Effects of isometric quadriceps strength training at different muscle lengths on dynamic torque production |
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Authors: | Marika Noorkõiv Kazunori Nosaka Anthony J Blazevich |
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Institution: | School of Exercise and Health Sciences, Centre for Exercise and Sports Science Research, Edith Cowan University, Joondalup, Australia |
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Abstract: | This study aims to (1) determine whether isometric training at a short vs. long quadriceps muscle length affects concentric torque production; (2) examine the relationship between muscle hypertrophy and concentric torque; and (3) determine whether changes in fascicle length are associated with changes in concentric torque.Sixteen men performed isometric training at a short (SL, n = 8) or a long muscle length (LL, n = 8). Changes in maximal concentric torque were measured at 30, 60, 90, 120, 180, 240 and 300 rad · s?1. The relationships between the changes in concentric torque, cross-sectional area, volume and fascicle length were tested.Concentric torque increased significantly after training only in LL and at angular velocities of 30 and 120 rad · s?1 by 12–13% (P < 0.05). Muscle size increased in LL only, the changes were correlated (r = 0.73–0.93, P < 0.05) with the changes in concentric torque. Vastus lateralis (VL) fascicle length increased in both groups (5.4 ± 4.9%, P = 0.001) but the change was not correlated with changes in concentric torque in either group.Isometric training-induced increases in muscle size and concentric torque were best elicited by training at long muscle lengths. These results highlight a clear muscle length dependence of isometric training on dynamic torque production. |
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Keywords: | dynamic torque length-specificity angular velocity |
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