• 대한기계학회논문집A
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• 제35권7호
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• pp.785-790
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• 2011

본 연구에서는 인체의 하지부를 다물체 시스템으로 모델링하여 무릎관절에 걸리는 구속력의 불확실성을 추정하였다. 일반적으로 근육의 기계적인 특성은 Hill-type muscle model 이 사용되며 여기에 적용되는 인체의 특성과 해부학적인 데이터는 지난 십 수년 동안 크게 발전되었다. 그러나 정확하게 그것들을 안다는 것은 불가능하며 개인마다 다른점을 고려해야 할 필요가 있다. 본 논문에서는 Hill-type muscle model 과 함께 인체의 해부학적인 데이터를 통계 방법론을 이용하여 무릎 관절에 걸리는 구속력의 불확실성을 추정하였다. 초기 앉아있는 자세에서 일어서는 과정에서 작용하는 구속력을 추정하였으며 이때 인체 하지 근육의 특성을 musculoskeleton-actuator 를 이용하여 해석하였다.

• 대한정형도수물리치료학회지
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• 제27권2호
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• pp.27-36
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• 2021

Background : Prone hip extension (PHE) is commonly used for exercises and tests in patients with low back pain. Previous studies have shown that pelvic compression belts (PCB) and non-elastic taping (NET) contribute greatly to improvements in lumbopelvic stability. This study aimed to compare the effect of two lumbopelvic stability methods such as PCB and NET on the trunk and hip extensor muscle activities during PHE tests. Methods: Subjects who experienced low back pain (low back pain group, LBPG; n=20) and those who did not experience low back pain (non-LBPG; n=20) participated in this study. The subjects were instructed to perform PHE with and without a PCB and NET. PHE tests were performed in the condition wherein the two stabilization methods were applied, and the actions of the muscles at that time were measured using surface electromyography (EMG). EMG data were collected from the hamstring, gluteus maximus, erector spine (ES), and multifidus (MF) muscles. The data were collected three times for 5 s with a 1-min rest between each of the three sets. Results: In the LBPG, EMG of the ES muscle was significantly reduced when NET or a PCB was applied (p<.05). There was no difference in the change in the ES muscle activity when NET and a PCB were applied. The ratio of MF/ES muscleactivity showed a significant increase in the LBPG with NET (p<.05). Conclusion: Both NET and PCB applied to subjects who experienced low back pain significantly reduced the ES muscle activity during PHE exercises and helped control the balance of the superficial and deep trunk extensor muscles.

• The Journal of Korean Physical Therapy
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• 제34권1호
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• pp.38-44
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• 2022

Purpose: The purpose of this study was to investigate the effects of complex training on injury, flexibility, and muscle stiffness in high school male football players. Methods: A total of 60 football players were included in the study and were divided into three groups viz. the complex training group (CTG), 11+ training group (11+TG), and traditional training group (TTG). Injuries were recorded based on the prospective investigation method after starting the study, and the flexibility and muscle stiffness of the subjects were evaluated. Results: The research results showed that the injury rate per match was significantly lower in the CTG and 11+TG than the TTG. In the CTG, the flexibility of the hamstrings significantly increased and the stiffness of the rectus femoris (RF), biceps femoris (BF), and tensor fascia latae (TFL) muscles significantly decreased (p<0.05). In the 11+TG, the stiffness of the RF significantly decreased (p<0.05). In the TTG, the flexibility of the hamstrings significantly increased (p<0.05). Hamstring flexibility showed a significantly higher increase in the CTG and TTG compared to the 11+TG (p<0.05). Also, the stiffness of the RF and TFL muscles showed a significantly higher decrease in the CTG compared to the 11+TG and TTG (p<0.05). The stiffness of the BF muscles too showed a more significant decrease in the CTG compared to the TTG (p<0.05). Conclusion: The complex training method of the Fédération International de Football Association (FIFA) 11+ and self-myofascial release (SMFR) as a warm-up program, prevent injuries, enhance flexibility, and lower muscle stiffness of football players in high school. Thus, it is necessary to ensure the widespread use of the complex training program by instructors and players under the supervision of the Korea Football Association (KFA), given its reliability in preventing injuries and improving the performance of football players.

• 대한물리치료과학회지
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• 제24권3호
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• pp.12-17
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• 2017

Purpose: The purpose of this study was to investigate the effects of backrest angle on lower extremity muscle strength in adult. Method: This research results are based on 10 healthy adults. 10 degree difference in pelvic angle does not effect the cross-connection of the Hamstring muscles, and created 3 types of rest with 20 degree differences each at 95, 115, and 135 degree angles. Result: significantly difference in contractibility muscle strength in accordance to the 3 rake angle. Conclusion: After putting together all these results, since both the expansibility muscle strength and contractibility muscle strength of the knee showed to be effected as the backrest angle changed during isokinetic muscle strength assessment, further research should be conducted if similar research results as this study can be acquired at various angles.

• 대한인간공학회지
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• 제14권2호
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• pp.1-14
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• 1995

Neuromuscular difference between normal subjects and low-back pain patients has been identified in terms of neural excitation signal measured by Electromyography (EMG) under the dynamic flexion/extension trunk motion. Ten healthy subjects and ten low-back pain patients were recruited for this study. New parameters and normalization technique were introduced to quantify the muscle excitation pattern among the flexor-extensor pairs of muscles : rectus abdominis (RA)-erector spinae (ES at L1 and L5 level), external oblique (EO)-internal oblique (IO), rectus femoris (quadricep : QUD)-biceps femoris( hamstring : HAM), and tibialis anterior (TA)-gastrocnemius (GAS). Results indicated that the temporal EMG pattern such as peak timing difference between the hip flexor (QUD) and extensor (HAM) and the duration of coexcitation between ES at L5 and RA muscle pairs showed a statistically significant difference between normal subjects and low-back pain patients. Improtantly, this study presented a new technique to identify the dynamic muscle excitation pattern that canb be least affected by EMG-length-velocity relationship. Further study can performed to validate this method for clinical application to quantitatively identify the low-back pain patients in the future.

• 한국운동역학회지
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• 제25권1호
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• pp.49-56
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• 2015

Objectives : The purpose of this study was to present quantitative data and basic references to decrease the accident risk of soccer instructors. Methods : To obtain data, we conducted an investigation on how H/Q ratio affects the dynamic stability of the lower extremity at the time of drop landing. The study targeted 13 soccer players from C University who have not had any injuries or wounds in the lower extremity joints and in any other parts of their bodies over the last 6 months. By using CMIS (USA), the players were divided into two groups according to H/Q ratios higher and lower than 69%, respectively. The subjects in each group were instructed to perform a drop landing. Results : The H/Q ratio did not affect the maximal flexion angle of the knee joints at the time of drop landing. In addition the dominant group with a relatively high H/Q ratio was observed to have increased time to reduce shock and to efficiently absorb the ground reaction force during drop landing. Also, the dominant group with a relatively high H/Q ratio utilized the strong performances of the antagonistic muscles around the hamstrings and the controlled rotatory powers of the thighs that were applied to the tibias supported by the ground. Finally, H/Q ratio, load factors, and mean and maximum EMG were significantly negatively related, whereas GRFx showed a positive relationship. In fact, these factors all affected the impact of the load from the H/Q ratio to the knee joints. Conclusion : From these findings it can be concluded that unbalanced H/Q ratio can be considered as a predictor of knee joint injury at the time of drop landing.

• 한국전문물리치료학회지
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• 제18권3호
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• pp.1-7
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• 2011

The effects of an abdominal drawing-in maneuver (ADIM) using a pressure bio-feedback unit (PBFU) were compared to the effects of a pelvic belt (PB) on the muscle activities of the hip and back extensor muscles during hip extension in the prone position. Fifteen healthy male participants all performed prone hip extensions under three conditions: 1) preferred hip extension (PHE), 2) performing an ADIM, and 3) using a PB. The muscle activities of the erector spinae, the gluteus maximus, and the medial hamstring on the right side were recorded by surface electromyography. The muscle activity of the erector spinae was significantly lower while performing an ADIM during prone hip extension than during PHE or with a PB (p<.05). Gluteus maximus muscle activity was significantly higher while performing an ADIM (p<.05). No significant difference was found for the medial hamstring muscle among the three conditions (p>.05). We concluded that the internal stabilization of the pelvis and lumbar spine afforded by the ADIM using a PBFU could be more effective than the external stabilization provided by a PB in terms of increasing selectively gluteus maximus activation during prone hip extension.

• The Journal of Korean Physical Therapy
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• 제26권5호
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• pp.296-301
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• 2014

Purpose: The purpose of this study was to investigate the effect of strengthening exercises of hip abductors on muscle strength and ambulation for patients with ACL reconstruction. Methods: The subjects were randomly assigned to the intervention group (general exercise plus strengthening of hip abductors) or the control group (general exercise without the strengthening of hip abductors). Both groups participated in a six-week exercise protocol after the surgery for ACL reconstruction. The knee strength test (quadriceps, hamstring, hip abductor) and gait analysis were performed in pretest and post-test. Results: Muscle strength was measured using the Biodex system III model (Biodex Medical System, Inc, NY, US). The results showed no significant difference in knee strength (quadriceps, hamstring) between the two groups (p>0.05), however, there was a significant difference in hip abductors (p<0.05). The gait analysis was measured with Gaitrite system (CIR System Inc, US). Results of comparison between groups showed a significant increase in the step length of both groups. (p<0.05), and there was a significant difference in the affected leg of the intervention group(p<0.05). Conclusion: Exercise of hip abductors for patients with ACL reconstruction provides significant benefits with respect to improvement of muscle strength in hip abductors, increasing the stride. This result indicates that a training program designed for ACL reconstruction patients should include strengthening of the hip abductor. We think that further study is needed to determine the relationship of hip muscles and knee joint for patients with ACL reconstruction.

• 한국전문물리치료학회지
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• 제12권1호
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• pp.45-54
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• 2005

The quadriceps-angle (Q-angle) and the ratio of hamstring/quadriceps (H/Q) are important for the stability of the knee and for protection from excessive stress. The aim of this study was to examine the association between Q-angle and H/Q ratio with and without knee osteoarthritis. We compared knee osteoarthritis patients with symptom-free women. The mean age of the patients in the arthritis group (25 women, osteoarthritis) was 59.7 years. The non-arthritis group consisted of 25 women with a mean age of 55.2 years. Of the 25 women with osteoarthritis, 5 had the condition in their left knee, 5 had it in their right knee, and 15 had it on both sides. There was no significant difference in the knee Q-angle of the left and right knees of the arthritis group and the non-arthritis-group (p>.05). The strength of all the muscles around the involved right knee in the arthritis group was significantly weaker than that of the non-arthritis group (p<.05). However, in the left knee, only the strength of the knee extensors and internal rotators was significantly weaker than that of the non-arthritis group (p<.05). The Q-angle was not associated with the H/Q ratio and internal rotators/external rotators ratio of the involved knee in the arthritis group (p>.05). Neither was the Q-angle associated with the pain level of an involved knee in the arthritis group (p>.05). The knee pain was not associated with the H/Q ratio of the involved knee in the arthritis group (p>.05). The Q-angle was not associated with the ratio of H/Q and pain level of the involved knee in the osteoarthritis women.

• 한국전문물리치료학회지
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• 제26권4호
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• pp.63-69
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• 2019

Background: Both the rapid concentric and eccentric contractions during exercise repeatedly impose excessive stress on muscle tissue. The hamstring muscles are very susceptible to injury due to the tensile stress. Various interventions are currently being undertaken to prevent strain injury before exercise. Stretching is the most common method and is known to have a positive effect on flexibility and muscle performance. However, relatively few studies have investigated the potential negative factors of stretching. Objects: The purpose of this study was to examine changes in pain following the different intensity of the stretching and types of physical stress. Methods: The subjects were divided into three groups based on the intensity of stretching: 100% (S100), 75% (S75), and 50% (S50) of the measured force at the point of discomfort in static stretching and 100% (P100), 75% (P75), and 50% (P50) of the maximum voluntary isometric contraction in Proprioceptive Neuromuscular Facilitation (PNF) stretching. The pain individual subjects perceived after stretching was measured via a Visual Analog Scale (VAS) and compared between the groups Results: Despite the decrease in the intensity of static stretching, no decrease in VAS value was observed. In PNF stretching, a significant decrease was observed at P50 compared to P100. S100 was significantly higher than P75 and P50. Conclusion: Previous studies have shown that PNF has a superior or the same effect on flexibility in comparison with static stretching. This effect was maintained even in moderate intensity. PNF stretching performed under moderate rather than high intensive static stretching, which causes pain and discomfort, might be recommended in clinical settings.