• PNF and Movement
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• v.19 no.3
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• pp.331-340
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• 2021

Purpose: The purpose of this study was to investigate the differences in body composition, upper and lower limb muscle strength, and functional physical ability in urban-dwelling elderly women with or without obesity. Methods: All study participants were assigned to the normal weight group (n=8, BMI<25) and the obesity group (n=7, BMI>25) based on their obesity rate. Anthropometric measurement was conducted and body composition was measured. For the upper and lower limb strength, grip strength and maximal isometric knee extension and flexion were evaluated by a dynamometer. The senior fitness test was performed to measure functional ability. Data analysis was conducted by the independent t-test and the alpha level was set at 0.05. Results: The waist, hips, and thighs of obese elderly women were thicker than those of normal-weight elderly women. This physical difference resulted from body fat mass, not muscle mass. Despite a similar level of limb muscle mass between the two groups, the upper limb grip strength was higher (24.00% for left, 19.95% for right) in the normal-weight women than the obese women (p<0.05), but otherwise there was no difference in maximal knee flexion or extension isometric strength. Functional physical ability showed no difference in a 30-second chair sit and stand test and a six-minute walk test, but a 30-second arm-curl (11.00% for left, 14.81% for right), back stretch (8.54cm for left, 8.99cm for right), chair sit and reach (9.22cm for left, 6.24cm for right), and 2.44 meter round trip walk (0.62 sec, 9.39%) were faster in performance for normal-weight elderly women than obese elderly women (p<0.05). Conclusion: Taken together, despite similar levels of upper and lower extremity muscle mass, normal-weight elderly women showed higher performance in upper limb strength, flexibility, and agility than obese elderly women, but there was no difference in lower extremity functional muscle strength and cardiopulmonary endurance.

• Journal of the Korean Society of Physical Medicine
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• v.12 no.3
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• pp.111-117
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• 2017

PURPOSE: To determine the effect of weight ball throw training as a preparatory exercise before golf practice for 8 weeks on back muscle strength, weight shifting of lower body, head speed of club, and driving distance of amateur golfers. METHODS: A total of 18 subjects were randomly assigned to the experimental group (n=9) and the control group (n=9), respectively. For the experimental group, Weight ball throw training was provided to the height of waist and shoulder similar to golf swing with the following schedule: 3 kg weight ball throw training from the first week to the 4th week; 5 kg weight ball throw training from the 5th week to the 8th week. Before and after 8 weeks of training, back muscle strength, weight shifting of lower body, head speed of club, and driving distance of subjects in the two groups were measured. RESULTS: The experimental group showed significant differences in rotational back extension torque, weight shifting of lower body, head speed of club, and driving distance during golf swing (p<.05). However, the control group only showed significant difference in driving distance during golf swing (p<.05). Back extension torque, weight shifting of lower body, and head speed of club showed significant differences between the two groups during golf swing (p<.05). CONCLUSION: Weight ball throw training can positively change rotational back muscle strength, weight shifting of lower body, head speed of club, and driving distance of amateur golfers. Therefore, it might be used as an effective warming up exercise for amateur golfers.

• Physical Therapy Korea
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• v.27 no.1
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• pp.45-52
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• 2020

Background: A backpack is available equipment for moving some objects. Most studies have found that the appropriate weight limit of backpack for students is between 10% to 15% of their body weight (BW). However, Some students should carry a backpack heavier than 15% of BW. Therefore, It is associated with abnormal shoulder and neck posture on students. Objects: This study tested the effects that various amounts of weight carried by university students in their backpacks had on their cervical posture and electromyography of neck muscle. Methods: The subjects consisted of 12 students (6 male, 6 female) in university. There were three loading conditions tested: no backpack, a backpack that weighed 10% and 15% of the student's BW. The dependent variables were the craniovertebral angle (tragus to C7) and the neck muscle activities (sternocleidomastoid, upper trapezius). All 12 subjects were asked to walk while wearing a backpack for 5 minutes and were then instructed to rest for 2 minutes. Results: When assessing the craniovertebral angle, the results of this study were significantly decreased in the order of 0%, 10%, and 15%. And then, there were significantly increased electromyography of neck muscles that comparison of the weight of 10% and 15% on 0%. It was found that as the weight of the backpack increased, the craniovertebral angle decreased (p < 0.05) and the muscle activities increased (upper trapezius p = 0.012, sternocleidomastoid p = 0.013). Conclusion: Our study recommended that some students shouldn't carry on over the 15% backpack of own weight, and also they should distribute backpack load to equal on body for optimal posture.

• Journal of Preventive Medicine and Public Health
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• v.45 no.6
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• pp.381-386
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• 2012

Objectives: To investigate the link between cigarette smoking and muscle strength in Japanese men. Methods: We used data on 4249 Japanese men, aged $43.3{\pm}13.9$ years, in this cross-sectional investigation study. Grip strength and leg strength were measured as indicators of overall muscle strength. Meanwhile, subjects' cigarette smoking habits were recorded by trained medical staff. The effect of cigarette smoking on muscle strength was evaluated. Results: A total of 1618 men (38.1%) were smokers and 1481 men (34.9%) exercised regularly. Significant differences in muscle strength were noted between men with and without a Brinkman index of 400 or greater, after adjusting for age. After adjusting for age, height, body weight and exercise habits, associations between the Brinkman index and leg strength and the ratio of leg strength to body weight were attenuated. Conclusions: Cigarette smoking might be negatively associated with muscle strength, especially grip strength in Japanese men.

• Korean Journal of Exercise Nutrition
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• v.23 no.1
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• pp.1-6
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• 2019

[Purpose] To date, there have been no studies on the response of wrist tremor to increased muscle activity during exercise. This study aimed to evaluate the wrist tremor response with increasing muscle activity during bench press exercise. [Methods] Triceps muscle activity and wrist tremor response were measured by electromyography and an accelerometer, respectively, during bench press exercise in 11 healthy men without weight-training experience. Subjects performed bench press at 30% repetition maximum (RM), and the rating of perceived exertion (RPE) and lactate concentration were measured before and after exercise. One week later, an equivalent number of bench presses at 30% RM was performed without weight load as a control trial (CT). [Results] RPEs and lactate concentrations significantly increased after resistance exercise (30% RM) from 7.4 to 14.3 and 1.7 to 4.9, respectively (P<.01), but no such difference was observed in the CT. Muscle activity linearly increased during the 30% RM exercise, and wrist tremors were shown to linearly decrease. A strong negative correlation was observed between the two variables (r=-0.88, P<.001). [Conclusion] We found that wrist tremors during resistance exercise, as measured using an accelerometer, can be used to predict muscle activity.

• The Korean Journal of Physiology
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• v.26 no.2
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• pp.159-166
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• 1992

The present study was designed to evaluate effects of intermittent electrical stimulation of the sciatic nerve on the atrophic response of antigravity muscles, such as the soleus (slow m.) and medial gastrocnemius (fast m.) muscles. Rats (Sprague-Dawley, 245-255g) were subjected to a hindlimb suspension and divided into three groups : one was with hindlimb suspension (MS) and another with hindlimb suspension plus intermittent electrical stimulation of the sciatic nerve (HS ES). Control group (CONT) was kept free without strain of the hindlimb. After 7 days of hindlimb suspension, the soleus and medial gastrocnemius muscles were cut at their insertion sites, and were then connected to the force transducer to observe their mechanical properties. Optimal pulse width and frequency of electrical stimulation were 0.2ms, 20Hz for the soleus muscle and 0.3ms, 40Hz for the medial gastrocnemius muscle under supramaximal stimulation. Body weight and circumference of the hindlimb were significantly decreased in HS and HS-ES groups compared with the control group. In HS-ES group, however, the weight of the soleus muscle was not different from that in the control group while the weight of the medial gastrocnemius muscle was lower than that in the control group. In HS group, mechanical properties of muscle contraction including contraction time, half relaxation time, twitch tension, tetanic tension, and fatigue index of both muscles were significantly decreased compared with the control group except for twitch tension and tetanic tension of medial gastrocnemius muscle. The degree of atrophy of the soleus muscle in HS group was more prominent than that of the medial gastrocnemius muscle. Twitch tension and fatigue index of the soleus muscle and fatigue index of the medial gastrocnemius muscle in HS-ES group were not different from those of the control group. While mechanical properties of the soleus muscle examined were all significantly increased in HS-ES group compared with HS group, only contraction time and fatigue index of the medial gastrocnemius muscle were significantly increased in HS-ES group. These data indicate that intermittent electrical stimulation may be useful in prevention of muscle atrophy.

• Food Science of Animal Resources
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• v.44 no.1
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• pp.51-73
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• 2024

This study investigated how birth weight differences in piglets affected carcass and muscle fiber properties as well as meat quality at slaughter. Within litters, piglets were grouped according to their birth weight as either normal (NBW; 1.62-1.73 kg) or low (LBW; 1.18-1.29 kg). At 5 weeks of age, NBW piglets were randomly transitioned to control (C) or isocaloric high fat diets derived from non-dairy (HF), while LBW piglets were randomly transitioned to high fat diets derived from non-dairy (HF) or dairy sources (HFHD). Piglets were reared in individual pens under standardized housing and feeding conditions. Live weight was recorded weekly, and pigs were slaughtered at 12 weeks of age. Hot carcass weights, dressing percentages, lean meat yield, and primal cut proportions were determined. The m. longissimus thoracis was collected from the right side of the carcass for measurement of physical and chemical properties of meat and muscle fiber characteristics. Results indicated that LBW pigs compensated for their live weight compared to NBW pigs at 6 weeks of age. The mean muscle fiber diameter of LBW-HFHD group is significantly higher than NBW-C and NBW-HF group, and the type I muscle fiber diameter is significantly higher than NBW-C group. Dairy fat inclusion in LBW pig diet reduced carcass back fat thickness. This increased the calculated lean meat yield to be comparable to that of NBW pigs fed a commercial diet. Incorporating dairy-sourced high-fat into LBW pigs' diets appears to be an effective strategy for producing carcasses equivalent to NBW pigs.

• Journal of the Ergonomics Society of Korea
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• v.29 no.3
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• pp.279-286
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• 2010

The purpose of this study was to compare the electromyographic(EMG) activities of trunk and hip muscles between right and left sides while subjects performed prolonged manual task in asymmetric and symmetric weight-bearing posture. Fifteen healthy male college students were recruited for this study. The subjects were asked to perform bimanual upper extremity task for 6 minutes in two different standing postures. In the symmetric weight-bearing posture, the subjects were standing with evenly distributed body weights to both legs. In the asymmetric weight-bearing posture, the subjects distributed about 90% of their body weight onto their preferred(supporting) leg and 10% of their body weight onto the opposite leg while they were standing. EMG activities of the right and left internal oblique, erector spinae, gluteus maximus, and gluteus medius were measured and normalized as % MVIC. Then the EMG data were statistically analyzed using paired t-tests. The EMG activities of all measured muscles were not significantly different between the right and left side in the symmetrical weight-bearing posture(p>0.05). However, the EMG of the supporting side internal oblique was significantly lower than the opposite side(p<0.05), and the EMG of the erector spinae, gluteus maximus, and gluteus medius were significantly greater on the supporting side(p<0.05). The results of this study support that unbalanced use of right and left muscle possibly causes the changes in muscle length which results in asymmetry of trunk and hip muscles. Furthermore, the uneven weight support onto right and left legs will cause a distortion of viscoelastic ligaments around hip and sacroiliac joints in the long run. Further studies to determine the effect of various manual tasks on the trunk and hip muscles as well as the effect of asymmetrical weight-bearing standing posture on hip and back muscle fatigue may be required.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1760-1764
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• 2002

In order to elucidate the physiological function of circulating IGF-I on muscle protein synthesis in the chicken under malnutritional conditions, we administrated recombinant chicken IGF-I using a osmotic mini pump to fasted young chickens and measured the rate of muscle protein synthesis and plasma metabolite. The pumps delivered IGF-I at the rate of $22{\mu}g/d\{300{\mu}g{\cdot}(kg\;body\;weight{\cdot}d)^{-1}\}$. Fractional rate of protein synthesis in the muscle was measured using a large dose injection of L-[$2,6-^3H$]phenylalanine. Constant infusion of chicken IGF-I did not affect plasma glucose level. Significant interaction between dietary treatment and IGF-I infusion was observed in plasma NEFA and total cholesterol concentrations. When chicks were fasted, IGF-I infusion decreased plasma NEFA and total cholesterol concentrations. On the other hand, IGF-I administration did not affect plasma levels of both metabolites. Fasting reduced plasma triglyceride concentration significantly. IGF-I infusion also decreased the level of plasma triglyceride. Plasma IGF-I concentration of young chickens was halved by fasting for 1 d. IGF-I infusion using an osmotic minipump for 1 d increased plasma IGF-I concentration in fasted chicks to the level of fed chicks. Fasting decreased body weight and the loss of body weight was significantly ameliorated by IGF-I infusion. There was a significant interaction between dietary treatment and IGF-I infusion in the fractional rate of breast muscle protein synthesis. There was no effect of IGF-I infusion on muscle protein synthesis in fed chicks. Muscle protein synthesis reduced by fasting was ameliorated by IGF-I infusion, but did not reach to the level of fed control. Muscle weight of fasted chicks infused with IGF-I was similar to fasted birds without IGF-I infusion, which suggests that muscle protein degradation would be increased by IGF-I infusion as well as protein synthesis in fasted chicks.

• Korean Journal of Applied Biomechanics
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• v.21 no.3
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• pp.297-308
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• 2011

The purpose of this study was to investigate the relationship among isometric and isokinetic muscle strength, lean body mass(LBM) and bone mineral density(BMD) in the elderly. Eleven males(age, 70.27${\pm}$5.78yr; height, 167.36${\pm}$6.68 cm; weight, 68.34${\pm}$8.23 kg) and thirteen female(age, 69.77${\pm}$4.13yr; height, 152.80${\pm}$4.45 cm; weight, 56.86${\pm}$7.40 kg) participated in this study. In all subjects, LBM and BMD segments was measured by using Dual-energy x-ray absorptiometry(DEXA, Lunar DPS-DM, U.S.A.). Maximum isometric and isokinetic muscle strength of flexion and extension at the knee and elbow, ankle, trunk joints were measured by using an isokinetic dynamometer(CON-TREX(R) Multi Joint Testing Module, Switzerland). The results of this study showed that isometric and isokinetic muscle strength was significantly higher in extension than flexion. In the male and female, hamstring to quadriceps strength ratio(H:Q ratio) was increased as contraction velocity increased. BMD was correlated significantly with trunk extension in the male, but not in the female. LBM was correlated significantly in the male and female with knee extension strength. This study suggests that in the elderly muscle strength training program should put more weight on extensor muscles of the body.