• Physical Therapy Korea
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• v.21 no.1
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• pp.47-54
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• 2014

The aim of this study was to compare the duration of hamstring flexibility improvement after 3 stretching interventions in people with limited hamstring flexibility. Twenty-two subjects (12 men, 10 women) with limited hamstring flexibility of the dominant leg received 3 stretching interventions- modified dynamic stretching (MDS), hold-relax (HR), and static stretching (SS)-in a random order. All the subjects received all 3 interventions at intervals of at least 24 hours to minimize any carry-over effect. Modified dynamic stretching was applied as a closed kinetic chain exercise in the supine position by using the sling suspension system (Redcord Trainer(R)). The SS and HR interventions were individually performed in the straight leg raising (SLR) position, and all 3 interventions were performed for 3 minutes. Outcome measures included passive knee extension (PKE) measurements. Five post-test measurements were recorded for all subjects at 3, 6, 9, 15, and 30 minutes after the interventions. MDS was associated with a significant increase in knee extension range of motion even at 30 minutes post-treatment. In contrast, the HR and SS stretching methods showed increased hamstring flexibility for only 6 minutes post-treatment. Improvements in the range of motion of knee extension (indicating enhancement in hamstring flexibility) with MDS were maintained longer than those with the HR and SS interventions. Therefore, MDS may be more effective than the other interventions for maintaining hamstring flexibility.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.5
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• pp.669-676
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• 2007

This study was conducted to detect quantitative trait loci (QTL) affecting growth and body composition in an $F_2$ reference population of Korean native pig and Landrace crossbreds. The three-generation mapping population was generated with 411 progeny from 38 $F_2$ full-sib families, and 133 genetic markers were used to produce a sex-average map of the 18 autosomes. The data set was analyzed using least squares Mendelian and parent-of-origin interval-mapping models. Lack-of-fit tests between the models were used to characterize QTL for mode of expressions. A total of 8 (39) QTL were detected at the 5% genome (chromosome)-wise level for the 17 analyzed traits. Of the 47 QTL detected, 21 QTL were classified as Mendelian expressed, 13 QTL as paternally expressed, 6 QTL as maternally expressed, and 7 QTL as partially expressed. Of the detected QTL at 5% genome-wise level, two QTL had Mendelian mode of inheritance on SSC6 and SSC9 for backfat thickness and bone weight, respectively, two QTL were maternally expressed for leather weight and front leg weight on SSC6 and SSC12, respectively, one QTL was paternally expressed for birth weight on SSC4, and three QTL were partially expressed for hot carcass weight and rear leg weight on SSC6, and bone weight on SSC13. Many of the Mendelian QTL had a dominant (complete or overdominant) mode of gene action, and only a few of the QTL were primarily additive, which reflects that heterosis for growth is appreciable in a cross between Korean native pig and Landrace. Our results indicate that alternate breed alleles of growth and body composition QTL are segregating between the two breeds, which could be utilized for genetic improvement of growth via marker-assisted selection.

• Korean Journal of Applied Biomechanics
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• v.27 no.2
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• pp.83-90
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• 2017

Objective: To investigate the effect of short-term vibration frequencies on muscle force generation capabilities. Method: Six healthy participants were recruited for this study and only their dominant leg was tested. The subjects were tested under five conditions of vibration frequencies with constant amplitude: 0 Hz (no vibration), 30 Hz, 60 Hz, and 90 Hz, and the vibration amplitude was 10 mm for all frequency conditions. The vibration was applied to the rectus femoris (RF). The subjects were then instructed to maintain a steady-state isometric knee joint torque (100 Nm) for the first 6 s. After the steady-state torque production, the subjects were required to produce isometric knee joint torque by leg extension as hard as possible with a start signal within the next 3 s. The vibration was applied for ~4 s starting from 1 s before initiation of the change in the steady-state knee joint torque. Results: The results showed that the maximum voluntary torque (MVT) of the knee joint increased with the vibration frequencies. On average, the MVTs were 756.47 Nm for 0 Hz (no vibration) and 809.61 Nm for 90 Hz. There was a significant positive correlation (r = 0.71) between the MVTs and integrated electromyograms (iEMGs). Further, the co-contraction indices (CCIs) were computed, which represent the ratio of the iEMGs of the antagonist muscle to the iEMGs of all involved muscles. There was a significant negative correlation (r = 0.62) between the CCIs and MVTs, which was accompanied by a significant positive correlation (r = 0.69) between the iEMGs of the vibrated muscle (RF). There was no significant correlation between the MVTs and iEMGs of the antagonist muscle. Conclusion: The results of this study suggest that the short-term vibration on the muscle increases the level of muscle activation possibly owing to the increased Ia afferent activities, which enhances the muscle force generation capability.

• Physical Therapy Rehabilitation Science
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• v.3 no.1
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• pp.38-42
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• 2014

Objective: In this study, we applied a neurodynamic sciatic nerve sliding technique to healthy adults to elucidate its effects on hamstring flexibility and postural balance. Design: Cross-sectional study. Methods: This study targeted twenty four healthy adults (16 men, 8 women). A neurodynamic sciatic nerve sliding technique was applied 5 times to all subjects' dominant leg. The subjects were asked to sit on the bed while performing cervical and thoracic flexion, as well as knee flexion with ankle plantar flexion. Then, they were asked to perform cervical and thoracic extension and knee extension with their ankle in dorsiflexion and maintain the position for 60 s. For postural balance, we measured postural sway while the subjects maintained a one-legged standing posture using the Good Balance System and measured the hip joint flexion range of motion using a standardized passive straight leg raise (SLR) test. Results: SLR test increased significantly from $79^{\circ}$ before the intervention to $91.67^{\circ}$ after the intervention (p<0.05). Regarding the participants' balance evaluated using the one-legged standing test, the X-speed decreased significantly from 18.61 mm/s to 17.17 mm/s (p<0.05), the Y-speed decreased from 22.28 mm/s to 20.52 mm/s (p<0.05), and the velocity moment was significantly decreased from $89.33mm^2/s$ to $74.99mm^2/s$ after the intervention (p<0.05). Conclusions: Application of the neurodynamic sciatic nerve sliding technique exhibited improved hamstring flexibility and postural balance of healthy adults.

• Korean Journal of Applied Biomechanics
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• v.32 no.1
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• pp.9-16
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• 2022

Objective: The purpose of this study was to investigate how the chronic ankle instability affects postural control during forward jump landing. Method: 20 women with chronic ankle instability (age: 21.7 ± 1.6 yrs, height: 162.1 ± 3.7 cm, weight: 52.2 ± 5.8 kg) and 20 healthy adult women (age: 21.8 ± 1.6 yrs, height: 161.9 ± 4.4 cm, weight: 52.9 ± 7.2 kg) participated in this study. For the forward jump participants were instructed to stand on two legs at a distance of 40% of their body height from the center of force plate. Participants were jump forward over a 15 cm hurdle to the force plate and land on their non-dominant or affected leg. Kinetic and kinematic data were obtained using 8 motion capture cameras and 1 force plates and joint angle, vertical ground reaction force and center of pressure. All statistical analyses were using SPSS 25.0 program. The differences in variables between the two groups were compared through an independent sample t-test, and the significance level was to p < .05. Results: In the hip and knee joint angle, the CAI group showed a smaller flexion angle than the control group, and the knee joint valgus angle was significantly larger. In the case of ankle joint, the CAI group showed a large inversion angle at all events. In the kinetic variables, the vGRF was significantly greater in the CAI group than control group at IC and mGRF. In COP Y, the CAI group showed a lateral shifted center of pressure. Conclusion: Our results indicated that chronic ankle instability decreases the flexion angle of the hip and knee joint, increases the valgus angle of the knee joint, and increases the inversion angle of the ankle joint during landing. In addition, an increase in the maximum vertical ground reaction force and a lateral shifted center of pressure were observed. This suggests that chronic ankle instability increases the risk of non-contact knee injury as well as the risk of lateral ankle sprain during forward jump landing.

• Physical Therapy Korea
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• v.31 no.1
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• pp.40-47
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• 2024

Background: Single-leg squat (SLS)s are commonly used as assessment tool and closed kinetic exercises are useful for assessing performance of the lower extremities. Pronated feet are associated with foot pressure distribution (FPD) during daily activities. Objects: To compare the FPD during SLSs between groups with pronated and normal feet. Methods: This cross-sectional study included 30 participants (15 each in the pronated foot and control groups) are recruited in this study. The foot posture index was used to distinguish between the pronated foot and control groups. The Zebris FDM (Zebris Medical GmbH) stance analysis system was used to measure the FPD on the dominant side during a SLS, which was divided into three phases. A two-way mixed-model ANOVA was used to identify significant differences in FPD between and within the two groups. Results: In the hallux, the results of the two-way mixed-model ANOVAs revealed a significant difference between the group and across different phases (p < 0.05). The hallux, and central forefoot were significantly different between the group (p < 0.05). Moreover, significant differences across different phases were observed in the hallux, medial forefoot, central forefoot, lateral forefoot, and rearfoot (p < 0.05). The post hoc t-tests were conducted for the hallux and forefoot central regions. In participants with pronated foot, the mean pressure was significantly greater in hallux and significantly lower, in the central forefoot during the descent and holding phases. Conclusion: SLSs are widely used as screening tests and exercises. These findings suggest that individuals with pronated feet should be cautious to avoid excessive pressure on the hallux during the descent-to-hold phase of a SLS.

• Journal of Biomedical Engineering Research
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• v.34 no.4
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• pp.197-203
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• 2013

The purpose of this study was to analyze the asymmetry of the reaction forces on lower limbs between dominant and nondominant sides during sit-to-stand movement in normal subjects. Fourteen normal subjects ($22.6{\pm}2.3yrs$, all men) participated in this study. To measure the reaction forces during sit-to-stand movement, two force plates were mounted on the ground and one dual top force plate was mounted on a chair. Five events(movement onset, max thigh reaction force, transition, max hip angle, seat off) were determined from the reaction force and joint angle trajectories. For each of thigh, foot, and total reaction forces, two-way ANOVA was performed with the events and sides as factors. Also investigated was the leg asymmetry expressed as the ratio of the reaction forces of dominant and nondominant sides. The significance of asymmetry was investigated and two-way ANOVA was performed with the events and body parts(foot, thigh and total) as factors. Thigh reaction force and total reaction force showed interaction of events and leg sides(p < 0.01). Post-hoc comparisons showed they were different between sides at the latter stage(transition, max hip angle, and seat off events) (p < 0.01). Asymmetry was also significant at the latter stage(transition, max hip angle, and seat off events) (p < 0.01). Interaction of events and body parts on asymmetry was significant(p < 0.01) and asymmetry was greater in thigh reaction forces than total and foot reaction forces at the events of the latter stage(p < 0.01). The results suggest that asymmetry exist in normal subject and should be fully considered when investigating sit-to-stand strategy of patients.

• Journal of the Korean Society of Clothing and Textiles
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• v.23 no.3
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• pp.447-458
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• 1999

The purpose of this study was to analyze jeans market faced with economic difficulties to provide jean's maker with a large representative data base for jeans marketing strategy. This study surveyed jeans market and analyzed brand awareness. brand image and consumer's seeking image for 700 young adults. The 700 questionnaires were distributed at the five locations(Opkujung Shinchon Munjungdong, Shinrimdong '||'&'||' Suwon) and 656 reliable ones were used for statistical analysis. A. SAS statistical package including frequency table factor analysis. analysis of variance. and Duncan's multiple range test was used. The results are as follows : 1. Brand awareness involves "brand recall" based on asking a person to name recalled first and "brand rcognition" based on asking to identify brand name from 30 given brands. The result indicated that "Levis" was dominant for brand recall and Guess was dominant for brand recognition. 2. Regarding the brand image the result showed that "Vov" was best represented for sophisticated '||'&'||' trendy brand images "Storm" for characteristics brand image "Jambangee" for reasonable price '||'&'||' comfortable brand images and "Levis" for classic '||'&'||' design/color brand images. 3. As a result of factor analysis on consumer's seeking image six factors(characteristic/gay, intelligent/sexy, feminine/sophisticated , active/functional, cute/young, simple/comfortable) were found. Several factors had a relationship with demographic variables and preferred design. 4 Many young adults favored following design details ; low waist relaxed thigh with straight leg and long length up to the end of shoes. Also they preferred basic pocket to cargo pocket and simple logo accessories to metal ones.simple logo accessories to metal ones.

• Physical Therapy Rehabilitation Science
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• v.9 no.4
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• pp.275-280
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• 2020

Objective: Compression wear is an external aid which promotes performance and recovery, diminishes muscular microtrauma, reduces muscle fiber recruitment, improves neuromechanics, enhances coordinative activities, and reduces the perceived exertion. The purpose of this study was to investigate the relationship between athletic taping and compression wear on dynamic postural balance in healthy young men. The hypothesis was that the athletic taping and compression wear would affect dynamic postural balance, with athletic taping having a different effect on dynamic postural balance in healthy young adults. Design: Cross-sectional study. Methods: Thirty-seven healthy young men participated in this study. To examine the association between athletic taping and compression wear, 3 clinical measurement tools, including 5 times sit-to-stand (5xSTS), one-leg standing (OLS) test, and Y-balance test (YBT) in 5 different conditions, namely (1) non-supporting, and support with (2) athletic taping, (3) regular compression wear, (4) silicon compression wear, and (5) double-fiber compression wear were used. Results: The distance of the Y-balance test (YBT) on both the dominant and non-dominant sides showed a statistically difference among the 5 supporting conditions (p<0.05). The distance measured via the YBT in the non-support condition was significantly different than that in the other four supporting conditions (p<0.05). However, 5xSTS and OLS were not significantly different in these supporting conditions. Conclusions: The results of this study suggest that athletic taping, silicon compression wear, and double-fiber compression wear were more effective for dynamic balance than non-supporting and regular compression wear.

• Journal of Navigation and Port Research
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• v.35 no.4
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• pp.323-334
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• 2011

Suspended and sinking particles were collected in austral summer during ODP Leg 119 to the Indian Ocean sector of the Antarctic Ocean. Field work was carried out at four sampling sites in Prydz Bay. Two of these sites were located in the Outer Bay, and two in the Inner Bay. At the four locations, a total of ten deployments of a sediment trap array were made. The concentrations of chlorophylls and their degradation products both in suspended and sinking particulate matter in Prydz Bay were analyzed using HPLC. Chlorophylls a and c were the dominant algal pigments both in suspended and sinking particles. Because of the abundance of fecal pellets at Site 740, the mean fluxes at 200 m averaged 6 fold greater than that at 50 m. This implies that a dense swarm of zooplankters, presumably large copepods and/or salps, may "feed and excrete" mainly in between 100-200 m depths at this site, closest to land in Prydz Bay. Interestingly, The flux of phaeophorbide a was generally similar in magnitude to that of chlorophyll a throughout the study areas. This is an evidence that materials escaping from near-surface regions in austral summer derive mainly from the gazing of zooplankters. "New production" from sediment-trapped CHL pigment fluxes in Prydz Bay was estimated using f-ratio of 0.15, ranging from 520 to $1,605\;{\mu}gC\;m^{-2}\;day^{-1}$.