阿基里斯肌腱對踝關節做蹠屈運動佔有重要的影響。阿基里斯腱病變好發於運動員，伴隨著疼痛、功能降低，與需要長時間的治療，對運動員有不良影響。肌肉施力與伸展的復健運動常在臨床上被使用，並對減輕疼痛，恢復功能有幫助。此實驗利用老鼠模型，探討不同復健方式對於肌腱材料力學特性與超音波評估上的影響。利用注射膠原蛋白酶至老鼠阿基里斯腱，模擬肌腱病變的狀態並休息四周，超音波評估受傷程度後，中等嚴重程度的Sprague-Dawley公鼠被採用，並隨機分配到四組: 離心收縮組、向心收縮組、來回擺動組、與控制組。此實驗設計一台復健運動系統，可以控制踝關節擺動速度與擺幅大小，搭配電刺激儀器刺激小腿肌肉收縮，以此製造需要的肌肉收縮模式。經過六周復健治療，利用超音波評估嚴重程度後，老鼠犧牲並取下阿基里斯腱、連接之肌肉端與跟骨端，進行材料力學性質測試。結果顯示，最大破壞力與最大應力，在離心收縮組顯著大於向心收縮組(p=0.032)，但積分力矩不論在最大破壞力與最大應力間皆無相關性出現。因此，材料力學結果對於臨床上，離心收縮運動比向心收縮運動有較好的結果提供一個佐證，但這結果可能與離心收縮可以提供較大的力矩值無關。在材料力學與超音波評估間的相關性分析上，楊氏係數與亮暗分布有負中度相關(r=-0.483)；截面積與血流有正中度相關(r=0.469)。此結果可以對臨床上，由超音波評估推測肌腱力學特性提供參考。

The Achilles tendon plays an important role in plantar flexion of ankle joint. The Achilles tendinopathy often occurs in athletes and it associates with tenderness, pain, and the long duration of conservative treatments. Strengthening and stretching exercises are commonly adapted to improve the pain score or activity level in clinical rehabilitation. The purpose of this study is to investigate the effects of different rehabilitation protocols on mechanical properties and sonographic assessments of the Achilles tendon with a rat model. The tendinopathy rat model was established by injecting collagenase in the Achilles tendon. After resting for 4 weeks, 12-week-old male Sprague-Dawley rats with a medium severity level of sonographic assessments were randomly assigned to 4 groups, eccentric group, concentric group, passive range of motion group, and control group. A self-designed rehabilitation system was developed and used to control the angular velocity, the range of motion of ankle joint and contraction types, as well as generate calf muscles contraction using electrical stimulation. After 6 weeks of training, the sonographic assessments were tested. Then the specimen, including parts of gastrocnemius, Achilles tendon and calcaneus, was collected for the following tensile testing. By Mann-Whitney analysis, there are significant differences between EE and CE groups in their maximum force (p=0.032) and maximum stress (p=0.032). However, neither maximum stress nor maximum force has correlation with integral torque. The results might explain why isolated eccentric exercise has better clinical effects on healing Achilles tendinopathy than isolated concentric exercise. The higher torque exerted from eccentric than concentric contraction may not be the dominant impact on why eccentric exercise is more effective than concentric exercise for healing Achilles tendon. In addition, correlating the results of mechanical testing with sonographic assessments, there are moderately negative correlation between Young’s modulus and echogenicity (r=-0.483), as well as moderate correlation between cross-sectional area and vascularity (p=0.469). These results provide the links from the non-invasive sonographic assessments to the mechanical properties of the tendon.

1. Doral, M.N., et al., Functional anatomy of the Achilles tendon, in Knee Surg Sports Traumatol Arthrosc2010. p. 638-43.
2. Maffulli, N., Rupture of the Achilles tendon. J Bone Joint Surg Am, 1999. 81(7): p. 1019-36.
3. O'Brien, M., The anatomy of the Achilles tendon. Foot Ankle Clin, 2005. 10(2): p. 225-38.
4. Komi, P.V., Relevance of in vivo force measurements to human biomechanics. J Biomech, 1990. 1: p. 23-34.
5. Maganaris, C.N., M.V. Narici, and N. Maffulli, Biomechanics of the Achilles tendon. Disabil Rehabil, 2008. 30(20-22): p. 1542-7.
6. Maganaris, C.N., Tendon conditioning: artefact or property? Proc Biol Sci, 2003. 7(270): p. S39-42.
7. Pollock, C.M. and R.E. Shadwick, Relationship between body mass and biomechanical properties of limb tendons in adult mammals. Am J Physiol, 1994. 266(3 Pt 2): p. R1016-21.
8. Kvist, M., Achilles tendon injuries in athletes. Sports Med, 1994. 18(3): p. 173-201.
9. Kujala, U.M., S. Sarna, and J. Kaprio, Cumulative incidence of achilles tendon rupture and tendinopathy in male former elite athletes. Clin J Sport Med, 2005. 15(3): p. 133-5.
10. Zafar, M.S., A. Mahmood, and N. Maffulli, Basic science and clinical aspects of achilles tendinopathy. Sports Med Arthrosc, 2009. 17(3): p. 190-7.
11. Myerson, M.S. and W. McGarvey, Disorders of the Achilles tendon insertion and Achilles tendinitis. Instr Course Lect, 1999. 48: p. 211-8.
12. Alfredson, H. and R. Lorentzon, Chronic Achilles tendinosis: recommendations for treatment and prevention. Sports Med, 2000. 29(2): p. 135-46.
13. Schepsis, A.A., H. Jones, and A.L. Haas, Achilles tendon disorders in athletes. Am J Sports Med, 2002. 30(2): p. 287-305.
14. Leppilahti, J. and S. Orava, Total Achilles tendon rupture. A review. Sports Med, 1998. 25(2): p. 79-100.
15. Langberg, H., et al., Time pattern of exercise-induced changes in type I collagen turnover after prolonged endurance exercise in humans. Calcif Tissue Int, 2000. 67(1): p. 41-4.
16. Cook, J.L. and C.R. Purdam, Is tendon pathology a continuum? A pathology model to explain the clinical presentation of load-induced tendinopathy. Br J Sports Med, 2009. 43(6): p. 409-16.
17. Andres, B.M. and G.A. Murrell, Treatment of tendinopathy: what works, what does not, and what is on the horizon. Clin Orthop Relat Res, 2008. 466(7): p. 1539-54.
18. Magnusson, S.P., et al., Human tendon behaviour and adaptation, in vivo. J Physiol, 2008. 586(1): p. 71-81.
19. Samiric, T., M.Z. Ilic, and C.J. Handley, Characterisation of proteoglycans and their catabolic products in tendon and explant cultures of tendon. Matrix Biol, 2004. 23(2): p. 127-40.
20. Danielson, P., H. Alfredson, and S. Forsgren, Distribution of general (PGP 9.5) and sensory (substance P/CGRP) innervations in the human patellar tendon. Knee Surg Sports Traumatol Arthrosc, 2006. 14(2): p. 125-32.
21. Warden, S.J., Animal models for the study of tendinopathy. Br J Sports Med, 2007. 41(4): p. 232-40.
22. Kraushaar, B.S. and R.P. Nirschl, Tendinosis of the elbow (tennis elbow). Clinical features and findings of histological, immunohistochemical, and electron microscopy studies. J Bone Joint Surg Am, 1999. 81(2): p. 259-78.
23. Fu, S.C., et al., Deciphering the pathogenesis of tendinopathy: a three-stages process. Sports Med Arthrosc Rehabil Ther Technol, 2010. 2(30): p. 1758-2555.
24. Paavola, M., et al., Achilles tendinopathy. J Bone Joint Surg Am, 2002: p. 2062-76.
25. McLauchlan, G. and H.H. Handoll, WITHDRAWN: Interventions for treating acute and chronic Achilles tendinitis. Cochrane Database Syst Rev, 2011. 10(8).
26. Asplund, C.A. and T.M. Best, Achilles tendon disorders. Bmj, 2013. 12(346).
27. Ahmed, I.M., et al., Blood supply of the Achilles tendon. J Orthop Res, 1998. 16(5): p. 591-6.
28. Chen, T.M., et al., The arterial anatomy of the Achilles tendon: anatomical study and clinical implications. Clin Anat, 2009. 22(3): p. 377-85.
29. Poltawski, L., et al., Reliability of sonographic assessment of tendinopathy in tennis elbow. Skeletal Radiol, 2012. 41(1): p. 83-9.
30. Alfredson, H., et al., Heavy-load eccentric calf muscle training for the treatment of chronic Achilles tendinosis. Am J Sports Med, 1998. 26(3): p. 360-6.
31. Stanish, W.D., R.M. Rubinovich, and S. Curwin, Eccentric exercise in chronic tendinitis. Clin Orthop Relat Res, 1986. 208: p. 65-8.
32. Kellis, E. and V. Baltzopoulos, Isokinetic eccentric exercise. Sports Med, 1995. 19(3): p. 202-22.
33. Magnussen, R.A., W.R. Dunn, and A.B. Thomson, Nonoperative treatment of midportion Achilles tendinopathy: a systematic review. Clin J Sport Med, 2009. 19(1): p. 54-64.
34. Roos, E.M., et al., Clinical improvement after 6 weeks of eccentric exercise in patients with mid-portion Achilles tendinopathy -- a randomized trial with 1-year follow-up. Scand J Med Sci Sports, 2004. 14(5): p. 286-95.
35. de Vos, R.J., et al., The additional value of a night splint to eccentric exercises in chronic midportion Achilles tendinopathy: a randomised controlled trial. Br J Sports Med, 2007. 41(7): p. 18.
36. Silbernagel, K.G., et al., Eccentric overload training for patients with chronic Achilles tendon pain--a randomised controlled study with reliability testing of the evaluation methods. Scand J Med Sci Sports, 2001. 11(4): p. 197-206.
37. Mafi, N., R. Lorentzon, and H. Alfredson, Superior short-term results with eccentric calf muscle training compared to concentric training in a randomized prospective multicenter study on patients with chronic Achilles tendinosis. Knee Surg Sports Traumatol Arthrosc, 2001. 9(1): p. 42-7.
38. SL, N.-V., The effect of eccentric versus concentric exercise in the management of Achilles tendonitis. in Physical Education. 1989, The University of British Columbia, 1989.
39. Yu, J., D. Park, and G. Lee, Effect of eccentric strengthening on pain, muscle strength, endurance, and functional fitness factors in male patients with achilles tendinopathy. Am J Phys Med Rehabil, 2013. 92(1): p. 68-76.
40. Ohberg, L. and H. Alfredson, Effects on neovascularisation behind the good results with eccentric training in chronic mid-portion Achilles tendinosis? Knee Surg Sports Traumatol Arthrosc, 2004. 12(5): p. 465-70.
41. Langberg, H., et al., Eccentric rehabilitation exercise increases peritendinous type I collagen synthesis in humans with Achilles tendinosis. Scand J Med Sci Sports, 2007. 17(1): p. 61-6.
42. Rees, J.D., et al., The mechanism for efficacy of eccentric loading in Achilles tendon injury; an in vivo study in humans. Rheumatology, 2008. 47(10): p. 1493-7.
43. Soslowsky, L.J., et al., Development and use of an animal model for investigations on rotator cuff disease. J Shoulder Elbow Surg, 1996. 5(5): p. 383-92.
44. Huang, T.F., S.M. Perry, and L.J. Soslowsky, The effect of overuse activity on Achilles tendon in an animal model: a biomechanical study. Ann Biomed Eng, 2004. 32(3): p. 336-41.
45. Ng, G.Y., et al., Enforced bipedal downhill running induces Achilles tendinosis in rats. Connect Tissue Res, 2011. 52(6): p. 466-71.
46. Kaux, J.F., et al., Eccentric training improves tendon biomechanical properties: a rat model. J Orthop Res, 2013. 31(1): p. 119-24.
47. Messner, K., et al., Rat model of Achilles tendon disorder. A pilot study. Cells Tissues Organs, 1999. 165(1): p. 30-9.
48. Wong, T.S. and F.W. Booth, Skeletal muscle enlargement with weight-lifting exercise by rats. J Appl Physiol, 1985. 65(2): p. 950-4.
49. Caiozzo, V.J., et al., A new animal model for modulating myosin isoform expression by altered mechanical activity. J Appl Physiol, 1985. 73(4): p. 1432-40.
50. Adams, G.R., et al., Skeletal muscle hypertrophy in response to isometric, lengthening, and shortening training bouts of equivalent duration. J Appl Physiol, 2004. 96(5): p. 1613-8.
51. Garma, T., et al., Similar acute molecular responses to equivalent volumes of isometric, lengthening, or shortening mode resistance exercise. J Appl Physiol, 2007. 102(1): p. 135-43.
52. Heinemeier, K.M., et al., Expression of collagen and related growth factors in rat tendon and skeletal muscle in response to specific contraction types. J Physiol, 2007. 582(Pt 3): p. 1303-16.
53. Kongsgaard, M., et al., Region specific patellar tendon hypertrophy in humans following resistance training. Acta Physiol, 2007. 191(2): p. 111-21.
54. Kongsgaard, M., et al., Corticosteroid injections, eccentric decline squat training and heavy slow resistance training in patellar tendinopathy. Scand J Med Sci Sports, 2009. 19(6): p. 790-802.
55. Lui, P.P., et al., Chondrocyte phenotype and ectopic ossification in collagenase-induced tendon degeneration. J Histochem Cytochem, 2009. 57(2): p. 91-100.
56. McArdle WD, K.F., Katch V., Exercise Physiology: Exercise, Nutrition,. Human Performance. 6th ed. Baltimore, MD: Lippincott Williams & Wilkins, 2006.
57. Murtaugh, B. and J.M. Ihm, Eccentric training for the treatment of tendinopathies. Curr Sports Med Rep, 2013. 12(3): p. 175-82.
58. Allison, G.T. and C. Purdam, Eccentric loading for Achilles tendinopathy--strengthening or stretching? Br J Sports Med, 2009. 43(4): p. 276-9.
59. Hansen, P., et al., Mechanical properties of the human patellar tendon, in vivo. Clin Biomech, 2006. 21(1): p. 54-8.
60. Knobloch, K., et al., Eccentric training decreases paratendon capillary blood flow and preserves paratendon oxygen saturation in chronic achilles tendinopathy. J Orthop Sports Phys Ther, 2007. 37(5): p. 269-76.
61. Frizziero, A., et al., The role of eccentric exercise in sport injuries rehabilitation. Br Med Bull, 2014. 110(1): p. 47-75.
62. Malliaras, P., et al., Achilles and patellar tendinopathy loading programmes : a systematic review comparing clinical outcomes and identifying potential mechanisms for effectiveness. Sports Med, 2013. 43(4): p. 267-86.
63. Sharma, P. and N. Maffulli, Tendon injury and tendinopathy: healing and repair. J Bone Joint Surg Am, 2005. 87(1): p. 187-202.
64. Shalabi, A., et al., Eccentric training of the gastrocnemius-soleus complex in chronic Achilles tendinopathy results in decreased tendon volume and intratendinous signal as evaluated by MRI. Am J Sports Med, 2004. 32(5): p. 1286-96.
65. Gardin, A., et al., The long-term clinical and MRI results following eccentric calf muscle training in chronic Achilles tendinosis. Skeletal Radiol, 2010. 39(5): p. 435-42.
66. Rompe, J.D., et al., Eccentric loading, shock-wave treatment, or a wait-and-see policy for tendinopathy of the main body of tendo Achillis: a randomized controlled trial. Am J Sports Med, 2007. 35(3): p. 374-83.