Background/objective There is a lack of information about relationship between physical characteristics and biomechanics of the lower extremity during the squat. Additionally, studies did not examine sex-related differences. The purpose of this study was to investigate relationships between physical characteristics and biomechanics of the lower extremity during the squat, and to determine if any sex differences are present. Methods Fifty three participants recruited (21.82 ± 2.3 years; 75.56 ± 14.98 kg; 171.57 ± 8.38 cm) performed three squats with 75% of one repetition maximum. Femur to tibia length ratio, hip and ankle joints’ flexibilities, and relative muscular strength were measured and used as physical characteristics. Net joint torques (NJT) and flexion angles of the lower extremity were extracted as dependent variables. Multiple regression (stepwise) analysis was conducted to examine the relationships with physical characteristics being factors. Pearson correlation coefficients were calculated to determine intercorrelations among the dependent variables. Results Relative muscular strength was related to hip NJT and knee flexion angle, and hip flexibility was related to ankle dorsiflexion. Hip and knee NJT showed moderate correlations with the corresponding flexion angles (r = 0.48-0.53; p < .01). Ankle dorsiflexion angle showed weak to moderate correlations with hip NJT and hip flexion angle (r = −0.36-0.50; p < .01) and a moderate correlation with knee NJT. No significant sex difference was observed (r = 0.52; p < .05). Conclusion Biomechanics of the lower extremity has been shown to correlate more with relative muscular strength and joint flexibility than with leg length ratio.

In this study, we found that BMP2 exerts neurotrophic effects, including a neuroprotective effect against nocodazole-induced neuritic degeneration, on neuronal cells. We also found that BMP2-induced neurotrophic effects are directly involved in Smad-dependent signaling as well as PI3K/PTEN-Akt-mTOR signaling. Moreover, BMP2-induced neurotrophic effects occur by stabilization of neuronal microtubules. Thus, these findings suggest that BMP2 can be a potential therapeutic target for nerve injury treatment.

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Physical activity is a crucial factor for maintaining not only physical health status, but vast amounts of research have shown its link with better mental health. Supporting the use of gyms for the safety of its practitioners is vital in the new norm and living with COVID-19. Therefore, in this study we show research supporting the development of a framework for a Total Safe-Care Fitness Solution based on a multimodal COVID-19 tracking system integrating computer vision and data from wearable sensors. We propose a framework with three areas that need to be integrated: a COVID-19 vaccine and health status recognition system (QR code scan prior to entry to the gym, and physiological signals monitored by a smart-band and a health questionnaire filled in prior to entry to the gym); an accident detection system (video and smart-band based); and a gym-user digital tracking system (CCTV and smart-band based). We show the proposed architecture for the integration of these systems and provide practical tips on how to implement it in testbeds for feasibility testing. To the best of our knowledge, this is the first proposed COVID-19 tracking system of use in gyms that includes a predictive model for accident detection for safer exercise participation through health monitoring.