The purpose of this study is to determine whether Tendoactive, eccentric training, or the combination or both could be effective in the treatment of Achilles tendinopathy.

Inclusion Criteria:

• Patients suffering from a gradually evolving painful condition in the Achilles tendon located at the midportion for at least 3 months (Diagnosis based on clinical examination showing a painful thickening of the Achilles tendon located at a level of 2 to 6cm above the tendon insertion, and confirmed by ultrasonography: local thickening of the tendon, irregular tendon structure with hypoechoic areas and irregular fiber orientation).
• Men and non-pregnant women aged 18-70 years
• Be informed of the nature of the study and provide written informed consent.

Exclusion Criteria:

• Clinical suspicion of insertional disorders (pain at the site of the insertion of the Achilles tendon on the calcaneum)
• Clinical suspicion of an Achilles tendon rupture (Thompson test abnormal and palpable "gap")
• Clinical suspicion of plantar flexor tenosynovitis (posteromedial pain when the toes are plantar flexed against resistance)
• Clinical suspicion of n.suralis pathology (sensitive disorder in the area of the sural nerve)
• Clinical suspicion of peroneal subluxation
• Suspicion of internal disorders: spondylarthropathy, gout, hyperlipidemia, Rheumatoid Arthritis and sarcoidosis.
• Condition that prevents the patients from executing an active exercise programme
• Patient has already performed eccentric exercises, according to the schedule of Alfredson et al (12 weeks)
• Patient has already received an injection of PRP for this injury
• Patient does not wish, for whatever reason, to undergo one of the two treatments
• Known presence of a pregnancy
• Condition of the Achilles tendon caused by medications (arising in relation to moment of intake), such as quinolones and statins