Introduction: Exercise-induced hypoalgesia is a phenomenon in which exercise bouts induce a reduction in pain sensitivity. Apnea training involves similar characteristics that could potentially induce hypoalgesia. Objectives: The objectives of this study are to explore the effect of apnea training on hypoalgesia; assess the correlation between conditioned pain modulation (CPM) response and apnea-induced hypoalgesia; and examine the association between hypoalgesia with hypoxemia, and heart rate (HR) during apnea. Methods: A randomized controlled trial was conducted comparing a walking protocol employing intermittent apnea compared with normal breathing in healthy volunteers. Hypoalgesia was tested with pressure pain thresholds (PPTs) and CPM. Oxygen saturation (SpO₂) and HR were also tested. Results: Relevant but not significant changes were detected in the thumb (MD = 0.678 kg/cm²), and tibialis (MD = 0.718 kg/cm²) in favor of the apnea group. No significant differences were detected in CPM. The apnea group presented lower SpO₂, but HR values similar to those of the control group during the intervention. Basal CPM and intrasession hypoxemia significantly correlated with the PPT response. However, HR did not correlate with the PPT response. Conclusions: The current results suggest a trend, though not statistically significant, toward an improvement in the PPT in favor of apnea training compared to normal breathing. Nevertheless, subjects who presented greater basal CPM and lower oxygen saturation during the session presented a greater PPT response, suggesting the possibility of mediators of response. Future investigations should clarify this phenomenon.

Cerebral palsy generates an elevated burden on both patients and health-care systems. Cost-effective therapies such as action observation therapy (AOT), have been proposed to enhance motor performance in these patients. Objective: This systematic review with meta-analysis aimed to evaluate the effectiveness of AOT in children and adolescents with CP and describe its prescription parameters. Results: Fourteen studies involving a total of 393 patients with CP were included. Most studies presented some concerns on risk of bias. Meta-analyses compared AOT to placebo (no motor content) observation and found inconclusive results for the following: unilateral upper limb function (g = 0.565; 95% CI −0.174, 1.305), assisting hand function during bimanual activities (g = 0.200; 95% CI −0.742, 1.143), manual function daily activities (g = −0.022; 95% CI −3.134, 3.090), and hand grip strength (MD (kg) = 1.175; 95% CI −0.280, 2.630). Meta-analysis comparing AOT and physical therapy also yielded inconclusive findings for standing (g = 0.363; 95% CI −5.172, 5.898), as well as the combined dimension of walking, standing, and jumping (g = 0.798; 95% CI −8.821, 10.417) within gross motor function. Conclusions: Current evidence is imprecise and does not support definitive conclusions regarding the effectiveness of AOT over placebo observation, or over physical therapy, on functional outcomes including upper limb, hand, and lower limb functioning parameters. Current findings prevent recommending AOT for its employment in clinical practice. Further evidence is required to draw precise conclusions.

Introduction: Knee osteoarthritis (KOA) is characterized by pain, stiffness, and functional limitation. Aerobic exercise (AE) is a key treatment with proven benefits. Aims: To determine the most effective AE intensity for KOA. Methods: Searches were performed in seven databases, including randomized controlled trials with AE-only groups. Outcomes assessed were pain, walking and sit-to-stand performance, stiffness, and disability. Methodological quality and bias were evaluated. Bayesian random-effects network meta-analyses compared AE intensities, reporting standardized mean differences (Hedges’ g) with 95% credible intervals. Certainty of evidence was rated using GRADE. Results: Fifteen studies were included (mean PEDro score: 5.93), showing “some concerns” or “high risk” of bias. Two meta-analyses (pain and walking performance) were conducted. Comparisons between AE intensities showed non-significant, imprecise results with very low certainty of evidence. Conclusions: Evidence is insufficient to identify the optimal AE intensity for KOA. Limitations include high risk of bias, wide credible intervals, and reliance on indirect comparisons. In this context, clinicians should apply a structured, patient-centered approach to AE prescription, considering gradual progression and monitoring of tolerance, and combine AE with other recommended interventions. High-quality trials with direct comparisons of AE intensity should be conducted for this inconclusive gap.

Introduction Knee osteoarthritis (KOA) is a degenerative disease of the articular cartilage, characterized by pain, stiffness, and functional limitation. Exercise is one of the main treatment options. Aerobic exercise has shown favorable effects in these patients. Aims Determine which intensity of aerobic exercise (AE) is most effective for these patients. Methods Searches were conducted in 7 databases, complemented by citation and manual searches. Eligible studies were randomized controlled trials with an AE-only group. Outcome measures were knee pain intensity, walking performance, sit-to-stand performance, combined sit-to-stand and walking performance, perceived knee stiffness and disability. Methodological quality and risk of bias were assessed. Two Bayesian random-effects network meta-analysis models were employed for comparing different AE intensities, reporting standardized mean differences (Hedges’ g) with 95% credible intervals. The certainty of evidence was evaluated using the adapted GRADE framework for network meta-analysis exploring risk of bias, indirectness, heterogeneity, publication bias, intransitivity, incoherence and imprecision of the estimate. Results Fifteen studies were finally included. They had an average of 5.93 points in the PEDro scale and a risk of bias including “some concerns” and “high risk”. Two meta-analyses (pain intensity and walking performance) were conducted. Comparisons between AE intensities presented non-significant and imprecise results, classified with a very low certainty of evidence. Conclusions Very low certainty of evidence prevents clear recommendations on the optimal dose of AE. Current findings are limited by high risk of bias, imprecise credible intervales, and reliance on indirect comparisons. Clinicians should strictly individualize intensity based on patient characteristics, preferences, and clinical response, and combine AE with other interventions (physiotherapy, self-management, education, medication control). Medium-to-long term AE programs are advisable given their additional benefits on frequent comorbidities. More high-quality trials directly comparing AE intensities are needed.