Weight Lifting Research Articles

Kinetic analysis of change of direction simulating a defensive action in soccer players with and without acute fatigue.

The objective of this study is to analyse the kinetic effects of acute fatigue during a 45° change of direction executed with the non-dominant limb, emulating a typical defensive action during pressing in soccer. Seventeen male professional soccer players (age: 21.7 ± 5.4 years) performed a 45° change of direction before and after a fatigue protocol. Participants were instructed to execute an approach run as quickly as possible, to change direction with their non-dominant foot on a force platform, and then continue running with the aim of stopping against an opponent. Times, forces, impulses, and force rates for different subphases during support were compared. Speeds remained consistent across pre-fatigue (4.53 ± 0.55 m s-1) and post-fatigue (4.58 ± 0.70 m s-1) trials. The results indicated a decrease in braking time (p = 0.01), impulse associated with the braking phase (p < 0.01), and impulse during body weight lifting (p = 0.01) under acute fatigue conditions. These changes suggest that, under acute fatigue, soccer players may not decelerate sufficiently in the initial direction of the run and may raise their body less in the first step after the change of direction. Maximum force values and force rates did not show significant changes; however, they were sufficiently high to suggest a potential injury risk in both conditions.

The Relationship Between Knowledge And Attitudes Towards Ergonomic Behavior Of Employees At Upt Lik Magetan District

Ergonomic problems are related to the body's suitability to work tools when performing work tasks. Based on an initial study conducted by researchers on 10 employees at UPT LIK, Magetan Regency. There are 7 out of 10 workers who lack understanding about ergonomics such as how to lift weights, the maximum limit of the weight lifted, the use of Personal Protective Equipment (PPE), the effects of excessive weight lifting. Meanwhile, in the IKM section, understanding the principles of ergonomics is very important, because the work done by employees is closely related to ergonomics. The lack of awareness of workers in implementing ergonomic behavior is influenced by knowledge factors and work attitudes. Poor work knowledge and attitude are caused by the lack of ergonomics application by the industry to workers. In addition, workers also lack understanding of ergonomics in the work environment. This type of research is a quantitative research with cross sectional research. The population in this study is 230 respondents with a sample of 70 respondents in this study. The data of this study was obtained from the collection of questionnaire sheets and observation sheets. Data analysis using the Chi Square Test. The results of the bivariate test in this study showed that there was no relationship between the independent variable of knowledge and ergonomic behavior with p = 0.687 and there was a relationship between the independent variable of attitude and ergonomic behavior with p = 0.000 The conclusion in this study is that there is no significant relationship between knowledge and ergonomic behavior and there is a significant relationship between attitudes to ergonomic behavior. Keywords: Knowledge, Attitude, Ergonomic Behavior

Acute Endocrine Responses With Long-Term Weight Lifting in a 51-Year-Old Male Weightlifter.

Eserhaut, DA, Fry, AC, Stone, MH, and Kraemer, WJ. Acute endocrine responses with long-term weightlifting in a 51 year old male weightlifter. J Strength Cond Res XX(X): 000-000, 2024-To study the effects of long-term (>35 years) competitive weightlifting on acute endocrine activity, a 51-year-old male two-time Olympian in weightlifting (Subject A) was compared with highly trained young male weightlifters (controls, n = 23; age = 17.7 ± 0.3 years). Between 1400 and 1700 hours, subjects performed 15 maximum effort vertical jumps, a series of single repetitions of the snatch progressing to a maximal effort, and 3 × 10 snatch pulls at 60% 1 repetition maximum. Blood sampling occurred at 0700 hours, pre-exercise, and +5 and +15 minutes postexercise. Exercise performances were comparable between Subject A and controls and elicited similar lactate responses at +5 minutes (mmol·L-1; A = 9.2; controls = 8.1 ± 0.4). Resting testosterone at 0700 hours was lower for Subject A than for the controls (nmol·L-1; A = 13.9; controls = 25.4 ± 2.0), although acute responses at +5 minutes were comparable (A = 21.6; controls 18.3 ± 1.5). Cortisol responses (nmol·L-1; A = 468.4, controls = 540.6 ± 32.3) and testosterone:cortisol ratio (A = 0.0461; controls = 0.0376 ± 0.004) were similar at +5 minutes. Subject A showed no 22 kDa growth hormone response at +5 minutes, while controls exhibited a substantial increase (µg·L-1; A = 0.4; controls = 16.7 ± 2.6). β-endorphin responses were no different at +15 minutes for Subject A relative to controls (pmol·L-1; A = 30.1; controls = 33.8 ± 3.7). Resting and exercise-induced endocrine physiology is partially modified with aging despite long-term participation in competitive weightlifting. Importantly, Subject A's testosterone response was largely preserved.

High Prevalence and Impact of Shoulder Pain Among Gym Instructors: A Study on Work-Related Musculoskeletal Disorders

INTRODUCTION :- Gym instructors within the fitness industry play a pivotal role in guiding individuals towards achieving a range of health and fitness goals. In addition to muscular and skeletal health, gym instructors are instrumental in boosting the immune system. Even though they help in maintaining the body gym trainers have a limited knowledge of mechanism of injury, neglecting and repetitive movements of the joint leads to worsening of injury and increase in the pain. Musculoskeletal pain can stem from various sources, including uncommon or repetitive activities that strain muscles, tendons, and ligaments. Additionally, it may result from sudden, jerky movements, falls, fractures, or underlying musculoskeletal conditions. The result of repetitive activities that strain the muscles, tendons and sprain the ligaments. Insufficient recovery time, rapid pace work, repetitive motion patterns, heavy weight lifting, forceful manual exertions, mechanical pressure concentrations or whole body vibrations can lead to development of other musculoskeletal disorders. The impact of a musculoskeletal condition on an individual's quality of life is substantial, extending beyond mere physical discomfort. Such conditions not only affect personal well-being but also impose a considerable financial strain, manifested through compensation payments and lost wages. Instances of sick leave, absenteeism, and even job abandonment contribute to diminished job efficiency,further exacerbating the socioeconomic repercussions of these disorders. METHODOLOGY :- A total of 147 participants were selected on the basis of inclusion and exclusion criteria. A consent form was filled by them and the study and questionnaire was explained to them.Self-made Questionnaire was explained to each gym instructors according to language understood by that person as well as google forms were also made available for their convenience.Each gym instructor completed a self administered questionnaire which included information regarding complaints of current shoulder pain. The total data was collected and was statistically analyzed. CONCLUSION :- The Prevalence of shoulder pain in gym instructors is high (78%). The presence of shoulder pain causes a gym instructors to avoid certain activities due to pain which causes a hindrance in their work related activities.

Spinal Stiffness: Reliability And Validity Of A Novel Tool To Evaluate Weight Lifters With Low Back Pain

Spinal Stiffness: Reliability And Validity Of A Novel Tool To Evaluate Weight Lifters With Low Back Pain

Effect of diet, vitamin D3 and other factors on genital prolapse recurrensce

&lt;p&gt;This study addresses the pressing need for further investigation into risk factors contributing to genital prolapse recurrence, with a focus on factors like younger age and body mass index (BMI) that have been confirmed in the literature. Conducted as a cross-sectional study involving 300 post-operative cases of genital prolapse patients, the case groups comprising 210 individuals received regular gynecological check-ups every six months during the initial five years post-surgery, followed by annual visits, wherein lifestyle, diet, and laboratory values were monitored and adjusted. In contrast, the control group (90 patients) did not undergo post-operative gynecological follow-up. The results indicate that weight lifting, heavy physical work, menopause, constipation, insufficient protein intake, diseases associated with prolonged cough, and BMI are strongly associated with the likelihood of recurrent genital prolapse, while a weight reduction of 5 kg or more exhibits a protective effect (p&amp;lt;0.001). The established regression model proves statistically significant, explaining 84.1% of genital prolapse recurrence factors, with a sensitivity of 84.8% and specificity of 98.8%. These findings emphasize the importance of postoperative lifestyle monitoring, nutritional guidance, and immune support to reduce the risk of genital prolapse recurrence.&lt;/p&gt;

Comparing Self-Efficacy, Resilience, and Perceived Loneliness Among Young Men Who Lift Weights in Gym and Who Don’t

Comparing Self-Efficacy, Resilience, and Perceived Loneliness Among Young Men Who Lift Weights in Gym and Who Don’t

Multilevel Spontaneous Spinal Epidural Hematomas in a Recreational Weight Lifter.

Spontaneous spinal epidural hematoma (SSEH) is a nontraumatic condition that potentially compresses the spinal cord by accumulating blood in the epidural space. We report a case of multilevel SSEH in a 27-year-old male recreational weight lifter, presenting with acute lower back pain and bilateral leg weakness after deadlifts. Initial magnetic resonance imaging (MRI) showed subacute epidural hematomas with distinct signal intensities. The hematomas spanned multiple thoracic and lumbar levels without any predisposing medical conditions. Conservative management, including strict bed rest and pain management, led to marked improvement, with follow-up MRI indicating reduced hematoma size and expanded dural sac dimension. This case highlights the rare possibility of long-extending SSEH from weight lifting in individuals without risk factors and underscores the effectiveness of conservative treatment for multilevel spinal epidural hematomas.

Effects of Chronic Exigencies on Efficacy of Myogenic Engine Among Elite Women

The heart is a myogenic engine of human body which propell the blood to meet the need of working muscles by supplying nutrients, oxygen and clear waste products. The human heart is a myogenic engine which is a hollow organ that will undergo the direct physical stress laid out by the performer when he/she exposed to a regular, panned, systematic and scientific training regimen. The acute and chronic impacts on the structure and functions of hollow myogenic organs leads to a variety of adaptations. The popularly coined statement that either structure decide the function or function decide the structure. This statement is complimentary with each other for any kind of physical stress. The heart will get direct impact, if the same stress in laydown for a prolonged period, then the heart will get certain changes those changes play an important role in deciding the cardiac dynamics like Heart rate at rest (HR), Stroke volume at rest (SV) and cardiac output at rest ( ). Based on these facts in the present study, the investigator would like to enlighten how a planned, systematic, prolonged physical stimulations will put impact on uninterruptedly working myogenic engine of elite athletes. To fulfill the condition of the study an elite woman of (N=15) fifteen each from long distance training, middle distance training, and weight lifting training were chosen as clients. All the volunteered clients had 7 to 9 years of sports age and trained by their respective coaches in their specific sports. The selected criterian parameters are Heart Rate at rest (HR), Stroke Volume at rest (SV) and Cardiac Output at rest ( ) and they were measure by M- Mode Doppler Echocardiography with the support of qualified cardiologist. Finally, the investigator came to an end that elite athletes from three experimental groups, underwent a significant alterations in the dynamics of myogenic engine. The level of significance was set at 0.01 level of assurance. In ordered to find out the significant difference the analysis of variance (ANOVA) was employed. When the ‘F’ ratio is significant, the Scheffe’s post-hock test was used to find the paired mean significant difference, if any, among the groups of chosen parameters.

A SCIENTIFIC STUDY ON HEART RATE AND MUSCULAR ENDURANCE OF AEROBIC, ANAEROBIC AND COMBINED AEROBIC AND ANAEROBIC ACTIVITIES AMONG ELITE WOMEN

A planned, systematic and chronic training regimen will always leads to significant adaptations on physical and cardiac functions. The heart is an involuntary organ which directly get impact by any systematic training protocol as compared to any other organ of the body, based on this the investigator is throwing a light on how a long distance running training, middle distance running and weight lifting training protocol leads to a significant impact on heart rate at rest and muscular endurance. To fulfill the objectives of the study the investigator has chosen (N=45) elite women volunteered athletes of each (N=15) of long distance running, middle distance running and weight lifting, between 18 to 22 years. All the volunteered elite athletes are trained by their coaches for about 7 to 9 years. The selected criterian parameters are Heart Rate at rest (HR) and Muscular endurance, and they were measure by M- Mode Doppler Echocardiography with the support of qualified cardiologist and bent knee sit-ups (1 min) respectively. The level of significance is set at 0.01 level of assurance. The investigator has concluded that a regular and systematic long distance running, middle distance running and weight lifting training have significantly brought desired changes in heart rate at rest and muscular endurance as compared the normal, healthy, and untrained women reference values. Further, the investigation come to an that the long distance running has significantly lowered heart rate at rest, and significantly enhanced muscular endurance as compared to the middle distance running and weight lifting groups. In ordered to find out the significant difference the analysis of variance (ANOVA) was employed. When the ‘F’ ratio is significant, the Scheffe’s post-hock test was used to find the paired mean significant difference, if any, among the groups of chosen parameters. KEYWORDS: long distance running, middle distance running, weight lifting, heart rate at rest, muscular endurance

Pre-clinical studies comparing the anti-inflammatory potential of artemisinic compounds by targeting NFκB/TNF-α/NLRP3 and Nrf2/TRX pathways in Balb/C mice.

Artemisinin, artemether, artesunate, and dihydroartemisinin are renowned for their antimalarial potential. The current study aims to repurpose the above-mentioned artemisinic compounds (ACs) by conducting an intercomparison to evaluate their antiinflammatory potential (AIP). In order to develop potential candidates for the evaluation of AIP of ACs (50 and 100 mg/kg BW), carbon tetrachloride (1ml/kg body weight (BW)) was administered intraperitoneally to BALB/c mice. Alterations in animal behavior were assessed weekly through tail suspension test, force swim test, open field test, Y-maze test, inverted screen analysis, and weight lifting test. Aberrations in hematological, serological, endogenous antioxidants, and oxidative stress marker profiles were assessed in all twelve groups. Histological alterations were read using hematoxylin and eosin staining. Levels of inflammatory markers including nuclear factor kappa B (NF-κB), tumor necrosis factor alpha (TNF-α), and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3), were determined using immunohistochemical analysis (IHCA). Antioxidant markers i.e., nuclear factor erythroid-2-related factor (Nrf-2) and thioredoxin (TRX) were also quantified through IHCA. Comet assay was performed to quantify DNA damage. Oral administration of ACs to mice significantly alleviated the carbon tetrachloride induced inflammation in comparison with silymarin. Reduced levels of several inflammatory markers including nitric oxide, thiobarbituric acid reactive substances, interleukin-1 beta, NF-κB, TNF-α, and NLRP3, underscore the substantial AIP of ACs. IHCA depicted the revitalized percent relative expression of Nrf-2 and TRX in groups treated with ACs. Behavioral analysis revealed that ACs-treated groups significantly (p<0.05) attenuated the memory deficit, anxiety, and depressive-like behavior. Moreover, histopathological, hematological, serological, and endogenous antioxidant profiles indicated substantial AIP of ACs. Findings of comet assay further bolstered the compelling evidence as DNA damage was significantly (p<0.05) curbed down after ACs (100 mg/kg) treatment. All these outcomes implied that ACs exhibited AIP in a dose-dependent manner with maximal AIP imparted by artemisinin (100 mg/kg). This pre-clinical investigation avers the tremendous AIP of ACs targeting key molecular pathways. The current study divulges artemisinin as the most potent antiinflammatory agent among the tested compounds.

Ergonomics assessment of loading and unloading bagged cargoes: Case study at Sai Gon Port

Abstract Musculoskeletal disorders (MSDs) are a prevalent global health issue, affecting workers in various industries, including port workers. The 28 labor postures are divided into independent manual loading and unloading, coordinated manual loading and unloading, and conveyor loading and unloading. Bagged loading and unloading personnel at Vietnam’s Saigon Port are assessed using OWAS, RULA, and REBA methods. 46.4% of unreasonable postures require further analysis, and 53.6% of exceptional inappropriate positions require adjustment. Replace manual and conveyor belt loading and unloading workgroups based on lifting weight and operational constraints, within a narrow range of recommendations. The chronic risk of MSDs in workers’ appearance is 43%, with an Orebro average score of 100.87±1.21 points, compared to 118,38±1,17 points in the disease group. The average pain location is 4.64±0.23 locations. The most painful positions in the workers were recorded: low back (58%), shoulder (57%), and neck (55%). The 8 main factors that affect the MSDs in objective workers are job satisfaction (10.71%); kneeling frequency (8.61%); positioning loads on the left shoulder (7.43%); hook usage frequency (5.86%); sex life frequency (3.79%); noise impact (3.11%); fatigue (3.02%); the number of working days per week (2.88%).

Risk factors for reoperation after discectomy of lumbar herniated intervertebral disc disease.

Discectomy is the most common surgery for lumbar herniated intervertebral disc (HIVD) disease. However, 5%-24% of patients undergo a second surgery due to recurrent disc herniation. This study was aimed to identify the risk factors for reoperation after discectomy of lumbar HIVD and recommend treatment for patients with a high risk of reoperation. We recruited patients diagnosed as having single-level lumbar HIVD who underwent open discectomy from January 1, 2000, to December 31, 2012 in our hospital. We used a survival curve to inspect the survival time and reoperation rate after surgery. We discussed the correlation of reoperation rate with discectomy level, body mass index, heavy lifting after surgery, sex, and age. Furthermore, we investigated the correlation between the experience of a surgeon and the reoperation rate. A total of 619 patients were enrolled in our study. Most patients were 40-60 years old (48.8%), and most of them had herniation at L4/5 level (48.9%). The 8-year survival rate was 92%. Weight lifting after surgery may increase the reoperation rate by 115 and 18 times for those >60 years and <40 years, respectively. In addition, less experience of the surgeon and female sex had a high reoperation rate. Postoperative working modification may be very important for preventing patients from recurrent HIVD. For elderly people with HIVD, a more conservative therapy could be selected. If patients with lumbar spine hypermobility or severe degeneration require wide laminectomy, primary fusion should be considered.

Estimation of lower back muscle force in a lifting task using wearable IMUs

Low back pain is commonly reported in occupational settings due to factors such as heavy lifting and poor ergonomic practices, often resulting in significant healthcare expenses and lowered productivity. Assessment tools for human motion and ergonomic risk at the workplace are still limited. Therefore, this study aimed to assess lower back muscle and joint reaction forces in laboratory conditions using wearable inertial measurement units (IMUs) during weight lifting, a frequently high-risk workplace task. Ten able-bodied participants were instructed to lift a 28 lbs. box while surface electromyography sensors, IMUs, and a camera-based motion capture system recorded their muscle activity and body motion. The data recorded by IMUs and motion capture system were used to estimate lower back muscle and joint reaction forces via musculoskeletal modeling. Lower back muscle patterns matched well with electromyography recordings. The normalized mean absolute differences between muscle forces estimated based on measurements of IMUs and cameras were less than 25 %, and the statistical parametric mapping results indicated no significant difference between the forces estimated by both systems. However, abrupt changes in motion, such as lifting initiation, led to significant differences (p < 0.05) between the muscle forces. Furthermore, the maximum L5-S1 joint reaction force estimated using IMU data was significantly lower (p < 0.05) than those estimated by cameras during weight lifting and lowering. The study showed how kinematic errors from IMUs propagated through the musculoskeletal model and affected the estimations of muscle forces and joint reaction forces. Our findings showed the potential of IMUs for in-field ergonomic risk evaluations.

Statics Analysis of a New Type of Wheeled Wind Crane

Under the background of the goal of "carbon peak, carbon neutrality", China's wind power development gradually transfers from the three northern regions to the central and eastern parts of the south, wind power installed capacity continues to increase, wind turbine height and single capacity continue to improve, while facing complex geographical environments such as mountains, forest areas, fish ponds, farmland, the functional demand for wind turbine hoisting equipment is increasing day by day. Due to the backwardness of China's metal material manufacturing technology and large wind power crane detection technology, the fatigue life of wind power crane is unpredictable, often in dangerous working conditions and negative loads, resulting in boom fatigue damage, which has a significant impact on personnel safety and national and company economic losses. Today, the demand for wind power has increased greatly, and the wind motor has changed from the previous slow speed, small wind blades and light weight to the single machine capacity is getting larger and larger, the blades are getting longer and longer, the tower height is getting higher and higher, and the lifting parts are getting heavier and heavier. This has created the characteristics of high, large and heavy wind turbines today. Therefore, the traditional wind turbine hoisting equipment has been unable to meet the needs of wind power construction, such as the all-ground crane high cost, weak wind resistance; Crawler crane lifting weight and lifting height is insufficient, and the site required for installation and demolition is large; The traditional tower crane needs to be attached to the tower barrel, which has low disassembly efficiency and great influence on the tower barrel, which seriously restricts the rapid development of wind power construction. Therefore, it is urgent to develop wind power cranes that can better adapt to complex geographical environments, ultra-high towers, and large megawatt units, while reducing installation costs and improving the safety and efficiency of hoisting, it is necessary to carry out mechanical analysis of wind power crane equipment. In order to ensure the reliable operation of the wind power crane, improve the utilization rate, extend the service life of the equipment, prevent potential production safety hazards, and reduce equipment maintenance costs, it is necessary to master its static performance through theoretical analysis and calculation, in order to propose and implement the design optimization and improvement program and the later use and maintenance measures. Due to overload, cracks, fatigue and corrosion, various failures caused by wind power cranes may reduce or lose their pre-designed functions and roles. Therefore, it is necessary to deeply analyze the static performance of the crane, find the largest dangerous force parts, eliminate potential safety hazards, and ensure its safe, stable and reliable operation, to monitor such complex structural parts is not only time-consuming, and may not be able to truly detect the safety hazards. In order to solve these problems, ANSYS (finite element analysis software) is used to analyze the theoretical stress of the 3D structure model, and the theoretical dangerous stress position of the structure is solved. Provide strong data support for the design and development of wind power crane industry in the later stage

Effects of the abdominal belt on the reduction of spinal forces and muscle activities during extreme transits of high-speed craft

Repeated high-g shocks and whole-body vibration (WBV) as experienced by operators of High-Speed Craft (HSC) increase the risk of fatigue, back pain, and acute and chronic injuries, especially in the lumbar region of the spine. Studies on abdominal belts have suggested their beneficial effects on lumbar torso stabilisation and back pain mitigation in both weight lifting and HSC scenarios. This paper presents a human musculoskeletal model to simulate belt effects for occupants on HSC under high-g shocks. Parameters included the shock severity with peak acceleration ranging from 3 g to 10 g, human dimensions and muscle strengths, the belt width and belt forces are investigated. The results show an average of 120% increase in the intra-abdominal pressure (IAP), a 9% reduction in the transverse abdominis activities, and a 12% reduction in the spinal compressive force at the L4/L5 joints when the abdominal belt is added to the human model. In conclusion, wearing an abdominal belt significantly assists abdominal muscles and maintains a solid core during intense WBV generated in different shock severity levels. It may cause a small negative influence on the neck region with a 2.4% increase in the shear force at the C4/C5 joints.

A Study on the Ultimate Span of a Concrete-Filled Steel Tube Arch Bridge

In order to study the ultimate span of a concrete-filled steel tube (CFST) arch bridge, taking the structural strength, stiffness, and stability as the limiting conditions, the finite element analysis method is adopted to carry out research on the influence law of a single parameter of the pipe diameter, wall thickness, and cross-section height on the ultimate span of the arch axial shape. The result is used as a sample point to determine the ultimate span of the CFST arch bridge under multifactor coupling based on the response surface method. The finite element method is used to check the strength, stiffness, stability, number of segments and maximum lifting weight, steel content rate, and steel pipe concrete constraint effect coefficient of the CFST arch bridge under the ultimate span diameter. The results show that, when analyzed using a single parameter, the ultimate span diameter of the CFST arch bridge increases with the increase in the steel pipe diameter and the cross-section height, and then decreases. Moreover, it increases with the increase in the wall thickness of the steel pipe, and the CFST arch bridge reaches the ultimate span with the increase in the steel pipe wall thickness. When the pipe diameter is 1.38 m, the CFST arch bridge reaches the ultimate span; according to a multi-parameter coupling analysis, when the pipe diameter is 1.49 m, wall thickness is 37 mm, and cross-section height is 17 m, the CFST arch bridge reaches the ultimate span of 821 m, which meets all of the limiting conditions, and, at this point, the arch axial coefficient is 1.2. The results of the finite element calculation show that the structural strength, prior to the stiffness, stability, and other limitations, just reaches the critical value of the limiting conditions.

The effect of CROSS FIT Training on Some Physical Abilities, Physiological Indicators, and The Performance of The Weight Lift for Young People

هدف البحث إلى أعداد تدريبات ) CROSS-FIT ( في القدرات البدنية والمؤشرات الفسيولوجية للاعبين الشباب لرياضة رفع الأثقال، والتعرف على نتائج تأثير تدريبات ) CROSS-FIT ( في بعض القدرات البدنية والمؤشرات الفسيولوجية لدى أفراد عينة البحث، والتعرف على الأفضلية بين التدريبات المستخدمة والتمرينات المتبعة على أفراد عينة البحث، استخدم الباحث المنهج التجريبي ذا المجموعتين التجريبية والضابطة كونه انسب المناهج لمعالجة مشكلة البحث، و ح د د مجتمع البحث الكلي بالطريقة العمدية بلاعبي الأثقال في محافظة ديالى قضاء بعقوبة للموسم 2023 / 2024 ، إذ بلغ مجموع أفراد عينة البحث ) 26 ( لاعبا يمثلون فئة الشباب بأعمار ( 17 - 19 ( سنة مقسمين على ثلاثة اندي ه وهي )نادي ديالى، نادي بهرز، نادي بلاد الرافدين(، واستبعد أفراد عد د ) 8( لاعبين لأجراء التجربة الاستطلاعية المتمثل بنادي ديالى، وبذلك اصبح عدد أفراد عينة البحث ) 18 ( لاعبا يمثلون نسبة ) 69.23 %( من مجتمع الأصل ووزعوا على مجموعتين وبواقع ) 9 ( لاعبين لكل مجموعة، من خلال ما تقدم استنتج الباحث إلى أن تدريبات ) Cross-fit ) التي استخدمت في المنهج التدريبي ساهمت بصورة فعالة في تطوير )القوة الانفجارية، والقوة المميزة بالسرعة وتحمل القوة( فضلاً عن المؤشرات الفسيولوجية لدى رباعي نادي بلاد الرافدين، مما أسهمت في تطور نسبي في إنجاز رفعة النتر، فضلاً عن أنها أسهمت في تحقق أفضلية التأثير في المؤشرات الفسيولوجية والمتمثلة في السعة الحيوية والطاقة المصروفة لدى أفراد المجموعة التجريبية مقارنة بإفراد المجموعة الضابطة التي استخدم المنهج المتبع، ويوصي الباحث إلى ضرورة الاهتمام بتدريبات ) CROSS FIT ) والعمل على وضع مناهج تدريبية تأخذ بالحسبان المراحل العمرية والقدرات البدنية والمؤشرات الفسيولوجية لما لها تأثير في رفع كفاءة الأجهزة الوظيفية في الجسم، إعادة تطبيق المنهج المعد من قبل الباحث على أندية أخرى والتعرف على مدى فاعليته في تطوير القدرات البدنية والمؤشرات الفسيولوجية لهم.

Enhancing weight perception in virtual reality: an analysis of kinematic features

This study investigates weight perception in virtual reality without kinesthetic feedback from the real world, by means of an illusory method called pseudo-haptic. This illusory model focuses on the dissociation of visual input and somatosensory feedback and tries to induce the sensation of virtual objects' loads in VR users by manipulating visual input. For that, modifications on the control-display ratio, i.e., between the real and virtual motions of the arm, can be used to produce a visual illusionary effect on the virtual objects' positions as well. Therefore, VR users perceive it as velocity variations in the objects' displacements, helping them achieve a better sensation of virtual weight. A primary contribution of this paper is the development of a novel, holistic assessment methodology that measures the sense of the presence in virtual reality contexts, particularly when participants are lifting virtual objects and experiencing their weight. Our study examined the effect of virtual object weight on the kinematic parameters and velocity profiles of participants' upward arm motions, along with a parallel experiment conducted using real weights. By comparing the lifting of real objects with that of virtual objects, it was possible to gain insight into the variations in kinematic features observed in participants' arm motions. Additionally, subjective measurements, utilizing the Borg CR10 questionnaire, were conducted to assess participants' perceptions of hand fatigue. The analysis of collected data, encompassing both subjective and objective measurements, concluded that participants experienced similar sensations of fatigue and changes in hand kinematics during both virtual object tasks, resulting from pseudo-haptic feedback, and real weight lifting tasks. This consistency in findings underscores the efficacy of pseudo-haptic feedback in simulating realistic weight sensations in virtual environments.

Capability of Machine Learning Algorithms to Classify Safe and Unsafe Postures during Weight Lifting Tasks Using Inertial Sensors.

Occupational ergonomics aims to optimize the work environment and to enhance both productivity and worker well-being. Work-related exposure assessment, such as lifting loads, is a crucial aspect of this discipline, as it involves the evaluation of physical stressors and their impact on workers' health and safety, in order to prevent the development of musculoskeletal pathologies. In this study, we explore the feasibility of machine learning (ML) algorithms, fed with time- and frequency-domain features extracted from inertial signals (linear acceleration and angular velocity), to automatically and accurately discriminate safe and unsafe postures during weight lifting tasks. The signals were acquired by means of one inertial measurement unit (IMU) placed on the sternums of 15 subjects, and subsequently segmented to extract several time- and frequency-domain features. A supervised dataset, including the extracted features, was used to feed several ML models and to assess their prediction power. Interesting results in terms of evaluation metrics for a binary safe/unsafe posture classification were obtained with the logistic regression algorithm, which outperformed the others, with accuracy and area under the receiver operating characteristic curve values of up to 96% and 99%, respectively. This result indicates the feasibility of the proposed methodology-based on a single inertial sensor and artificial intelligence-to discriminate safe/unsafe postures associated with load lifting activities. Future investigation in a wider study population and using additional lifting scenarios could confirm the potentiality of the proposed methodology, supporting its applicability in the occupational ergonomics field.