Secomb Josh L, Nimphius Sophia, Farley Oliver R L, Lundgren Lina E, Tran Tai T, Sheppard Jeremy M
Hurley Surfing Australia High Performance Centre , Casuarina Beach, Australia ; Centre for Exercise and Sport Science Research, Edith Cowan University , Joondalup, Australia.
Centre for Exercise and Sport Science Research, Edith Cowan University , Joondalup, Australia.
J Sports Sci Med. 2015 Nov 24;14(4):691-7. eCollection 2015 Dec.
The purpose of the present study was to determine whether any relationships were present between lower-body muscle structure and, lower-body strength, variables measured during a countermovement jump (CMJ) and squat jump (SJ), and eccentric leg stiffness, in adolescent athletes. Thirty junior male (n = 23) and female (n = 7) surfing athletes (14.8 ± 1.7 y; 1.63 ± 0.09 m; 54.8 ± 12.1 kg) undertook lower-body muscle structure assessment with ultrasonography and performed a; CMJ, SJ and an isometric mid-thigh pull (IMTP). In addition, eccentric leg stiffness was calculated from variables of the CMJ and IMTP. Moderate to very large relationships (r = 0.46-0.73) were identified between the thickness of the vastus lateralis (VL) and lateral gastrocnemius (LG) muscles, and VL pennation angle and; peak force (PF) in the CMJ, SJ and IMTP. Additionally, moderate to large relationships (r = 0.37-0.59) were found between eccentric leg stiffness and; VL and LG thickness, VL pennation angle, and LG fascicle length, with a large relationship (r = 0.59) also present with IMTP PF. These results suggest that greater thickness of the VL and LG were related to improved maximal dynamic and isometric strength, likely due to increased hypertrophy of the extensor muscles. Furthermore, this increased thickness was related to greater eccentric leg stiffness, as the associated enhanced lower-body strength likely allowed for greater neuromuscular activation, and hence less compliance, during a stretch-shortening cycle. Key pointsGreater thickness of the VL and LG muscles were significantly related to an enhanced ability to express higher levels of isometric and dynamic strength, and explosiveness in adolescent athletes.Isometric strength underpinned performance in the CMJ and SJ in these athletes.Greater lower-body isometric strength was significantly related to eccentric leg stiffness, which is potentially the result of greater neuromuscular activation in the muscle-tendon unit.
本研究的目的是确定青少年运动员的下肢肌肉结构与下肢力量、反向纵跳（CMJ）和深蹲跳（SJ）过程中测量的变量以及离心腿部刚度之间是否存在任何关系。30名青少年男性（n = 23）和女性（n = 7）冲浪运动员（14.8±1.7岁；身高1.63±0.09米；体重54.8±12.1千克）接受了超声下肢肌肉结构评估，并进行了CMJ、SJ和等长大腿中部拉力（IMTP）测试。此外，根据CMJ和IMTP的变量计算离心腿部刚度。股外侧肌（VL）和腓肠外侧肌（LG）的厚度、VL羽状角与CMJ、SJ和IMTP中的峰值力（PF）之间存在中度到非常大的相关性（r = 0.46 - 0.73）。此外，离心腿部刚度与VL和LG厚度、VL羽状角以及LG肌束长度之间存在中度到较大的相关性（r = 0.37 - 0.59），与IMTP PF也存在较大相关性（r = 0.59）。这些结果表明，VL和LG厚度增加与最大动态和等长力量的改善有关，这可能是由于伸肌肥大增加所致。此外，这种厚度增加与更大的离心腿部刚度有关，因为相关的增强下肢力量可能在拉长缩短周期中允许更大的神经肌肉激活，从而减少顺应性。要点VL和LG肌肉厚度增加与青少年运动员表达更高水平等长和动态力量以及爆发力的能力增强显著相关。等长力量是这些运动员在CMJ和SJ中表现的基础。更大的下肢等长力量与离心腿部刚度显著相关，这可能是肌肉 - 肌腱单元中更大神经肌肉激活的结果。
