Effects of 8 weeks of eccentric exercise and extracorporeal shockwave therapy on tendon tissue, perceived pain, and muscle power and strength in athletes diagnosed with patellar tendinopathy: A longitudinal study

Background: Patellar tendinopathy (PT) is an injury with a high prevalence in athletes that causes pain, loss of strength and sport performance levels. Purpose: to analyse the effects of 8 weeks of a conservative physical rehabilitation program that combine eccentric exercise (EE), stretching, extracorporeal shockwave therapy (ESWT), and manual therapy on tendon tissue, perceived pain, and muscle power and strength in athletes diagnosed with PT. Material and methods: Eight athletes diagnosed with PT, performed 8 weeks of EE, stretching, and ESWT. At the beginning (PRE), at 4-weeks (INT), and at the end of the 8-week intervention (POST), participants performed a countermovement jump test (CMJ), and a gradual back squat (BS) test to determine peak power (PP), mean velocity in PP (PPMV), and load lifted (PPKG). Furthermore, a maximum test of 5-repetition (5-RM) was evaluated in leg extension exercise, perceived pain using the Victorian Institute of Sport Assessment-Patella scale (VISA-P), and thickness in the injured and uninjured knee. Results: It was reported a lower tendon thickness POST vs. PRE in the injured knee (p=0.045), and lower values compared to the uninjured knee at PRE (p=0.004), and INT (p=0.025), but not POST (p=0.123). The CMJ and 5-RM tests showed statistical differences POST vs. PRE, and INT (p < 0.05). Regarding BS, differences were reported in PPKG POST vs PRE (p=0.033), and INT (p = 0.007), while in PP differences were found in POST vs PRE (p=0.037). Conclusions: 8 weeks of EE, stretching, ESWT, and manual therapy induce positive effects on tendon tissue healing, lower limbs muscle power and strength performance in athletes with PT.