Simulated Casualty Evacuation Performance Is Augmented by Deadlift Peak Force.

INTRODUCTION: The purpose of the current study was to examine if isometric peak force and rate of force development (RFD) were related to the ability to successfully perform a simulated casualty evacuation task in both unweighted and weighted conditions. METHODS: Eighteen male participants from Army Reserve Officers' Training Corps (ROTC) completed a maximum isometric deadlift on a force plate (IRB#HE16227). Isometric peak force and RFD were calculated from ground reaction force. Two simulated casualty evacuation performance trials were then completed. The unweighted trial consisted of lifting and carrying a 75 kg dummy as quickly as possible for 50 m. The weighted trial was similar except 9 kg vests were added to both the simulation dummy and the participant to represent 18 kg of duty gear. Independent sample t-tests and Pearson correlations were performed to compare the characteristics of those who passed and failed the weighted trial. RESULTS: All of the participants (n = 18) completed the unweighted casualty evacuation trial, while 72% (n = 13) were able to complete the weighted casualty evacuation trial. The participants that successfully completed the weighted evacuation trial had significantly (p < 0.05) greater isometric peak force (1420 ± 165 vs. 1076 ± 256 N) and lean mass (74.18 ± 3.89 vs. 65.34 ± 3.89 kg) when compared to participants (n = 5) that could not complete the weighted evacuating task trial. Additionally, greater Army Physical Fitness Test scores (288 ± 13 vs. 269 ± 16 arbitrary units) and significantly faster (30.34 ± 4.41 vs. 44.92 ± 10.62 seconds) unweighted evacuation trial times were observed in participants that could complete the weighted evacuation task. Peak force was also significantly correlated with lean mass (r = 0.51, p < 0.05). There was no relationship between RFD and performance of the unweighted or weight trial. CONCLUSION: Isometric deadlift peak force represents an important determinant for the success of a simulated casualty evacuation task and may be a useful marker to include in periodic fitness evaluations of military personnel.

Comparison of the firefighter candidate physical ability test to weight lifting exercises using electromyography.

BACKGROUND: Muscular strength and endurance are important attributes for structural firefighting. Matching resistance exercises to firefighter job demands is not well-established. OBJECTIVE: This study compared the electromyographic (EMG) activity of major muscles during the Candidate Physical Ability Test (CPAT) and weight lifting exercises in firefighters. METHODS: A repeated measures study was conducted in 13 full-duty career firefighters (1 F, 12 M; age 18-44 years). Participants completed seven weight lifting exercises at a university laboratory. They separately completed the CPAT at a firefighting training grounds. During each activity, surface EMG (% maximum voluntary isometric contraction - MVIC) of major muscle groups was recorded and compared between exercises and CPAT. RESULTS: No difference in EMG activity was observed between exercises and CPAT for the deltoid, trapezius, lumbar multifidus, gluteal, and biceps femoris muscles. EMG activity was significantly greater during the CPAT for the abdominal obliques (32.3% ±27.7% vs. 12.1% ±8.3%, p <  0.001) and for the latissimus dorsi (21.8% ±25.1% vs. 11.4% ±7.7%, p <  0.001). CONCLUSIONS: Standard weight lifting and abdominal oblique exercises should be incorporated into resistance training programs for firefighters.

Influence of age on lifting capacity among manual materials handlers.

BACKGROUND: Recommended weight limit for manual materials handlers has to be decided based on the individual characteristics of the person and age is one of the major variable affecting maximal lifting capacity. But there is limited information on pattern of change in lifting capacity with age. OBJECTIVE: To determine the influence of age on the maximum acceptable weight of lift among manual materials handlers. METHODS: Two hundred and seventeen male construction workers were grouped into four age quotas- 19-28, 29-38, 39-48 and 49-58 years. Lifting capacity was determined using progressive isoinertial lifting evaluation, adopting semi-squat technique of lifting at two levels: waist and shoulder. RESULTS: A statistically significant increase in the maximum acceptable weight was observed from first to second age group followed by a gradual decline. The percentage of decline from second to third age group was 11.89% and 14.34% and from third to fourth age group was 5.60% and 19.90% for waist and shoulder level respectively. CONCLUSION: Pattern of change in lifting capacity with age among manual materials handlers has been investigated in this study. Lifting capacity was found to be the greatest in 29-38 year age group, therefore prescribing recommended weight limit uniformly for all the workers may not be the best practice.

Functional Capacity Evaluation-Military: Program Description and Case Series.

A functional capacity evaluation (FCE) evaluates the ability of an individual to perform activities related to employment. There is no FCE specific to the military population; therefore, a FCE for the military population (FCE-M) was developed to evaluate an injured service member's (SM) ability to return to duty. The FCE-M is herein described along with descriptions of three active duty SMs who completed the evaluation. The three SMs completed all categories of the FCE-M with the first two cases achieving a work-level classification of Heavy-Very Heavy and the third a classification of Medium-Heavy. The FCE-M provides a systematic assessment of performance of highly specified military tasks and may provide value in assessing readiness for returning to duty.

Age and gender normative data for lift capacity.

BACKGROUND: Functional Capacity Evaluations (FCEs) are routinely used in physical medicine to ascertain an individual's work ability; with lift capacity being an important aspect of many evaluations. Despite the widespread use of lift capacity tests, there are few studies that provide age and gender normative data. OBJECTIVE: To evaluate the safety, reliability, and validity of the EPIC Lift Capacity test, and to examine the effects of age and gender on lift capacity. METHODS: This study used a test-retest design with 4,443 adult participants in good general health. Test-retest of participants' lift capacity was undertaken to examine safety and reliability. Age and gender and the self-reported physical demands of each employed participant's usual and customary job were collected to examine validity. RESULTS: Safety and reliability were demonstrated for both measures of lift capacity for each of the six sub-tests in the EPIC Lift Capacity test battery. Inter-subtest differences and expected age and gender differences were found across all subtests. CONCLUSIONS: The EPIC Lift Capacity test is a safe and reliable test of lift capacity.Normative data are presented that allow comparison within age and gender categories.

The effect of load in a floor-to-bench lift during the WorkHab functional capacity evaluation.

BACKGROUND: The safe maximal lift for a person is often determined during a functional capacity evaluation. This determination is based upon observation of unsafe lifting techniques, however there is limited information on specific kinematic changes that assist a therapist's clinical reasoning and determination of the safe maximal lift. OBJECTIVE: To evaluate any change in kinematics between safe minimum and safe maximum floor-to-bench lifts during the WorkHab Functional Capacity Evaluation. METHOD: Twenty-eight healthy participants (age range 18-22 years) were digitally recorded completing the evaluation. Lumbar spine, hip, knee and ankle joint angles were measured using Dartfish Pro-suite software at the beginning (0/3), one third (1/3), two thirds (2/3) and end (3/3) of the lift in descending and ascending phases. Paired t-tests were used to compare joint angles at each point of minimum and safe maximum lifts. RESULTS: Significant changes in joint angles occurred lifting safe maximum weight compared to minimum weight. The lumbar spine was in greater flexion [4.9, 95% CI 2.1:7.7, p=0.001]; the knee joint was in less flexion descending [-4.5, 95% CI -8.1: -0.8, p=0.004 (3/3)] and ascending [-9.7, 95% CI -18.3: -1.16, p=0.027 (0/3)] and hip flexion increased at all points of the ascending phase (p⩽ 0.021). The ankle joint was in less dorsiflexion while descending [8.0, 95% CI 3.4:12.7, p=0.001(2/3); 6.7, 95% CI 4.4:9.0, p⩽0.001(3/3)] and ascending [8.9, 95% CI 6.24:11.6, p=0.001(0/3); 3.6, 95% CI 1.5:5.7, p⩽0.001(3/3)]. CONCLUSIONS: This study provides insight into kinematic changes and support observations made by the WorkHab assessor in determining a safe maximal lift during floor-to-bench lifts.

Mechanical properties of weightlifting bars.

Weightlifting training and competition involves lifting a revolving shaft bar loaded with weights. The design of a bar and the location of the weights result in bar deformation during lifting tasks. Because there are many manufacturers of weightlifting bars, the actual deformation of a bar may vary, depending on the steel alloys used. A modified 4-point static bending test was used to assess deformation of 8 weightlifting bars and 1 general purpose weight training bar. The apparent stiffness of the bars was determined by plotting bending moment vs. bar deformation (the vertical height difference between the center vs. ends of the bar). All bars tested had an absence of hysteresis during cyclic loading and unloading in 50-kg increments (up to 220-kg total barbell weight), demonstrating pure elastic properties. At maximum loading, bar deformation was 4-5 cm. A large range existed for apparent stiffness. Based on apparent stiffness calculations, recommendations are made for which bars are suitable for weightlifting training and competition. The deformable nature of weightlifting and weight training bars should be considered before their use in exercise, sport, or research.

Canadian Society for Exercise Physiology position paper: resistance training in children and adolescents.

Many position stands and review papers have refuted the myths associated with resistance training (RT) in children and adolescents. With proper training methods, RT for children and adolescents can be relatively safe and improve overall health. The objective of this position paper and review is to highlight research and provide recommendations in aspects of RT that have not been extensively reported in the pediatric literature. In addition to the well-documented increases in muscular strength and endurance, RT has been used to improve function in pediatric patients with cystic fibrosis and cerebral palsy, as well as pediatric burn victims. Increases in children's muscular strength have been attributed primarily to neurological adaptations due to the disproportionately higher increase in muscle strength than in muscle size. Although most studies using anthropometric measures have not shown significant muscle hypertrophy in children, more sensitive measures such as magnetic resonance imaging and ultrasound have suggested hypertrophy may occur. There is no minimum age for RT for children. However, the training and instruction must be appropriate for children and adolescents, involving a proper warm-up, cool-down, and appropriate choice of exercises. It is recommended that low- to moderate-intensity resistance exercise should be done 2-3 times/week on non-consecutive days, with 1-2 sets initially, progressing to 4 sets of 8-15 repetitions for 8-12 exercises. These exercises can include more advanced movements such as Olympic-style lifting, plyometrics, and balance training, which can enhance strength, power, co-ordination, and balance. However, specific guidelines for these more advanced techniques need to be established for youth. In conclusion, an RT program that is within a child's or adolescent's capacity and involves gradual progression under qualified instruction and supervision with appropriately sized equipment can involve more advanced or intense RT exercises, which can lead to functional (i.e., muscular strength, endurance, power, balance, and co-ordination) and health benefits.

Determinação de perfil de repetições máximas no exercício de extensão de pernas e supino reto com diferentes percentuais de força / Determination of the profile of maximum repetitions in the leg extension exercise and straight supino with different percentages of strength

Os objetives desse estudo foram verificar se tabelas de força padrões são praticáveis, se há diferença entre o número de repetições máximas (RM) intra-exercício e entre grupamentos musculares, para a mesma intensidade. A amostra compõe-se de 20 indivíduos do sexo masculino, entre 17 e 30 anos. Foram aplicados testes de carga, máxima e RM, para o grupo muscular peitoral e quadríceps. A análise estatística foi realizada ao nível de significância de até P=0,05. Os resultados do exercício supino reto (SR) comparados a cadeira extensora (CE), apresentou diferença estatística para a intensidade 80% (P<0,05). Os resultados da CE foram superiores aos do SR, exceto para intensidade de 50%. A análise intra-exercício apresentou diferença estatística (P<0,05) no supino reto em diferentes percentuais de força. Para a CE não houve diferença estatística para as intensidades 60-70 % e 70-80 %. As tabelas analisadas se mostraram sem padronização de valores, com enormes variações de valores entre as diversas tabelas e no número de repetições entre membro superior e inferior. Concluise que diferentes faixas de força proporcionam diferenças no número de RM, entre indivíduos e entre grupamento muscular. As limitações destas tabelas padrões evidenciam a importância de programas de treinamento de força de forma individualizada.

The objectives of this study was to verify if the standard force tables are practicable, if there is difference between the number of maximum repetitions (RM) intra-exercise and between muscular groups, for the same intensity. The sample is composed by 20 individuals of the masculine sex, between 17 and 30 years. Load tests, maximum and RM were applied, for the pectoral muscular group and quadriceps. The statistics analysis was carried through to the level of significance P=0,05. The straight supine year-end results (MR.) compared the extensive chair (CE), presented statistic difference for intensity 80% (P<0,05). The results of the CE were superior to the ones of MR., except for 50% intensity. The intra-exercise analysis presented statistic difference (P<0,05) in the straight supine in different percentages of strength. For the CE there was not statistic difference for the intensities 60-70% and 70-80%. The analyzed tables were shown without standardization of values, with enormous variations of values between diverse tables and the number of repetitions between upper/lower member. One concludes that different bands of strength pr vide differences in the RM number, between individuals andmuscular grouping. The limitations of these standard tables evidence the importance of individualized strength programs.

Progressive resistance exercise in physical therapy: a summary of systematic reviews.

Progressive resistance exercise (PRE) is a method of increasing the ability of muscles to generate force. However, the effectiveness and safety of PRE for clients of physical therapists are not well known. The purpose of this article is to review the evidence on positive and negative effects of PRE as a physical therapy intervention. Electronic databases were searched for systematic reviews on PRE and any relevant randomized trials published after the last available review. The search yielded 18 systematic reviews under major areas of physical therapy: cardiopulmonary, musculoskeletal, neuromuscular, and gerontology. Across conditions, PRE was shown to improve the ability to generate force, with moderate to large effect sizes that may carry over into an improved ability to perform daily activities. Further research is needed to determine the potential negative effects of PRE, how to maximize carryover into everyday activities, and what effect, if any, PRE has on societal participation.

Resistance training effectiveness in patients with Charcot-Marie-Tooth disease: recommendations for exercise prescription.

OBJECTIVES: To determine the effects of a 12-week, home-based resistance exercise program on strength, body composition, and activities of daily living (ADLs) in men and women with Charcot-Marie-Tooth (CMT) disease and to design an ADL-based resistance exercise prescription template. DESIGN: Double-blind, placebo-controlled study. SETTING: Testing in a university setting; exercise in patients' homes. PARTICIPANTS: Twenty CMT patients who volunteered. INTERVENTION: Subjects progressively strength trained at home 3 d/wk for 12 weeks. MAIN OUTCOME MEASURES: Timed ADLs, isometric strength, and body composition. RESULTS: Absolute strength was greater in men with CMT in only 4 of 10 baseline measures (P<.05), but not when strength was normalized by lean mass. Training compliance was 87% with no gender differences. At baseline, women had 80% of normal strength in 4 of 10 measures, whereas men did not achieve 80% of normal strength in any measure. After training, women had 80% of normal strength in 8 of 10 measures, whereas men only had 80% of normal strength in 1. Training volumes and strength change scores showed no gender differences. ADLs improved after training with no gender differences (P<.05). An exercise prescription template was developed by using chair-rise time to estimate starting weights for lower body and supine rise for upper body. CONCLUSIONS: Resistance training improved strength and ADLs equally in men and women. We designed an exercise prescription recommendation, based on ADL performance.

The role of exercise in falls prevention for older patients.

Falls prevention is a key area of health promotion that is familiar to all nurses who work with older people. However, the suggestion that t'ai chi should be used as a prevention intervention may be new to many nurses. The evidence supporting t'ai chi and many other forms of exercise have been evaluated within the National Institute for Clinical Evidence (NICE) falls guidance. This should enable nurses to look at the prevention interventions that they currently recommend and question the evidence for or against their effectiveness. Nurses should also be able to identify factors that may present as barriers to participation.

An exercise program to improve fall-related outcomes in elderly nursing home residents.

This study tested a 3-month ankle-strengthening and walking program designed to improve or maintain the fall-related outcomes of balance, ankle strength, walking speed, risk of falling, fear of falling, and confidence to perform daily activities without falling (falls efficacy) in elderly nursing home residents. Nursing home residents (N = 81) between the ages of 64 and 100 years participated in the study. Two of the fall-related outcomes, balance and fear of falling, were maintained or improved for the exercise group in comparison to the control group.

Exercise and depressive symptoms: a comparison of aerobic and resistance exercise effects on emotional and physical function in older persons with high and low depressive symptomatology.

This study examines and compares the effect of aerobic and resistance exercise on emotional and physical function among older persons with initially high or low depressive symptomatology. Data are from the Fitness, Arthritis and Seniors Trial, a trial among 439 persons 60 years or older with knee osteoarthritis randomized to health education (control), resistance exercise, or aerobic exercise groups. Depressive symptoms (assessed by the Center for Epidemiologic Studies--Depression scale) and physical function (disability, walking speed, and pain) were assessed at baseline and after 3, 9, and 18 months. Compared with results for the control group, aerobic exercise significantly lowered depressive symptoms over time. No such effect was observed for resistance exercise. The reduction in depressive symptoms with aerobic exercise was found both among the 98 participants with initially high depressive symptomatology and among the 340 participants with initially low depressive symptomatology and was the strongest for the most compliant persons. Aerobic and resistance exercise significantly reduced disability and pain and increased walking speed both, and to an equal extent, in persons with high depressive symptomatology and persons with low depressive symptomatology.

Standardization and validation of the body weight adjustment regression equations in Olympic weightlifting.

The problems in comparing the performances of Olympic weightlifters arise from the fact that the relationship between body weight and weightlifting results is not linear. In the present study, this relationship was examined by using a nonparametric curve fitting technique of robust locally weighted regression (LOWESS) on relatively large data sets of the weightlifting results made in top international competitions. Power function formulas were derived from the fitted LOWESS values to represent the relationship between the 2 variables in a way that directly compares the snatch, clean-and-jerk, and total weightlifting results of a given athlete with those of the world-class weightlifters (golden standards). A residual analysis of several other parametric models derived from the initial results showed that they all experience inconsistencies, yielding either underestimation or overestimation of certain body weights. In addition, the existing handicapping formulas commonly used in normalizing the performances of Olympic weightlifters did not yield satisfactory results when applied to the present data. It was concluded that the devised formulas may provide objective means for the evaluation of the performances of male weightlifters, regardless of their body weights, ages, or performance levels.

Prescription of resistance training for healthy populations.

Although there are well documented protective health benefits conferred by regular physical activity, most individuals of all ages are not physically active at a level for sufficient maintenance of health. Consequently, a major public health goal is to improve the collective health and fitness levels of all individuals. The American College of Sports Medicine (ACSM) and other international organisations have established guidelines for comprehensive exercise programmes composed of aerobic, flexibility and resistance-exercise training. Resistance training is the most effective method available for maintaining and increasing lean body mass and improving muscular strength and endurance. Furthermore, there is an increasing amount of evidence suggesting that resistance training may significantly improve many health factors associated with the prevention of chronic diseases. These health benefits can be safely obtained by most segments of the population when prescribed appropriate resistance-exercise programmes. Resistance-training programmes should be tailored to meet the needs and goals of the individual and should incorporate a variety of exercises performed at a sufficient intensity to enhance the development and maintenance of muscular strength and endurance, and lean body mass. A minimum of 1 set of 8 to 10 exercises (multi-joint and single joint) that involve the major muscle groups should be performed 2 to 3 times a week for healthy participants of all ages. More technical and advanced training including periodised multiple set regimens and/or advanced exercises may be more appropriate for individuals whose goals include maximum gains in strength and lean body mass. However, the existing literature supports the guidelines as outlined in this paper for children and adults of all ages seeking the health and fitness benefits associated with resistance training.

Circuit weight training in cardiac patients: determining optimal workloads for safety and energy expenditure.

BACKGROUND: While most studies suggest circuit weight training (CWT) to be safe in cardiac rehabilitation populations, few investigators have controlled variables known to impact CWT intensity. Therefore, the purposes of this study were to determine the energy cost and evaluate safety of cardiac patients while varying rest interval duration and lifting load in a CWT format. METHODS: Nine male subjects with documented coronary artery disease had maximal oxygen uptake (VO2max), one-repetition maximum (1-RM), and body composition tested. In random order and on separate days, 4 CWT sessions using either 40% or 60% of the 1-RM, and either 30 or 60 seconds of rest between stations were completed. Energy cost, heart rate (HR), blood pressure (BP), and rate-pressure product (RPP) were measured. Data were analyzed with a repeated measures analysis of variance, and Tukey's post-hoc test was performed when significant results were found. The alpha level was set at < .05. RESULTS: Subjects exercised at 25% to 32% of VO2max (58%-67% of HRmax) during CWT. The HR and RPP responses were lower during all CWT protocols than at 85% of the treadmill VO2max. No subject displayed any ST-segment depression or angina during CWT. The 40%-60-second protocol had an energy cost (2.98 kcal/min) that was lower (P < .05) than the other protocols (3.48-3.81 kcal/min). Increasing the lifting load resulted in increases (P < .05) in energy cost, and decreasing the rest interval increased energy cost only during the 40% 1-RM protocols. CONCLUSIONS: Results indicate that CWT protocols of varied intensity are safe for cardiac patients when compared to treadmill exercise, and changes in rest interval duration and load can impact the energy cost.

A controlled trial of circuit weight training on aerobic capacity and myocardial oxygen demand in men after coronary artery bypass surgery.

BACKGROUND: Cardiovascular benefits of resistance training in cardiac patients have been suggested but not studied in a randomized, controlled trial of circuit weight training (CWT) without an aerobic exercise component. The purpose of the current study was to examine the effects of 10 weeks of CWT on muscular strength, peak oxygen consumption (peak VO2), and myocardial oxygen demand (mVO2) in men after coronary artery bypass surgery. METHODS: Twenty-six, post-coronary bypass male subjects (mean 19 months after bypass), aged 60 +/- 8.5 years, were randomly allocated to 10 weeks of CWT at 40 to 60% of maximum voluntary contraction (n = 12) or to a control group (n = 14). Muscular strength was assessed using a modified one repetition maximum technique. Peak VO2 was recorded during symptom-limited treadmill exercise. Rate pressure product, as an indirect measure of mVO2, was measured during isometric, isodynamic, and dynamic exercise. RESULTS: No ischemic symptoms nor electrocardiographic changes were recorded during testing or training. Strength increased by 18% (P < 0.005) in five out of seven exercises in the training group, but was unchanged in the control group. Training did not improve peak VO2. Rate pressure product during isometric and isodynamic exercise decreased from pre- to post-testing (P < 0.05) but was equivalent to that seen in the control group. CONCLUSIONS: Moderate intensity CWT is safe and can improve strength in selected low-risk patients after coronary artery bypass surgery. However, it does not significantly increase peak VO2 nor reduce mVO2 during isometric, isodynamic, and dynamic exercise.

Ergonomia na empresa / Ergonomics in the enterprise

Este material foi elaborado através de pesquisas baseadas em informaçöes bibliográficas e dados de levantamentos antropométricos realizados em várias empresas. Apresenta conceitos e definiçöes de Ergonomia; estudos de Postos de Trabalho, Iluminaçäo, Ruído e Temperatura; Coluna Vertebral e cuidados no Levantamento e Transporte Manual de Pesos; Antropometria e Biomecânica; Estatística; Elaboraçäo e Desenvolvimento de um Trabalho de Ergonomia