The purposes of this study were to measure the acute effects of knee wraps (KWs) on knee and hip joint kinematics, dynamic muscle activation from the vastus lateralis (VL) and gluteus maximus (GM), and rating of perceived exertion (RPE) during the back squat exercise at 2 different intensities. Fourteen resistance-trained men (age: 24 ± 4 years, height: 176 ± 6 cm, body mass: 81 ± 11 kg, back squat 1 repetition maximum [1RM]: 107 ± 30 kg, 3 ± 1 year of back squat experience) performed 1 set of 3 repetitions under 4 different conditions, to a depth of approximately 90 degrees of knee joint flexion, and in random order: KWs at 60% 1RM (KW60), KWs at 90% 1RM (KW90), without knee wraps (NWs) at 60% 1RM (NW60), and NWs at 90% 1RM (NW90). The dependent variables obtained were vertical and horizontal bar displacement, peak joint angle in the sagittal plane (hip and knee joints), concentric and eccentric muscle activation (by integrated electromyography) from the VL and GM, and RPE. For muscle activity, there were significant decreases in the VL NWs at 60% 1RM (p = 0.013) and a significant increase NWs at 90% 1RM (p = 0.037). There was a significant increase in VL muscle activity at 90% 1RM, when compared with 60% 1RM (KW: p = 0.001, effect size (ES) = 1.51 and NW: p < 00.001, ES = 1.67). There was a decrease in GM muscle activity NWs only at 60% 1RM (p = 0.014). There was a significant increase in GM muscle activity at 90% 1RM, when compared with 60% 1RM (KW: p < 0.001 and NW: p < 0.001). For peak hip joint flexion angle, there was significant decreases between intensities (90% 1RM < 60% 1RM) only to NWs condition (p = 0.009), and there was greater knee flexion NWs for both intensities: 60% 1RM (p < 0.001) and 90% 1RM (p = 0.018). For normalized vertical barbell displacement, there were significant differences between intensities when using KWs (p = 0.022). There were significant differences in RPE between 60 and 90% 1RM for each condition: KWs (p < 0.001) and NWs (p < 0.001). In conclusion, the use of KWs results in decreased muscle activation of the VL at the same intensity (90% 1RM).
Marchetti, PH, Magalhaes, RA, Gomes, WA, da Silva, JJ, Stecyk, SD, and Whiting, WC. Different knee and ankle positions affect force and muscle activation during prone leg curl in trained subjects. J Strength Cond Res 35(12): 3322–3326, 2021—Different joint positions for biarticular muscles may affect force and muscular activity during single-joint exercises. The aim of this study was to compare the maximal isometric contractions and muscle activation in 2 different knee and ankle positions during prone leg curl exercise in trained subjects. Fifteen resistance-trained men (27 ± 4 years, 178.80 ± 5.72 cm, 86.87 ± 12.51 kg) were recruited. The peak force (PF) and muscle activation of biceps femoris, gastrocnemius lateralis (GL), and soleus lateralis (SL) were measured during knee flexion at 0 and 90° and maximal dorsiflexion (D) or plantarflexion (P). Three maximal voluntary isometric contractions of 5 seconds were performed for each combination of knee and ankle positions. Two-way repeated-measures analysis of variances were used for all dependent variables. For PF, there was a significant difference between ankle positions (D × P) at 90° (p = 0.009) and knee positions (0 × 90°) for D (p < 0.001) and P (p < 0.001). Peak force was greater with the knee at 0° and the ankle maximally dorsiflexed. For GL, there was a significant difference between ankle (D × P) at 0° (p = 0.002) and knee positions (0 × 90°) for D (p = 0.005). Gastrocnemius lateralis activation was greater with the knee at 90° of flexion and the ankle maximally dorsiflexed. For SL, there was a significant difference between ankle positions (D × P): at 90° (p = 0.001) and at 0° (p = 0.002). Soleus lateralis is more active in plantarflexion irrespective of the knee joint position. Isometric contractions with full knee extension produce more strength regardless of the ankle position; neither the knee position nor the ankle position may influence the activity of the hamstrings.
Background: Kinesiology Tape (KT) is widely used in sports rehabilitation and by those performing physical activity, however, there is no consensus in the scientific literature about its effectiveness on performance, strength or muscle activation. Purpose:The purpose of this study was to measure the acute effects of KT in static rest, and during knee extension maximal voluntary isometric contraction (MVIC) performance in resistance trained men. Study Design: Observational, descriptive, comparative.Methods: Eighteen young, healthy, trained males (age: 25±6 years, height: 176.0±5 cm, and mass: 81.8±8.0 kg) volunteered to participate. Initially, they were in a relaxed sitting position of 90 degrees knee flexion with their limb supported by the machine lever arm to measure passive tension of the tissues of the knee joint. Then, they performed three MVIC trials of five seconds each with a three-minute rest between trials, in four randomized experimental conditions, with 10-min rest between conditions: (a) control, no taping; (b) Knee Sleeve; (c) KT; and (d) sham. During all MVICs, peak force, impulse, and muscle activation of the vastus lateralis (integrated electromyography [IEMG] and median frequency) were measured. Results:Repeated measures ANOVAs revealed no statistical differences between conditions for passive tension (p>0.05), peak force (p>0.05), impulse (p>0.05), IEMG (p>0.05), or median frequency (p>0.05). Conclusion:KT does not influence passive tension during static position at 90 degrees of knee flexion. KT does not affect quadriceps activation or force production during a maximal voluntary isometric contraction in the same position. Level of Evidence: 3a
RESUMOIntrodução: Diferentes ordens no sequenciamento dos exercícios na musculação podem afetar o desempenho neuromuscular. Objetivo: Investigar o efeito da ordem dos exercícios de musculação (pré-exaustão, (PE) e tradicional, (TR) sobre o desempenho e atividade muscular de peitoral maior (PM) e tríceps braquial (TB) durante a realização dos exercícios de supino reto (SR) e tríceps na polia (TP). Métodos: A amostra foi composta de 14 homens treinados (idade: 25±4 anos, estatura: 175±4 cm, massa: 80±11 kg). O experimento foi conduzido em duas sessões. Na primeira, foi realizada a familiarização e determinação de 10 repetições máximas (RM) nos exercícios SR e TP. A segunda foi dividida em duas fases. A primeira fase avaliou o desempenho dos exercícios isoladamente, considerado o controle (CON). A segunda fase, avaliou duas diferentes ordens de exercícios: pré-exaustão, PE (TP e SR) e tradicional, TRAD (SR e TP). Foram avaliados o desempenho e a atividade muscular do PM e TB. One-way ANOVA foi utilizada para comparar as condições. ANOVA (2x3) de medidas repetidas foi utilizada para comparar a atividade muscular. Resultados: Os resultados demonstraram um menor número de RM no TP na condição TRAD em comparação com CON e PE. Foi observado um menor número de RM no exercício SR na condição PE em comparação com CON e TRAD. Quanto à atividade muscular avaliada pela eletromiografia integrada não foram observadas diferenças significantes para PM e TB durante a realização dos exercícios em todas as condições. Conclusão: Conclui-se que em ambas as estratégias o número de RM realizadas no segundo exercício foi reduzida, entretanto não foram observadas alterações na ativação dos músculos principais de cada exercício.Descritores: eletromiografia, força muscular, treinamento de força. : pre-exhaustion, PE (TE and BP) and traditional, TRAD (BP and TE). ABSTRACT Introduction: Different orders in exercise sequences during resistance training can affect neuromuscular performance. Objective: To investigate the effect of resistance training exercises (pre-exhaustion and traditional) on the performance and muscle activity of pectoralis major (PM) and triceps brachii (TB) during execution of bench press (BP) and triceps extension (TE) exercises. Methods: The sample was composed by 14 trained men (age: 25±4 years, height: 175±4 cm, weight: 80±11 kg). The experiment was carried out in two sessions. In the first, familiarization and determination of 10 repetition maximum (RM) of BP and TE exercises were carried out. The second was divided in two phases. The first evaluated exercise performance separately (control condition, CON). The second evaluated two different exercise orders
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