Background: Total knee arthroplasty (TKA) recovers the alignment of the knee joint, but fails to automatically restore the alignment and function of the hip and ankle joints. It may affect the alignment and stability of the knee joint, therefore therapeutic intervention in hip and ankle joint is necessary for the rehabilitation process after TKA. Objects: The aim of this study was to comparison of the effects of the two exercise methods on the coronal plane alignment after TKA. This study conducted an experiment by dividing subjects into a lower extremity isometric co-contraction group (LEIC) and a quadriceps isolated isometric contraction (QIIC) group. Methods: A total of 37 subjects were randomly assigned to the LEIC (n1=19) or the QIIC (n2=18). Exercise was applied to five times per week for three weeks, starting on the eighth day after surgery. Range of motion exercises were performed as a common intervention and then each group performed quadriceps isometric contraction exercises with 10 sets of 5 repetitions. Radiological imaging was performed prior to surgery, one month and six months after surgery. In addition, the hip-knee-ankle angle (HKA) and tibiotalar angle (TTA) were measured. Results: The HKA was close to neutral in the LEIC rather than the QIIC (p<.05). The LEIC showed varus and the QIIC exhibited valgus TTA (p<.05). In a comparison of HKA and TTA over time, there was no significant change in either group (p>.05). According to the comparison of the TTA before surgery, the LEIC showed significant changes in the varus direction (p<.05), while there was no significant change in the QIIC (p>.05). Conclusion: The LEIC method triggered changes in the TTA and brought the HKA close to the neutral. Thus, LEIC is more effective than QIIC in creating stability in the coronal plane alignment of the knee and ankle joints after TKA.

The lower trapezius muscle is an important stabilizer and primary mover of the scapula. The potential use of ultrasound imaging to evaluate scapular muscle function warrants investigation. The purpose of this study is to use ultrasound imaging for determining the effectiveness of 4 different isometric exercises for maximally activating the lower trapezius muscles in healthy subjects. Twenty-eight (14 men and 14 women) volunteers were recruited for this study. Thickness measurements of the lower trapezius muscles were recorded during 4 exercises: latissimus pulldown (LP), prone V-raise (PV), prone row (PR), and modified prone cobra (MP). Lower trapezius muscle thickness was measured 3 times by 2 investigators at a point 3 cm lateral to the lateral edge of the T8 spinous process. The order of 4 exercise execution was randomized for each participant. To identify statistical significance, one-way ANOVA with repeated measures was used with the significance level of .05. Intraclass correlation coefficient (ICC) for intra-reliability was .86~.98 and inter-rater reliability .83~.96 for the lower trapezius, respectively (p<.01). Thickness changes in the lower trapezius muscles between the relaxed and contracted states in men were as follows: LP (, 182%), MP (, 167%), PV (, 149%), and PR (, 133%). In women the values were as follows: LP (, 163%), MP (, 131%), PV (, 129%), and PR ( mm, 100%). Thickness of the lower trapezius muscles significantly differed between exercises in both the gender (p<.01). The LP was the most effective exercise for increasing the activation of the lower trapezius muscle in both the gender. We recommend performing the LP exercise for strengthening the lower trapezius muscles.

The purpose of this study was to suppose basis data the influence of different chair type and pelvic control on quadriceps muscle activity and strength during knee joint extension isometric exercise in hemiplegic patients. This research were investigated in ten healthy adults and tens hemipelgic patients. Surface electromyography (EMG) and Biodex system were used to collect kinematic data and muscle activity, respectively. Independent t-test, paired t-test and one-way repeated ANOVA were used to determine a statistical significance. The results showed as follows: (1) Posterior pelvic angles in healthy group and hemiplegic group were significantly different on isokinetic equipment (p<.05). (2) Different chair type and pelvic control on quadriceps muscle activity and strength were significantly different in hemiplegic patients (p<.05). From the result of this research, posterior pelvic angle control during knee joint extension isometric exercise in hemiplegic patients on isokinetic equipment is necessary to increase quadriceps muscle strength in hemiplegic patients.

Median frequency can be regarded as a valid indicator of local muscle fatigue. As local muscle fatigue develops, the muscle fiber conduction velocity decreases, the fast twitch fibers are recruited less, and consequently the median frequency shifts toward the lower frequency area. The aim of this study was to test the characteristics of the median frequency according to exercise load (30% and 60% of MVC on the biceps brachii, 40% and 80% of MVC on the vastus lateralis) during the fatiguing isometric exercise. Thirteen healthy male volunteer students of Yonsei University were recruited. After the testing maximal voluntary isometric contraction, three variables (initial median frequency, regression slope, fatigue index) from the regression line of MDF data were measured in each exercise load. The results showed that the regression slope and fatigue index were significantly different for the biceps brachii, but not for the vastus lateralis initial MDF was not significant difference according to the exercise load on both muscles. The regression slope and fatigue index could monitor physiologic muscle change during fatiguing isometric exercise. The results showed that two MDF variables reflect the local muscle fatigue according to the exercise load.

Physical therapists have been using biofeedback training to induce improvements in various circumstances. The purpose of this study was to compare the effects of visual and tactile feedback using electrical stimulation on quadriceps strength. Nineteen women without known impairment of the neuromusculoskeletal system volunteered for this study. Subjects were randomly allocated into three groups: visual feedback, tactile feedback, and control group. The torque of isometric knee extension force was measured. Subjects were asked to exert the maximal isometric contraction force of quadriceps over a 30 second period. The resting period of 10 minutes was given after the maximal isometric contraction to avoid the muscle fatigue. In between groups comparison, significant differences of the peak torque and the torque area were found on the performance of the maximal isometric contraction of quadriceps (p<.05). The values peak of torque and torque area were significantly higher during visual feedback than tactile feedback. The results of this study suggest that visual feedback is more powerful than tactile feedback (p<.01).

Fatigue is the decline in force produced as a result of prolonged muscle activity. Localized muscle fatigue can be identified by a shift toward low in the frequency components of the EMG signal, typically represented by a fall in the median frequency. Previous studies show that a shortened muscle develops a higher fatigue than elongated muscles. The purpose of this study was to investigate the time-related change of median frequency and torque during maximal isometric back extension exercises at different exercise angles (, , , ). Twenty healthy subjects (mean age = ) were evaluated in this study. Median frequency was extracted from the EMG signals by fast Fourier transform (FFT). Initial median frequency and the slope of median frequency change over time were computed from linear regression analysis. Pearson's product moment correlation was used to quantify the relationship between slope of median frequency and torque. The results were as follows: 1) Significant differences in y-intercepts of torque regression equation with respect to exercise angle were shown. However, there were no differences in the slopes of the median frequency and torque, and y intercept of the median frequency among exercise angles. 2) There was no significant correlation between slope of median frequency and torque. 3) But there was moderate correlation between median frequency and torque at each exercise angle. In conclusion, the exercise angle during maximal isometric back extension exercise is not a direct effect on slope of median frequency and torque. But results showed that median frequency and torque shift were highly correlated in all subjects.

The purpose of this study was to determine the effect of electrical stimulation biofeedback on motor learning of quadriceps muscle isometric exercise in 3 patients who have undergone total knee replacement surgery. A multiple baseline design across subjects was used. The electrical stimulation biofeedback was provided with each patient during quadriceps isometric exercise, which last 10 to 14 sessions with 10 repetitions each sessions. After training patients received 4 retention tests. Maximum muscle activity was measured pre- and post- electrical stimulation biofeedback training and retention test to evaluate the effect of biofeedback training. Maximum isometric muscle activity of quadriceps was increased after electrical stimulation biofeedback training in all subjects. The results indicate that a electrical stimulation biofeedback training is a useful method to improve motor learning of quadriceps isometric exercise in total knee replacement.

The purpose of this study was to determine whether the vastus medialis oblique muscle(VMO) had greater electrical activity than the vastus lateralis muscle(VL) when hip adduction and knee extension exercise were performed. Electrical activity of the VMO and VL was measured on 42 healthy subjects (28 men, 14 women) during maximal voluntary isometric contractions of hip adduction and knee extension by an EMG-BIOFEEDBACK. The results showed that the electromyographic activity of the VMO was significantly greater than that of the VL during the hip adduction exercise. Differences noted with knee extension by performing hip adduction exercises. Isometric hip adduction exercises, therefore, may be advisable in the treatment of patients with patellofemoral pain.

Our purpose of this study was to determine the most effective cool-down exercise. The recovery times of dynamic strength after isometric and isotonic cool-down exercise were measured immediately post cool-down exercise, 30 seconds later and 60 seconds later in 30 normal, healthy men from 19 to 29 years, using dumbells(Model, Iron). The recovery time of dynamic strength had a significant positive correlation with isotonic and isometric cool-down exercise using the Chi-square method (p<0.01). Sources of significant differences were determined by the Wilcoxon signed-ranks test (p<0.01). The isometric cool-down exercise significantly shortened the recovery time of dynamic strength. We suggest that the isometric cool-down exercise may be more effective than isotonic cool-down exercise in shortening the recovery time of dynamic strength.