Teninitis or tendonitis (from the Greek Τενοντίτις, 'itis' denoting inflammation or swelling) used to be thought of as a painful inflammation of a tendon, however, there is rarely much inflammation associated with the condition, thus 'tendinitis' is a redundant term, 'tendinopathy' being currently used. More recent research indicates that tendinopathy is an overuse injury resulting in microtears in the muscle fibres, leading to an increase in tendon repair cells, yet an absence of inflammatory cells. This may lead to reduced tensile strength, thus increasing the chance of tendon rupture. Generally tendinitis is referred to by the body part involved, such as Achilles tendinitis (affecting the Achilles tendon), or patellar tendinitis (jumper's knee, affecting the patellar tendon). Chronic overuse of tendons leads to microscopic tears within the collagen matrix, which gradually weakens the tissue.