• Korean Journal of Exercise Nutrition
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• v.23 no.1
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• pp.48-54
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• 2019

[Purpose] The combined effect of different types of post-exercise treatment has not been fully explored. We investigated the effect of combined cold water immersion (CWI) and compression garment (CG) use after maximal eccentric exercise on maximal muscle strength, indirect muscle damage markers in the blood, muscle thickness, and muscle soreness score 24 h after exercise. [Methods] Ten men performed two trials (CWI + CG and CON) in random order. In the CWI + CG trial, the subjects performed 15 min of CWI (15℃), followed by wearing of a lower-body CG for 24 h after exercise. In the CON trial, there was no post-exercise treatment. The exercise consisted of 6 × 10 maximal isokinetic (60°·s^-1) eccentric knee extensions using one lower limb. The maximal voluntary contraction (MVC) and maximal isokinetic (60°·s^-1) strength during knee extension, as well as the indirect muscle damage markers, were evaluated before exercise and 24 h after exercise. [Results] The maximal muscle strength decreased in both trials (p < 0.001), with no difference between them. The exercise-induced elevation in the myoglobin concentration tended to be lower in the CWI + CG trial than in the CON trial (p = 0.060). The difference in the MVC, maximal isokinetic strength, muscle thickness, and muscle soreness score between the trials was not significant. [Conclusion] CWI followed by wearing of a CG after maximal eccentric exercise tended to attenuate the exercise-induced elevation of indirect muscle damage markers in the blood.

• Food Science of Animal Resources
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• v.23 no.3
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• pp.221-226
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• 2003

This study investigated the effect of different electrical stunning methods on pH, water holding capacity(WHC), cooking loss(CL), meat color and blood spot rate in broilers. One-hundred and forty broiler chickens were slaughtered by 50, 65 and 90 voltage with the same electrical frequency(255 Hz) and stunning time(5 sec) in commercial abattoir. The ultimate pH of leg muscle and WHC of breast muscle decreased with increasing the stunning voltage. However, there were no significant differences in ultimate pH, WHC and CL of breast muscle, and ultimate pH of leg muscle. Lightness(L*) and yellowness(b*) values of leg muscle stunned with 90V, 255 Hz, 5 sec were higher than those stunned with 50V, 255 Hz for 5 sec(p<0.05). But there were no significant differences in color value on skin, breast and wing muscle. Our experiments showed that change of stunning voltage affected some broiler meat quality parameters. However, further research is necessary to examine the effects of stunning condition on broiler meat quality.

• Korean Journal of Food Science and Technology
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• v.18 no.3
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• pp.173-180
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• 1986

To investigate on the biochemical characteristics of muscle fiber, myofibrils and actomyosins were prepared front red muscle and white muscle, and their ATPase activities and SDS-polyacrylamide gel electrophoretic patterns were compared. Also biochemical characteristics of bovine muscle were compared with those of chicken muscle for the detection of species characteristics. SDS-polyacrylamide gel electrophoretic analysis indicated that red muscle contained nlore 30K component of myofibril than white muscle. Differences in KCI concen-tration dependency of actomyosin ATPase activities and ATPase activity-pH cone were observed, when bovine muscle were compared with chicken muscle.

• Korean Journal of Applied Biomechanics
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• v.19 no.4
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• pp.617-625
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• 2009

The primary purpose of this study was to compare the hamstring-to-quadriceps strength(H/Q) ratios in collegiate soccer players and normal age-matched healthy students, and the secondary purpose was to investigate the changes in the H/Q ratio according to the degree of knee flexion. Twenty-five subjects volunteered to participate in this study. The study group comprised 12 healthy male collegiate soccer players, and the control group, 13 healthy age-matched male collegiate students. The modified N-K table was used for isometric strength measurement(unit: N). Mann-Whitney tests were performed to determine the differences in the H/Q ratios of soccer players and age-matched students at different knee flexion angles of the dominant leg. The strength of the hamstring muscle in the study group was significantly lower than that observed in the control group at knee flexion angles of $60^{\circ}$ (p<.001), $90^{\circ}$ (p<.01), and $120^{\circ}$ (p<05). The strength of the quadriceps muscle in the study group was significantly higher than that observed in the control group at flexion angles of $30^{\circ}$ (p<.001) and $60^{\circ}$ (p<.05). The H/Q ratios in the study and control groups differed significantly at all angles ($60^{\circ}$, p<.001, $90^{\circ}$, p<.001 and $120^{\circ}$, p<.001).

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.13 no.1
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• pp.44-57
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• 2007

Purpose: The objective of this study is to analyze the activities of muscles importantly functioning when walking with different inclinations and speeds of a treadmill, in order to provide basic data on walking exercise using a treadmill. Method: The selected subjects of this study were 16 men and women who had lower extremity injury. A treadmill was used to provide the activation of muscle, and the electromyography was used to analyze the muscle activity variables. The Biodex was used to measure the value of maximum isometric contraction. The inclinations of the treadmill were 0%, 5% and 10%, respectively, and its speeds were 2Km/h. 3Km/h, 4Km/h, 5Km/h, and 6Km/h, respectively. Result: For quadriceps femoris muscle and trunk muscle, there were significant differences in muscle activity when different speeds were applied at 0%, 5% and 10% inclinations.(p<0.05) The activity of vastus medialis muscle was 9.78% at 0% inclination and 2km/h speed, whereas it was 9.32% at 0% inclination and 3km/h, which was slightly lower. The activity of erector spinae muscle was 24.93% at 0% inclination and 2km/h speed, whereas it was 24.84% at 0% inclination and 3km/h, whereas it was 23.99% at 0% inclination and 4km/h, which was slightly lower. The activity of vastus medialis muscle was 11.89% at 10% inclination and 2km/h speed, whereas it was 10.65% at 10% inclination and 3km/h, which was slightly lower. The activity of rectus femoris muscle was 10.26% at 10% inclination and 2km/h speed, whereas it was 9.77% at 10% inclination and 3km/h, which was slightly lower. Conclusion: It was found that the activities of trunk muscle and quadriceps femoris muscle increase as the inclination and the speed of a treadmill increase during treadmill walking.

• Journal of Animal Science and Technology
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• v.53 no.4
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• pp.289-296
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• 2011

Swine industry in Korea plays an important role in providing the meat for domestic consumption, and the number of pigs in Korea was about 9.72 million heads as of June, 2010. Meat quality is used to describe any traits which impact the consumer acceptability of fresh meat products. Meat color, firmness, water holding capacity, ultimate muscle $pH_{24h}$ (measured 24 hours post-mortem), shear force, and intramuscular fat percentage (IMF) are generally accepted as important indicators of meat quality and ultimately, consumer acceptance of fresh pork. The objective of this study was to estimate genetic parameters for meat quality traits in Berkshire pigs. The heritability estimates for muscle $pH_{24h}$, lightness (CIE $L^*$), NPPC marbling were 0.61, 0.56 and 0.57, respectively, The heritability estimates for drip loss, cooking loss, shear force were 0.51, 0.66 and 0.56, respectively. The phenotypic correlations between $pH_{24h}$ and lightness (CIE $L^*$), drip loss, cooking loss were negative, ranging from -.45 ~ -.13. The genetic correlations between muscle $pH_{24h}$ and lightness (CIE $L^*$), drip loss were negative, ranging from -.35 ~ -.32. Genetic parameters obtained herein indicate that genetic improvement of muscle $pH_{24h}$ is not related to the NPPC marbling of meat, but rather to improved lightness(CIE $L^*$) and drip loss. Genetic trends of meat quality traits showed increased muscle $pH_{24h}$ and decreased cooking loss and drip loss.

• Food Science of Animal Resources
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• v.40 no.1
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• pp.34-43
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• 2020

The objectives of this study was to compare palatability changes of the longissimus thoracis (LT) and vastus lateralis (VL) muscles of Hanwoo steers from different beef quality grades (1⁺ and 1) during 28 d of wet-aging in order to improve the utilization of the VL muscle as a steak. The VL muscle showed a higher collagen content and a lower intramuscular fat content than the LT muscle (p<0.05). As expected, the Warner-Bratzler shear force value was greater in the LT 1 grade (LT-1) muscle than the LT-1⁺ muscle (p<0.05); whereas no difference was observed between the grades in the VL muscle at 24 h postmortem. Compared to 0 d of aging, tenderness scores significantly increased after 14 and 21 d of aging in the LT and VL muscles, respectively (p<0.05). Additionally, there was no difference in tenderness score between the VL-1⁺ aged for 21 d and the LT-1 at 24 h postmortem, although tenderness score was greater in the LT than the VL at each period (p<0.05). Moreover, the VL-1⁺ steak exhibited a higher tenderness score than the VL-1 steak at 21 and 28 d of aging (p<0.05). On the other hand, the effect of aging time on juiciness and flavor in the VL muscle was somewhat limited unlike the LT muscle. Taken together, the VL muscle requires a longer aging time than the LT muscle to improve consumer preference. Considering the tenderness, using a higher quality grade for aging is more useful in the VL muscle.

• Journal of Preventive Medicine and Public Health
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• v.52 no.4
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• pp.250-257
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• 2019

Objectives: Flatfoot, or low medial longitudinal arch, contributes to back and lower extremity injuries and is caused by weak abductor hallucis (AbdH) muscles. The purpose of this study was to investigate the effects of short foot exercise (SFE) alone or with neuromuscular electrical stimulation (NMES) on navicular height, the cross-sectional area (CSA) of the AbdH muscle, and AbdH muscle activity in flexible flatfoot. Methods: Thirty-six otherwise healthy people with flexible flatfoot were randomly assigned to a group that received SFE with placebo NMES treatment (the control group) or a group that received both SFE and NMES treatment (the experimental group). Each group received 4 weeks of treatment (SFE alone or SFE with NMES). Navicular height, the CSA of the AbdH muscle, and AbdH muscle activity were assessed before and after the intervention. Results: No significant differences were found in navicular height or the CSA of the AbdH muscle between the control and experimental groups, while AbdH muscle activity showed a statistically significant difference between the groups ($SFE=73.9{\pm}11.0%$ of maximal voluntary isometric contraction [MVIC]; SFE with $NMES=81.4{\pm}8.3%$ of MVIC; p<0.05). Moreover, the CSA of the AbdH muscle showed a statistically significant increase after treatment in the SFE with NMES group ($pre-treatment=218.6{\pm}53.2mm^2$ ; $post-treatment=256.9{\pm}70.5mm^2$ ; p<0.05). Conclusions: SFE with NMES was more effective than SFE alone in increasing AbdH muscle activity. Therefore, SFE with NMES should be recommended to correct or prevent abnormalities in people with flexible flatfoot by a physiotherapist or medical care team.

• Korean Journal of Food Science and Technology
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• v.20 no.1
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• pp.19-22
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• 1988

For decreasing the level of fluoride content in Antarctic krill, the changes of the content in solubel protein from the krill muscle depended on pH, ion species and ionic strength of the extracting solutions were investigated. The content of total fluoride of boiled muscle was higher than that of raw material, and the portions of fluoride with ionic form to the total content were 70% and 49%, respectively. In the effect of pH, fluoride contents of soluble protein from raw and boiled muscle showed the lowest values near 10. The effective ionic strength for decrease of fluoride content was 0.05M as NaCl at pH 11, and the content in the protein from raw material in this conditions was about 8 ppm.

• Korean Journal of Food Science and Technology
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• v.18 no.3
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• pp.226-233
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• 1986

Myofibrillar proteins were prepared from red muscle and white muscle, and their thermostabilities were compared. Rate constants of inactivation of myofibrillar proteins were increased as the ionic strength of reaction mixture increased and also dielectric constant of reaction mixture decreased. Thermodynamic data forinactivation of myofibrillar proteins, such as $D-value,\;{\Delta}H^{\ddag},\;{\Delta}G{\ddag}\;and\;{\Delta}S^{\ddag$, revealed that thermostabilities of myofibrillar proteins from white muscle were higher than those from red muscle, and that myofibrillar proteins from chicken muscle were more heatlabile than from bovine muscle.