• Journal of Korean Physical Therapy Science
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• v.30 no.1
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• pp.31-40
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• 2023

Hamstring flexibility is an important factor that affects muscle performance of the lower extremities and is closely associated with sports injuries. Therefore, evaluation of flexibility is important in clinical practice. Results of evaluation are determined by types of tests and cut-off values used; therefore, accurate and detailed understanding of these is necessary before examination. Although the straight leg raise and sit and reach tests are used to evaluate hamstring extensibility, structures including the nerves, fascia, and other muscles can significantly confound the results of these tests. The knee extension test is performed at 90° of hip flexion to minimize the posterior pelvic tilt that occurs during the straight leg test. The knee extension test is most recommended for selective evaluation of hamstring flexibility. The knee extension test is classified into active and passive tests. The cut-off value is usually set at 20° for the active and at 10° for the passive knee extension test. Although a strong association is observed between the two tests, the active knee extension test is preferred in clinical practice because it can be performed by a single examiner, which serves as an advantage. Age, sex, and warm-up exercise tend to affect flexibility; therefore, results should be interpreted with caution. Detailed understanding of each flexibility test is important for reliable evaluation.

• Journal of Korean Physical Therapy Science
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• v.28 no.1
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• pp.76-84
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• 2021

Background: In clinical practice, active knee extension (AKE) test has been widely used to measure hamstring flexibility. During the AKE test, the knee extension is repeated six times. The first five repetitions are considered as warm-up, and the sixth is used as baseline. In order to accurately measure the subject's inherent flexibility, warm-up trials have been proposed as mentioned above; but currently, the evidence is insufficient. Design: Cross-sectional study. Methods: Forty-three healthy adults participated in this study. The AKE was performed slowly after flexing the hip and knee joints by 90° in a supine position. The knee was extended as far as could be done without causing discomfort or pain. When reaching the end range, knee flexion was performed without stopping. As per standard protocol, the subjects performed the knee extension six times. Results: There was no significant difference between the AKE value in the first trial with those in the other five trials. During the repetitions, the average value in the group with higher flexibility tended to decrease and the Intraclass correlation coefficient gradually decreased. Conclusion: Successive repetitions of the AKE test can misrepresent an individual's inherent hamstring flexibility. In order to avoid a decrease in hamstring flexibility, it is strongly recommended that individuals with high initial hamstring flexibility avoid unnecessary repetitions of the AKE test.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.13 no.2
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• pp.45-54
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• 2007

The purpose of this study was effect of hamstring length on one leg stance test(OLST) in 108 persons. (men 28, women 80). The active knee extension test(AKE) was applied 3 times on both leg and high score was selected. Then, one leg stance test(OLST) was applied 3 times on both leg and high score was selected. Also, persons divided two group that is normal hamstring length group and shortening group). The result were as follows : 1. The correlation analysis between Lt. hamstring length and one leg stance time was no significant relation($p_{Lt.}=0.271$, $p_{Rt.}=0.051$). 2. The correlation analysis between Rt. hamstring length and one leg stance time was no significant relation($p_{Lt.}=0.837$, $p_{Rt.}=0.334$). 3. The independent T -test between Lt. hamstring normal (knee extension > 150degrees) & shortening group (knee extension ${\leq}$ 150 degrees) in Lt. leg stance time was no significant difference(p=0.73), but in Rt. leg stance time was statistically significant difference(p=0.04). 4. The independent T-test between Rt. hamstring normal (knee extension > 150degrees) & shortening group (knee extension ${\leq}$ 150 degrees) in one leg stance time was no significant difference($p_{Lt.}=0.09$, $p_{Rt.}=0.16$).

• Physical Therapy Korea
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• v.28 no.1
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• pp.65-71
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• 2021

Background: The hamstring is a muscle that crosses two joints, that is the hip and knee, and its flexibility is an important indicator of physical health in its role in many activities of daily living such as sitting, walking, and running. Limited range of motion (ROM) due to hamstring tightness is strongly related to back pain and malfunction of the hip joint. High-frequency diathermy (HFD) therapy is known to be effective in relaxing the muscle and increasing ROM. Objects: To investigate the effects of HFD on active knee extension ROM and hamstring tone and stiffness in participants with hamstring tightness. Methods: Twenty-four participants with hamstring tightness were recruited, and the operational definition of hamstring tightness in this study was active knee extension ROM of below 160° at 90° hip flexion in the supine position. HFD was applied to the hamstring for 15 minutes using the WINBACK device. All participants were examined before and after the intervention, and the results were analyzed using a paired t-test. The outcome measures included knee extension ROM, the viscoelastic property of the hamstring, and peak torque for passive knee extension. Results: The active knee extension ROM significantly increased from 138.8° ± 9.9° (mean ± standard deviation) to 143.9° ± 10.4° after the intervention (p < 0.05), while viscoelastic property of the hamstring significantly decreased (p < 0.05). Also, the peak torque for knee extension significantly decreased (p < 0.05). Conclusion: Application of HFD for 15 minutes to tight hamstrings immediately improves the active ROM and reduces the tone, stiffness, and elasticity of the muscle. However, further experiments are required to examine the long-term effects of HFD on hamstring tightness including pain reduction, postural improvement around the pelvis and lower extremities, and enhanced functional movement.

• Physical Therapy Korea
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• v.24 no.3
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• pp.40-46
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• 2017

Background: The active knee extension (AKE) test commonly used to assess the flexibility of the hamstring muscles. Many researchers have tested the reliability of the AKE test; however, no published studies have examined the intrarater and interrater reliability of the AKE test using a PBU. Objects: The purpose of this study was to determine the intrarater and interrater reliability of the AKE test performed with a pressure biofeedback unit (PBU) on healthy subjects. Methods: Sixteen healthy male participants volunteered and gave informed consent to participate in this study. Two raters conducted AKE tests independently with a PBU. Each knee was measured twice, and the AKE testing was repeated one week after the first round of testing. Results: The interrater reliability's intraclass correlation coefficients ($ICC_{2,1}$) were .887~.986 for the right knees and .915~.988 for the left knees. In addition, the intrarater (test-retest) reliability ($ICC_{3,1}$) values ranged between .820~.915 and .820~.884 for Raters 1 and 2, respectively. The values for the standard error of mesurement were low for all tests ($.81{\sim}2.97^{\circ}$); the calculated minimum detectable change was $2.24{\sim}8.21^{\circ}$. Conclusion: These findings suggest that the AKE test performed with a PBU had excellent interrater and intrarater reliability for assessing hamstring flexibility in healthy young males.

• 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 Academy of Orthopedic Manual Physical Therapy
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• v.5 no.1
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• pp.39-51
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• 1999

Background and Purpose. Objective measurements of hamstring muscle length are needed to quantify baseline limitations and to document the effectiveness of therapeutic interventions. Several indirect clinical tests for measuring hamstring muscle length are available, but influence of their test procedure is not well documented. The purpose of this study were 1) to describe hamstring muscle length as reflected by use of six tests(active straight leg raising(ASLR), passive straight leg raising(PSLR), passive straight leg raising with the lower back flat(PSLRB), active knee extension(AKE), passive knee extension(PKE), hip joint angle(HJA). 2) to examine the correlation among the tests. Subjects, Sixty subjects(30 men. 30 women) ranging in age from 18 to 25 years(mean 20.2 years) and with no limitation hamstring flexibility and no neurological and orthopedical problems. Methods. All subjects performed six tests. A inclinometer was used to determine the end point of range of motion. HJA was measured using an inclinometer placed over the sacrum. PSLRB were tested PSLR with the low back flat and the opposite thigh slightly flexed and support on pillows. Results, A mean ASLR value of 85.9 degrees, PSLR value of 99.9 degrees, PSLRB value of 109.8 degrees, AKE value of 77.2 degrees PKE value of 83.1 degrees and HJA value of 73.0 degrees were obtained for all subjects. A dependent t-test showed significant difference between the angles of ASLR and PSLR(p<0.001). There was a significant difference between the angles of PSLR and PSLRB(p<0.001). There was a significant difference between the angles of AKE and PKE(p<0.001). The highest correlation was between PSLR and PSLRB(r=0.915, p<0.001). All SLR tests were significants related(p<0.001), as well as AKE and PKE(p<0.001). The lowest correlation was between PKE and HJA(r=0.171. p>0.05). Conclusion and Discussion. The results indicated that the hip flexion angles for ASLR, PSLR and PSLRB were a difference, and the knee extension angles for AKE and PKE were a difference.

• Journal of Korean Physical Therapy Science
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• v.17 no.1_2
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• pp.41-52
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• 2010

Purpose: The purpose of this study was to compare the effects of continuous passive motion(CPM) and continuous active motion(CAM) on proprioception of the knee after total knee replacement(TKR). Methods: Twenty patients with TKR were randomly allocated into two groups, the CPM group(n=10) and the CAM group(n=10). All subjects were evaluated for levels of pain, passive range of motion and angle reproduction of the knee. An angle reproduction test was used to assess the proprioceptive deficit. Two types of angle reproduction test were used: a passive angle reproduction(PAR) test and an active angle reproduction(AAR) test. The relevant examinations were performed before and after intervention(on the 5th day and the 10th day). The statistical significance were calculated using a t-test and a one-way repeated ANOVA. Results: A pre-intervention significant difference was not found between the two groups. Significantly better results were before and after the intervention at 10 days, for the PAR(flexion direction) test; however, only in the CAM group. There were no significant difference, either before or after the intervention, for the AAR test(flexion and extension direction) in both group. Both groups experienced similar levels of pain and passive range of knee motion before and after the intervention. Conclusion: This study revealed that CAM was a better effect to restore position sense of the knee joint after TKR.

• The Journal of Korean Physical Therapy
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• v.17 no.3
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• pp.429-440
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• 2005

The purpose of this study was to compare the effects of knee joint position sense following local and general load protocols in 25 healthy male subjects. Proprioception of the knee joint was evaluated by measuring absolute angular errors at matching angles before, after and between 2 different types of load protocols. Proprioception tests(on the dominant knee) were performed in which proprioception of the passivepassive reproduced and active-active reproduced knee position was measured. Local load was provided with maximum isokinetic knee extension-flexion on the isokinetic dynamometer(Cybex), and general load was 10 minutes running on a treadmill. Peak torque(knee extension and flexion) and heart rate(beats per minute) was evaluated as an indicator of local and general fatigue during load protocols. The results were as follows: 1. For pasive-pasive reproduced knee position test, significant difference in absolute angular errors after general load protocol was detected compared with that before general load protocol(P<.05), significant difference in absolute angular errors after local load protocol was detected compared with that before local load protocol(P<.05). However, no significant difference in absolute angular errors of general load protocol was detected compared with that of local load protocol (P>.05), no significant difference in absolute angular errors of local load protocol was detected compared with that of general load protocol(P>.05). 2. For active-active reproduced knee position test, significant difference in absolute angular errors after general load protocol was detected compared with that before general load protocol(P<.05), significant difference in absolute angular errors after local load protocol was detected compared with that before local load protocol (P<.05). Also, significant difference in absolute angular errors of general load protocol was detected compared with that of local load protocol(P<.05), significant difference in absolute angular errors of local load protocol was detected compared with that of general load protocol(P<.05). 3. A significant decrease of peak torque of knee extensors and flexors was seen after local load, although heart rate was significantly increased(P<.05). No significant change of peak torque of knee extensors and flexors was seen after general load(P>.05), although heart rate was also significantly increased(P<.05). The previous study revealed that knee proprioception is significantly altered when the muscle mechanoreceptors are dysfunctional due to muscle fatigue, although the joint mechanoreceptors have no significantly effect on knee proprioception when the presence of knee muscle fatigue. However, the results of this study are different from those of the previous study in that muscle weakness of the knee could not be seen after general load. This study shows that general load may diminish motor control by the central nervous system. Proprioceptional decline without muscle weakness of knee after general load suggests a change in the proprioceptional pathway without influence from muscle mechanoreceptors.

• Journal of International Academy of Physical Therapy Research
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• v.9 no.4
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• pp.1602-1607
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• 2018

This study examined the correlation between power error (PE) and velocity error (VE) according to the condition and frequency of self-controlled feedback (SCF) during knee extension. One hundred participants were randomly assigned to 30% SCF, 70% SCF, 30% yoked feedback (YF), 70% YF and control group, respectively. The SCF group was provided with feedback when they requested it, whereas the YF group did not influence the feedback schedule. Participants in the control group were not given any visual feedback during the experiment. The isotonic, isometric, and isokinetic dynamometer (PRIMUS RS, BTE, USA) was used to measure the power and velocity error during knee extension. The collected data was analyzed using a Pearson test and SPSS 21.0. The correlation between PE and VE according to the condition and frequency of feedback on each phase during knee extension was significant. Both PE and VE were significantly higher when the feedback was provided with high frequency, passive, and no feedback. Our study suggests that application of SCF can help to improve the proprioception of the healthy person while reducing errors through low frequency and active feedback.