Tendinopathy affects millions of people in athletic and occupational settings as well as the general population.[7]Maffulli N, Kader D. Tendinopathy of tendo achillis. J Bone Joint Surg Br. 2002 Jan;84(1):1-8.
http://www.ncbi.nlm.nih.gov/pubmed/11837811?tool=bestpractice.com
[8]Paavola M, Kannus P, Järvinen TA, et al. Achilles tendinopathy. J Bone Joint Surg Am. 2002 Nov;84-A(11):2062-76.
http://www.ncbi.nlm.nih.gov/pubmed/12429771?tool=bestpractice.com
[9]Maffulli N, Wong J, Almekinders LC. Types and epidemiology of tendinopathy. Clin Sports Med. 2003 Oct;22(4):675-92.
http://www.ncbi.nlm.nih.gov/pubmed/14560540?tool=bestpractice.com
Because tendinopathy affects such a diverse population and can occur at different sites, the true incidence is unknown.
It is estimated that half of all sports injuries are secondary to overuse. Of these injuries, the muscle-tendon unit is the most commonly affected.[10]Herring S, Nilson K. Introduction to overuse injuries. Clin Sports Med. 1987 Apr;6(2):225-39.
http://www.ncbi.nlm.nih.gov/pubmed/3319201?tool=bestpractice.com
Approximately 10% of runners develop Achilles tendinopathy, which tends to affect men ages >30 years.[11]Lopes AD, Hespanhol Júnior LC, Yeung SS, et al. What are the main running-related musculoskeletal injuries? A Systematic Review. Sports Med. 2012 Oct 1;42(10):891-905.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4269925
http://www.ncbi.nlm.nih.gov/pubmed/22827721?tool=bestpractice.com
Patellar tendinopathy usually affects young adults in their teens to 30s, but can also occur in older individuals.[12]Hyman J, Rodeo SA, Wickiewicz T. Patellofemoral tendinopathy. In: DeLee JC, Drez D, Miller MD, eds. DeLee & Drez's orthopaedic sports medicine: principles and practice. Philadelphia, PA: Saunders; 2003:1840-56. There is a 1% to 3% annual incidence of lateral epicondylitis, which affects men and women equally. It is more common in people ages >40 years.[13]Johnson GW, Cadwallader K, Scheffel SB, et al. Treatment of lateral epicondylitis. Am Fam Physician. 2007 Sep 15;76(6):843-8.
http://www.ncbi.nlm.nih.gov/pubmed/17910298?tool=bestpractice.com