Objective To examine the effects of autoregulated (AUTO) and non-autoregulated (NAUTO) blood flow restriction (BFR) application on adverse effects, performance, cardiovascular and perceptual responses during resistance exercise. Methods Fifty-six healthy participants underwent AUTO and NAUTO BFR resistance exercise in a randomised crossover design using a training session with fixed amount of repetitions and a training session until volitional failure. Cardiovascular parameters, rate of perceived effort (RPE), rate of perceived discomfort (RPD) and number of repetitions were investigated after training, while the presence of delayed onset muscle soreness (DOMS) was verified 24 hours post-session. Adverse events during or following training were also monitored. Results AUTO outperformed NAUTO in the failure protocol (p<0.001), while AUTO scored significantly lower for DOMS 24 hours after exercise (p<0.001). Perceptions of effort and discomfort were significantly higher in NAUTO compared with AUTO in both fixed (RPE: p=0.014, RPD: p<0.001) and failure protocol (RPE: p=0.028, RPD: p<0.001). Sixteen adverse events (7.14%) were recorded, with a sevenfold incidence in the fixed protocol for NAUTO compared with AUTO (NAUTO: n=7 vs AUTO: n=1) and five (NAUTO) vs three (AUTO) adverse events in the failure protocol. No significant differences in cardiovascular parameters were found comparing both pressure applications. Conclusion Autoregulation appears to enhance safety and performance in both fixed and failure BFR-training protocols. AUTO BFR training did not seem to affect cardiovascular stress differently, but was associated with lower DOMS, perceived effort and discomfort compared with NAUTO. Trial registration number NCT04996680.

Unlike in neurological patient populations, the effects of Extended Reality within the context of sports medicine have rarely been studied. This systematic review was conducted to investigate the value of Extended Realty-assisted rehabilitation and injury prevention strategies on injury rehabilitation and prevention outcomes. PubMed and Web of Science databases were consulted. The search strategy consisted of the terms Virtual Reality (Intervention), rehabilitation and injury prevention (Outcome) and healthy athletes or athletes with a musculoskeletal sports injury (Population). After eligibility and Risk of Bias screening, ten articles were included. Risk of Bias analysis resulted in a level of evidence varying between C (three articles), B (six articles) and A2 (one article) scores. Extended Reality was found to provide an added value for both sports injury prevention and rehabilitation outcomes. It particularly provides clinicians with the opportunity to address the underlying biomechanical risk profile for common sports injuries, allowing the athletes to train protective movement patterns more effectively. More large-scale high-quality prospective research is needed in order to determine whether Extended Reality-assisted therapy is superior to conventional therapy in sports rehabilitation and injury prevention circles with strong conclusive evidence.

Despite the high prevalence of tendon pathology in athletes, the underlying pathogenesis is still poorly understood. Various aetiological theories have been presented and rejected in the past, but the tendon cell response model still holds true. This model describes how the tendon cell is the key regulator of the extracellular matrix and how pathology is induced by a failed adaptation to a disturbance of tissue homeostasis. Such failure has been attributed to various kinds of stressors (eg, mechanical, thermal and ischaemic), but crucial elements seem to be missing to fully understand the pathogenesis. Importantly, a disturbance of tissue pressure homeostasis has not yet been considered a possible factor, despite it being associated with numerous pathologies. Therefore, we conducted an extensive narrative literature review on the possible role of intratendinous pressure in the pathogenesis of tendon pathology. This review explores the current understanding of pressure dynamics and the role of tissue pressure in the pathogenesis of other disorders with structural similarities to tendons. By bridging these insights with known structural changes that occur in tendon pathology, a conceptual model was constituted. This model provides an overview of the possible mechanism of how an increase in intratendinous pressure might be involved in the development and progression of tendon pathology and contribute to tendon pain. In addition, some therapies that could reduce intratendinous pressure and accelerate tendon healing are proposed. Further experimental research is encouraged to investigate our hypotheses and to initiate debate on the relevance of intratendinous pressure in tendon pathology.

Background: Several risk factors have been suggested in the development of Achilles tendinopathy, but large-scale prospective studies are limited. Purpose: To investigate the role of the vascular response to activity of the Achilles tendon, tendon thickness, ultrasound tissue characterization (UTC) of tendon structure, and foot posture as possible risk factors in the development of Achilles tendinopathy. Study Design: Cohort study; Level of evidence, 2. Methods: The study began with 351 first-year students at Ghent University. After 51 students were excluded, 300 were tested in the academic years 2013-2014 and 2014-2015 and were followed prospectively for 2 consecutive years by use of a multilevel registration method. Of those, 250 students were included in the statistical analysis. At baseline, foot posture index and UTC were investigated bilaterally. Blood flow and tendon thickness were measured before and after a running activity. Cox regression analyses were performed to identify significant contributors to the development of Achilles tendinopathy. Results: During the 2-year follow-up, 27 of the included 250 participants developed Achilles tendinopathy (11%). Significant predictive effects were found for female sex and blood flow response after running ( P = .022 and P = .019, respectively). The risk of developing Achilles tendinopathy increased if the blood flow increase after running was reduced, regardless of sex, foot pronation, and timing of flow measurements. The model had a predictive accuracy of 81.5% regarding the development of Achilles tendinopathy, with a specificity of 85.0% and a sensitivity of 50.0%. Conclusion: This prospective study identified both female sex and the diminished blood flow response after running as significant risk factors for the development of Achilles tendinopathy. UTC of tendon structure, Achilles tendon thickness, and foot posture did not significantly contribute to the prediction of Achilles tendinopathy. A general evaluation of tendon structure by UTC, measurement of tendon thickness, or determination of the foot posture index will not allow clinicians to identify patients at risk for developing Achilles tendinopathy. Furthermore, it may be possible to improve blood flow after activity by using noninvasive techniques (such as prostaglandins, compression stockings, heat, massage, and vibration techniques). These techniques may be useful in the prevention and management of Achilles tendinopathy, but further research is needed.