Abdomen-thigh contact during forward reaching tasks in obese individuals

Associations between body composition and physical fitness among Chinese medical students: a cross-sectional study

Background

This study examined associations between body composition and physical fitness scores among medical students in Shenyang, China.

Methods

A total of 2291 medical students aged 18–20 (815 male and 1476 female) in Shenyang of China were recruited to participate in the research in May 2019. With the use of the BCA-1B body composition analyzer and standard method of physical fitness assessment, the body composition and seven measures of physical fitness (body mass index, vital capacity, sit and reach, standing long jump, pull-ups/crunches, 50-m sprint, and 800/1000-m run) of college students were measured, respectively. The associations between body composition and physical fitness scores were assessed using multiple linear regression analysis.

Results

The height, weight, total body water, protein mass, mineral content, body mass index, vital capacity, and body function scores of male students were significantly higher than those of female students. However, fat mass (FM), body shape score, physical quality score, and total physical fitness score of female students were significantly higher than those of male students. The results of the multiple linear regression analysis indicated that in male students, only FM was negatively associated with body shape score, body function score, physical quality score, and total physical fitness score. In female students, FM was associated with lower body shape scores, physical quality scores, and total physical fitness scores. Furthermore, the ratio of overweight to obesity in male students was significantly higher than that in female students.

Conclusions

In Chinese medical colleges, the physical fitness level of female students is better than that of male students, and a higher FM was significantly associated with worse physical fitness of medical students. Moreover, male students with a higher rate of overweight and obesity are an important group that needs weight control.

Use of various obesity measurement and classification methods in occupational safety and health research: a systematic review of the literature

BACKGROUND

This study systematically examined obesity research in occupational safety and health regarding the use of various obesity measurement and classification methods.

METHODS

A systematic search of the PubMed database on English language publications from 2000 to 2015 using related keywords and search of citations resulted in selection of 126 studies. They were categorized into two groups based on their main research question: 1) general physical or mental work-related functioning; and 2) task or body part specific functioning.

RESULTS

Regardless of the study group, body mass index (BMI) was the most frequently used measure. Over 63% of the studies relied solely on BMI to define obesity. In only 22% of the studies, body fat was directly measured by methods such as dual energy x-ray absorptiometry. Abdominal obesity was defined using waist circumference in recent years, and waist-hip ratio in earlier years. Inconsistent cut-offs have also been used across studies investigating similar topics.

CONCLUSIONS

Few authors acknowledged the limitations of using indirect obesity measures. This is in part due to the limited understanding of some occupational safety and health researchers regarding the complex issues surrounding obesity classification and also the mixed recommendations over the past 2-3 decades and across populations. Efforts need to be made to promote appropriate obesity measurement and reporting in this field.

Effect of angular deformities of the proximal femur on impingement-free hip range of motion in a three-dimensional rigid body model

INTRODUCTION

Abnormalities in hip morphology can reduce range of motion (ROM) through femoroacetabular impingement (FAI). Structural issues, such as asphericity of the head-neck junction and regional or global acetabular over-coverage, have been extensively discussed in the literature. The effect of varying femoral neck-shaft angle or torsion on native hip range of motion, however, has been poorly studied. Our hypothesis was that varying neck-shaft angles or femoral torsion affect the impingement-free ROM of the hip and can be treated by femoral osteochondroplasty or acetabular rim resection.

MATERIAL AND METHODS

A computer-aided design tool and a 3-D model of the hip were used to simulate incremental deformation of the proximal femur. Neck-shaft angles ranging from 90-160°, and femoral torsions ranging from -15-50°, were created. Femoroacetabular impingement was defined as bone-to-bone contact within physiological hip ROM, as described in the literature.

RESULTS AND CONCLUSION

With decreasing neck-shaft angles (≤110°) or femoral torsion (≤10°), impingement occurred at the anterosuperior rim area. With increasing neck-shaft angles (≥135°) and femoral torsion (≥25°) posteroinferior or ischiofemoral impingement occurred. Acetabular rim trimming could compensate for neck-shaft angles ≥90° and femoral torsion ≥-5°, without creating acetabular dysplasia. Femoral impingement zones in low neck-shaft and low femoral torsion angles were found to be distal to the head-neck junction at the mid-cervical region. The cross-sectional area at this neck region was the smallest, and thus osteochondroplasty at this location may prove potentially dangerous.

Influences of Obesity on Job Demands and Worker Capacity

Evidence suggests that the growing prevalence of obesity in the workforce has resulted in an increase in the incidence and cost of musculoskeletal injuries. Obesity can modify job demands and affect worker capacity in terms of anthropometry and occupational biomechanics, which may place workers at greater risk of injury. This paper presents a review of studies quantifying the work-relevant impacts of obesity, specifically related to work task demands, capacities, and their potential imbalance. The increased body fat that accompanies obesity leads to larger anthropometric dimensions and inertial parameters, particularly in the trunk and thigh areas. Consequently, individuals who are obese adjust their work postures and motions as an accommodation. These changes may affect the biomechanical demands on the joints and increase the burden on the musculoskeletal system. Independent of job demands, obesity-related differences also occur with respect to strength, fatigue, and task performance. Directions for future research are provided, focusing on the need for workplace redesign to account for changing workforce demographics.