Table 1.  Classification systems of tendinopathy developed by Nirschl et al. (2003).

Pathologic stages:

Stage I: temporary irritation (chemical inflammation?)

Stage II: permanent tendinosis – less than 50% tendon cross-section

Stage III: permanent tendinosis – greater than 50% tendon cross-section

Stage IV: partial or total rupture of tendon

Phases of pain:

Phase I: mild pain after exercise activity, <24 hours

Phase II: pain after exercise activity, >48 hours, resolves with warm-up

Phase III: pain with exercise activity, does not alter activity

Phase IV: pain with exercise activity that alters activity

Phase V: pain caused by heavy activities of daily living

Phase VI: intermittent pain at rest that does not disturb sleep; pain caused by light activities of daily living

Phase VII: constant rest pain and pain that disturb sleep