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Objectives: To a) determine the acute effects of a single-dose patellar tendon isometric exercise protocol on involved limb landing biomechanics in individuals with patellar tendinopathy and asymptomatic patellar tendon pathology, and b) determine if individuals with patellar tendinopathy demonstrated changes in pain following a single-dose patellar tendon isometric exercise protocol., Design: Single-blinded randomized cross-over trial., Setting: Laboratory; PARTICIPANTS: 28 young male athletes with symptomatic (n = 13, age: 19.62 ± 1.61) and asymptomatic (n = 15, age: 21.13 ± 1.88) patellar tendinopathy., Main Outcome Measures: Participants completed a single-dose patellar tendon isometric exercise protocol and a sham-TENS protocol, randomized and separated by 7-10 days. Pain-levels during a single-limb decline squat (SLDS) and three-dimensional biomechanics were collected during a double-limb jump-landing task before and after each intervention protocol. A mixed-model repeated measures ANOVA was conducted to compare change scores for all dependent variables., Results: There were no group × intervention interactions for change in pain (F (1, 26)  = 0.555, p = 0.463). There was one significant group × intervention interaction for vertical ground reaction force (VGRF) (F (1, 26)  = 5.33, p = 0.029). However, post-hoc testing with Bonferroni correction demonstrated no statistical significance for group (SYM: t = -1.679, p = 0.119; ASYM: t = -1.7, p = 0.107) or intervention condition (isometric: t = -2.58, p = 0.016; sham-TENS: 0.72, p = 0.460). There were no further significant group × intervention interactions (p > 0.05)., Conclusions: A single-dose patellar tendon isometric exercise protocol did not have acute effects on landing biomechanics or pain levels in male athletes with patellar tendinopathy or asymptomatic patellar tendon pathology., Competing Interests: Declaration of competing interest None declared., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Objective: To examine differences in biomechanical and physical activity load in young male athletes with and without patellar tendinopathy., Design: Cross-sectional cohort study., Methods: Forty-one young male athletes (15-28 years of age) were categorized into 3 distinct groups: symptomatic athletes with patellar tendon abnormalities (PTA) (n = 13), asymptomatic athletes with PTA (n = 14), and a control group of asymptomatic athletes without PTA (n = 14). Participants underwent a laboratory biomechanical jump-landing assessment and wore an accelerometer for 1 week of physical activity monitoring., Results: The symptomatic group demonstrated significantly less patellar tendon force loading impulse in the involved limb compared with both the control and asymptomatic groups ( P <.05), with large effects ( d = 0.91-1.40). There were no differences in physical activity between the 3 groups ( P >.05)., Conclusion: Young male athletes with symptomatic patellar tendinopathy demonstrated smaller magnitudes of patellar tendon force loading impulse during landing compared to both asymptomatic athletes with patellar tendinopathy and healthy control participants. However, these 3 distinct groups did not differ in general measures of physical activity. Future investigations should examine whether comprehensively monitoring various loading metrics may be valuable to avoid both underloading and overloading patterns in athletes with patellar tendinopathy. J Orthop Sports Phys Ther 2020;50(3):158-166. Epub 6 Jan 2020. doi:10.2519/jospt.2020.9065 .

Interleukin-1 (IL1) is a cytokine that plays a role in inflammation and is a potential contributor to the inflammation present in tendinopathy. Its inhibition may be of use in the treatment of tendinopathy and has been a target for treatment. To evaluate how an IL1-receptor antagonist (IL1-RA) reverses pathologic changes associated with established patellar tendinopathy, we randomized 48 Sprague-Dawley retired breeder rats into three groups having weekly bilateral patellar tendon injections for 6 weeks. The control group received 0.1 mL saline for 6 weeks. The intervention groups were treated with 0.1 mL 2% carrageenan for 4 weeks. Beginning at week three, the IL1-RA group received 0.94 mg of the IL1-RA (2.5 mg/kg) added to the 0.1 mL 2% carrageenan and 0.94 mg of the IL1-RA alone for the final 2 weeks, while the CAR received 0.1 mL saline for the final 2 weeks. Animals were euthanized 6 weeks after initial injection. The CAR group demonstrated significantly (P < 0.05) shorter tendon lengths (7.81 ± 0.44 mm) than the control (8.25 ± 0.58 mm) and IL1-RA (8.34 ± 0.52 mm) group (P < 0.05). Macroscopically, plaque-like formations were reduced and margins of the tendon were more evident in the IL1-RA group compared to the CAR group. CAR group demonstrated significantly greater histopathologic changes (inflammatory cell density, disorganization of collagen, nuclear rounding, and angiogenesis) than the control and IL1-RA group. No significant difference in mechanical properties of the tendon was noted. These findings demonstrate IL1-RA can reduce pathologic changes in the patellar tendon in an established tendonitis model although did not demonstrate a difference in mechanical properties., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

This study evaluated if inhibiting IL1-β activity with an IL1-receptor antagonist (IL1-RA) will prevent pathologic changes commonly seen in tendinopathy. Thirty-six Sprague-Dawley retired-breeder rats were divided into three groups having weekly bilateral patellar tendon injections: CON (0.1 ml Saline), CAR (0.1 ml 2% carrageenan), IL1-RA (0.1 ml 2% CAR plus 0.94 mg of the IL1-RA, 2.5 mg/kg). Carrageenan was used to establish tendinopathy in two groups due to its ability to develop tendinopathy in prior studies. Animals were euthanized 3 weeks after initial injection. The CAR group demonstrated significantly (p < 0.05) shorter tendon lengths (8.61 ± 0.38 mm) relative to CON (8.94 ± 0.38 mm) that was prevented in the IL1-RA (9.02 ± 0.30 mm) as well as significantly increased collagenase activity in the CAR (0.061 ± 0.043) compared to CON (0.027 ± 0.015) (p<  0.05). By histological evaluation, the CAR group demonstrated significantly greater inflammation than IL1-RA, and CON (p < 0.05). CAR showed a trend for increased cross-sectional area relative to CON that was absent in the IL1-RA. IL1-RA can effectively inhibit the development of mechanical, chemical, and histologic changes seen with carrageenan-induced tendonitis., (© 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)