Inverse problems for Jacobi operators II: Mass perturbations of semi-infinite mass-spring systems

We consider an inverse spectral problem for infinite linear mass-spring systems with different configurations obtained by changing the first mass. We give results on the reconstruction of the system from the spectra of two configurations. Necessary and sufficient conditions for two real sequences to be the spectra of two modified systems are provided.Comment: 25 pages, 2 figures. Typos were corrected, two remarks were added, material added to Sec.

Effect of training on street simulators with variable load on the strength women and men in powerlifting

Background: The training process to develop the strength of athletes on street exercise simulators with a variable load for powerlifting is not a systematically studied problem. The aim of the study was to analyse the impact of systematic training on street simulators with a variable load on the strength indicators of women and men in powerlifting. Study participants: athletes from 20 to 35 years old (n = 48), engaged in powerlifting at least four times a week, divided into groups: women (n = 24) and men (n = 24). Interventions: Implementation of systematic exercises for women and men in powerlifting on street exercise simulators with variable load for five months. For the performance diagnosis, the powerlifter coefficient (Pl) was applied: (bench press + sed + deadlift) / athlete's mass in kilograms. Main outcome measures: the experiment revealed a positive result in increasing the strength of men (p .05) in increasing the strength in women between the control and experimental groups. Based on an individual comparison of each participant in the experimental group, it was revealed that the implementation of the street training process is significantly (p < .01) more effective in increasing strength in men with a Pl coefficient below the average (< 3.53). Findings. The data obtained are especially valuable in the condition of the activation of street fitness among women and men in the conditions of the closure of gyms caused by the regime of self-isolation during the spread of COVID-19

Realization of step exercises using the independent calorimetry during the period of self-isolation

Background: In home conditions population of Russian Federation do not have an opportunity to do optimal physical activities during the period of spreading COVID-19. The aim of the study was to develop a system of realization step exercises in home conditions using the independent calorimetry during the period regime of self-isolation and to prove its effectiveness on the indicators of body mass index of the people. Study participants: 62 women and men between the ages of 18 and 45 who have problems with being overweight. Interventions: The study was being conducted in home conditions during 60 days. During the experiment the participants independently carried out the calorimetry, taking into account the consumed calories during the day and burning kilocalories while doing step exercises and another physical activity. For carrying out the calorimetry during the day a formula was developed due to available and simple counting: «N = 0.00168 - 0.098/P», where N - the amount of burning kilocalories per one heartbeat per one kg of body mass, P - heart rate per minute. Main outcome measures: It is defined out that the introduction of step exercises in home conditions with the use of independent calorimetry to the author's system has made a significant impact (p < .05) on body mass index of participants. Findings. In the presented study, for the first time, the regularities of increasing the burning of kilocalories in people at various levels of intensity depending on their body weight were experimentally revealed