Data envelopment analysis (DEA) can be used for assessing the relative efficiency of a number of operating units, finding, for each unit, a target operating point lying on the strong efficient frontier. Most DEA models project an inefficient unit onto a most distant target, which makes its attainment more difficult. In this paper, a linear bilevel programming problem for obtaining the closest targets and minimum distance of a unit from the strong efficient frontier by different norms is provided. The idea behind this approach is that closer targets determine less demanding levels of operation for the inputs and outputs of the units to perform efficiently. Finally, it will be shown that the proposed method is an extension of the existing methods.

Evaluating group performance of decision-making units (DMUs) is an application of data envelopment analysis (DEA) and usually provides a measure to compare the frontiers of the production possibility sets (PPSs) corresponding to different groups and the internal inefficiencies of DMUs associated with their group. In this paper, first, a method is presented for obtaining the minimum distance of DMUs from the frontier of the PPS by ‖⋅‖1, which itself can be a very important subject in DEA, and then, for stating an application of these distances, an approach is provided for evaluating group performance of DMUs based on the production ability of the PPSs such that both constant and variable returns to scale assumptions can be used in this method in contrast with some other methods. Therefore, providing the methods for both obtaining the minimum distance of DMUs from the frontier of the PPS and evaluating group performance of DMUs is the most important contribution of this paper.

Background: Angiogenesis and increased capillary density of skeletal muscle is one of the potential physiological changes during the flow restriction exercise (BFR). Therefore, the aim of this research was to evaluate the effect of four weeks rock climbing with or without blood flow restriction on vascular endothelial growth factor and Growth Hormone in elite climbers.Methods: In this semi-experimental study, 26 elite climbers (aged 25-30 years; body fat percent 8-14%; 4 years athletic training history) in a randomized and double-blind design were divided in two equal rock climbing with blood flow restriction (BFR) or rock climbing without blood flow restriction (NBFR) groups. The training protocol included three sessions per week for 4 weeks of rock climbing with a severity of 80-60% of the difficulty of the route. The cuff pressure was in the range of 40 to 100 mm Hg during rock climbing. Blood samples were obtained in the 2 phases: before and 24 hours after rock climbing protocols. Vascular endothelial growth factor and Growth Hormone were analyzed. Finally, Data were analyzed independent and independent T test. The significance level was set at p<0.05.Results: Basal levels of GH and VEGF was significantly increased after four weeks rock climbing with BFR. However, the rock climbing without BFR had not any significant effect on the basal levels of GH and VEGF. Conclusion:It can be concluded that the rock climbing with BFR by increasing of basal levels of GH and VEGF could be increased angiogenesis process.

Background and Aim: Obesity is a clinical condition that affects the growth-related hormonal system, especially in adolescents. High-Intensity Intermittent Training (HIIT) might reduce such destructive effects. Methods & Materials: In this quasi-experimental research, among adolescent boys [age: 13-18 years, height: 154±8 cm, Body Mass Index (BMI): 27.05±1.4 kg/m²], 30 volunteer subjects were selected. The study participants were divided into 3 groups of short-term and long-term periodic exercises as well as controls. The short-term exercise group performed 9 bouts of 30 seconds with 150-second breaks between sessions; the long-term exercise group performed 4 bouts of 150 seconds with 240-second breaks between sessions 3 times a week for 8 weeks. Body composition and blood samples were obtained 48 hours before and after conducting the training protocol to measure the desired parameters. The changes of each index were analyzed by repeated-measures Analysis of Variance (ANOVA) at the significant level of P<0.05. Ethical Considerations: This study was approved by the Ethics Committee of Tabriz University (Code: IR.TABRIZU.REC.1398.021). Results: After 8 weeks of HIIT, growth hormone increased and thigh, arm circumference, and fat percentages decreased (P<0.05). However, no changes were detected in the insulin-like growth factor I, BMI, and weight of the examined subjects (P>0.05). Conclusion: Short- and long-term HIIT have the potential to improve the growth hormone status and body composition of overweight adolescents.

In data envelopment analysis (DEA), calculating the distances of decision making units (DMUs) from the weak efficient boundary of a production possibility set (PPS) is a very important subject which has attracted increasing interest of researchers in recent years. The distances of DMUs to the weak efficient boundary of the PPS can be used to evaluate the performance of DMUs, obtain the closest efficient patterns and also assess the sensitivity and stability of efficiency classifications in DEA. The present study proposes some new models which compute the distances of DMUs from the weak efficient boundary of a PPS for both convex and nonconvex PPSs using Hölder norms. In fact, the presented models assist a DMU to improve its performance by an appropriate movement towards the weak efficient boundary.