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