Obst S J, Newsham-West R, Barrett R S
School of Allied Health Sciences, Centre for Musculoskeletal Research, Griffith Health Institute, Griffith University, Gold Coast, Queensland, Australia.
Scand J Med Sci Sports. 2016 Apr;26(4):421-31. doi: 10.1111/sms.12466. Epub 2015 Apr 27.
Mechanical loading of the Achilles tendon during isolated eccentric contractions could induce immediate and region-dependent changes in mechanical properties. Three-dimensional ultrasound was used to examine the immediate effect of isolated eccentric exercise on the mechanical properties of the distal (free tendon) and proximal (gastrocnemii) regions of the Achilles tendon. Participants (n = 14) underwent two testing sessions in which tendon measurements were made at rest and during a 30% and 70% isometric plantar flexion contractions immediately before and after either: (a) 3 × 15 eccentric heel drops or (b) 10-min rest. There was a significant time-by-session interaction for free tendon length and strain for all loading conditions (P < 0.05). Pairwise comparisons revealed a significant increase in free tendon length and strain at all contraction intensities after eccentric exercise (P < 0.05). There was no significant time-by-session interaction for the gastrocnemii (medial or lateral) aponeurosis or tendon for any of the measured parameters. Immediate changes in Achilles tendon mechanical properties were specific to the free tendon and consistent with changes due to mechanical creep. These findings suggest that the mechanical properties of the free tendon may be more vulnerable to change with exercise compared with the gastrocnemii aponeurosis or tendon.
在孤立的离心收缩过程中，跟腱的机械负荷可引起其力学性能的即时且区域依赖性变化。采用三维超声检查孤立的离心运动对跟腱远端（游离肌腱）和近端（腓肠肌）区域力学性能的即时影响。参与者（n = 14）进行了两次测试，在以下两种情况之前和之后立即在静息状态以及30%和70%等长跖屈收缩期间测量肌腱：(a) 3×15次离心足跟下落；(b) 10分钟休息。在所有负荷条件下，游离肌腱长度和应变均存在显著的时间×测试交互作用（P < 0.05）。两两比较显示，离心运动后所有收缩强度下游离肌腱长度和应变均显著增加（P < 0.05）。对于腓肠肌（内侧或外侧）腱膜或肌腱的任何测量参数，均未观察到显著的时间×测试交互作用。跟腱力学性能的即时变化特定于游离肌腱，且与机械蠕变引起的变化一致。这些发现表明，与腓肠肌腱膜或肌腱相比，游离肌腱的力学性能可能更容易因运动而发生变化。
