• The Journal of Korean Physical Therapy
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• v.8 no.1
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• pp.33-47
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• 1996

This study was performed to examine the correlation between calcaneus to tibia angle and Q-angle, and the effects of step width and toe out angle on the calcaneus to tibia angle and Q-angle. The age of participated subjects was from 19 to 29 years(Mean=22.95, SD=2.23) who have no significant orthopedic and neurological dysfunction. The marking tapes for measurement of Q-angle and calcaneus to tibia angle were placed on seven location of each subject. Video data were collected while the subject walked on a walking grid. The result as follows : 1. There were significant differences in the step width, toe out angle, and Q-angle but not calcaneus to tibia angle between male and female. 2. There were significant differences in toe calcaneus to tibia angle and Q-angle n step width increased, respectively. 3. There were significant differences between tee out angle and calcaneus to tibia angle but not toe out angle and q-angle. 4. There was statistically significant correlation between calcaneus to tibia angle and Q-angle.

• Physical Therapy Korea
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• v.6 no.1
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• pp.1-14
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• 1999

The quadriceps angle (Q angle) has been used to reflect the quadriceps muscle's force on the patella in the frontal plane. Previous investigations of the Q angle and it's relationship to knee disorders have yield equivocal results. The purpose of this study was to analyze the factors related to the Q angle and it's relation to other variables such as leg length, body weight, CTA (calcaneus to tibia angle), TOA (toe out angle), and pelvic width in normal subjects. The participants were 60 students (30 men and 30 women) who had no orthopedic and neurological impairments, aged from 20 to 29 years of age, with an average age of 22.1 years. Prior to participation, each subject was informed of the procedures of the experiment from a researcher and assistant researchers. The equipment used in this study were modified standard goniometer, ruler, marking pen, and Martin apparatus for pelvic width. In order to determine the statistical significance of the experiment, regression analysis, independent t-test, and Pearson correlation were used at the 0.05 level. The results were as follows: 1) It was found that the Q angle of women is greater than that of men's from both knees. 2) There was no significant difference between right and left quadriceps angle. 3) The Q angle decreased as the body weight (leg length) shifted from low to high. 4) It seems that factors related to the Q angle were body weight, CTA, and pelvic width, but there was no significant difference at the 0.05 level.

• Journal of Veterinary Science
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• v.21 no.5
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• pp.69.1-69.11
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• 2020

Background: An inappropriate Q angle may affect the biomechanics of the canine patellofemoral joint. Objectives: The purpose of this study was to evaluate the effects of changes in quadriceps angle (Q angle) on patellofemoral joint pressure distribution in dogs. Methods: Eight stifles were positioned at 45, 60, 75, 90, 105, and 120° of flexion in vitro, and 30% body weight was applied through the quadriceps. Patellofemoral contact pressure distribution was mapped and quantified using pressure-sensitive film. For the pressure area, mean pressure, peak pressure, medial peak pressure, and lateral peak pressure, differences between groups according to conditions for changing the Q angle were statistically compared. Results: Increases of 10° of the Q angle result in increases in the pressure area (P = 0.04), mean pressure (P = 0.003), peak pressure, and medial peak pressure (P ≤ 0.01). Increasing the Q angle by 20° increases the pressure area (P = 0.021), mean pressure (P ≤ 0.001), peak pressure (P ≤ 0.01), and medial peak pressure (P ≤ 0.01) significantly, and shows higher mean (P ≤ 0.001) and peak pressures than increasing by 10°. Decreasing the Q angle increases the mean pressure (P = 0.013), peak pressure, and lateral peak pressure (P ≤ 0.001). Conclusions: Both increases and decreases in the Q angle were associated with increased peak patellofemoral pressure, which could contribute to the overloading of the cartilage. Therefore, the abnormal Q angle should be corrected to the physiologically normal value during patellar luxation repair and overcorrection should be avoided.

• Physical Therapy Korea
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• v.12 no.1
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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.

• The Journal of Korean Physical Therapy
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• v.26 no.2
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• pp.68-73
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• 2014

Purpose: The purpose of this study was to investigate the effect of closed kinetic chain exercise using EMG-biofeedback for selective training of the vastus medialis oblique on functional ability and Q-angle in subjects with patellofemoral pain syndrome. Methods: Thirty participants who met the criteria were included in this study. Participants were randomly allocated to the control group (Group I, n=10), closed kinetic chain exercise group (Group II, n=10), and closed kinetic chain exercise using EMG-biofeedback group (Group III, n=10). Intervention was performed in three groups, three times per week, for a period of six weeks. Kujala patellofemoral score and Q-angle were measured before and after the experiment. Results: Some significant differences in kujala patellofemoral score were observed in group II and group III, compared with group I (p<0.01). There was no significant difference on in Q-angle at knee flexion angle $0^{\circ}$. However, some significant differences in Q-angle at knee flexion $60^{\circ}$ were observed in group III, compared with group I (p<0.01). Conclusion: Closed kinetic chain exercise using EMG-biofeedback that provides real-time biometric information on selected muscles in order to increase the efficiency of treatment may be helpful in improvement of functional ability and Q-angle in patellofemoral pain syndrome.

• The Journal of Korean Physical Therapy
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• v.28 no.2
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• pp.65-70
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• 2016

Purpose: The aim of this study was to determine the effects of electromyographic (EMG)-Biofeedback using closed kinetic chain exercise (EB-CKCE) on quadriceps angle (Q-angle) and quadriceps muscle activation and muscle activation ratio in subjects with patellofemoral pain syndrome and to provide fundamental information on rehabilitation exercise in patellofemoral pain syndrome. Methods: Thirty participants who met the criteria were included. The subjects were randomly divided into three groups: control group (Group I, n=10), semi-squat exercise group (Group II, n=10), and EMG-Biofeedback using closed kinetic chain exercise group (Group III, n=10). Intervention was provided to each group for eight weeks (three times per week; 30 minutes per day). Subjects were measured on Q-angle and quadriceps muscle activation. Results: Significant difference in Q-angle and quadriceps muscle activation was observed in groups II and III compared with control group I (p<0.01). Results of post-hoc analysis showed a significant difference in Q-angle and quadriceps muscle activation in on group III compared with groups I and II. Conclusion: Findings of this study suggest that closed kinetic chain exercise using EMG-Biofeedback that provides real-time biofeedback information on muscle contraction may have a beneficial effect on improvement of Q-angle and quadriceps muscle activation in patellofemoral pain syndrome.

• The Journal of Korean Physical Therapy
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• v.14 no.4
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• pp.342-366
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• 2002

An excessive Q-angle has been implicated in the development of knee injuries by altering the lower-extremity locomotion kinematics. The purpose of this study was measured the Q-angle and the CTA when the foot moves pronation and supination of the foot in the standing status. The participants of this examination were 60 adult(30 men and 30 women) who had no orthopaedic and neurological impairment, aged between 20 and 40years. The foot tilt(FT 1)is made of acrylic plate and the slope of the suface is altered as $0^{\circ}$, pronation ($10^{\circ},20^{\circ},30^{\circ}$)and supination($10^{\circ},20^{\circ},30^{\circ}$). The results were as follows : 1. The result about the left/right Q-angle and the left/right CAT There was no statistical significant difference between the left and the right side of the Q-angle with different position of the foot(P > 0.05). While significant difference in the left CTA at the $0^{\circ}$, pronation($10^{\circ},20^{\circ},30^{\circ}$) and supination($10^{\circ},20^{\circ}$) has been observed(P < 0.05). 2. The result about the Q-angle and the CTA between male and female There was significant difference in the Q-angle between male and female with different position of the foot(P < 0.05). while significant different in the right CTA at the $0^{\circ}$ pronation ($20^{\circ}$)(P < 0.05), no significant difference in the left CTA have been observed(P > 0.05). 3. The result about correlation between the left/right Q-angle and the left/right CAT There was statistical significant positive correlation between the left/right Q-angle and the left/right CAT with the different position of the foot(P < 0.01).

• The Journal of Korean Physical Therapy
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• v.14 no.3
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• pp.203-225
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• 2002

An excessive Q-angle has been implicated in the development of knee injuries by altering the lower-extremity locomotion kinematics. The purpose of this study was performed to examine the correlation between the Q-angle and the CTA during pronation and supination of the foot in the standing status. The participants of this examination were 60 adult(30 men and 30 women) who had no orthopaedic and neurological impairment, aged between 20 and 40years. The foot tilt(FT1)is made of acrylic plate and the slope of the surface is altered as $0^{\circ}$ pronation$(10^{\circ},\;20^{\circ},\;30^{\circ})$ and supination $(10^{\circ},\;20^{\circ},\;30^{\circ})$. The results were as follows : 1. The result about the Q-angle and the CTA by comparing pronation and supination of the foot There was statistical significance difference in the left /right Q-angle and the left/right CTA with pronation and supination of the foot(P<0.05). 2. The result about correlation in the left /right lower-extremity There were positive correlation between the right Q-angle and the right CTA and negative correlation except the supination$(30^{\circ})$ between the left Q-angle and the left CTA.

• Korean Journal of Applied Biomechanics
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• v.21 no.1
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• pp.107-114
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• 2011

Closed kinematic chain exercises such as squatting have been widely indicated for knee rehabilitation in patients with patellofemoral disorders such as osteoarthritis and patellofemoral pain. Patellofemoral disorders are thought to be associated with abnormal patellar kinematics. In addition, the Q-angle may be undervalued in patients with patellofemoral pain and a laterally displaced patella. The purpose of this study was to assess patellar kinematics and the Q-angle during double-leg semi-squat and wall-slide semi-squat exercises. In this study, 28 asymptomatic subjects(16 male, 12 female) were assessed. Patellar tilt, patellar spin, and Q-angle were recorded using a motion analysis system during double-leg semi-squat and wall-slide semi-squat exercises. The Q-angle and patellar tilt were significantly increased, whereas patellar spin was significantly decreased, at $45^{\circ}$ of knee flexion compared with $0^{\circ}$. No differences were observed for the Q-angle, patellar tilt, and patellar spin during double-leg semi-squat and wall-slide semi-squat exercises. However, a significant interaction was observed between squat type and knee angle for patellar spin. We found that the patella is laterally tilted during semi-squat exercises and that there was no difference in patellar tracking between knee flexion during double-leg semi-squat and wall-slide semi-squat exercises.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.19 no.1
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• pp.41-47
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• 2013

Background: The purpose of this study is to examine the effects of visual feedback squat exercise on the young adults with Patellofemoral pain syndrome. Methods: The subjects of this study were 22 female and 8 male who were equally and randomly allocated to a visual feedback exercise group (VSEG), an experimental group, and squat exercise group (SEG), a control group. Both did so for 30 minutes three times per week over a six-week period. Using Dartfish, their static Q-angle (SQA) and dynamic Q-angle (DQA) were evaluated. Results: The static Q-angle was significantly reduced in both groups of VSEG and SEG and in the comparison of difference values before and after exercise between groups, VSEG had more significant effect than SEG but in the comparison of the effects of dynamic Q-angle both VSEG and SEG had significant effects and in the comparison of difference values before and after exercise between groups, VSEG had more significant effect than SEG. Conclusion: Visual feedback squat exercise may be applied as a method to correct the lower extremity alignment with PFPS.