• The Journal of Korean Physical Therapy
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• v.36 no.4
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• pp.124-130
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• 2024

Purpose: This study aimed to investigate the effects of weight-bearing exercises, including deadlifts, on the balance ability, gait patterns, and leg strength in patients who have undergone knee replacement surgery, thus emphasizing the importance of strengthening the leg muscles. Methods: The subjects included nineteen patients diagnosed with degenerative arthritis and who underwent knee arthroplasty at H Hospital in B City. Following the surgeon's recommendations and patients' consent, they were prescribed exercises starting 7 days post-surgery, 3 times a week for 8 weeks, including a 10-minute warm-up, 20-minute main exercise, and 15-minute cool-down exercises. Results: The fall index significantly decreased, indicating improved balance. The gait cycle significantly decreased, while step length increased. However, the increase was not statistically significant. Walking speed significantly increased, and step time significantly decreased. The sit-to-stand time significantly decreased, indicating improved leg strength. Conclusion: In conclusion, weight-bearing leg exercises for knee arthroplasty patients led to significant improvements in balance abilities, gait patterns, and leg strength. This signifies the need to incorporate active weight-bearing leg exercises from an early stage post-surgery. Additionally, weight-bearing leg strengthening exercises can increase the accessibility of exercises for knee arthroplasty patients, emphasizing the importance of early exercise and motivation in their treatment. Therefore, functional leg strengthening exercises, including weight-bearing routines, should be implemented early on in clinical settingsI, alongside traditional pain reduction and joint range of motion exercises, to maximize recovery outcomes and enhance overall patient mobility and quality of life.

• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.75-78
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• 1997

A dual birdcage RF coil is proposed for MRI and MRA of the human leg. The proposed coil c can be used to cover the whole human leg by imaging upper and lower parts of the leg separately. In the conventional leg imaging scheme using a single RF coil, the leg has to be r relocated when changing the position of the RF coil thus causing problems in matching the i images from two sets of coils. When using the proposed dual RF coil, however, only the bed h has to be moved to select the imaging region while only one part of the dual coil is used each t time by using current switching and PIN diodes. The utility of proposed coil has been verified b by volunteer MRI and MRA and the imaging results show that the coil is useful for the clinical MRI and MRA of the leg.

• PNF and Movement
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• v.15 no.2
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• pp.177-183
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• 2017

Purpose: This study compared and analyzed the effect of the proprioceptive neuromuscular facilitation (PNF) arm extension pattern and leg flexion pattern on the contralateral lower extremity muscles when the patterns were applied to the same subject. Methods: In the study, 35 healthy men and women who understood the PNF patterns were selected as participants. The participants completed the PNF arm extension-abduction-internal rotation pattern and leg flexion-adduction-external rotation with knee flexion pattern in the supine position. While the patients' completed each pattern, the contralateral leg muscle activity was measured to examine the irradiation effect. The maximum isometric contraction time of the muscles to be measured was kept for 5 seconds, and the mean value was obtained by repeating the pattern three times. Results: When the leg flexion-adduction-external rotation with knee flexion pattern was completed, the muscle activity in the vastus lateralis, vastus medialis, biceps femoris, tibialis anterior, and gastrocnemius of the contralateral lower extremity was significantly greater than that found in the PNF arm extension-abduction-internal rotation pattern. Conclusion: The PNF leg flexion pattern showed greater muscle activity on the contralateral lower extremity than the arm extension pattern. Thus, the PNF leg extension pattern is more effective in the activation of the muscles associated with weight-bearing activity.

• Journal of Power Electronics
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• v.16 no.6
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• pp.2231-2242
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• 2016

A simplified model predictive control method is presented in this paper. This method is based on a future reference voltage vector for a three-phase four-leg voltage source inverter (VSI). Compared with the three-leg VSIs, the four-leg VSI increases the possible switching states from 8 to 16 owing to a fourth leg. Among the possible states, this should be considered in the model predictive control method for selecting an optimal state. The increased number of candidate switching states and the corresponding voltage vectors increase the calculation burden. The proposed technique can preselect 5 among the 16 possible voltage vectors produced by the three-phase four-leg voltage source inverters, based on the position of the future reference voltage vector. The discrete-time model of the future reference voltage vector is built to predict the future movement of the load currents, and its position is used to choose five preselected vectors at every sampling period. As a result, the proposed method can reduce calculation load by decreasing the candidate voltage vectors used in the cost function for the four-leg VSIs, while exhibiting the same performance as the conventional method. The effectiveness of the proposed method is demonstrated with simulation and experiment results.

• Journal of Fashion Business
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• v.7 no.1
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• pp.27-37
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• 2003

This study is the first part of the research to reveal the effects of somatotype characteristics on body temperature control reaction as well as thermal sensation. Nine healthy female collegians (classified into 3 body types of thin, normal, and obese according to Rohrer index) living in Busan were chosen as the subjects. The following are the results: Significant differences of skin temperature appeared in the parts of epigastrium (thin/normal>obese), anterior forearm (normal>thin/obese), and anterior leg (obese > thin/normal) as well as mean skin temperature. Mean skin temperature temporarily dropped owing to the exercise but tended to recover as time went by. Skin temperature of normal/thin shows higher than obese type. The change of skin temperature was noticed in the order of forehead > epigastrium > anterior forearm > anterior leg > anterior thigh (obese type) ; epigastrium > forehead > anterior forearm > anterior thigh > anterior leg (normal type) ; epigastrium > forehead > anterior forearm > anterior thigh > anterior leg (thin type, before and after exercise); epigastrium > forehead > anterior forearm > anterior leg > anterior thigh (thin type, during exercise). Significant differences were shown in the temperature change inside clothes according to somatotypes. No significant differences were revealed in thermal sensation, moisture sensation, and comfortable sensation according to body types and time.

• Korean Journal of Applied Biomechanics
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• v.18 no.1
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• pp.179-190
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• 2008

The purpose of this study was to identify whether or not in one-leg vertical jump of each limb asymmetry between both sides is present and to identify how the discrepancies between both limbs affect two-leg jumping performance, that is bilateral deficit. We had 13 healthy subjects perform one-leg jump for both sides and two-leg countermovement jump. The result of biomechanical analysis showed significantly difference of 4-7% in net impulses and work output between dominant and non-dominant one-leg jump and bilateral deficit of 24% when sum of those of each one-leg jump was compared with two-leg jump. But asymmetry in lower extremity was not significantly correlated with bilateral deficit. Two-leg jump could be characterized by relatively short propulsion time, long propulsion distance and high joint angular velocity compared with one-leg jump. These factors seemed to contribute to decreased performance in two-leg jump. Furthermore bilateral deficit was attributed to lower activities of extensor muscles found in two-leg jump.

• Korean Journal of Human Ecology
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• v.24 no.4
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• pp.555-569
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• 2015

During a design process of a protective equipment for sports activities, minimizing movement restrictions is important for enhancing its functions particularly for protection. This study presents a three-dimensional(3D) modeling methodology for designing baseball catcher's leg guards that will allow maximum possible performance, while providing necessary protection. 3D scanning is performed on three positions frequently used by a catcher during the course of a game by putting markings on the subject's legs at 3cm intervals : a standing, a half squat with knees bent to 90 degrees and 120 degrees of knee flexion. Using data obtained from the 3D scan, we analyzed the changes in skin length, radii of curvatures, and cross-sectional shapes, depending on the degree of knee flexion. The results of the analysis were used to decide an on the ideal segmentation of the leg guards by modeling posture. Knee flexions to 90 degrees and to $120^{\circ}$ induced lengthwise extensions than a standing. In particular, the vertical length from the center of the leg increases to a substantially higher degree when compared to those increased from the inner and the outer side of the leg. The degree of extension is varied by positions. Therefore, the leg guards are segmented at points where the rate of increase changed. It resulted in a three-part segmentation of the leg guards at the thigh, the knee, and the shin. Since the 120 degree knee-flexion posture can accommodate other positions as well, the related 3D data are used for modeling Leg Guard (A) with the loft method. At the same time, Leg Guard (B) was modeled with two-part segmentation without separating the knee and the shin as in existing products. A biomechanical analysis of the new design is performed by simulating a 3D dynamic analysis. The analysis revealed that the three-part type (A) leg guards required less energy from the human body than the two-part type (B).

• Korean Journal of Applied Biomechanics
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• v.26 no.1
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• pp.101-113
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• 2016

Objective: The purpose of this study was to investigate the effect of leg length discrepancy (LLD) on the human body during gait and standing posture. Methods: The study group comprised of 17 adult participants with LLDs of <1 cm. LLDs were artificially induced to 0, 1, 2, and 3 cm. The proportion of weight distribution, shift of the mean center of pressure, and Cobb's angle were measured in the standing position. Kinematic variables such as walking and striding width and time, and the proportion of stance phase for single- and double-limb gait were measured as well. The participants were required to either stand or walk on a treadmill (Zebris FDM) with a pressure plate, and the Cobb's angle measurements were obtained from radiographs. Results: A discrepancy of 3 cm in leg length resulted in a statistically significant shift of the center of pressure in the standing position. Moreover, the Cobb angle increased as the discrepancy became larger. The step length and width of the longer (left) leg during gait statistically significantly increased when the discrepancy was 2 cm. In addition, step time was statistically significant when the discrepancy between the longer (right) and shorter (left) legs was more than 2 cm. The proportion of single-limb stance phase was statistically significant as the discrepancy became larger, especially when the discrepancy was >2 cm for the longer (right) leg and 1 cm for the shorter (right) leg. Conclusion: The study showed that LLD influenced deformations of the human body and walking.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.25 no.1
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• pp.29-36
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• 2019

Background: This study was conducted to investigate the effect of leg lift difference on the serratus anterior muscle and the upper trapezius muscle when a subject with winged scapula performs a scapula protraction exercise in a four-leg crawling posture. Method: Twenty normal adults and 20 subjects with winged scapula participated in the experiment. Surface EMG recordings were collected from serratus anterior muscle and back trapezius muscle during scapula protraction exercises. Scapular winging is measured with the lifting distance of scapula retraction to the back using an electronic digital caliper. In two groups of four-leg crawling posture, the two legs support, the dominant leg lifting, and the non-dominant leg lifting, including the scapula protraction, were performed. To examine the difference between groups in the variance analysis, the Bonferroni correction was used (significance level ${\alpha}=.017$). Statistical significance level ${\alpha}$ was .05. Results: There was a significant difference in serratus anterior muscle and upper trapezius muscle during push-up plus exercise in leg lifting in four-leg crawling posture, but there were no significant differences in muscle activity between serratus anterior muscle and upper trapezius muscle, and there was no significant difference according to the presence or absence of scapular winging. Conclusion: For the shoulder stability of the ipsilateral side with the serratus anterior muscle, the leg-lifting posture is effective in the four-leg crawling, and also when a subject with winged scapula chooses an exercise, lifting the ipsilateral side of leg with scapula protraction exercises at the same time may have a positive effect on scapula dysfunction.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.21 no.1
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• pp.5-11
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• 2015

Background: The purpose of this study was to investigate the effects of Mulligan's straight leg raise with traction technique and hold-relax technique on flexibility of hamstring in people with shortened hamstring. Methods: Thirty two subjects participated in this study. The subjects were assigned to either the Mulligan's straight leg raise with traction technique group (n=16) or the hold-relax technique group (n=16). 90-90 straight leg raise test was performed for evaluation of hamstring shortening at initial time of study. After intervention, immediate effect (immediately after intervention) and lasted effect (60 min after intervention) were assessed. Results: In the both Mulligan's straight leg raise with traction technique and hold-relax technique groups, significant improvements on flexibility of hamstring was observed in immediately and 60 minute after intervention (p<.05). However, there are no significant difference was observed between groups (p>.05). Conclusion: In the results of this study, both Mulligan's straight leg raise with traction technique and hold-relax technique show immediately and 60 minute after evaluation effectiveness in flexibility of hamstring of people with shortened hamstring. In addition, although the difference is not statistically significant, Mulligan's straight leg raise with traction technique was more increased average extension angle of knee joint at 90-90 straight leg raise test than the hold-relax technique.