• Journal of the Korean Society of Physical Medicine
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• v.16 no.1
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• pp.103-109
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• 2021

PURPOSE: This study examined the effects of the Visual Analog Scale (VAS) and knee function index on the knee strength and endurance in the national male field-hockey athletes. METHODS: Twenty-four male field-hockey athletes with a painful knee who trained at the national training center in 2019 were enrolled. The VAS and knee function index questionnaire were used to evaluate the degree of pain and functional state of the knee. The muscle strength and endurance of the knee were measured by Biodex (System 4, USA). The Pearson product moment correlation was performed to examine the effects of the VAS and knee function index the of knee on the strength and endurance. In addition, the VAS and knee function index and muscle strength and muscle endurance were examined to determine the relationship using Simple Linear Regression. The statistical significance level was α=.05. RESULTS: An analysis of the correlation between VAS and knee function index and muscle strength and muscle endurance revealed the VAS and knee function index to be statistically significant (r = .700). In addition, the extensor muscle strength, knee VAS (r = -.457), and knee function index (r = -.414) were also statistically significant. A 1-point increase in the VAS and knee function index was associated with an approximately 9.881 and 1.006 extensor muscle strength. CONCLUSION: The VAS and knee function index of field-hockey athletes are related to the strength of the knee extensors. Therefore, field-hockey athletes should develop a program to strengthen the extensor muscle strength of the knee.

• Physical Therapy Korea
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• v.26 no.2
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• pp.69-75
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• 2019

Background: Knee osteoarthritis (OA) diagnosis using Kellgren-Lawrence scores is commonly used to help decision-making during assessment of the severity of OA with assessment of pain, function and muscle strength. The association between Kellgren-Lawrence scores and functional/clinical outcomes remains controversial in patients with knee OA. Objects: The purpose of this study was to examine the relationships between Kellgren-Lawrence scores and knee pain associated with OA, function during daily living and sports activities, quality of life, and knee muscle strength in patients with knee OA. Methods: We recruited 66 patients with tibiofemoral knee OA and determined knee joint Kellgren-Lawrence scores using standing anteroposterior radiographs. Self-reported knee pain, daily living function, sports/recreation function, and quality of life were measured using the knee injury and OA outcome score (KOOS). Knee extensors and flexors were assessed using a handheld dynamometer. We performed Spearman's rank correlation analyses to evaluate the relationships between Kellgren-Lawrence and KOOS scores or muscle strength. Results: Kellgren-Lawrence scores were significantly negatively correlated with KOOS scores for knee pain, daily living function, sports/recreation function, and quality of life. Statistically significant negative correlations were found between Kellgren-Lawrence scores and knee extensor strength but not flexor strength. Conclusion: Higher Kellgren-Lawrence scores were associated with more severe knee pain and lower levels of function in daily living and sports/recreation, quality of life, and knee extensor strength in patients with knee OA. Therefore, we conclude that knee OA assessment via self-reported KOOS and knee extensor strength may be a cost-effective alternative to radiological exams.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.6_1
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• pp.917-925
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• 2022

The purpose of this study was to investigate the effect of wearing a soft knee brace during balance training on paretic side foot pressure and knee joint muscle strength in stroke patients. The recruited 20 stroke patients were randomized into 10 experimental group and 10 control group. All subjects were subjected to balance training, and only the experimental group was trained in balance while wearing a soft knee brace. Experimental group and the control group before and after the intervention showed significant increases in foot pressure and knee joint muscle strength on the paralyzed side (p<0.05), experimental group showed a significant increase in foot pressure and knee joint muscle strength compared to the control group (p<0.05). This study confirmed that wearing a soft knee brace had a positive effect on paretic side foot pressure and knee joint muscle strength in stroke patients.

• The Journal of Korean Physical Therapy
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• v.33 no.1
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• pp.34-39
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• 2021

Purpose: The purpose of this study was to verify the effectiveness of repetitive sit to stand training to improve knee extensor strength and walking ability of total knee replacement patients. Methods: In this study, 12 patients with total knee replacement patients were recruited from a rehabilitation hospital. They were divided into two groups: a repetitive sit to stand group (n=6) and a control group (n=6). They all received 30 minutes of continuous passive motion (CPM). After that, the repetitive sit to stand group performed repetitive sit to stand training, and the control group performed resistance exercise for 15 minutes five times a week for 2 weeks. After 2 weeks of training, knee extensor strength and spatiotemporal gait parameters were measured. Knee extensor strength was measured by Biodex system 3, walking ability was measured by Biodex gait trainer 2. Paired t test was performed to verify the difference between before and after intervention within the group, and analysis of covariance was used to verify the differences between the two groups. Results: After the training periods, the repetitive sit to stand group showed a significant improvement in knee extensor muscle strength, walking speed, step length of the operated side, and step length of the non-operated side (p<0.05). Conclusion: The results of this study showed that repetitive sit to stand training was more effective in improving knee extensor muscle strength and walking ability. Therefore, to strengthen knee extensor muscles and improve the walking ability of total knee replacement patients, it is necessary to consider repetitive sit to stand training.

• Journal of the Korean Society of Physical Medicine
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• v.15 no.3
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• pp.127-133
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• 2020

PURPOSE: The study examined the relationship between the knee function score and knee strength and muscular endurance of an elite female handball athletes according to their position in the team. METHODS: Thirty handball athletes participated on the study: 12 front positions, 12 back positions, and five goalkeepers. The knee function score consisted of symptoms, pain, daily activity, sports and recreation, and quality of life. In addition, CSMI (Cybex, USA) was used to measure the strength and muscular endurance of the knee. The muscular strength and muscular endurance were measured at an angular velocity of 60°/s and 180°/s, respectively. RESULTS: The overall items of the knee function score showed a significant difference (p = .017), and goalkeepers had significantly higher scores than the back positions. In addition, significant differences were observed in all five items depending on the position (p ≤ .05). On the other hand, both the flexor and extensor muscles of the knee strength and muscular endurance were not significant. Moreover, there was no correlation between the knee function score and the knee strength and muscle endurance. CONCLUSION: Elite female handball athletes have different knee functions score depending on their position in the team, but the, strength and muscular endurance of the knee were similar for each position. Furthermore, the knee function score showed no correlateion with the strength and muscular endurance of the knee.

• Physical Therapy Korea
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• v.24 no.1
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• pp.79-85
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• 2017

Background: The wall squat is considered an effective exercise because it can reduce the knee load and prevent excessive lumbar movement. However, the relationship between wall squat performance and strength of knee extensors and hip extensors remained unclear. Objects: The purpose of this study was to compare the strengths of the knee extensors and hip extensors between groups with low and high wall squat performance. Method: Nineteen males (low performance group: 9 subjects, high performance group: 10 subjects) participated in this study and performed wall squats. The subjects who were performing less than 30% of the average wall squat count were classified into the low wall squat performance group (less than or equal to 4 times) and the subjects who performed more than 30% of the average wall squat count were classified into the high wall squat performance group (greater than or equal to 8 times). Knee extensor and hip extensor strength were measured with a strength measurement system. An independent t-test was used to compare the strengths of the knee extensors and hip extensors between the groups with low and high wall squat performance. Results: The ratios of knee extensor and hip extensor strength to bodyweight were greater in the high wall squat performance group than in the low wall squat performance group (knee extensors: p<.001; hip extensors: p=.03). In the high- and low-performance groups, the ratios of knee extensor strength to bodyweight were $42.74{\pm}5.72$ and $30.76{\pm}8.54$, respectively, and the ratios of hip extensor strength to bodyweight were $31.95{\pm}10.61$ and $20.66{\pm}11.25$, respectively. Conclusion: Our findings suggest that knee extensor and hip extensor strength are needed for high wall squat performance. Thus, exercise to increase the knee and hip extensors strength can be recommended to improve squat performance.

• Korean Journal of Applied Biomechanics
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• v.16 no.4
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• pp.73-81
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• 2006

The purpose of this study was to investigate the effects of strength training on knee joint torque during walking in an adolescent with trisomy-21 Down syndrome. One adolescent with Down syndrome and one normal child participated in this study. Strength training consisted of eight exercises: squat, hamstring curl, hip adduction, hip abduction, knee extension, toe raise, sit-ups, and hyperextension of the waist. The participant with Down syndrome was participated in strength training for 12 weeks, three times a week, three sets, 10-15 RM; resistance was adjusted according to the principle of progressive overload. To measure the effect of strength training, isokinetic strength variables and knee joint torques were measured before training and after 12 weeks of training. The participant with Down syndrome had some abnormalities in controlling knee motion during walking due to muscle hypotonia, ligament laxity, and weakness of muscles. Post-training isokinetic strength increased compared to pre-training measurements. Knee range of motion were increased after strength training. Strength training did not affect ad/adduction and in/exteranl moments but did have an effect on flexor/extensor moment and timing.

• Journal of Convergence for Information Technology
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• v.9 no.7
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• pp.153-158
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• 2019

The purpose of this study was to compare the isokinetic muscular strength of the knee joint between female volleyball and table tennis players. A total of 27 elite volleyball players and 27 table tennis players participated in the study. This study measured both knee extensor and flexor strengths of volleyball and table tennis players using the isokinetic dynamic test. Peak torque was measured by performing maximal voluntary flexion and extension three times at $60^{\circ}/s$. Volleyball players had higher knee extensor and flexor strengths than table tennis players. No significant difference in both knee strengths was noted in table tennis players. However, volleyball players showed significant differences in both knee strengths. Height and weight showed a positive correlation with knee strength. This study found that volleyball players had greater knee strength than that of table tennis players. We also found that volleyball players have asymmetrical knee strength. Comparison with other sport players is warranted to better understand isokinetic muscular strength of the knee joint.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.1
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• pp.101-108
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• 2021

Purpose : The purpose of this study is to verify the effect of selective muscle strengthening of the knee joint extensor muscles using a pressure biofeedback unit to improve knee extensor strength and the balance ability of total knee replacement patients. Through this, we tried to provide clinical information. Methods : In this study, 12 patients with total knee replacement were recruited from a rehabilitation hospital. They were divided into two groups: a feedback group (n=6) and a control group (n=6). All patients received 30 minutes of continuous passive motion and leg-strengthening exercises for 15 minutes five times a week for two weeks. Subjects performed knee extension exercises with or without biofeedback units in the sitting position. The knee extensor strength and balance ability were measured before and after exercise. Knee extensor strength was measured by Biodex system 3 and balance ability was measured by Balancia software. Results : Both the experimental group and the control group showed a significant difference in the muscle strength of the knee joint extensor muscles after intervention (p<.05). In comparison, the experimental group showed a significant difference than the control group (p<.05). Both the experimental group and the control group showed a significant difference in the velocity average, path length, area 95 % center of pressure (COP), weight distribution, five times sit to stand test (FTSST) after intervention. In comparison, the experimental group showed a significant difference in velocity average, area 95 % COP, and FTSST than the control group (p<.05). Conclusion : In order to strengthen the knee extensor muscle and improve the balance ability in total knee replacement patients, it is necessary to consider providing pressure biofeedback unit during leg strengthening exercises.

• Physical Therapy Korea
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• v.27 no.4
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• pp.241-249
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• 2020

Background: Prolonged standing during work causes a lower extremity pain and disorders. Patellofemoral pain syndrome (PFPS) is one of the common diagnoses of the knee pain. Although the etiology of PFPS is not completely understood, it is considered to be multifactorial. Objects: The purpose of this study was to investigate difference in strength of knee muscles, quadriceps:hamstring muscles strength ratio (Q:H ratio), asymmetry ratio of knee muscles strength and dorsiflexion range of motion (ROM) between standing workers with and without PFPS. Methods: Twenty-eight standing workers with PFPS and 26 age-, height-, and weight-matched standing workers without PFPS participated in this study. A tension sensor measured knee muscle strength, and motion sensor measured dorsiflexion ROM. The asymmetry ratio of knee muscles was calculated by a specific formula using the knee muscles strength of the dominant side and the sound side. An independent t-test was used to identify significant differences in the strength, ROM, Q:H ratio, and asymmetry ratio between the PFPS and normal groups. Results: The standing worker with PFPS have significantly lower dorsiflexion ROM (p < 0.000) and higher asymmetry ratio of the hamstring muscles strength (p < 0.000) compare to the standing worker without PFPS. No significant differences were seen in the strength of quadriceps muscle and hamstring muscles, Q:H ratio, and asymmetry ratio of quadriceps muscle strength. Conclusion: There was a significant difference in the asymmetry ratio of the isometric hamstring muscle strength. This finding suggests that the asymmetry ratio of isometric hamstring muscle strength may be more important than measuring only the hamstring muscle strength of the PFPS side. Furthermore, the results of this study showed a significant difference in dorsiflexion ROM between the standing industrial workers with and without PFPS. Dorsiflexion ROM and isometric hamstring muscle strength should be considered when evaluating the subjects with PFPS.