Force Development Research Articles

Research on the Impact of Digital Infrastructure on Urban Breakthrough Green Innovation: A Case Study of the Yangtze River Economic Belt in China

Breakthrough green innovation acts as a critical leverage point and a fundamental driver of the development of new productive forces. This study employs a sample of 108 cities along the Yangtze River Economic Belt from 2011 to 2021 to investigate the impact of digital infrastructure on urban breakthrough green innovation and its underlying mechanisms. The findings are as follows: (1) Digital infrastructure construction facilitates urban breakthrough green innovation, with a notably more substantial impact on strategic breakthrough green innovation. This result is validated through robustness and endogeneity tests. (2) Heterogeneity analysis indicates that the enhancement effect of digital infrastructure on breakthrough green innovation is more prominent in non-resource-based cities, cities with higher levels of marketisation, and those with weaker environmental regulations, with a particularly significant influence on substantive breakthrough green innovation. (3) Mechanism analysis reveals that upgrading industrial structures, optimising market resource allocation, and increasing public environmental awareness are critical mechanisms through which digital infrastructure strengthens urban breakthrough green innovation capacity. Additionally, as improvements occur in industrial structure, market resource allocation efficiency, and public environmental awareness, the impact of digital infrastructure on urban breakthrough green innovation capacity displays a nonlinear effect.

Dynamic Analysis of Upper- and Lower-Extremity Performance During Take-Offs and Landings in High-Wall Climbing: Effects of a Plyometric and Strength Training Intervention

This study used a 12-week plyometric and strength training program as an intervention to improve upper- and lower-extremity muscle strength for jumping and landing when climbing high walls. Sixty general non-athlete male college students were openly recruited and divided into an experimental group and a control group. The experimental group underwent a plyometric and strength training program twice a week for 12 weeks (24 sessions). The intervention was divided into three phases, each lasting four weeks, with the training intensity gradually increasing in each phase. A hand grip dynamometer was used to measure grip strength, and a PASCO double-track force plate was used to assess upper-extremity push-up force and lower-extremity take-off and landing strength. The results of the 12-week intervention showed that the experimental group experienced significant increases in grip strength (both hands), hand-ground reaction force, and upper-extremity hang time. Additionally, the time of upper-extremity action on the force plate decreased. Lower-extremity take-off strength improved, as reflected in increased ground reaction force, rate of force development, and passage time. Upon landing, ground reaction force decreased by 3.2%, and cushioning time shortened by 52.7%. This study concludes that plyometric and strength training have promising effects in enhancing upper- and lower-extremity strength, particularly in climbing and landing tasks.

Robustness analysis of dynamic progressive collapse of precast concrete beam–column assemblies using dry connections under uniformly distributed load

A series of dynamic progressive collapse tests using the uniformly distributed load (UDL) was conducted, to analyze the robustness of three precast concrete (PC) beam–column assemblies using dry connections of top-and-seat angles (TSA-D), strengthened top-and-seat angles (STSA-D), and high-ductility reinforcement (DSTSA-D), under a middle column removal scenario. Finite element (FE) models were also developed to accurately simulate the collapse process. Based on the tests and FE models, comparative studies were conducted on dynamic and static collapse responses of the PC assemblies with identical configuration, loading regime, and boundary conditions. The results showed that: the horizontal reaction force developments were similar under dynamic and static collapse scenarios; under dynamic collapse scenarios, the initial stiffness of the PC assemblies increased due to the strain rate effect, while the peak vertical reaction forces under the compressive arch action (CAA) were smaller than those under static collapse scenarios, attributed to dynamic damage; under both dynamic and static collapse scenarios under UDL, the beam deformed in a downward convex curved shape, with local material deformation becoming more concentrated under dynamic collapse scenarios. An energy-based method for calculating dynamic collapse resistance was evaluated and revised: 1) the traditional method, which converts static responses from static analysis into dynamic responses was found to underestimate the resistance under small deformations due to neglecting the strain rate effect, and to overestimate ultimate resistance by ignoring dynamic damage; 2) by using dynamic vertical reaction forces instead, a more accurate prediction of the dynamic collapse resistance was achieved with a single dynamic collapse analysis. Additionally, dynamic amplification factors for the PC assemblies were calculated based on FE models and static test results providing basic knowledge in whole PC structural level research.

Change-of-Direction Performance and Its Deficits in Relation to Countermovement-Jump Height and Phase-Specific Performance Among Female Athletes.

Jump and linear sprint performances both correlate with pro-agility performance. However, correlation does not imply causation, and potential confounders may affect the correlation. Therefore, this study aimed to determine the relationship between change-of-direction (COD) performance and COD deficits (COD-D) in linear-sprint and countermovement-jump (CMJ)-related performance using multiple stepwise linear-regression models. The study included 42 female national-level intercollegiate athletes. The 10- and 20-m linear-sprint and pro-agility times, COD-D, CMJ height, and phase-specific force production and rate of force development during eccentric unloading, eccentric braking, and the concentric phases of CMJ were measured. Stepwise linear-regression analyses were used to predict the factors related to COD and COD-D. CMJ height was the sole predictor in the 10-m pro-agility model (adjusted R2 = .234, P = .001). Modified Reactive Strength Index (standardized coefficient, -.710) and the lowest center-of-mass depth during the CMJ (standardized coefficient, .323) were predictors in the 20-m pro-agility model (adjusted R2 = .330, P < .001). For the 10- and 20-m COD-D models, the rate of force development at 30 and 60milliseconds, respectively, during the concentric phase was the only predictor of performance (adjusted R2 = .183, P = .003 and .237, P = .001, respectively). These results suggest that athletes should concentrate on improving their CMJ height, increasing their ability to lower their center of mass more deeply, and increasing their instantaneous force-production abilities immediately after the eccentric braking phase of CMJ to improve their COD performance.

Plyometric training with additional load improves jumping performance and isokinetic strength parameters of knee extensors and flexors in young male soccer players

ABSTRACT This study investigated the effect of plyometric training with and without additional load on young male soccer players’ jumping ability and isokinetic strength. Methods: In this randomized controlled trial, 39 U-17 male trained soccer players were randomly divided into plyometric training with additional load (PT+AL), plyometric training with just bodyweight (PTBW) and control (CON) groups. PT+AL and PTBW were performed for six weeks (2 days/week). Absolute peak torque (APT), relative peak torque (RPT), average peak torque (AvPT), time-to-peak torque (TPT), average rate of force development (AvRFD), vertical jump height (VJH), standing long jump (SLJ) and 15-second repeated jump tests (RJ15s) were assessed before and after the interventions. The findings showed that the performance of knee extensors in TPT-60°/s and AvRFD-60°/s, and knee flexors in APT-60°/s, RPT-60°/s, AvPT-60°/s, AvPT-120°/s, AvRFD-60°/s and AvRFD-120°/s significantly increased after PT+AL, compared to the CON (p < 0.05). Also, a significant improvement in jumping ability was observed in PT+AL compared to CON (p < 0.05). Additionally, PTBW also improved the performance of knee flexors in TPT-120°/s and AvRFD-120°/s, as well as RJ15s performance compared to the CON (p < 0.05). Furthermore, knee flexors AvRFD-60°/s increased significantly after PT+AL, compared to PTBW (p < 0.05). SO, plyometric training, with or without additional load, improved young male soccer players’ strength and jumping ability. However, strength parameters – especially the rate of force development – showed a greater increase following PT + AL compared to PTBW.

An Analysis of Human Nature in Fromm's Humanistic Thought

In contemporary society, the problem of human existence has increasingly aroused the common concern of all mankind, and the rich and colorful material life has enriched people's daily life, but the spiritual life of human beings is relatively impoverished, and the great abundance of material wealth to a certain extent makes people enslaved to material things, and the spiritual life of individuals is in a state of imbalance. While elaborating on the actual state of human existence, Fromm's humanistic thought critically exposes the social problems caused by the development of productive forces, and fundamentally points out the confusion of human beings, on the basis of which it indicates that we can realize the breakthrough of the state of human beings' gradual dissolution in a certain way, so as to generate a brand-new space for the survival of human beings. In this way, human beings will be able to find their way out of numbness and self-loss, and thus step into the “kingdom of existence”. Fromm's anthropological point of view mainly centers on human nature, including three aspects: human nature, human nature alienation, and human nature liberation. This paper is a brief analysis of this aspect of human nature.

Neuromuscular mechanisms for the fast decline in rate of force development with muscle disuse - a narrative review.

The removal of skeletal muscle tension (unloading or disuse) is followed by many changes in the neuromuscular system, including muscle atrophy and loss of isometric maximal strength (measured by maximal force, Fmax). Explosive strength, i.e. the ability to develop the highest force in the shortest possible time, to maximise rate of force development (RFD), is a fundamental neuromuscular capability, often more functionally relevant than maximal muscle strength. In the present review, we discuss data from studies that looked at the effect of muscle unloading on isometric maximal versus explosive strength. We present evidence that muscle unloading yields a greater decline in explosive relative to maximal strength. The longer the unloading duration, the smaller the difference between the decline in the two measures. Potential mechanisms that may explain the greater decline in measures of RFD relative to Fmax after unloading are higher recruitment thresholds and lower firing rates of motor units, slower twitch kinetics, impaired excitation-contraction coupling, and decreased tendon stiffness. Using a Hill-type force model, we showed that this ensemble of adaptations minimises the loss of force production at submaximal contraction intensities, at the expense of a disproportionately lower RFD. With regard to the high functional relevance of RFD on one hand, and the boosted detrimental effects of inactivity on RFD on the other hand, it seems crucial to implement specific exercises targeting explosive strength in populations that experience muscle disuse over a longer time.

Theoretical Thinking on the Development of New Quality Productive Forces According to Local Conditions in Heilongjiang Province

The new quality productive forces reflects the systematic remodeling and revolutionary transition of the old productive forces, which is the quality of productivity in line with the requirements of high-quality development. The formation of new quality productive forces can effectively energize the revitalization and development of Heilongjiang Province. From the perspective of the revitalization of the old industrial base in Northeast China, opportunities, advantages and challenges coexist in the development of new quality productive forces in Heilongjiang Province. Based on the current situation, the practical path for the development of new quality productive forces according to local conditions in Heilongjiang Province is proposed: Cultivate innovative thinking leading the development of new quality productivity, form the industrial base for the development and growth of new quality productivity, shape the innovation economic system for the development of new quality productivity, and build innovation clusters of new quality productivity.

Rate of Force Development During a Handgrip Task Is Correlated with the Post-Impact Ball Speed of the Flat Serve

The aim of the present research was to test the hypothesis that rate of force development (RFD) during a handgrip task of the dominant arm in three different positions is associated with maximal post-impact ball speed of flat serve (PIBS). Altogether 23 elite junior boys (aged 14.84 ± 2.47 years; weight 59.51 ± 13.83 kg; height 170.47 ± 16.34 cm) tennis players participated in the study. To assess the maximal voluntary contraction (MVC) and RFD during the task, four handgrip tests and a serve test were applied to estimate PIBS. Spearman’s rank correlation showed a significant positive correlation between RFD of dominant arm in each three position and PIBS (r = 0.82–0.86; p &lt; 0.001). A very large, significantly positive correlation was also found between MVC of the dominant arm and PIBS (r = 0.88; p &lt; 0.01). The result of the present study indicated that rapid force generation of muscles in the forearm and wrist may probably play a role in the formation of a stable contact point, and it is in connection with PIBS. It is in contrast to the slow maximal force exertion that much rather characterizes the general strength state of players. Therefore, measurement of the RFD during a handgrip task is suggested in the testing session of the flat serve of junior tennis players.

On the rate-limiting dynamics of force development in muscle.

Skeletal muscles produce forces relatively slowly compared with the action potentials that excite them. The dynamics of force production are governed by multiple processes, such as calcium activation, cycling of cross-bridges between myofilaments, and contraction against elastic tissues and the body. These processes have been included piecemeal in some muscle models, but not integrated to reveal which are the most rate limiting. We therefore examined their integrative contributions to force development in two conventional types of muscle models: Hill-type and cross-bridge. We found that no combination of these processes can self-consistently reproduce classic data such as twitch and tetanus. Rather, additional dynamics are needed following calcium activation and facilitating cross-bridge cycling, such as for cooperative myofilament interaction and reconfiguration. We provisionally lump such processes into a simple first-order model of 'force facilitation dynamics' that integrate into a cross-bridge-type muscle model. The proposed model self-consistently reproduces force development for a range of excitations including twitch and tetanus and electromyography-to-force curves. The model's step response reveals relatively small timing contributions of calcium activation (3%), cross-bridge cycling (3%) and contraction (27%) to overall force development of human quadriceps, with the remainder (67%) explained by force facilitation. The same set of model parameters predicts the change in force magnitude (gain) and timing (phase delay) as a function of excitatory firing rate, or as a function of cyclic contraction frequency. Although experiments are necessary to reveal the dynamics of muscle, integrative models are useful for identifying the main rate-limiting processes.

Is the Rate of Force Development Produced in the Squat Jump a Reliable Metric and is it Related to Jump Height?

ABSTRACT This study aimed to analyze the intrasession reliability of the rate of force development (RFD) in different time windows in squat jumps (SJ) performed at different knee starting angles, and identify the relationship of RFD with vertical jump height (VJH). Twenty male volleyball and basketball players participated. Athletes randomly performed SJ from four different knee-flexion angles. The RFD was analyzed from six different windows, from force onset to instant peak force, in each position using the ground reaction forces. Reliability analysis was performed based on the intraclass correlation coefficient (ICC) and coefficient of variation (CV%); Spearman’s rho was used to test the relationship between RFD and VJH. The results demonstrated that RFD0-PF was the only variable assumed to be reliable, demonstrating an ICC > 0.84 and CV < 8.5% in all positions, and significant correlations between RFD metrics and VJH were observed at SJ70 and SJPREF. Some variables were underpowered due to the small sample size, as a limitation of the study.

Analysis of requirements for labor force development of hydrometeorological services in modern conditions

Analysis of requirements for labor force development of hydrometeorological services in modern conditions

Comprehensive guide to tobacco control policy implementation

Background: Tobacco use remains one of the leading causes of preventable death and disease worldwide. Effective tobacco control policies are essential in mitigating these health risks. The Framework Convention on Tobacco Control (FCTC), adopted by the World Health Organization (WHO) in 2003, provides a comprehensive framework for implementing evidence-based tobacco control measures globally. This project aims to develop and implement robust tobacco control policies to reduce tobacco consumption and its associated health risks. Methods and Materials: The project involved a comprehensive review of existing tobacco control policies, data collection on tobacco use and related health outcomes, and the development of a multi-sectoral task force. Key strategies included setting clear goals, stakeholder engagement, public awareness campaigns, and the drafting of legislative and policy documents. Implementation mechanisms such as enforcement and evaluation systems were also established to ensure compliance and measure the policy's impact. Results: The implementation of the tobacco control policies resulted in a significant reduction in smoking prevalence and exposure to secondhand smoke. Public awareness of the health risks associated with tobacco use increased, and there was enhanced support for smoking cessation services. The project also identified best practices and strategies that can be adopted by other regions to achieve similar outcomes. Conclusion: This project highlights the importance of comprehensive research, effective coordination, and well-planned implementation in developing and executing tobacco control policies. The findings and recommendations presented serve as a valuable resource for policymakers and public health professionals aiming to reduce smoking rates and protect public health. Continued collaboration and adaptation of these strategies are essential for sustaining the progress made in tobacco control.

Emphasizing the innovation of urological robotic-assisted surgical instruments and technology driven by new quality productivity forces

New quality productivity force is an advanced form of productive force that is innovation-driven, characterized by high technology, high efficiency, and high quality. It aligns with the new development philosophy and represents an advanced state of productivity. Within the medical sphere, this concept is epitomized by the progressive evolution of surgical instruments and techniques. In recent years, the rapid development of new quality productivity forces in the medical field has generated significant anticipation for innovations in urological robotic surgery instruments and techniques. Advancements in domestically produced robotic surgery systems, remote robotic surgery, single-port robotic surgery, and pediatric-specific robotic surgery exemplify the critical application of new quality productivity forces in urology. The integration of artificial intelligence, haptic feedback technology, and sensory enhancement technologies has further enhanced the safety and precision of surgeries. Driven by these new quality productivity forces, the development of urological robotic surgery instruments and techniques has reached a new milestone, potentially setting a new gold standard for urological surgeries and providing patients with safer, more efficient, and personalized medical care. However, certain emerging technologies still face challenges in their application, necessitating further research and clinical validation.

"Endogenous forces" and "exogenous forces": a study on the development of the rural teaching workforce in the context of rural revitalization

In the context of rural revitalization, the development of the rural teaching workforce relies on the synergistic promotion of endogenous forces and exogenous forces. endogenous forces mean internal driving forces that emphasize proactive and innovative personal motivation, while exogenous forces refer to external supports that focus on resource investment and policy guidance. However, an increasing emphasis on exogenous forces while neglecting endogenous forces has limited the sustainable development of China’s current rural teaching workforce. We believe that activating endogenous forces is a key and weak link in promoting the synergistic development of rural revitalization and the rural teaching workforce. Only when endogenous forces are activated by exogenous forces and achieve a "feedback" effect on exogenous forces can a positive cycle in the development of rural teachers be established. In summary, the collaborative development and mutual reinforcement of endogenous and exogenous forces will enhance the professional development of the rural teaching workforce.

Military Equipment Entity Extraction Based on Large Language Model

The technology of military equipment entity extraction, a crucial component in constructing military knowledge bases, holds significant research value and theoretical importance for guiding the development and improvement of equipment support forces. In the military domain, equipment entities exhibit a phenomenon of nesting, where one entity is contained within another, and abbreviations or codes are frequently used to represent these entities. To address this complexity, this paper proposes a method named CoTNER for extracting entities. Initially, a large-scale language model is used to perform data augmentation with chain-of-thought on the original dataset, providing additional semantic and contextual information. Subsequently, the augmented dataset is fine-tuned on a small-scale language model to adapt it to the task of military equipment entity extraction and to enhance its ability to learn complex rules specific to the domain of military equipment. Additionally, a high-quality data filtering strategy based on instruction-following difficulty scoring is proposed to address the catastrophic forgetting issue that may occur during the fine-tuning of large language models. The experimental results demonstrate that the proposed military equipment entity extraction method outperforms mainstream traditional deep learning methods, validating the effectiveness of CoTNER.

Reliability and Validity of the Rate of Force Development for Quadriceps in Older Patients with Cardiovascular Disease

Background/Objectives: The rate of force development (RFD), which is the change in force over a period of time during muscle contraction, quantifies rapid muscle contractions. RFD may serve as a measure of physical rehabilitation in patients with cardiovascular disease (CVD); however, its reliability and validity in older patients remain unclear. This study examined the reliability and validity of quadricep RFD in older patients with CVD. Methods: This prospective study enrolled 30 outpatients undergoing cardiac rehabilitation (median age, 77 years) and 30 inpatients hospitalized for CVD (median age, 76 years). The quadricep RFD values at three time points (RFD50, 0–50 ms; RFD100, 0–100 ms; and RFD200, 0–200 ms) were calculated from the slope of the force–time curve. Physical performance was assessed using the Short Physical Performance Battery (SPPB). Intra- and inter-rater correlation coefficients were assessed for outpatients. The correlation coefficients between RFD values and physical performance indicators were assessed separately for outpatients and inpatients. Results: The intraclass correlation coefficients (1,1) and (2,1) for RFD50, RFD100, and RFD200 were 0.742, 0.893, and 0.873 and 0.810, 0.918, and 0.930, respectively. The correlation coefficients for SPPB with RFD50, RFD100, and RFD200 were 0.553, 0.547, and 0.597 (all p &lt; 0.05), respectively, for inpatients; similar moderate correlations were observed for gait speed and the chair stand test. Conclusions: The test–retest reliability of the RFD was excellent in older patients with CVD. The RFD was positively correlated with physical function indicators, suggesting its validity as a measure of physical rehabilitation.

Role of Na+-K+ ATPase Alterations in the Development of Heart Failure.

Na+-K+ ATPase is an integral component of cardiac sarcolemma and consists of three major subunits, namely the α-subunit with three isoforms (α1, α2, and α3), β-subunit with two isoforms (β1 and β2) and γ-subunit (phospholemman). This enzyme has been demonstrated to transport three Na and two K ions to generate a trans-membrane gradient, maintain cation homeostasis in cardiomyocytes and participate in regulating contractile force development. Na+-K+ ATPase serves as a receptor for both exogenous and endogenous cardiotonic glycosides and steroids, and a signal transducer for modifying myocardial metabolism as well as cellular survival and death. In addition, Na+-K+ ATPase is regulated by different hormones through the phosphorylation/dephosphorylation of phospholemman, which is tightly bound to this enzyme. The activity of Na+-K+ ATPase has been reported to be increased, unaltered and depressed in failing hearts depending upon the type and stage of heart failure as well as the association/disassociation of phospholemman and binding with endogenous cardiotonic steroids, namely endogenous ouabain and marinobufagenin. Increased Na+-K+ ATPase activity in association with a depressed level of intracellular Na+ in failing hearts is considered to decrease intracellular Ca2+ and serve as an adaptive mechanism for maintaining cardiac function. The slight to moderate depression of Na+-K+ ATPase by cardiac glycosides in association with an increased level of Na+ in cardiomyocytes is known to produce beneficial effects in failing hearts. On the other hand, markedly reduced Na+-K+ ATPase activity associated with an increased level of intracellular Na+ in failing hearts has been demonstrated to result in an intracellular Ca2+ overload, the occurrence of cardiac arrhythmias and depression in cardiac function during the development of heart failure. Furthermore, the status of Na+-K+ ATPase activity in heart failure is determined by changes in isoform subunits of the enzyme, the development of oxidative stress, intracellular Ca2+-overload, protease activation, the activity of inflammatory cytokines and sarcolemmal lipid composition. Evidence has been presented to show that marked alterations in myocardial cations cannot be explained exclusively on the basis of sarcolemma alterations, as other Ca2+ channels, cation transporters and exchangers may be involved in this event. A marked reduction in Na+-K+ ATPase activity due to a shift in its isoform subunits in association with intracellular Ca2+-overload, cardiac energy depletion, increased membrane permeability, Ca2+-handling abnormalities and damage to myocardial ultrastructure appear to be involved in the progression of heart failure.

Status of Women Police in India: An Analytical Study of Uttar Pradesh State Police

Despite a number of efforts by the Government to increase the representation of women in police, it has continued to be relatively sluggish. The Government's data shows that there were a total of 2,17,026 women in police forces, which made up 10.5 percent of the entire police force in the country. Very few women police are recruited for leadership positions. The reasons behind the lesser representation of women police in the police department include the working conditions, societal status of women, recruitment rules, retention and promotion discrimination, inadequate infrastructure, and the police image in society etc. Article 355 of the 7th Schedule of the Constitution of India mandates the Union to safeguard each State from both internal and external disturbances. The responsibility for public order crimes and law enforcement falls under the State's jurisdiction, as designated by Article 246 of the Constitution. Therefore, each State has to establish a police force capable of enforcing laws, maintaining public order, and ensuring the safety of its citizens. The United Nations report underscores the importance of women in the police force, noting that the current ratio of 137 police per lakh population falls short of the required 181 police per lakh population. The United Nations recommends a ratio of 222 police per lakh population, a goal that we are currently far from achieving. The present paper provides police data along with the strength of the women police in India. This also highlights the various committees' recommendations for women's policing and the development of the police force through equality and quality of women working in the police system. Some crucial suggestions and recommendations have been provided to increase the recruitment of women in police organisations.

Computational fluid dynamics analysis of aerodynamic characteristics in long-endurance unmanned aerial vehicles

Long-endurance unmanned aerial vehicles (UAVs) play an increasingly important role in various aspects of societal life. In response to the national emphasis on air force development, a study on the aerodynamic characteristics of long-endurance UAVs was conducted. This paper utilizes SolidWorks software to construct a geometric model based on the MQ-9 UAV, and a CFD method to establish a simulation model for UAV cruising flight. The aerodynamic coefficients, required thrust, and total mass during UAV cruise were calculated, and the variation of aerodynamic coefficients as airflow passes through the UAV was described. A comparative analysis was performed on the effects of different angles of attack, flight speeds, and flight altitudes on aerodynamic efficiency. The study results indicate that at an altitude of 10 km, with a 0° angle of attack, the UAV achieves a lift coefficient of 0.8888, a drag coefficient of 0.0679, and a lift-to-drag ratio of 13.0988. The required thrust is approximately 2236 N, and the total flight mass is approximately 3090 Kg. The angle of attack has the greatest impact on aerodynamic efficiency, followed by flight altitude, while flight speed has the least impact on aerodynamic performance. The lift-to-drag ratio initially increases sharply and then decreases rapidly with increasing angle of attack. It is recommended to control the angle of attack within the range of 0°–6°. The lift-to-drag ratio increases slowly with increasing flight speed, suggesting that the flight speed should be maintained near the maximum cruise speed. The lift-to-drag ratio generally decreases with increasing flight altitude, and it is recommended to maintain the flight altitude within the range of 9 km–11 km.