Mixed Session Periodization as a New Approach for Strength, Power, Functional Performance, and Body Composition Enhancement in Aging Adults.

Berzerra, ES, Orssatto, LBR, Moura, BM, Willardson, JM, Simão, R, and Moro, ARP. Mixed session periodization as a new approach for strength, power, functional performance, and body composition enhancement in aging adults. J Strength Cond Res 32(10): 2795-2806, 2018-The purpose of this study was to compare the effects of mixed session periodization (MSP) vs. traditional periodization (TP) on strength, power, functional performance, and body composition in aging adults. Forty-five healthy aging adults were randomly divided into 3 groups: MSP, TP, and Control. Subjects were tested before the intervention for baseline values (week 4) and then repeated testing during (week 7 and week 11), as well as after the intervention (week 15). Subjects were tested on the following performance measures: 5 repetition maximum (5RM) leg press and seated leg curl; 12RM cable chest press; countermovement jump (CMJ) and squat jump; up-and-down stairs; timed up and go (TUG); and body composition. All comparisons were analyzed through a mixed-model analysis with repeated measures (group × time) and with Bonferroni post hoc tests (p ≤ 0.05). After the intervention, no significant differences were observed between experimental groups; however, the MSP and TP groups demonstrated significantly greater values vs. the Control group in the 5RM leg press (p < 0.01), seated leg curl (p < 0.01), and 12RM cable chest press (p < 0.001). For CMJ performance, the MSP and TP groups significantly increased at week 7 (p < 0.001). The MSP and TP groups significantly improved functional task performance, including TUG (p < 0.001), upstairs (p < 0.01), and downstairs (p < 0.01) after training. Furthermore, body composition for the lower limbs significantly changed for the MSP and TP groups, with increased fat-free mass (p < 0.001) and decreased fat mass (p < 0.01) after training. In conclusion, the MSP and TP models used in this study were equally effective in developing strength, power, and functional performance while increasing fat-free mass and improving body fat percentage in aging adults. However, it should be considered that the MSP protocol did result in greater effect sizes in lower-limb strength, lower-limb fat-free mass, up-and-down stair, and TUG performance.

Physiological and neuromuscular indices associated with sprint running performance.

The purpose of the study was to analyze the relationships among physiological and neuromuscular indices with the 200- and 400-m sprint running performance. Fourteen male sprinters performed the following tests: determination of 200- (P200) and 400-m (P400) running performance; determination of VO2max and the velocity associated at VO2max; squat jump (SJ) and countermovement jump (CMJ); and maximal accumulated oxygen deficit (MAOD). Significant correlations were observed between SJ (r = -0.53), CMJ (r = -0.69), and MAOD (r = -0.65) with P200. Countermovement jump (CMJ) and MAOD explained 70% of the P200. The MAOD was the only variable to correlate significantly with P400 (r = -0.56); VO2max and CMJ were also selected in the regression together and explained 79% of P400. The indicators of muscular power and anaerobic capacity are capable of explaining P200. In the 400 m, the performance was determined by indices of anaerobic capacity, in conjunction with the athletes' aerobic and muscular power.

Effect of elastic resistance training on functional capacity in older adults: a systematic review with meta-analysis.

PURPOSE: This systematic review and meta-analysis investigated the effects of Elastic Resistance Training (ERT) on functional capacity (FC) in older adults. METHODS: The databases used were Embase, Virtual Health Library, PubMed, SciElo, Scopus, SPORTS Discus, and Web of Science. Eligibility criteria: aged ≥ 60 years; both sexes; intervention of at least 8 weeks; structured ERT; comparator group that performed other types of training or without any intervention; at least one functional test measurement. Functional tests were grouped according to their specificity for the sub-group meta-analyses. RESULTS: Twenty-six studies were considered eligible for qualitative synthesis, of which 16 were used for quantitative analysis. Favorable effects (p < .001) of ERT compared to the control group without intervention were observed in the 30-second sit to stand test, Timed Up and Go test, arm curl test, handgrip strength test, 6-minute walk test, lower and upper limb flexibility, and Short Physical Performance Battery (p = .007). Comparisons between ERT and other types of training were not performed because of the high heterogeneity of the studies. CONCLUSIONS: Our findings suggest that ERT is able to improve the FC of older adults when compared to older adults not involved in any type of training.

Quadriceps Muscle Morphology Is an Important Determinant of Maximal Isometric and Crank Torques of Cyclists.

The aim of this study was to determine if quadriceps morphology [muscle volume (MV); cross-sectional area (CSA)], vastus lateralis (VL) muscle architecture, and muscle quality [echo intensity (ECHO)] can explain differences in knee extensor maximal voluntary isometric contraction (MVIC), crank torque (CT) and time-to-exhaustion (TTE) in trained cyclists. Twenty male competitive cyclists performed a maximal incremental ramp to determine their maximal power output (POMAX). Muscle morphology (MV; CSA), muscle architecture of VL and muscle quality (ECHO) of both quadriceps muscles were assessed. Subsequently, cyclists performed three MVICs of both knee extensor muscles and finally performed a TTE test at POMAX with CT measurement during TTE. Stepwise multiple regression results revealed right quadriceps MV determined right MVIC (31%) and CT (33%). Left MV determined CT (24%); and left VL fascicle length (VL-FL) determined MVIC (64%). However, quadriceps morphological variables do not explain differences in TTE. No significant differences were observed between left and right quadriceps muscle morphology (p > 0.05). The findings emphasize that quadriceps MV is an important determinant of knee extensor MVIC and CT but does not explain differences in TTE at POMAX. Furthermore, quadriceps morphological variables were similar between the left and right quadriceps in competitive cyclists.

Usability and effects on gait of an optimized schoolchildren backpack.

BACKGROUND: Backpacks used by children is a global concern, because may cause musculoskeletal discomforts and pain. OBJECTIVE: The purpose of this study was to test the usability and effects on gait kinematics wearing the Trunkpack versus a traditional backpack and no backpack. METHODS: Twenty-four children (9 to 11 years old) from a public school participated in this study. The usability was evaluated after a five-week testing period using a questionnaire. Gait kinematics was evaluated (Vicon) when the children were wearing a standard backpack, an optimized backpack (Trunkpack), and no backpack. Both backpacks were loaded with 10% of body weight. RESULTS: Was observed more trunk, hip and knee flexion when the children carried a standard backpack in comparison using the Trunkpack and not carrying a backpack (p < 0.01). The Trunkpack and no backpack were similar. The Trunkpack was well accepted by the schoolchildren (81% positive responses), 79% liked the head opening, 88% liked the waist straps, and 83% liked the facility to put and take objects in and out of the Trunkpack. CONCLUSION: Trunkpack requires less postural adjustments during gait than a standard backpack. Gait kinematics with the Trunkpack was comparable to the gait without carrying a backpack.

The effect of different work-rest schedules on ergonomic risk in poultry slaughterhouse workers.

BACKGROUND: Rest breaks are an organizational measure to reduce the high risk of upper limb work-related musculoskeletal disorders (UL-WMSDs) to which slaughterhouse workers are subject. OBJECTIVE: To analyze the effect of different work-rest schedules on ergonomic risk in poultry slaughterhouse workers. METHODS: A total of 36 repetitive tasks was selected in a Brazilian slaughterhouse. Using the Occupational Repetitive Action (OCRA) Checklist, the level of exposure of workers to risk factors of UL-WMSDs in two work-rest schedules was evaluated. In the real condition, 6 rest breaks of 10 minutes were performed, and in the simulated condition, 3 rest breaks of 20 minutes. RESULTS: The right side of the body presented a higher score on the OCRA Checklist (72%of the tasks) than the left side (p = 0.037) in the real condition. Additionally, the OCRA score (18.3±2.5) was significantly lower (p < 0.001) than the simulated condition (21.9±3.0). It was verified that the risk level in simulated condition remained the same in 13 (36%) tasks, while in 23 (64%) tasks there was an increase in the risk level. CONCLUSIONS: Work-rest schedule of 6 breaks of 10 minutes was better than 3 breaks of 20 minutes to reduce the risk of UL-WMSDs in poultry slaughterhouse workers.

A low-cost and efficient participatory ergonomic intervention to reduce the burden of work-related musculoskeletal disorders in an industrially developing country: an experience report.

Work-related musculoskeletal disorders (WMSDs) are the first cause of occupational illness in Brazil and the number of cases in the industrial sector has increased progressively in the last 6 years. In order to prevent WMSDs, workplace ergonomics interventions are frequently implemented worldwide. This article describes the implementation strategy of a participatory ergonomic intervention conducted in the quality control department of a medium-sized Brazilian garment company. The intervention was carried out based on the nine steps presented by Vink, Imada and Zinck, and workers' exposure to risk factors was investigated using the rapid upper limb assessment method. A low-tech and low-cost solution that successfully reduced workers' exposure to WMSD risk factors was proposed, prototyped, tested and, finally, introduced. Participatory ergonomic interventions can be a feasible and effective approach to reduce the exposure to work-related risk factors for WMSDs in industrially developing countries.

Cutting force measurement: Hand tool instrumentation used in slaughterhouses - a systematic review.

Workers' intensive use of hand tool cutting in the meat packing industry is a risk factor for occupational health, mainly by mechanical compression of tissues in the upper limbs, which can cause Work-Related Musculoskeletal Disorders (WMSDs). This systematic review aimed to identify the characteristics and measured variables of instrumented knives and determine how they should be designed. The review process and article extractions occurred through an analysis of the (article) titles, keywords and abstracts, followed by reading the full texts by two reviewers independently. Searches were conducted in Medline, Web of Science, Science Direct, Scopus, Ebsco and Engineering Village for articles published in peer-reviewed journals from January 2000 to March 2019, in the English language. The result of (the) search included 1289 potentially eligible studies, with 894 duplicated/triplicated/quadruplicated articles that were excluded, resulting in 404 remaining articles of which 33 were considered eligible, with 36 additional articles, totaling 69 evaluated full texts. After the review, none of the 14 analyzed studies, were rated as having good methodological quality. In addition, four types of instrumented knives were used. Data acquisition was performed in both laboratory and meat processing plants. It is noteworthy that only one knife was submitted to a validation process and that the articles did not provide complete technical information about the knives. The result demonstrated that the cutting force varies within and between subjects, tasks, plants and blade finishings. All knives used some type of electrical connection via cable or wires. Of the articles found, none considered the influences that the workers are subject to when they do not use the same tool daily for data acquisition. Therefore, the development of different types of instrumented knives, with wireless data transmission and more rigorous studies are necessary to expand the knowledge of the cutting force and development of WMSD in slaughterhouse workers who perform meat cutting.

Exertion Perception When Performing Cutting Tasks in Poultry Slaughterhouses: Risk Assessment of Developing Musculoskeletal Disorders.

Brazil is the leader in poultry meat exports, in which most products are in the form of cuts. This study analyzed the exertion perception of poultry slaughterhouses workers when performing cutting tasks, as well as the influence of knife sharpness on the risk of developing musculoskeletal disorders by Occupational Repetitive Action (OCRA) method. Participants (n = 101) from three slaughterhouses were asked to rate their perceived exertion on the Borg scale during the cutting task when the knife was well and poorly sharpened. The OCRA results showed that the score for cutting with a dull knife was greater (43.57 ± 13.51) than with a sharp knife (23.79 ± 3.10) (p < 0.001). Consequently, there was a significant increase in the risk level of acquiring upper-limb work-related musculoskeletal disorders (UL-WMSD) by using a "poorly sharpened" knife (29%; p < 0.001; Borg scale 2-8). Thus, maintaining well-sharpened knives for optimal performance of the cutting task (fewer technical actions) is suggested, as well as including knife sharpening in the standard operating procedure to reduce musculoskeletal disorders.

Human factors related to the use of a personal computer: A case study.

The aim of this study was to determine and compare the ergonomic requirements in the use of desktop computers and laptops. For comparison, postures in the sagittal and transversal planes involved while performing a typing and editing task on a desktop and laptop computers were verified. Thus, a case study was conducted with a Brazilian male of medium height, who works around 20 hours per week in a computer. Nine spherical markers of 2.5 cm in diameter were joined up with duct tape on the right side of the participant and the positions adopted by the subject were analyzed in the use of a desktop and a laptop computer, through direct observation and filming, using the videography technique. It is concluded that the use of desktop computers has lesser biomechanical demands since it showed angles closer to a neutral position and consequently having a lower risk of musculoskeletal complaints.

Occupational health and safety management systems: a systemic approach / Sistemas de gerenciamento em saúde e segurança do trabalho: uma abordagem sistêmica

Abstract Risks are intrinsic to any human activity. Occupational Health and Safety Management Systems (OHSMSs) are mechanisms designed to mitigate risks, protect workers, and ensure productivity. This study aimed to support researchers' reflective analysis by examining scientific literature related to OHSMSs and identifying possibilities for future research with practical significance. Employing a qualitative approach, this systematic review was conducted using bibliographic procedures and action research. The intervention instrument ProKnow-C guided by a structured process from a constructivist perspective, was applied. A total of 3,130 studies were analyzed to select the bibliographic portfolio. The systemic analysis revealed that most articles neither demonstrate legitimacy nor consider companies' particularities. The paper advances theoretical knowledge of OHSMSs by assessing relevant studies in the field, identifying evolution patterns, and highlighting gaps. A research agenda is proposed to guide the development of future models. We conclude that the challenges of designing ad hoc OHSMSs and incorporating the decision-makers' knowledge throughout the process when addressed, have the potential to significantly contribute to the advancement of this field of knowledge.

Resumo Os riscos são intrínsecos a todas as atividades humanas. Os sistemas de avaliação de desempenho de saúde e segurança no trabalho (SADSSTs) são mecanismos projetados para lidar com riscos, proteger os trabalhadores e garantir produtividade. Este estudo objetivou apoiar a análise reflexiva dos pesquisadores com base na literatura científica relacionada aos SADSSTs, identificando possibilidades de pesquisas futuras de importância prática. Com abordagem qualitativa, esta revisão sistemática foi desenvolvida com a adoção de procedimentos bibliográficos e pesquisa-ação. Foi utilizado o instrumento de intervenção ProKnow-C, um processo estruturado orientado pela perspectiva construtivista. Um total de 3.130 estudos foi analisado para a seleção do portfólio bibliográfico. A análise sistêmica revelou que a maioria dos artigos não apresenta legitimidade, nem considera as particularidades das empresas. O artigo avança no conhecimento teórico dos SADSSTs avaliando os estudos relevantes na área e identificando padrões de evolução e lacunas. Propõe-se uma agenda de pesquisa para orientar o desenvolvimento de modelos futuros. Conclui-se que o desenvolvimento de um SADSST ad hoc, não genérico e concebido com o conhecimento do decisor em todo o processo, permanece sendo um desafio e tem potencial para contribuir para o avanço deste campo do conhecimento.

Association between perception of bodily discomfort and individual and work organisational factors in Brazilian slaughterhouse workers: a cross-sectional study.

OBJECTIVE: Brazil is the world's second largest poultry meat producer and leading exporter. Many poultry processing tasks are physically demanding and involve factors that increase the risk of developing a work-related musculoskeletal disorder (WMSD). However, little is known about the assessment of bodily discomfort in these workers. The aim of this study was to evaluate the association between perception of bodily discomfort and individual and work organisational factors in poultry slaughterhouse workers. DESIGN: Descriptive, cross-sectional study. SETTING: Three poultry slaughterhouses in the South of Brazil. PARTICIPANTS: This paper included 925 workers of 3 poultry slaughterhouses, 575 women and 350 men. The selection of the participants was random. MAIN OUTCOME MEASURE: Workers were asked about individual factors, work organiation, perception of bodily discomfort and cold, as well as ingestion of pain medication. Crude and adjusted ORs were estimated and 95% CIs were derived from binary logistic regression analysis for perception of bodily discomfort. RESULTS: There was a significant association (p<0.05) between perception of bodily discomfort and female gender (OR=1.77; 95% CI 1.30 to 2.41), performance of repetitive tasks (OR=1.81; 95% CI 1.12 to 2.91) and perception of cold (OR=2.05; 95% CI 1.44 to 2.91). CONCLUSIONS: The findings of this research demonstrated that the sector of occupational safety and health management in poultry slaughterhouses should monitor the symptoms of WMSD among their workers, especially female workers, workers who perform repetitive tasks, as well as those who perform tasks in cold environments because these groups are more likely to experience bodily discomfort.

Psychometric properties of a medium version of the Copenhagen Psychosocial Questionnaire (COPSOQ II) for southern Brazil.

BACKGROUND: The emerging frequency of Behavioural Mental Health Disorders among Brazilian workers and the recent legal demand for analysis of psychosocial risks in the workplace highlight the importance of standardizing measures to assess these risks as a way to allow identification and proper comparison among different populations. OBJECTIVE: To assess the psychometric properties of the COPSOQ II questionnaire medium version for southern Brazil, based on the Spanish medium-length version of COPSOQ-ISTAS21 II. METHODS: A sample of 426 workers from a university in southern Brazil answered the model under study online. Content validity and internal consistency were analyzed through Confirmatory Factor Analysis (AFC) and Exploratory Factor Analysis (AFE) and Cronbach's α coefficient. RESULTS: The study model presented a response rate of 48.46%. The analyses indicated the possibility of the instrument to present reliability and validity of content. From the AFE, the final model consisted of 13 dimensions and 70 items, and presented a Cronbach's alpha of 0.82, which is considered a good internal consistency. CONCLUSIONS: The results showed that the final model of this study presents acceptable levels of reliability and internal validity for the application in Brazil, along with the groups of workers that resemble the participants of the research, to assess psychosocial risks in the workplace.

Effects of different strength training volumes and subsequent detraining on strength performance in aging adults.

The purpose of the present study was to investigate the volume-dependence of upper-body strength performance improvement and the retention effects after detraining in aging adults. Eighteen healthy, untrained, middle-aged volunteers were randomized into two groups: low volume (LV), mean = 494 kg. and high volume (HV), mean = 686 kg. load. Participants were tested and retested before a 12-week (2 times/week) period of RT for baseline values (pre-); after 6 weeks (middle) and 12 weeks of training (post-), and 12 weeks after interruption (detraining - no systematic exercise). On each test day, a five-repetition maximum (5-RM) for the seated row; handgrip strength test (HGS); and local muscular endurance for elbow flexors (LME) were carried out. Participants performed seated row training 2 times per week with a rest interval of at least 48 h between sessions. After 24 sessions of RT (resistance training), LME significantly increased in both groups (p < 0.05), without differences between groups (14 vs. 18%, for LV and HV, respectively). In addition, 5-RM increased in both the LV (22%) and HV (20%) groups. There were no significant increases in HGS in either group (LV 3% and HV 6%). After detraining, both groups lost up to 15% of LME and 5-RM. In untrained, middle-aged adults, there is an increase in maximal dynamic strength and local muscular endurance, independent of volume chosen. Furthermore, after 12 weeks detraining, the loss does not decrease to baseline values.

Aquatic exercise and Far Infrared (FIR) modulates pain and blood cytokines in fibromyalgia patients: A double-blind, randomized, placebo-controlled pilot study.

Fibromyalgia (FM) has an inflammatory component, as elevated serum levels of inflammatory biomarkers are associated with its diagnosis. Treatments decreased pain, body temperature, improved quality of life and reduced serum levels of IL-6 in both groups; however, these beneficial effects were more pronounced in aquatic exercise (AE) + Far-Infrared (FIR) group. The findings of the present study suggest that the association of AE to FIR increases the benefits of aquatic exercise in patients with FM.

The Use of Personal Protective Equipment: Finger Temperatures and Thermal Sensation of Workers' Exposure to Cold Environment.

This study analyzed the finger temperatures of poultry slaughterhouse workers and its association with personal and organizational variables, bodily discomfort perception, and cold thermal sensation. The study included 143 poultry slaughterhouse workers. A thermograph was used to measure finger temperature and an interview to collect worker data. There were two groups: workers who used a tool and those without. The binary logistic regression, Friedman and Wilcoxon tests were used (p ≤ 0.05). Most workers presented at least one finger with an average temperature ≤15 °C (66.4%) and ≤24 °C (99.3%), perceived their cold hands, and wore three overlapping gloves (57.3%). There were no associations between finger temperatures (≤15 °C) and the analyzed variables. The chance of feeling cold for a worker who used a tool was greater than for a worker who did not (OR = 3.19, 95% CI 1.46; 6.94). There was a difference between the finger temperatures of each hand on both surfaces and the analyzed groups (p < 0.01). The temperature of each finger with its respective contralateral was different in the little fingers (no tool), index, middle, ring, and little fingers (using a tool) (p < 0.05). The use of several overlapping gloves was not sufficient to promote thermal insulation of the hands.

Estimating bone mineral content based on different types of muscle strength tests.

The aims of this pilot study were to verify which muscle strength tests better explain bone mineral content (BMC) of the femoral neck and lumbar spine and to develop predictive equations to estimate femoral neck and lumbar spine BMC. Twenty-nine subjects aged 56-76 years old (12 women and 17 men) participated in the study. Femoral neck and lumbar spine BMC was evaluated by Dual X-ray absorptiometry (DXA). Muscle strength measurements included maximal isometric voluntary contractions of knee extensors and flexors, vertical jump, 5-repetition maximum of the leg press (5-RMLP) and seated leg curl (5-RMLC), and handgrip strength. Women presented a moderate to strong correlation between femoral neck BMC and 5-RMLP (r = 0.819), 5-RMLC (r = 0.879), knee extensors peak torque (r = 0.699), and handgrip strength (r = 0.663), as well as between lumbar spine BMC and the 5-RMLP test (r = 0.845) and manual grip strength (r = 0.699). For females, the 5-RMLP and 5-RMLC tests most fully explained femoral neck BMC (R2 = 0.859) and the 5-RMLP test and body mass explained lumbar spine density (R2 = 0.757) for females. Men did not present correlations between BMC and strength variables. For females, the 5-RMLP and 5-RMLC variables explained the variations of femoral neck BMC, while 5-RMLP and body mass explained lumbar spine BMC. Future studies should evaluate a larger sample size and prioritize the strength tests with a greater predictive capacity.

Muscular performance and body composition changes following multi-joint versus combined multi- and single-joint exercises in aging adults.

The aim of the present study was to compare muscular performance and body composition changes following low-volume resistance-training programs consisting of multi-joint (MJ) exercises (cable chest press and seated row) versus a combination of multi- and single-joint (MJ+SJ) exercises (cable chest press, seated row, biceps curl, and triceps extension). Thirty untrained healthy aging adults were randomly assigned to 3 groups: MJ (n = 11), MJ+SJ (n = 11), and control (n = 8). Twelve-repetition maximums (12-RMs) for the cable chest press and seated row, localized muscular endurance for the elbow flexors handgrip strength, and body composition were assessed before and after the 8-week training program. All comparisons were analyzed via a mixed-model analysis with repeated measures (group × time) and the Bonferroni post hoc test (p < 0.05). The MJ and MJ+SJ groups increased performance in the 12-RM cable chest press (MJ = 61.5% ± 24.6% and MJ+SJ = 71.1% ± 25.6%), 12-RM seated row (MJ = 46.4% ± 26.3% and MJ+SJ = 51.5% ± 21.0%), localized muscular endurance (MJ = 24.7% ± 16.7% and MJ+SJ = 37.0% ± 11.4%), and handgrip strength (MJ = 9.3% ± 10.4% and MJ+SJ = 16.6% ± 25.3%) after the intervention. Body composition (i.e., trunk and upper limb fat and lean mass) did not change for any groups. No significant differences were observed between the MJ versus the MJ+SJ protocols after the intervention for any variables. In conclusion, for aging adults, either MJ or MJ+SJ low-volume resistance training resulted in similar increases in 12-RM, localized muscular endurance, and handgrip strength, without changes in body composition after 8 weeks of training.

Thermographic Evaluation of the Hands of Pig Slaughterhouse Workers Exposed to Cold Temperatures.

Brazil was rated the fourth leading producer and exporter of pork meat in the world. The aim of this study was to evaluate the temperature of the hands of pig slaughterhouse workers and its relation to the thermal sensation of the hands and the use of a cutting tool. The study included 106 workers in a pig slaughterhouse. An infrared camera FlirThermaCAM E320 (Flir Systems, Wilsonville, OR, USA) was used to collect the images of the dorsal and palmar surfaces of both hands. A numerical scale was used to obtain the thermal sensation. Chi-square test, Pearson correlation and Student's t test or Wilcoxon were used (p ≤ 0.05). The majority of workers felt cold in the hands (66%) and workers who used the knife felt the coldest. There was an association between the thermal sensation and the use of knife (p = 0.001). Workers who used the tool showed correlation between the thermal sensation and the temperatures of the left fingers, with a difference between the temperatures of the right and left hands of those who used the knife (p ≤ 0.05). The hands (left) that manipulated the products presented the lowest temperatures. Findings indicate that employers of pig slaughterhouses should provide gloves with adequate thermal insulation to preserve the health of workers' hands.

Muscle architecture of the vastus lateralis and rectus femoris in the production of knee extensor torque in physically inactive women

Abstract Aim: This study aimed to verify the data reliability of muscle architecture (MA) variables, and the relationship between MA and the isometric peak torque (PT) of the monoarticular and biarticular knee extensor (KE) muscle in physically inactive women. Methods: Ten physically inactive women (24.0 ± 1.64 years; 162.9 ± 5.34 cm; 63.5 ± 11.90 kg) participated in the study. An ultrasound device assessed the MA variables (muscle thickness, fascicle length, and pennation angle) of the Vastus Lateralis (VL) and Rectus Femoris (RF), and an isokinetic dynamometer assessed the PT. Pearson correlation evaluated the relationship between PT and MA variables, with a significance level of 5%. Additionally, the intraclass correlation coefficient, coefficient of variation, and standard error of measurement. Results: Excellent reliability between images was observed, and no significant relationships were observed between the PT and MA variables of the VL and RF. Conclusion: Isolated variables of the MA of a monoarticular or a biarticular muscle do not influence the production of the isometric PT of the KE.