**7. Prolotherapy**

Prolotherapy derives its name from "proliferation therapy," or "proliferative injection ther‐ apy". It has also been called "regenerative injection therapy" ("RIT"), and some contem‐ porary authors name the therapy according to the injected solution. The precise mechanism of action is not known. It involves injecting a non-pharmacological and nonactive irritant solution into the body. This is hypothesized to reinitiate the inflammatory process which deposits additional new fibers, thereby repairing lax tendons or ligaments and also possibly promote the release of local growth factors. However, the precise mech‐ anism of action still remains unknown. It has been used for approximately 100 years, however, its modern application can be traced to the 1950s.This was when the prolothera‐ py injection protocols were formalized by George Hackett, a general surgeon in the U.S.,and were based on his clinical experience of over 30 years. The concept of creating irritation or injury to stimulate healing has been recorded as early as Roman times when hot needles were poked into the shoulders of injured gladiators [28].

There are no trials on the use of prolotherapy in a population with acute muscle tears. There is some evidence for its use in chronic pathologies such as LBP [29], groin pain [30], and knee OA [31]. However, existing evidence is inconclusive. Its actual use is based on "expert opinion" and some practitioners advocate a positive impact of the use of prolotherapy in athletes in term of return to play timeframes.
