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Strength training and muscle architecture : with special reference to effects of range of motion on muscle structure.

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Resumo:The purpose of the present study was to investigate adaptations on vastus lateralis (VL) muscle size, pennation angle and force (torque max) to a 15 week training program with either a full or partial range of motion (ROM). Nineteen previously untrained students were randomly distributed in one of two groups: control (CG) (n = 8; age, 26.6 ± 5.2 years; height, 177 ± 5.3 cm; body mass, 75.7 ± 10.6 kg; means ± SD) or training (TG) (n = 11; age, 21.6 ± 3.5 years; height, 174 ± 4.5 cm, body mass, 71.0 ± 6.9 kg; means ± SD) group. In the TG, one of the subject’s legs was randomly chosen to be trained with a full ROM (FULL) and the other partial ROM (PAR). Training consisted on 15 weeks of isokinetic training, with either a full (100º of knee flexion to 0º) or partial (60º of knee flexion to 0º) ROM. Pennation angle (PA) was measured with ultrasonography at 50% of total muscle length. VL maximum anatomical cross sectional area (ACSAmax), volume and regional ACSA (measured at 25, 50 and 75% of total muscle length - ACSA25, 50, 75) was obtained with magnetic resonance imaging (MRI). Maximum torque was obtained isometrically with isokinetic dynamometer at 75º of knee flexion. Together with PA, all muscle size measures increase significantly (p<0.05) from preto post-training. The changes were respectively for FULL and PAR, PA: 9.6 and 12.3%; ACSAmax: 5.3 and 4.1%; Volume: 5.1 and 4.6%. When comparing regional adaptations on muscle size of VL, the changes were respectively for FULL and PAR, ACSA25: 3.0 and 2.9%; ACSA50: 5.5 and 4.5%; ACSA75: 6.9 and 6.7%. Although we verified a trend to a greater increase from proximal to distal site, we only found differences when comparing ACSA50 and ACSA75 to ACSA25. In PAR and FULL maximal torque increased 27.9 and 33.3%, respectively. No significant differences (p<0.05) were found for PA, isometric knee extensor torque or any muscle size measures between training groups. As expected no significant changes (p<0.05) were found for the control group for any measured variable. The present findings suggest that vastus lateralis adapts to training independent of ROM when muscle time under tension is similar.
Autores principais:Tavares, António Francisco Furtado Salgueiro
Assunto:Muscle architecture Muscle size Muscle structure Range of motion Regional hypertrophy Strength training Vastus lateralis Amplitude de movimento Arquitectura muscular Hipertrofia regional Treino de força Volume muscular
Ano:2014
País:Portugal
Tipo de documento:dissertação de mestrado
Tipo de acesso:acesso aberto
Instituição associada:Universidade de Lisboa
Idioma:inglês
Origem:Repositório da Universidade de Lisboa

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