• The Journal of Korean Physical Therapy
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• 제22권4호
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• pp.49-55
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• 2010

Purpose: The purpose of this study was to investigate the effects of isokinetic exercise on muscular performance and thickness of the quadriceps muscle. Methods: Twenty one healthy male students participated in this study. Participants were divided into 2 groups: $60^{\circ}/sec$ of isokinetic exercise (n=7), $180^{\circ}/sec$ (n=7) and $300^{\circ}/sec$ (n=7). Each group did isokinetic exercises 3 times a week for 6 weeks. Each group was measured for peak torque per body weight, average power and total work using a Biodex System 4. Rectus femoris, vastus laterails and vastus medialis were measured for muscle thickness using a SONOACE 6000C. Data were analyzed by repeated measures ANOVA using SPSS 12.0. Results: There was a significant time-related effect in peak torque per body weight, average power and total work. There was a significant time-related effect in the vastus medialis and rectus femoris muscle thickness. However, there was a significant group by time interaction for vastus laterlis muscle thickness. Conclusion: Isokinetic exercise may be an effective method for improving quadriceps muscle performance regardless of angular velocity. However, the thickness of the rectus femoris and vastus medialis muscle may be increased regardless of the angular velocity of the quadriceps muscle the vastus lateralis muscle may only be remarkably improved when doing exercise with low angular velocity.

• 대한통합의학회지
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• 제6권2호
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• pp.117-123
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• 2018

Purpose : The purpose of this study was to investigate the effect of increased brain activity on the muscle endurance and the effect of brain activation through the combination of transcranial direct current stimulation and aerobic exercise on elderly woman. Methods : To investigate the effect of the muscle endurance on right leg, muscle endurance was evaluated by measuring the surface EMG of the muscles of the rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius muscle. Results : There was a significant difference in the pre and post comparisons of muscle endurance on rectus femoris, biceps femoris, tibialis anterior muscle (p<.05). Difference of Combination of transcranial direct current stimulation and aerobic exercise group median frequency was smaller than control group (p<.05). There was not a significant difference in the pre and post comparisons of muscle endurance on biceps femoris, and gastrocnemius muscle. Difference of Combination of transcranial direct current stimulation and aerobic exercise group median frequency was showed a similar pattern. Conclusion : Through these results, It was found that increasing the brain activity by the transcranial direct current stimulation improves the exercise capacity on the elderly women. Combination of transcranial direct current stimulation and aerobic exercise maybe applied as an effective treatment for improving muscular endurance.

• The Journal of Korean Physical Therapy
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• 제35권2호
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• pp.53-57
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• 2023

Purpose: The purpose of this study was to compare the changes in the muscle activation of the quadriceps muscle (rectus femoris, vastus lateralis, vastus medialis) during the stand-to-sit (StandTS) movement according to the plantar flexion angle of the ankle joint. Methods: A total of 22 healthy young females participated in this study. During the StandTS under the three conditions (plantarflexion angle 0°, 20°, and 45° of the ankle), electromyography (EMG) data (% maximum voluntary iso¬metric contraction) of the rectus femoris, vastus lateralis, and vastus medialis were recorded using a wireless surface EMG system. Results: There was a significant difference in the muscle activation of rectus femoris, vastus lateralis, and vastus medialis according to the plantar flexion angle (0°, 20°, and 45°) of the ankle. The muscle activation of the quadriceps was the highest at a 45° angle of plantarflexion and the lowest at 0°. One-way repeated ANOVA was used to analyze the muscle activation data of the lower extremity muscles according to the angle of the ankle joint. Conclusion: Based on the results of our study, it was confirmed that the muscle activity of the quadriceps can be increased even in the StandTS movement, which involves the eccentric contraction of the quadriceps muscle. This suggests that maintaining a plantar flexion posture for a long time, say by wearing high-heeled shoes, can quickly cause muscle fatigue in the lower-limb muscles, which can cause a decrease in balance ability leading to falls.

• International Journal of Internet, Broadcasting and Communication
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• 제16권1호
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• pp.156-162
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• 2024

The purpose of this study was to investigate the muscle activity of internal oblique, rectus femoris, and multifidus according to knee posture and foot bar angle during pilates reformer high flank exercise. Twelve women in their 20s were recruited within six months of their experience as pilates instructors. The subjects performed six types of high flanks according to knee posture and foot bar angle. EMG signals of internal oblique, rectus femoris, and multifidus during exercise were measured and analyzed by integral EMG. The collected data were processed by repeated measures two-way ANOVA. In this paper it shows the following results. First, internal oblique iEMG was not significantly different according to knee posture and foot bar angle. Second, the rectus femoris had an interaction effect according to knee posture and foot bar angle. Third, there was no significant difference in multifidus according to knee posture and foot bar angle. In conclusion, according to the exercise method, the activity of the rectus femoris was the highest in the knee bending and high foot-bar angle high plank exercise, and there was no difference between the internal oblique and multifidus.

• 대한임상전기생리학회지
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• 제11권1호
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• pp.21-29
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• 2013

Purpose : The purpose of this study was to determine the changes in ultrasound imaging of the lower limbs in patients with degenerative osteoarthritis who received a total knee replacement (TKR). Methods : The participants for the study were ten patients who were to receive a total knee replacement. Measurements were taken a total of three times: before receiving a total knee replacement, and one week and two weeks after receiving a total knee replacement. The vastus medialis, rectus femoris muscle, tibialis anterior and gastrocnemius muscle were measured using ultrasound imaging. Results : Muscle thickness of the vastus medialis, rectus femoris muscle, tibialis anterior and gastrocnemius muscle had no significant interaction over time whether surgery was performed or not. White area index (WAI) and density of vastus medialis, rectus femoris muscle, tibialis anterior and gastrocnemius muscle had no significant interaction over time whether surgery was performed or not. Conclusion : In conclusion, lower quality muscles were due to a decrease in muscle fiber and an increase in fat fiber. Therefore, initial physical therapy after total knee replacement should consider this point and be designed appropriately as a therapeutic approach for total knee replacement patients.

• 대한산업공학회지
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• 제7권2호
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• pp.3-17
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• 1981

Isometric muscle strength has become important as it is realized that a large variation in the human exists and is affected by many personal and environmental factors. Experiments have been performed for estimating the individual capabilities of the quadriceps femoris muscle in man. The surface EMG has been recorded on the belly of the rectus femoris muscle during voluntary isometric continuous exertion at 25%, 50%, 75%, and 100% MVC. As a muscle force (% MVC) increases, the rectified mean EMG amplitude increases in a non-linear form. The rectified mean EMG amplitude also increases in a non-linear with respect to fatigue progression. As the muscle force (% MVC) increases, an endurance time of isometric exertion decreases linearly. Analysis shows that rectified mean EMG amplitude is a consistent and sensitive measure of motor unit recruitments and can be useful in estimating an individual capability of a local muscle. Further, the result satisfies the sufficient condition that type S motor units are recruited first, while large motor units are recruited progressively as the fatigue develops.

• PNF and Movement
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• 제10권3호
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• pp.25-31
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• 2012

Purpose : This study was intended to compare muscle activity in relation to knee joint angles on closed kinetic chain. Methods : A total of 13 subjects consisting of 5 adult males and 8 adult females were made to make movements maintaining knee joint angles at $30^{\circ}$, $45^{\circ}$ and $90^{\circ}$ on closed kinetic chain and the muscle activity occurring in their vastus medialis, rectus femoris and vastus lateralis was measured. Statistical data were analyzed using oneway ANOVA. Results : On closed kinetic chain, the muscle activity of the vastus medialis, rectus femoris and vastus lateralis increased the most at $90^{\circ}$ among the knee joint angles with statistically significant differences(p<0.05). Conclusion : On closed kinetic chain, it could be seen that as the angle of the knee joint increased, the muscle activity increased.

• PNF and Movement
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• 제9권1호
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• pp.21-29
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• 2011

Purpose : The purpose of this study was to assess the effects of the lower extremity muscle activity on bridging exercise according to the knee joint angle. Methods : Twenty-five healthy adults volunteered to participate in this study. Subjects were required to complete following four bridging exercises; knee joint flexion $120^{\circ}$, $90^{\circ}$, $60^{\circ}$, $45^{\circ}$. Surface electromyography from selected lower extremity muscles was normalized to maximum voluntary isometric contraction. Muscle activity was measured by QEMG-4 system (LXM 3204, Laxtha Korea). A repeated measures of one-way ANOVA was used to determine the influence of bridging exercise on muscle activity for each muscle and descriptive statistics was used to determine muscle ratio. Results : The biceps femoris of all bridging exercises showed significantly(p<.05). The vastus medialis and lateralis of all bridging exercises showed significant excepted $120^{\circ}$(p<.05). The rectus femoris of all bridging exercises showed no significant. Median of vastus medialis/rectus femoris ratio of $120^{\circ}$ was 2.03, $90^{\circ}$ was 2.16, $60^{\circ}$ was 2.67, $45^{\circ}$ was 4.10. Median of vastus lateralis/rectus femoris ratio of $120^{\circ}$ was 1.70, $90^{\circ}$ was 1.70, $60^{\circ}$ was 2.08, $45^{\circ}$ was 2.58. Median of vastus medialis/vastus lateralis ratio of $120^{\circ}$ was 1.26, $90^{\circ}$ was 1.50, $60^{\circ}$ was 1.52, $45^{\circ}$ was 1.47. Conclusion : Angular motion decreasing with knee joint flexion made increase biceps femoris and vastus medialis activation. This result will be use knee joint stabilizing exercises during bridging or unstable surface training and biceps femoris strength training.

• The Journal of Korean Physical Therapy
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• 제21권4호
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• pp.57-63
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• 2009

Purpose: To better understand falls in elderly women, we measured differences in muscle activities of 4 lower extremity muscles (tibialis anterior, soleus, rectus femoris, biceps femoris) based on angle plantar-flexion in elderly women. Methods: Subjects were 15 healthy elderly women. No subjects had musculoskeletal or nervous disorders. EMGs were used to check muscle activity of lower extremity muscles. For statistic analysis, data were expressed as a percentage of maximal voluntary isometric contraction (%MVIC). We measured %MVIC for 5 sec under 4 conditions and did not use data for the first and last second. Muscle activities of the muscles of the lower extremities were measured based on the degree of plantar-flexion of the ankle joint. The 4 conditions corresponded to different degrees of: 0, 10, 20 and 30 degrees. This was done using a 50 cm board for measuring the degrees. Results: The tibialis anterior, soleus, and bicpes femoris showed increasing muscle activity associated with increasing degree of plantar-flexion of the ankle joint. All muscles showed a significant increase in muscle activities in association with increasing degrees. Rectus femoris showed a significant increase in muscle activity for 0 degrees and for the other degrees, but there were no further changes when plantar flexion of the ankle joint was over 10 degrees. Conclusion: Activities of the muscles of the lower extremities except rectus femoris were higher with increasing degree of plantar flexion. High muscle activity may result in muscle fatigue. Thus, increasing degree of plantar flexion may be risk factors of falls in elderly women.

• Physical Therapy Rehabilitation Science
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• 제10권3호
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• pp.367-373
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• 2021

Objective: Short foot exercise(SFE) is frequently used to increase the medial longitudinal arch of the foot, as well as the intrinsic foot muscles. This studyinvestigated the effects of SFE onmuscular activity and the onset of contraction of the quadriceps femoris muscle during squats in healthypeople. It also aimed to compare and analyze the results with those of the general squat method and propose a more efficient squat method. Design: Cross-sectional study. Methods: This study compared 20 adults (male=10, female=10) who statisfied the inclusion criteria for the muscle activity and onset of the muscle contraction of the quadriceps femoris using surface EMG under two conditions: general squats and SFE squats. Results: Separate analyses and comparisons of the outcomes of the SFE squat and the general squat, showed a significant increase in the muscle activities of the rectus femoris and vastus medial muscles in both males and females (p<0.05). The onset of muscle contraction was significantly delayed for the vastus lateralis relative to that for the vastus medialis (p<0.05). However, it delayed significantly in females, but not in males. Conclusions: The SFE squats induced selective muscular activities of the rectus femoris and vastus medialis muscels and affected the onset of contraction of the vastus medialis and lateralis muscles.