

Introduction: about 5% of the Brazilian population practices street running and the lack of physical fitness for this sport contributes to the increase in the injury rate, with the knee being one of the most affected joints. Knowing that muscle parameters directly interfere performance and that limb dexterity may lead to inferences regarding strength increase in the dominant limb, it is important to evaluate the strength and balance ratio of these athletes' knee in both dominant and contralateral limbs. Objective: to verify muscle balance of dominant and non-dominant knee extensors and flexors in recreational runners. Methodology: 111 individuals aged between 18 and 65 years old, male and female, who have been running for at least 4 continuous months, with no history of injury in the last 3 months, were included. Participants were interviewed and referred for the collection of isokinetic muscle strength of the knee extensor and flexor groups with a protocol of 60°/s, 180°/s and 300°/s. The variables of interest studied were: dominant limb, running practice time, maximum torque, total work and power. Muscle deficiency indices (MDI) were calculated and accepted as a balance reference up to 10% in the difference between the limbs. The research was approved by the Research Ethics Committee of the Institute of Health Sciences of the Federal University of Bahia, under technical advice no 2.621.166. Results: the MDI indicated that 54.1% of the knee extensors were balanced and 55.9% of the knee flexors were in a muscular imbalance ratio. Conclusion: limb dominance is not a factor related to lower limb imbalance of forces. This finding of strength imbalance between knees may be associated to injury predisposition and should guide multidisciplinary health teams to define preventive work on muscle and sports training

Multivariate linear regression analysis to evaluate multiple-set performance in active and inactive individuals

Abstract Aim: To determine how EMG, anthropometric, and psychological factors, and physical activity levels affect isokinetic peak torque performance (IPT) of multiple set exercise sessions. Methods: 20 participants (27±7 years old), classified as active (A=10) and inactive (I=10), performed 10x10:40secs of maximal unilateral knee flexions and extensions at 120o.s-1. The IPT, EMG, glucose, LDH, and lactate concentrations and perceptions of pain, effort, recovery. Results: Active volunteers showed higher muscularity (52±5 vs 47±4 cm; p<0.05), PTI (262±4 vs 185±4 Nm; p<0.05), relative lower drop in performance (14±2 vs 27±3% ; p<0.05), major MDF (83±1 vs 76±1 Hz; p<0.05), lower log -Fins5 (-12.9±0.3 vs -12.7 ± 0.3 Hz; p<0.05), smaller subjective perception of effort (14.8±0.3 vs 17.0±0.3) and higher subjective perception of recovery (14.2±0.2 vs 12.3±0.3). There was a significant interaction between relative fatigue and the number of sets (F=6.18; p<0.001). Stepwise multiple regressions revealed that subjective perception of recovery best explained the fatigue level generated in the active volunteers [fatigue level= 85.084-5255(SPR)] while for body mass was the best determinant for the inactive group [fatigue level = -21.560 +1.828(BMI)]. Conclusion: Data from the present analysis suggest that physically active individuals show higher torque development and a smaller fatigability index when compared to inactive individuals. Among the fatigue models studied, it is possible that alterations in biochemical components, psychophysiological and EMG are not sensitive to the direct influence of the fatigue dynamics protocol, both in active or inactive individuals.