Relationship Between Maximum Pull-up Repetitions and First Repetition Mean Concentric Velocity.

Beckham, GK, Olmeda, JJ, Flores, AJ, Echeverry, JA, Campos, AF, and Kim, SB. Relationship between maximum pull-up repetitions and first repetition mean concentric velocity. J Strength Cond Res 32(7): 1831-1837, 2018-Mean concentric velocity (MCV) of exercise execution has been used by strength and conditioning professionals to improve exercise technique, provide accurate feedback, and predict exercise 1 repetition maximum. There is still limited research on velocity-based training and currently only one research study on the pull-up exercise. The primary purpose of this research was to determine whether the maximum number of pull-ups an individual can perform can be predicted by the MCV of a single pull-up repetition. Forty-nine healthy men and women were recruited who reported they could do at least 2 pull-ups. Each subject performed a standardized warm-up, then a single pull-up repetition, followed by one set of pull-up repetitions to failure. The GymAware PowerTool, a linear position transducer, was used to measure the MCV of each pull-up repetition. Both the MCV of the single repetition and first repetition of the set to failure were recorded, and the greater of the 2 was used in later analysis. Weighted least squares linear regression was used to estimate the relationship between the single-repetition MCV and maximum amount of pull-up repetitions. We observed a statistically significant linear relationship between the maximum number of pull-ups and the MCV of a single pull-up repetition (y = -6.661 + 25.556x, R = 0.841). Prediction of the maximum pull-up number by a single repetition rather than testing the maximal pull-up number may improve efficiency and effectiveness of exercise testing batteries for military, police, and other populations.

The development and implementation of a low-cost mechanical ventilator in a low-middle-income country during the COVID-19 pandemic: The Unisabana-HERONS.

Background: The COVID-19 pandemic in Latin America generated the need to develop low-cost, fast-manufacturing mechanical ventilators. The Universidad de La Sabana and the Fundacion Neumologica Colombiana designed and manufactured the Unisabana-HERONS (USH) ventilator. Here, we present the preclinical and clinical study results to evaluate its effectiveness and safety characteristics in an animal model (Yorkshire Sow) and five patients with acute respiratory failure receiving mechanical ventilatory support for 24 h. Methods: The effectiveness and safety outcomes included maintaining arterial blood gases and pulse oximetry saturation (SpO2), respiratory pressures and volumes (during continuous monitoring) in the range of ARDS and lung-protective strategy goals, and the occurrence of barotrauma. A significance level of 0.05 was used for statistical tests. This clinical trial was registered on Clinicaltrials.gov (NCT04497623) and approved by the ethics committee. Results: Among patients treated with the Unisabana-HERONS, the most frequent causes of acute respiratory failure were pneumonia in 3/5 (60 %) and ARDS in 2/5 (40 %). During the treatment, the ventilatory parameters related to lung protection protocols were kept within the safety range, and vital signs and blood gas were stable. The percentage of time that the respiratory pressures or volumes were out of safety range were plateau pressure >30 cm H2O: 0.00 %; driving pressure >15 cm H2O: 0.06 %; mechanical power >15 J/min: 0.00 %; and Tidal volume >8 mL/kg: 0.00 %. There were no adverse events related to the ventilator. The usability questionnaire retrieved a median score for all items between 9 and 10 (best score: 10), indicating great ease of use. Conclusion: The Unisabana-HERONS ventilator effectively provided adequate gas exchange and maintained the ventilatory parameters in the range of lung protection strategies in humans and an animal model. Furthermore, it is straightforward to use and is a low-cost medical device.

Wireless data transmission from inside electromagnetic fields.

This paper describes analytical and experimental work developed to evaluate the effects of the electromagnetic fields produced by high-voltage lines (400 kV) on wireless data transmission at the 900MHz band. In this work the source of the data transmission is located inside the electromagnetic field and the reception station is located at different distances from the power lines. Different atmospheric conditions are considered.