• International Journal of Contents
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• 제6권1호
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• pp.41-46
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• 2010

The aim of this study was to investigate the effect of different shoe-heel heights on the surface electromyographic (EMG) activity of vastus medialis (VM) and vastus lateralis (VL) during treadmill walking in female patients with patellofemoral pain (PFP). Nineteen women with PFP participated in this research. EMG signals were recorded from the VM and VL of both sides and were compared during the treadmill walking. The subjects walked on a treadmill wearing shoes of three different heel heights: 1 cm, 3 cm and 7 cm. Each subject walked on a treadmill for five minutes at a speed of 2 km/hour with three minutes resting intervals between consecutive trials. The data were analyzed by one-way repeated-measures analysis of variance. The results of the present study indicate that EMG data of the VM and VL of female patients with PFP did improve with an increase in the height of the shoe heel, which were statistically significant. Additionally, the EMG activity of VM increased more dramatically than that of VL associated with the task of walking with high-heeled shoes on the treadmill. This study suggests that the type of high-heeled shoes is related to the VM and VL muscle activation patterns contributing to knee joint pathologies in female patients with PFP.

• 대한물리의학회지
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• 제6권2호
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• pp.135-143
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• 2011

Purpose: The purpose of this study was to investigate onset timing of vastus medialis oblique(VMO) relative to vastus lateralis(VL) the VMO/VL electromyographic(EMG) ratio according to heel height Methods: A repeated measures design was used. Fifteen healthy female college students with no known knee musculoskeletal dysfunction were recruited this study. They carried out a standardised stair acent activity under 4 conditions; barefoot, and with heel height of 1, 3, 7 cm. Muscle activity was measured by surface EMG (Myosystem 1400A, Noraxon Inc., U.S.A). Data were analysed using $1{\times}4$ repeated measures ANOVA. Results: Onset timing differed with heel height(p<.05). However, the VMO/VL EMG ratio was not significantly difference between conditions. Conclusion: We found that 7 cm heel height delayed in VMO onset compared with 3 cm heel height during stair ascent, but no change in the relative EMG intensity of VMO and VL as measured by th VMO/VL ratio. The findings indicate that high-heeled shoes may have disadvantages in knee stability because of delayed onset of VMO. Due to a lack of knee joint stability, wearing of high heeled shoes should be avoided.

• 수산해양교육연구
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• 제26권2호
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• pp.308-315
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• 2014

The aims of this study are to analysis about surface muscle activity of lower and upper musculus erector spinae according to walkers form. The subjects of the current step is inconvenient to use a walker and five people over the age of 65 valid samples were selected as final. All the subjects were measured in three forms. Wireless EMG muscle activity is a measure of surface measurements were measured using a system, both musculus vastus lateralis, outside the erector spinae muscle, musculus biceps femoris, gastrocnemius muscle was attached to the channel electrodes. According to the results, First, gastrocnemius muscle activity showed significant differences by type of gait. Second, the muscle activity of the erector spinae muscle walking showed significant differences by type, side grip type showed the lowest muscle activity. Consequently, the present study is the efficient use of the four-wheel walker will provide the baseline data.

• 대한의용생체공학회:의공학회지
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• 제28권6호
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• pp.832-839
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• 2007

In this study, a new bicycle system was developed to improve muscular strength using the Magneto-Rheological(MR) rotary brake. The friction load of the MR rotary brake is adjusted according to muscle strength of the subjects. The characteristic of muscular strength was studied with various friction loads of MR rotary brake. The friction load was occurred with the current, applied to the MR. rotary brake. Experiments was composed of several cycling trials for various friction loads. In training programs involving muscle improvement, it is necessary to confirm muscle activity and fatigue. To measure the muscle activity and fatigue, EMG signals of rectus femoris (RF), biceps femoris (BF), tensor fasciae latae (TFL), vastus lateralis (VL), vastus medialis (VAS), gastrocnemius (GAS), tibialis anterior (TA) and soleus (SOL) muscles were collected with surface electromyography and analyzed into time and frequency domain. The experimental results showed that the muscle activity according to the applied current to the MR rotary brake was significantly different. The more the current was applied, the higher value of the integrated EMG (IEMG) was obtained. Especially, the magnitude of IEMG of the RF, BF, TFL and VL varied in direct proportion to the current. However, there was not significant in the median frequency as the cycling time continue.

• International Journal of Contents
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• 제6권1호
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• pp.1-5
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• 2010

Kinesio Taping (KT) is widely used by physical therapists to treat a variety of neuromusculoskeletal disorders. In this study it was examined whether or not KT has an effect on the peak torque and muscle activity of the quadriceps muscles in healthy subjects. KT was applied to the anterior thigh and tibia of fifteen healthy males (mean age, 25.42${\pm}$1.38 years, mean body height 178.58${\pm}$3.03 cm, mean body weight 71.58${\pm}$6.42 kg) who have no problem within past 2 months. The quadriceps peak torque was assessed using an isokinetic dynamometer while the mean data of muscle activity was measured by surface electromyography (EMG). The maximal voluntary isometric contraction was carried out on all subjects at $0^{\circ}$, $30^{\circ}$ and $60^{\circ}$ before, during, and after KT. There were no significant differences in the peak torque and mean data of quadriceps muscle(vastus lateralis, rectus femoris, and vastus medialis oblique) activity at $0^{\circ}$, $30^{\circ}$ and $60^{\circ}$ before, during and after application of KT (p>.05). From this study it could be concluded that the application of KT to the anterior thigh and tibia doesn't affect the peak torque and the muscle activity.

• 대한통합의학회지
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• 제4권4호
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• pp.67-75
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• 2016

Purpose: The purpose of this study was to compare Hip-Knee-Ankle(HKA) angle and muscle activation ratio between vastus medialis(VM), rectus femoris(RF), and vastus lateralis (VL), and by this, to examine their relationship. It is aimed to explore how the activation ratio among the muscles involved in patellofemoral kinetics would vary in relation with the frontal alignment of the lower extremity. Subjects and Methods: 26 healthy subjects were recruited for the study. The HKA angles were measured with radiograph. The VM, RF, VL muscle activation level were measured by surface electromyography while each participant performed 4 different types of movement (isometric knee extension, squat, ambulation, step-up) and VM/RF, VM/VL, RF/VL ratios were calculated. Pearson correlation was used to estimate the relationship between the HKA angle and the muscle ratio. Results: There was significant moderate correlation between HKA angle and VM: RF on the left side during ambulation (p<0.05). Moderate correlations were also observed during step-up and squat with less significance (p<0.1). Conclusion: The frontal alignment of the knee measured by the HKA angle was conditionally associated with muscle activation ratio between VM and RF (VM:RF); On the left, during ambulation, step-up, and squat, the more valgus knee tended to correlate with the more VM muscle activation ratio, which is expected to induce more stabilizing effect to the patella and its tracking. It suggests that the frontal alignement measured by the HKA-angle can affect PF kinetics. It also indicates a possibility that increase in valgus alignment of the knee, by the HKA measurement, may not act unfavorably to generate PFP.

• 대한물리의학회지
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• 제17권1호
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• pp.127-137
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• 2022

PURPOSE: This study sought to evaluate muscle activity and foot pressure during gait, and balance in female college students with genu valgum. METHOD: Participants were assigned based on their Q-angle to genu valgum group greater than 20° (GVG, n = 12), unilateral genu valgum group greater than 20° (UVG, n = 11), and control group (CON, n = 13). All subjects were evaluated for balance (Trace length, C90 area, C90 angle, and the Romberg test), muscle activity (gluteus medius; GM, tensor fasciae latae; TFL, vastus medialis; VM, vastus lateralis; VL, biceps femoris; BF, gastrocnemius; GCM and tibialis anterior; TA) and foot pressure (F/F ratio, R/F ratio, Hallux, 2~5 toe, 1st MT, 2~4 MT, 5th MT, Midfoot, M/heel, and L/heel) during gait. RESULTS: Romberg test showed significantly increased loss of balance in the UVG group compared with the CON. In the forward position, the imbalance was significantly increased in the UVG and GVG groups compared to the CON. Muscle activity of VL, GCM, and TA significantly increased in the GVG group compared with the CON. Static foot pressure, 1st MT significantly increased in the GVG compared to the CON group. The 5th MT significantly decreased in the CON compared with the GVG group. The R/F ratio significantly decreased in the GVG compared to the CON group. In dynamic foot pressure, the 2~5 toe significantly increased in the GVG compared with the UVG group. The left 5th MT significantly decreased in the UVG compared with the CON and GVG groups. CONCLUSION: These results indicate that genu valgum has a negative effect on balance, muscle activity, and foot pressure during gait in female college students.

• 한국운동역학회지
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• 제33권1호
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• pp.17-24
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• 2023

Objective: The purpose of this study was to investigate the effects of different frequency on of knee extensors muscle function during electrical muscle stimulation (EMS). Method: In this research, 40 subjects who have no musculoskeletal disorder, and less than a year workout experience were recruited in order to analyze effects of EMS with different stimulus frequency. Forty subjects were randomly divided into four groups of ten subjects in each group. A EMS training program with different frequencies (without EMS [WE], EMS with frequency 30 Hz [E30], EMS with frequency 60 Hz [E60], EMS with frequency 90 Hz [E90]) was assigned to each group. Throughout eight weeks of training, test subjects were simultaneously carried out knee extension exercises such as squat, leg extension, and leg-press while using EMS with different frequency (20 min, pulse width 250 ㎲, on-off ratio 1:1). Isokinetic knee extension strength, muscle activity of the rectus femoris (RF), the vastus medialis (VM), and the vastus lateralis (VL), and the median frequency of the RF, the VM, and the VL were collected and compared between pre and post training in order to find effects of applying EMS with different frequencies. For each dependent variable, a one-way ANOVA was to determine whether there were significant differences among four different conditions (p<.05). When a significant difference was found, post hoc analyses were performed using the contrast procedure. Results: When compared to WE and E90, E30 causes significant increase in isokinetic knee extension strength. No significant differences were found in EMG values across different EMS conditions. However, the median frequency of the VM in E30 was significantly increased than the corresponding value for WE. Conclusion: The results of this study showed that EMS training with 30 Hz frequency had positive effect on knee extensor. Based of the findings of the present study, EMS training with lower frequency may help the performer to focus on developing strength in knee extensor muscles.

• 대한의용생체공학회:의공학회지
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• 제15권4호
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• pp.429-438
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• 1994

An electrical stimulator was designed to induce locomotion for paraplegic patients caused by central nervous system injury. Optimal stimulus parameters, which can minimize muscle fatigue and can achieve effective muscle contraction were determined in slow and fast muscles in Sprague-Dawley rats. Stimulus patterns of our stimulator were designed to simulate eleclromyographic activity monitored during locomotion of normal subjects. Muscle types of the lower extremity were classified according to their mechanical property of contraction, which are slow muscle (msoleus m.) and fast muscle (medial gastrocnemius m., rectus femoris m., vastus lateralis m.). Optimal parameters of electrical stimulation for slow muscles were 20 Hz, 0.2 ms square pulse. For fast muscle, 40 Hz, 0.3 ms square pulse was optimal to produce repeated contraction. Higher'stimulus intensity was required when synergistic muscles were stimulated simultaneously than when they were stimulated individually. Electrical stimulation for each muscle was designed to generate bipedal locomotion, so that individual muscles alternate contraction and relaxation to simulate stance and swing phases. Portable electrical stimulator with 16 channels built in microprocessor was constructed and applied to paraplegic patients due to lumbar cord injury. The electrical slimulator restored partially gait function in paraplegic patients.

• PNF and Movement
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• 제13권2호
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• pp.95-102
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• 2015

Purpose: The purpose of this study was to analyze the effect of arm flexion patterns of proprioceptive neuromuscular facilitation on muscle activation in the contralateral lower extremity. Open kinematic chain and closed kinematic chain positions were used. Methods: This study used an electromyogram (MP150, Biopac Systems, USA) to measure muscle activation in 20 healthy male students. Comparative analysis was completed on muscle activation of the vastus lateralis, biceps femoris, tibialis anterior, and gastrocnemius of the contralateral lower extremity. Open kinematic chain and closed kinematic chain positions were used with a unilateral arm flexion-abduction-external rotation pattern. Paired t-tests using the SPSS 12.0 for Windows analyzed the data produced by the electromyogram. Results: There was a statistically significant difference in muscle activation in the biceps femoris, gastrocnemius, and tibialis anterior when the open kinematic chain and closed kinematic chain positions were compared (p < 0.05). Conclusion: The biceps femoris, gastrocnemius, and tibialis anterior muscles showed greater muscle activation in the closed kinematic chain position when compared to the open kinematic chain position.