• Journal of Korean Physical Therapy Science
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• v.27 no.1
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• pp.9-17
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• 2020

Background: This study aimed to examine the repeatability of hamstring strength during maximal voluntary contractions (MVCs) and to examine the sex difference. Design: Quasi-experiment design. Methods: The study recruited 23 healthy young individuals as participants. Hamstring flexibility was measured before and after MVCs by active knee extension test. Five trials of MVCs were performed, and hip extension forces were measured using a strain gauge during MVCs. Repeatability was confirmed by intraclass correlation coefficient (ICC) and coefficient of variation, and the difference between male and female participants was confirmed by independent samples t-test. Results: The forces measured during MVCs were significantly different between men and women over five trials. We observed the minimum and maximum force production at the first and fifth trial of MVCs in both men and women. Excellent to moderate reliability of the hamstring strength during MVCs was found in men (ICC range, 0.70-0.98) and women (ICC range, 0.66-0.90). There was no significant difference in hamstring flexibility between men and women. Conclusion: In clinical settings, we recommend excluding the first trial of MVCs in both men and women. Additionally, performing at least three trials of MVCs would be useful to improve the reliability of the baseline measures in women.

• Journal of the Korean Society of Physical Medicine
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• v.11 no.1
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• pp.83-91
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• 2016

PURPOSE: There are several methods, such as the abdominal drawing-in maneuver (ADIM), maximal expiration (ME), and Kegel exercise, to strengthen the core muscles. However, to date no study has been conducted to compare the effects of the ADIM, ME, and Kegel exercise on the transverses abdominis (TrA), internal oblique (IO), external oblique (EO), and pelvic floor muscles (PFMs). The purpose of this study was to find out which of the three aforementioned exercises is most effective for contracting the core muscles. METHODS: The thickness of the TrA, IO, EO and PFMs was measured by ultrasonographic imaging during the ADIM, ME and Kegel exercise in 34 healthy participants. RESULTS: There was the significant difference between ADIM and Kegel exercise in the thickness of the TrA (p<0.05). There were the significant differences between ADIM and ME and between ME and Kegel exercise in the thickness of the IO and PFM (p<0.01). There was no significant activation in the thickness of the EO (p>0.05). Measurement reliability was assessed using intraclass correlation coefficients (ICC) and the standard error of measurement (SEM). An ICC value of >0.77 indicated that reliability measurements was good. CONCLUSION: Kegel exercise was the most effective exercise for the TrA and the PFM, and ME was the most effective exercise for the IO muscles.

• Physical Therapy Korea
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• v.14 no.2
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• pp.29-36
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• 2007

Muscle tone (stiffness/hardness) or muscle compliance changes during muscle contraction. The purposes of this study were to assess the intrarater and interrater reliabilities of the Myotonometer$^{(R)}$, electronic device that quantifies muscle tone. Two raters used the Myotonometer to assess the right bicep brachia and quadriceps muscles of 30 voluntary persons without any orthopedic or neurological problems (age range, 18~21 yrs). Muscles were measured in a relaxed state and during brief sustained voluntary maximal isometric contraction. Intrarater correlation coefficients were calculated for each muscle and for each condition (relaxed and contracted). Intrarater reliabilities (intraclass correlation coefficients, ICCs) ranged from .778 to .954, relaxed, biceps brachia), .926 to .963 (contracted, biceps brachia), .935 to .990 (relaxed, quadriceps) and .679 to .952(contracted, quadriceps). Interrater reliabilities ranged from .652 to .790 (relaxed, biceps brachii), .813 to .907 (contracted, biceps brachii), .831 to .950 (relaxed, quadriceps) and .849 to .937 (contracted, quadriceps). Myotonometer measurements had high to very high intrarater and interrater reliability for measurements of the biceps brachia and quadriceps muscles.

• The Journal of Korean Physical Therapy
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• v.31 no.3
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• pp.147-150
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• 2019

Purpose: The purpose of this study was to compare the reliability of unilateral hip abductor strength assessment in side-lying with break and make test in subjects with pelvic drop. Hip abduction muscles are very important in the hip joint structures. Therefore, it is essential to evaluate their strength in a reliable way. Methods: Twenty-five subjects participated in this study. Unilateral isometric hip abductor muscle strength was measured in side-lying, with use of a specialized tensiometer using smart KEMA system for make test, of a hand held dynamometer for break test. Coefficients of variation, and intra class correlation coefficients were calculated to determine test-retest reliability of hip abductor strength. Results: In make test, maximal hip abductor strength in the side-lying position was significantly higher compared with break test (p<0.05). Additionally, Test-retest reliability of hip abductor strength measurements in terms of coefficients of variation (3.7% for make test, 16.1% for break test) was better in the side-lying position with make test. All intraclass correlation coefficients with break test were lower than make test (0.90 for make test, 0.73 for break test). Conclusion: The side-lying body position with make test offers more reliable assessment of unilateral hip abductor strength than the same position with break test. Make test in side-lying can be recommended for reliable measurement of hip abductor strength in subjects with pelvic drop.

• Communications for Statistical Applications and Methods
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• v.13 no.3
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• pp.577-585
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• 2006

This paper presents a method for reliability evaluation of a telecommunication network with variable link-capacities when the simple paths of the network are known. The LP-EM, suggested by Lee and Park (2001), identifies a composite path as a subnetwork and adds only a minimal set of links at each step which gives maximal increase on the maximum capacity flow of the subnetwork. Thereby the LP-EM reduces the possible occurrence of redundant composite paths significantly over other existing methods. Based on the LP-EM, our method further reduces the possible redundancy by identifying such simple paths that could give no increase of maximum capacity flow on the current subnetwork and excluding those simple paths from consideration in the process of constructing composite paths.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.30 no.1
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• pp.82-88
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• 2007

This paper considers a topological optimization of a computer network design with a cost constraint. The objective is to find the topological layout of links, at maximal reliability, under the constraint that the network cost is less or equal than a given level of budget. This problem is known to be NP-hard. To efficiently solve the problem, a genetic approach is proposed. Two illustrative examples are used to explain and test the proposed approach. Experimental results show evidence that the proposed approach performs more efficiently for finding a good solution or near optimal solution in comparison with a simulated annealing method.

• Physical Therapy Korea
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• v.16 no.4
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• pp.1-7
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• 2009

The active-knee-extension (AKE) test has been used to measure hamstring muscle length. The traditional AKE test measures the popliteal angle to the point of resistance with a 90-degree flexion of the hip fixed by straps, while the stabilized AKE test measures the popliteal angle to the point of resistance with a 90-degree flexion of the hip stabilized using a pressure biofeedback unit providing lumbopelvic stabilization. The purpose of this study was to determine test-retest reliability of the traditional AKE test and stabilized AKE test. Twenty healthy adults participated in the study. The popliteal angles were measured with a digital inclinometer during each test. To assess the test-retest reliability between the 2 test sessions, intraclass correlation coefficients (ICCs) were calculated. The intrasubject coefficient of variation ($CV_{intra}$) was also calculated. To compare the traditional and stabilized AKE tests for changes in pressure, paired t-tests were applied. The results of this study were as follows: 1) ICCs(3,1) value for test-retest reliability was .96 in the traditional AKE test, and was .98 in the stabilized AKE test. 2) The maximal $CV_{intra}$ was 33.7% in the traditional AKE test and 15.7% in the stabilized AKE test. 3) Differences of $6.1{\pm}2.1$ mmHg in pressure were measured in the traditional AKE test, and differences of $1.2{\pm}1.0$ mmHg in pressure were measured in the stabilized AKE test. The results show the traditional and stabilized AKE test to be highly reliable, with test-retest reliability. However, the stabilized AKE test represented less variation and more stabilization than the traditional AKE test. Further study is needed to measure the inter-rater reliability of the stabilized AKE test for generalization and clinical application.

• The Journal of Korean Physical Therapy
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• v.28 no.2
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• pp.124-127
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• 2016

Purpose: The flexor hallucis longus stretch test can determine the shortness of the flexor hallucis longus muscle by measuring the angle of extension in the first metatarsophalangeal (MTP) joint at maximum ankle dorsiflexion. Less than 30 degrees of the first MTP joint at the maximal ankle dorsiflexion indicates shortness of the flexor hallucis longus muscle. The purpose of this study was to examine the intra- and inter-reliability of the flexor hallucis longus stretch test in subjects with asymmetric hallux valgus (HV) angles. Methods: Sixteen subjects with asymmetric HV angles participated in this study. In sitting position, dorsiflexion angles of the first MTP joint were measured with maximum ankle dorsiflexion on each side. ICC (3,1) and ICC (3,k) models were used, respectively, to assess the intra-reliability and inter-reliability of the flexor hallucis longus stretch test. The paired-t test was used to compare the dorsiflexion angle of the first MTP joint on the side with the smaller HV angle with that of the side with the larger HV angle. Results: The results of the study showed that both intra- and inter-reliability were more than 0.95 of the coefficient. Dorsiflexion angle of the first MTP joint was higher on the side with the smaller HV angle. Conclusion: Use of the flexor hallucis longus stretch test is acceptable in clinical settings because both intra- and inter-reliability were high in subjects with asymmetric HV angles. In addition, shortness of the flexor hallucis longus muscle is associated with HV angle. This study provides useful information for use in management of HV deformity.

• Physical Therapy Korea
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• v.10 no.1
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• pp.51-62
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• 2003

The purpose of this study was to compare the relative accuracy of a range of computer-based analysis with respect to EMG onset determined visually by an experienced examiner. Ten healthy students (6 male, 4 female) were recruited and three times randomly selected trials of isometric contraction of wrist flexion and extension were evaluated using four technique. These methods were compared which varied in terms of EMG processing, threshold value and the number of samples for which the mean must exceed the defined threshold, and beyond 7% of maximum amplitude. To identify determination of onset time, ICCs(Intraclass Correlation Coefficients) was used and inter-rater arid intra-rater reliability ranged good in visually derived onset values. The results of this study present that in wrist flexion and extension, the reliability of the inter and intra-examiner muscle contraction onset times through visual analysis showed beyond .971 with ICCs. The reliability of the muscle contraction onset time decision through visual reading, tested with computer analysis, showed a relationship of all the selected analysis methods with ICCs .859 and .871. The objective computer-based analysis comparing with visual reading at the same time is the effective and qualitative data analysis method, considering the specificity of each study method.

• ETRI Journal
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• v.43 no.3
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• pp.400-413
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• 2021

This paper theoretically and empirically explores the reliability gain that can be obtained by installing multiple antennas in on-vehicle broadcasting receivers. Analytical derivations reveal that maximal-ratio-combining-based diversity allows a multi-antenna receiver (MR) to achieve significantly better coverage probability than a single-antenna receiver (SR). In particular, the notable MR gains for low-power reception and high-throughput services are highlighted. We also discuss various aspects of mobile MRs, including geometric coverage, volume of the users served, and impact of receiver velocity. To examine the feasibility of MRs in the real world, extensive field experiments were conducted, particularly with on-air ATSC 3.0 broadcast transmissions. Relying on the celebrated erroneous second ratio criterion, MRs with two and four antennas were verified to achieve notable reliability gains over SRs in practice. Furthermore, our results also prove that layered-division multiplexing can cope better with receiver mobility than traditional time-division multiplexing when multiple services are intended in the same radio frequency channel.