In the scientific literature focused on surface electromyography (sEMG) and functional near-infrared spectroscopy (fNIRS), which have been described together and separately many times, presenting different possible applications, researchers have explored a diverse range of topics related to these advanced physiological measurement techniques. However, the analysis of the two signals and their interrelationships continues to be a focus of study in both static and dynamic movements. The main purpose of this study was to determine the relationship between signals during dynamic movements. To carry out the analysis described, the authors of this research paper chose two sports exercise protocols: the Astrand–Rhyming Step Test and the Astrand Treadmill Test. In this study, oxygen consumption and muscle activity were recorded from the gastrocnemius muscle of the left leg of five female participants. This study found positive correlations between EMG and fNIRS signals in all participants: 0.343–0.788 (median-Pearson) and 0.192–0.832 (median-Spearman). On the treadmill, the signal correlations between the participants with the most active and least active lifestyle achieved the following medians: 0.788 (Pearson)/0.832 (Spearman) and 0.470 (Pearson)/0.406 (Spearman), respectively. The shapes of the changes in the EMG and fNIRS signals during exercise suggest a mutual relationship during dynamic movements. Furthermore, during the treadmill test, a higher correlation was observed between the EMG and NIRS signals in participants with a more active lifestyle. Due to the sample size, the results should be interpreted with caution.

The paper describes the design concept and findings from technological and initial clinical trials conducted to develop a helmet for non-invasive oxygen therapy using positive pressure, known as hCPAP (Helmet Continuous Positive Airway Pressure). Methods: The study utilized PET-G filament, a recommended material for medical applications, along with the FFF 3D printing technique. Additional technological investigations were performed for the production of fitting components. The authors proposed a parameter identification method for 3D printing, which reduced the time and cost of the study while ensuring high mechanical strength and quality of the manufactured elements. Results: The proposed 3D printing technique facilitated the rapid development of an ad hoc hCPAP device, which was utilized in preclinical testing and treatment of Covid-19 patients, and yielded positive results. Based on the promising outcomes of the preliminary tests, further development of the hCPAP device's current version was pursued. Conclusion:The proposed approach offered a crucial benefit by significantly reducing the time and costs involved in developing customized solutions to aid in the fight against the Covid-19 pandemic.