Bokun Kim

High-Intensity Aerobic Exercise Improves Both Hepatic Fat Content and Stiffness in Sedentary Obese Men with Nonalcoholic Fatty Liver Disease

We compared the effects of 12-week programs of resistance training (RT), high-intensity interval aerobic training (HIAT), and moderate-intensity continuous aerobic training (MICT). The primary goal was to evaluate the therapeutic effects of the exercise modalities for the management of nonalcoholic fatty liver disease (NAFLD). A total of 61 sedentary obese men with NAFLD were randomized into one of the following exercise regimens (RT, HIAT, or MICT). Hepatic fat content was decreased to a similar extent in the RT, HIAT, and MICT groups (−14.3% vs. −13.7% vs. −14.3%) without significant changes in weight and visceral fat. The gene expression levels of fatty acid synthesis were significantly decreased in the subjects’ monocytes. Hepatic stiffness was decreased only in the HIAT group (−16.8%). The stiffness change was associated with restored Kupffer cell phagocytic function (+17.8%) and decreased levels of inflammation such as leptin (−13.2%) and ferritin (−14.1%). RT, HIAT, and MICT were equally effective in reducing hepatic fat content, but only HIAT was effective in improving hepatic stiffness and restoring Kupffer cell function. These benefits appeared to be independent of detectable weight and visceral fat reductions; the benefits were acquired through the modulation of in vivo fatty acid metabolism and obesity-related inflammatory conditions.

Changes in lower extremity muscle mass and muscle strength after weight loss in obese men: A prospective study

BACKGROUND Obesity is not only associated with internal diseases but also with surgical problems. Surgical diseases related to obesity frequently occur in the load bearing joints of the lower limbs. To decrease the occurrence of surgical diseases related to obesity, weight loss has been recommended. It is important for obese men to maintain muscle mass and muscle strength after weight loss because low muscle mass and muscle strength are also related to the occurrence of surgical diseases. To date, the importance of muscle mass and muscle strength after weight loss in obese men has been underappreciated. OBJECTIVE The purpose of this study was to investigate changes in lower extremity muscle mass and muscle strength resulting from a weight loss programme consisting of caloric restriction and exercise. METHODS All participants concurrently attended a 12-week diet class 1day/week and a 12-week exercise class 3days/week. Body weight and body composition by dual-energy X-ray absorptiometry and knee extensor strength by dynamometry were assessed. RESULTS The weight loss programme led to a 14.1% weight loss accompanied by significant loss of leg muscle mass, static maximal muscle strength, dynamic maximal muscle strength and dynamic muscle endurance but not with significant loss of dynamic muscle power. Decline of muscle strength was related to a decrease in muscle mass, but not completely dependent on a decrease in muscle mass. Body weight-normalised muscle strength increased significantly. CONCLUSION We recommend utilising resistance exercise to restore muscle mass and muscle strength in the legs after substantial weight loss.

New Approach for Obesity Treatment Incorporating Individual Self- Management Education

Background: Obesity is a global issue, and its prevalence is a major public health concern. To help resolve this obesity epidemic, we propose an education program for positive behavior change. This program incorporates diet and exercise behaviors at the individual level. Objective: To demonstrate the effects of a new approach for treating obesity by improving individual selfmanagement through investigating, i) behavior modification in the treatment of obesity, ii) the change of obesity states and physical performance capacity, and iii) the risk factors to be diagnosed with metabolic syndrome. Design: Twenty-four men during the 2011 and thirty-three men during the 2012 intervention contributed to the current study. Over 12 weeks, a total of 57 subjects participated in individual self-management education program. Results: For a short-term program, in both the years 2011 and 2012 subjects showed a decrease in daily energy intake (-30.1% and -27.7%) accompanied by an increase in daily energy expenditure (+5.7% and +5.9%), suggesting an ability of individuals to keep obesity under control through behavior therapy. Subjects also showed a marked change in obesity states and physical capacity such as decreased body weight (-12.1% and -13.6%), and higher VO2max (+22.0% and +21.4%). Further, our comprehensive protocol led to a improvement in components for metabolic syndrome; reduction in waist circumference (-10.4% and -11.7%), blood pressure (systolic: -12.9% and -9.8%; diastolic: -14.6% and -9.6%), fasting plasma glucose (-8.6%, -7.6%), and triglyceride (-60.6% and -46.7%) along with an increase in the levels of HDL-C (+16.5% and +10.5%) was seen. Conclusion: Under our protocol, subjects achieved optimal results for treating obesity during two consecutive years. We recognize that these results are due to an acquired ability like broader perspective and greater acumen about individual obesity management. Therefore, the methods and delivery of our new public approach are useful to the general public.

Effects of increasing physical activity on foot structure and ankle muscle strength in adults with obesity.

[Purpose] The purpose of this study was to examine the effects of increasing physical activity on foot structure and ankle muscle strength in adults with obesity and to verify whether the rate of change in foot structure is related to that in ankle muscle strength. [Subjects and Methods] Twenty-seven adults with obesity completed a 12-week program in which the intensity of physical activity performed was gradually increased. Physical activity was monitored using a three-axis accelerometer. Foot structure was assessed using a three-dimensional foot scanner, while ankle muscle strength was measured using a dynamometry. [Results] With the increasing physical activity, the participants’ feet became thinner (the rearfoot width, instep height, and girth decreased) and the arch became higher (the arch height index increased) and stiffer (the arch stiffness index increased); the ankle muscle strength also increased after the intervention. Additionally, the changes in the arch height index and arch stiffness index were not associated with changes in ankle muscle strength. [Conclusion] Increasing physical activity may be one possible approach to improve foot structure and function in individuals with obesity.

Weight reduction does not induce an undesirable decrease in muscle mass, muscle strength, or physical performance in men with obesity: a pilot study

[Purpose] To date, there have been no reports on whether weight reduction causes decreases in muscle mass, muscle strength, or physical performance that could lead to health problems. Thus, in this pilot study, we investigated the appropriateness of the changes in muscle mass, muscle strength and physical performance after weight reduction. [Methods] Obese men who completed a weight reduction program to decrease and maintain a body mass index (BMI) of less than 25 kg/m2 for one year were recruited for the study. One year after the completion of a weight reduction program, the participants’ muscle mass, muscle strength, and physical performance were compared with those in a reference group composed of individuals whose BMI was less than 25 kg/m2. Whole-body scanning was performed using dual-energy X-ray absorptiometry to analyze muscle mass. Handgrip strength and knee extensor strength were measured to evaluate arm and leg muscle strength, respectively. For physical performance, a jump test was employed. [Results] The results showed that the biceps, triceps, subscapular, and suprailiac areas of professional fashion models were significantly thinner than those of women in general (p<.001), and that their waist size was also significantly smaller (p<.001). However, hip circumference showed no significant difference. Body mass index, waist-to-hip ratio, and body fat (%) in professional fashion models were significantly lower than those in women in general (p<.001), while the body density in professional fashion models was significantly greater (p<0.001). [Conclusion] Weight reduction participants showed an average reduction in body weight of -16.47%. Normalized arm muscle mass and handgrip strength were significantly greater in the weight reduction group than in the reference group; however, no significant differences were detected between the two groups with respect to the other variables. After one year, there were no significant differences between the two groups.

Characteristics of foot morphology and their relationship to gender, age, body mass index and bilateral asymmetry in Japanese adults

BACKGROUND Different characteristics of foot morphology are commonly accompanied by altering lower extremity biomechanical characteristics and foot function. Clarifying what factors affect foot morphology is helpful in understanding the basis of foot deformity and foot dysfunction. OBJECTIVE The aim of this study was to investigate characteristics of foot morphology and whether related factors such as gender, age, body mass index (BMI) and bilateral asymmetry have an impact on foot morphology. METHODS One hundred and eighty adults without exercise habit were included in this cross-sectional study. Participants were categorized by gender, age, BMI, and left and right foot respectively to compare foot morphology differences. The characteristics of foot morphology were measured using a 3D foot scanner. RESULTS Compared with females, males had longer, larger and higher feet. In terms of age differences, older adults had shorter and stiffer feet. Regarding BMI differences, the value of height and width parameters of foot was larger, and the value of height of arch also larger in those with greater BMI. Regarding bilateral asymmetry, the right foot had a higher foot than the left foot. Multiple linear regression models indicated that gender, age and BMI significantly affected length and girth parameters of foot together. CONCLUSIONS This study showed that gender has a bigger impact on length, width, height and girth parameters of foot than BMI or age. BMI has an impact on both arch height and stiffness. Besides, bilateral asymmetry affects values of height parameters of foot and arch.

Weight loss may be a better approach for managing musculoskeletal conditions than increasing muscle mass and strength.

To prevent or remedy musculoskeletal conditions, the relationship between obesity and the characteristics of muscle mass and strength need to be clarified. [Subjects and Methods] A total of 259 Japanese males aged 30–64 years were classified into 4 groups according to the Japanese obesity criteria. Body composition was evaluated, and handgrip strength and knee extensor strength were measured for the upper and lower extremities, respectively. Physical performance was evaluated with a jump test. [Results] Obesity was positively correlated with skeletal muscle mass index, percentage of whole-body fat, and leg muscle strength and negatively correlated with the percentage of muscle mass index, body weight-normalized handgrip strength, and knee extensor strength, and the jump test results. [Conclusion] Weight loss may be a better approach than increasing muscle mass and strength to improve musculoskeletal conditions in obese adult males.

Association of Foot Structure with the Strength of Muscles that Move the Ankle and Physical Performance

ABSTRACT The human foot plays an important role in supporting body weight, maintaining postural balance, and absorbing ground reaction forces. Although many studies have indicated that a causal relationship exists between foot structure and alterations in lower extremity kinematics, there is little evidence regarding the possible association of foot structure with strength of muscles that move the ankle and physical performance. A total of 67 adult men with a mean age of 51.19 ± 8.82 years participated in this study. Foot structural parameters were assessed using a 3‐dimensional foot scanner. Strength of muscles that move the ankle was measured with a dynamometer. Physical performance items, including agility, force, and proprioception, were also measured. We found that all the measured parameters of the length, width, girth, and height of the foot were positively correlated with the strength of plantarflexion, dorsiflexion, eversion, and inversion (r ranged from 0.26 to 0.57; p < .05). Moreover, all or part of the parameters of the length, width, and girth of the foot but not the height and angles of the foot were correlated significantly with vertical jump, stepping forward and backward, and stepping side to side (r ranged from 0.25 to 0.44; p < .05). These findings indicate a weak‐to‐moderate association between foot structure and the strength of muscles that move the ankle, as well as physical performance. We therefore suggest that a larger foot may have greater muscle strength of the ankle joint and better physical performance. &NA; Level of Clinical Evidence: 3

Mild-to-Moderate Hallux Valgus Does Not Decrease Ankle Muscle Strength in Middle-Aged Japanese Women: A Comparative Study

ABSTRACT Extreme hallux valgus has been documented to be related to lower functional ability and health‐related quality of life. It also has a negative effect on foot structure and biomechanical characteristics, which in turn may affect muscle strength in the foot and ankle. Thus, the purposes of this study were to determine whether there is a difference of ankle muscle strength in varied hallux valgus deformities and to investigate correlations between hallux valgus angles and ankle muscle strength. Hallux valgus angles and ankle muscle strength data were collected from 31 middle‐aged Japanese women. The hallux valgus angle was measured with a 3‐dimensional foot scanner; ankle muscle strength was measured with a dynamometer. Results showed no differences in ankle muscle strength between normal and mild‐to‐moderate hallux valgus at both 60°/second and 120°/second (p > .05). Unexpectedly, women with mild‐to‐moderate hallux valgus had a greater value for inversion peak torque per body weight and eversion‐to‐inversion ratio than those with normal hallux valgus (p = .019 and p = .022) at 120°/second. Furthermore, hallux valgus was correlated with inversion peak torque and peak torque per body weight (r = 0.47; p = .012 and r = 0.50; p = .007) and associated with eversion‐to‐inversion strength ratio (r = –0.47; p = .012). The findings indicated that mild‐to‐moderate hallux valgus did not result in a decrease in ankle muscle strength. Conversely, mild‐to‐moderate hallux valgus had greater ankle inversion strength in middle‐aged Japanese women. Further studies are needed to investigate ankle muscle strength in severe hallux valgus deformities. &NA; Level of Clinical Evidence: 3

Association of arch height with ankle muscle strength and physical performance in adult men

Differences in arch height may have a certain impact on lower extremity muscle strength and physical performance. However, there is little evidence from investigation of the possible correlation of arch height with ankle muscle strength and physical performance measures. Sixty-seven participants took part in this study. Arch height index (AHI) was assessed and categorized using a 3-dimension foot scanner. Ankle muscle strength was measured employing a dynamometer. Physical performance measures including agility, force and proprioception were randomly tested. Compared to the medium AHI, the high AHI had lower plantarflexion and inversion peak torque. The high AHI also had lower peak torque per body weight value for plantarflexion and inversion at 120°/s (P = 0.026 and 0.006, respectively), and dorsiflexion at 30°/s (P = 0.042). No significant ankle muscle strength difference was observed between the low and medium AHI. Additionally, AHI was negatively correlated with eversion and inversion peak torque at 120°/s, and negatively associated with plantarflexion, eversion and inversion peak torque per body weight at both 30°/s and 120°/s (r ranged from -0.26 to -0.36, P values < 0.050). However, no significant relationship was found between arch height and physical performance measures. The results showed that high arches had lower ankle muscle strength while low arches exhibited greater ankle muscle strength. Arch height was negatively associated with ankle muscle strength but not related to physical performance. We suggest that the lower arch with greater ankle muscle strength may be an adaptation to weight support and shock absorption.