It is difficult to separate the muscle from the tendon as they are incorporated as a functional unit. The tendon is connective tissue comprised of dense, regular connective tissue that continues around the muscle as epimysium as well as through the muscle as perimysium and endomysium.1 Tendon fibers are arranged in parallel to allow the continuation of the force transmission from the contracting muscle to the bone in order for osteokinematics to occur.2 Connective tissue has been found to have more tensile force in a proximal-distal orientation rather than medial-lateral.3 While textbooks teach muscle actions as concentric contractions, most real-world contractions are eccentric in nature in order to control our movement patterns. Eccentric exercise puts more strain on the tissues and when the strain exceeds the tensile strength of the tissue, injury occurs.

Tendon degeneration occurs on a continuum from healthy tendon to tears.4 As the person moves through the continuum, there is the development of symptoms (pain) and loss of stiffness that impairs its ability to transmit forces.4 Structural changes can occur prior to onset of symptoms. Normal tendon typically is comprised of 86.4% normal tendon while asymptomatic tendon may only contain 81.8% with symptomatic tendon only containing 79.5% of normal tissue.5 Fortunately, the patient can move both directions on the continuum.4

Physical therapists have a variety of treatment options available to treat patients. Following the University of St. Augustine for Health Sciences treatment approach via the 18-steps, pain and swelling are the first impairments that are identified and should be addressed.6 Kinesiology tape can be used for a variety of treatment techniques. Application of kinesiology tape has been shown to slow the Ia afferent nerve fibers to reduce pain.7

Tendinopathy can be identified specifically throughout the examination process. Muscle selective tissue tension (MSTT) would have findings of pain during submaximal contraction of the involved tendons while muscle length tests (MLT) would also produce pain as the muscle and tendon lengthen.6 Once tissue specific impairments have been identified, treatment of the tendon can involve instrument assisted soft tissue mobilization (IASTM) in the form of Graston Technique (GT). In early research, it was thought that IASTM helped with pain and healing by increasing microcirculation within the superficial capillary beds.8 GT has also been found to stimulate fibroblasts to lay down new collagen to help heal and re-enforce connective tissue such as tendon.9 Use of GT in a cross-friction pattern has been shown to increase stiffness of ligaments which are also dense, regular connective tissue.10 This technique has also been shown to specifically increase the elastic modulus of tendons by 28.1% allowing for increased range of motion of the joint as well as the ability to withstand more strain.11-12 Treatment can be further augmented by use of kinesiology taping applied distally to proximally in line with the muscle fibers to assist in unloading the tendon.13

As symptoms begin to subside and the emphasis of care is changed to function, exercise becomes the better treatment option. Isometric contractions can be utilized early in the rehab progress to gradual load the tendon to increase its tensile strength.14 Isometric exercise can also be used for analgesic effects through cortical inhibition.14

End-phase rehabilitation as well as prevention should focus on eccentric exercise. Eccentric exercise mimics real-world contraction of muscles and tendons in a functional manner.1, 15 Interestingly, eccentric exercise combined with GT is more effective than eccentric exercise alone.16 However, like any exercise intervention, eccentric exercise success has a correlation with compliance of home exercises.17

SUMMARY
After a thorough examination and evaluation, treatment should initially address any pain or swelling in the involved tendon.6 Direct treatment to the tendon can be applied via GT to increase blood flow while also increasing fibroblast activity to encourage healing.8-12 After application of IASTM, emphasis is placed on lengthening the tissue if it is tight and can be performed with a sustained stretch of 120-240 seconds.3 With the tissue still on stretch, kinesiology tape can be applied to further decrease pain and relax the tissues.7, 13 Finally, treatment sessions end with exercise which is progressed from isometric in the early stages to eccentric activities in the later stages.14-16 This sequencing should assist in progressing the patient from the tendinopathy end of the continuum towards the normal tissue range.4

References
1. Krause F, Wilke J, Vogt L, Banzer W. Intermuscular force transmission along myofascial chains: a systematic review. J Anatomy. 2016;228(6):910-918.
2. Paris SV, Loubert PV. Foundations of Clinical Orthopaedics. St. Augustine, FL: Institute Press, 1999.
3. Stecco C, Pavan P, Pachera P, Caro R, Natali A. Investigation of the mechanical properties of the human crural fascia and their possible clinical implications. Surgical & Radiologic Anatomy. 2014;36(1):25-32.
4. Lawrence D, Cook J, Rio E. The tendinopathy continuum explained. SportEX Medicine. 2014;60:21-26.
5. Docking SI, Rosengarten SD, Daffy J, Cook J. Structural integrity is decreases in both Achilles tendons in people with unilateral Achilles tendinopathy. Journal of Science & Medicine in Sport. 2015;18(4):383-387.
6. Patla CE. E1: Extremity Evaluation and Manipulation. St. Augustine, FL: Institute Press,
7. Konishi Y. Tactile stimulation with kinesiology tape alleviates muscle weakness attributable to attenuation of Ia afferents. Journal of Science & Medicine in Sport. 2013; 16(1):45-48.
8. Nielsen A. Gua sha research and the language of integrative medicine. Journal of Bodywork & Movement Therapies. 2009;13(1):63-72.
9. Gehlsen GM, Ganion LR, Helfst R. Fibroblast responses to variation in soft tissue mobilization pressure. Medicine and Science in Sports and Exercise. 1999;31(4):531-535.
10. Loghmani MT, Warden SJ. Instrument-assisted cross-fiber massage accelerates knee ligament healing. JOSPT. 2009;39(7):506-514.
11. McConnell J, Cruser S, Warder SJ, Bayliss AJ. Instrument assisted soft tissue mobilization alters material and mechanical properties in Achilles tendinopathy. JOSPT. 2016;46(1):A114.
12. Palmer TG, Wilson B, Kohn M, Miko S. The effect of an instrument-assisted soft tissue mobilization technique on talocrural joint range of motion. International Journal of Athletic Therapy and Training. 2016. [epub ahead of print].
13. Farquharson C, Greig M. Temproal pattern of kinesiology tape efficacy on hamstring extensibility. IJOSPT. 2015;10(7):984-991.
14. Rio E, et al. Isometric exercise induces analgesia and reduces inhibition in patellar tendinopathy. British Journal of Sports Medicine. 2015;49(19):1-8.
15. Murtaugh B. Eccentric training for the treatment of tendinopathies. Current Sports Medicine Reports. 2013;2(3):175-182.
16. McCormack JR, Underwood FB, Slaven EJ, Cappaert TA. Eccentric exercise versus eccentric exercise and soft tissue treatment (Astym) in the management of insertional Achilles tendinopathy. Sports Health. 2016;8(3):230-237.
17. Goode AP, et al. Eccentric training for prevention of hamstring injuries may depend on intervention compliance: a systematic review. British Journal of Sports Medicine. 2015;49(6):349-356.