• Journal of the Korean Society of Physical Medicine
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• v.14 no.4
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• pp.153-162
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• 2019

PURPOSE: This study compared ankle joint exercise and thigh exercise on the isometric strength of the lower limb and balance ability. METHODS: Twenty-seven subjects were divided into ankle joint exercise (AEG, n=9), tight exercise (TEG, n=9), and control group (CON, n=9). AEG and TEG performed ankle joint and tight exercises three times a week for four weeks. The following were measured before and four weeks after each exercise: isometric strength at knee flexion and extension of the lower limb; isometric strength at ankle plantar flexion and dorsiflexion of the lower limb; static balance of trace length and C90 area; and the dynamic forward, backward, leftward, and rightward balance for each region. RESULTS: The results showed that the isometric strength of plantar flexion (p<.05) was increased significantly in AEG compared to those in TEG and CON. The dynamic leftward (p<.05) and rightward balance (p<.05) were increased significantly in both AEG and TEG compared to that in CON. On the other hand, the static balance of the trace length and C90 area, isometric strength of ankle dorsiflexion, knee flexion and extension of the lower limb, and dynamic forward and backward balance did not show significant differences between the groups. CONCLUSION: Ankle joint exercise improves the isometric strength of plantar flexion compared to tight exercise.

• Korean Journal of Applied Biomechanics
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• v.17 no.3
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• pp.61-68
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• 2007

When an active muscle is stretched, its steady-state isometric force following stretch is greater than that of a purely isometric contraction as the corresponding muscle length, referred to as force enhancement (FE). The purpose of this study was to investigate possible effects of muscle architecture on the FE. While subject performed maximal isometric dorsiflexion (REF) and isometric-stretch-isometric dorsiflexion (ECC) contractions, ankle joint angle and dorsiflexion torque using a dynamometer and electromyography of the tibialis anterior and the medical gastrocnemius muscles were measure. Simultaneously, real-time ultrasound images of the tibialis anterior were acquired. Regardless of the speed of stretch of the ECC contractions. the torques produced during the isometric phase following stretch ($37.3{\pm}1.5\;Nm$ ($10{\pm}3%$ FE) and $38.3{\pm}1.5$ ($12{\pm}3%$ FE) for the ECC contractions with $15^{\circ}$/s and $45^{\circ}$/s stretch speeds, respectively) were greater than those of the REF contractions ($34.5{\pm}2.5\;Nm$). Moreover, the amount of FE was found to be stretch speed dependent. Angles of pennation ($\alpha$) during the isometric phase following stretch were the same for the REF ($15{\pm}1^{\circ}$) and the ECC ($14{\pm}1^{\circ}$(LS), $15{\pm}1^{\circ}$(LF)). During the same phase, muscle thicknesses were the same ($14.9{\pm}0.6$, and $14.9{\pm}0.5\;mm$ for the REF and the ECC contractions, respectively). For a large limb muscle, the tibialis anterior muscle, a similar amount of force enhancement was observed as did for other human skeletal muscles. Architectural variables, pennation angle and thickness, were not systematically different between the REF and ECC contractions when FE occurred. Therefore, the results of this study suggest that muscle architecture may have little influence on the production of FE.

• Journal of Korean Physical Therapy Science
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• v.28 no.2
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• pp.19-29
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• 2021

Background: The purpose of this study was to investigate the effects of pulsed-ultrasound intervention and continued-ultrasound on the MVIC (maximal voluntary isometric contraction) and active ROM (range of motion) recovery of before EIMD (exercise-induced muscle damage). Design: Randomized controlled trial. Methods: Thirty subjects who are student in their 20s at a university participated in this study, these subjects were assigned into three groups, a control group (n=10), experiment group I (n=10) and experiment group II (n=10). The subjects in experimental group were intervened by pulsed-ultrasound and continued-ultrasound, while ones on control group weren't by any intervention after induced EIMD. Results: First, In comparison of the MVIC, in the among group comparison, the MVIC of continued-ultrasound group was significantly larger than those of other groups (p<.005). Second, In the among group comparison, the active extension angle of continued-ultrasound group was significantly smaller than those of other groups (p<.005). Third, In the among group comparison, the active flexion angle of continued-ultrasound group was significantly lager than those of other groups (p<.05). Conclusion: The above results revealed that the continued-ultrasound intervention before an exercise had a significantly improve of muscle function after EIMD. Therefore we can consider the continued ultrasound as a considerable intervention method to prevent or reduce an exercise injury.

• Korean Journal of Applied Biomechanics
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• v.31 no.2
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• pp.140-147
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• 2021

Objective: The purpose of this study is to identify the mechanism of changes in maximum voluntary torque with the magnitude and duration of pre-activation torque during voluntary isometric knee extension. Method: 11 male subjects (age: 25.91±2.43 yrs., height: 173.12±3.51 cm, weight: 76.45±7.74 kg) participated in this study. The subjects were required to produce maximal voluntary isometric torque with a particular pre-activation torque condition. The properties of pre-activation torque consisted of the combinations of 1) three levels of magnitude, e.g., 32 Nm, 64 Nm, 96 Nm, and 2) two levels of duration, e.g., 1 sec, and 3 sec; thus, a total of six conditions were given to the subjects. The force and EMG data were measured using the force transducers and wireless EMG sensor, respectively. Results: The results showed that the maximum voluntary torque increased the most with relatively large and fast (96 Nm, 1 sec) pre-activation condition. Similarly, with relatively large and fast (96 Nm, 1 sec) preactivation, it was found that the integrated EMG (iEMG) of the agonist muscles increased, while no significant changes in the co-contraction of the antagonist muscles for the knee extension. Also, the effect of pre-activation conditions on the rate of torque development was not statistically significant. Conclusion: The current findings suggest that relatively larger in magnitude and shorter in duration as the properties of pre-activation lead to a larger magnitude of maximal voluntary torque, possibly due to the increased activity of the agonist muscles during knee extension.

• Journal of the Korea Convergence Society
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• v.7 no.2
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• pp.43-52
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• 2016

The purpose of this study was to suggest the effective squat exercise position to strengthening vastus medialis oblique, and vastus lateralis in quadriceps. Subjects were twenty patients with patellofemoral pain syndrome (PFPS) volunteered to participate in this study. All subjects were applied to static squat convergence exercise with knee flexed $45^{\circ}$, $60^{\circ}$, and $90^{\circ}$ for 30 seconds total 5 times. Measurement variables were maximal voluntary isometric contraction (MVIC) of the quadriceps, Q angle and length of thigh. Those were measured before and after the squat exercise on knee joint angle, change rate of which were used for statistical analysis. As a result, squat exercise with knee flexed $90^{\circ}$ increase significantly among knee joint angle in the MVIC change rates of quadriceps (p<.05), however the rates of Q-angle and length change of thigh showed no significant difference. Therefore, this findings suggest that squat exercise with knee flexed $90^{\circ}$ strengthen quadriceps effectively in patients with PFPS.

• Physical Therapy Korea
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• v.23 no.1
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• pp.20-30
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• 2016

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 ($n_1$=19) or the QIIC ($n_2$=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.

• Journal of Oral Medicine and Pain
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• v.38 no.4
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• pp.333-338
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• 2013

Purpose: A growing number of studies have been providing evidence for neural connections between the auditory and somatosensory systems that might be a critical part of the mechanisms underlying certain forms of tinnitus. The aim of this study was to investigate the effect of temporomandibular joint (TMJ) movements on tinnitus. Methods: One hundred sixty-three tinnitus patients participated in this study. All patients underwent a thorough audiological examination including pure-tone audiometry, tinnitus handicap inventory, and evaluation of tinnitus loudness, frequency and severity on a visual analog scale. Somatic testing consisting of nine forceful jaw muscle contractions was performed to evaluate the effect of TMJ movements on modulation of tinnitus. Results: 66.9% of patients had unilateral tinnitus. Somatic testing modulated tinnitus loudness in 125 ears (57.6 %) of 217 ears tested. An increase in tinnitus loudness was observed more often than a decrease. Loudness was most commonly increased by opening and clenching jaw. Tinnitus could be induced by opening, clenching and deviating jaw to the left. Conclusion: Our study showed evidence that TMJ movements may aggravate and even evoke tinnitus and somatic testing can be used for evaluating if stimulation of the TMJ induces or aggravates tinnitus.

• Journal of the Korean Applied Science and Technology
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• v.36 no.3
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• pp.1028-1040
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• 2019

The current study was performed to investigate the magnitude of exercise-induced muscle damage (EIMD) after downhill running (DR) of different intensities and to examine the availability of muscle echo intensity as biomarkers to detect regional damage within quadriceps muscle group (QG) following DR. Healthy college-age men (n=11) were experienced twice DR sessions [$50%HR_{max}$ DR, LDR; $70%HR_{max}$ DR, HDR] separated by a 2-week wash-out period with the random order. After DR, severity of EIMD according to exercise intensity were determined by serum creatine kinase (CK) activity, muscle tenderness, and neuromuscular function indicators such as a maximal voluntary isometric contraction (MVIC) and range of motion (ROM). Transvaginal B-mode imaging had been employed to evaluate regional muscle echo intensity within QG [rectus femoris, RF; vastus lateralis, VL; vastus medialis, VM; vastus intermedius, VI]. After both DR sessions, changes in serum CK activity and muscle tenderness have tended to more increase in HDR compared to those of LDR. There was a significant interaction effect between exercise intensity during DR and the time course of serum CK activity(p<.05). However, there were no statistical differences between sessions in muscle tenderness. The time course of changes in the neuromuscular functions after DR were similar to those of regional muscle echo intensity regardless exercise intensity. Although neuromuscular function showed to decline in HDR more than those of LDR after DR, no statistical differences between sessions. In contrast, there were significant interaction effects between sessions and time course of changes in RF and VL muscle echo intensity(p<.01), but not shown in those of VI and VM. These results indicated that each muscles within the QG show different response profiles for EIMD during DR, exercise intensity influences on these responses as well. In particular, current findings suggested that muscle echo intensity derived from ultrasound imaging is capable of detecting regional muscle damage in QG following DR.

• Journal of Biomedical Engineering Research
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• v.23 no.1
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• pp.9-16
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• 2002

Localized muscle fatigue can be identified by a downward shift of the EMG frequency typically represented by a fall in the median frequency The Present experimental study was Performed to investigate the time change of the median frequency and the muscle torque during maximal isometric back extension exercises at different exercise angles (0$^{\circ}$, 12$^{\circ}$, 36$^{\circ}$and 72$^{\circ}$) Twenty heath subjects (mean age : 24.35 $\pm$ 2.70) were Participated in this study Median frequency was extracted from EMG signals by employing the fast Fourier transform. Initial median frequency and the slope of median frequency was not significantly correlated with the muscle torque. Pearson's Product moment correlation was used to quantify the relationship between slopes of median frequency and torque. The results may suggest that the exorcise angle during maximal isometric back extension exercises does not affect the slopes of the median frequency and torque, and y-intercept of the median frequency among exercise angles There was no significant correlation between slopes of median frequency and torque. But there was a 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 slopes of median frequency and torque. But results showed that the shift of median frequency and torque shift were highly correlated in all subjects.

• The Journal of Korean society of community based occupational therapy
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• v.10 no.1
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• pp.31-38
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• 2020

Objective : The purpose of this study is to investigate the effects of bilateral chewing exercise applied for 6 weeks on occlusion force and masseter muscle thickness in the elderly living in the community. Methods : This study recruited 25 community residents. All participants performed bilateral chewing exercise using equipment developed for the purpose of oral chewing exercise. The chewing exercise was divided into isometric and isotonic type and applied for about 20 minutes a day, five times a week for six weeks. For the evaluation, the masseter muscle thickness and the maximum occlusion force were measured three times at three week intervals using a portable ultrasound instrument and an occlusion force gauge. Results : As a result of the change in masseter muscle thickness, baseline, 3 weeks later, and 6 weeks later referred to 7.51±0.43, 7.63±0.44, and 7.83±0.46, respectively (F=3.819, p<.05). The post hoc test resulted in a significance between baseline and 6 weeks later (p=0.023). Similarly, as a result of the change in occlusion force, baseline, 3 weeks later, and 6 weeks later referred to 265±9.22, 268±9.57, and 271.59±10.16, respectively (F=3.031, p<.05). The post hoc test resulted in a significance between baseline and 6 weeks later (p=0.048). Conclusion : This study confirmed that bilateral chewing exercise was effective for increasing masseter muscle thickness and occlusion force in the elderly. Therefore, bilateral chewing exercise can be applied as a therapeutic exercise method for improving oral function.