• The Journal of Korean Physical Therapy
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• 제22권4호
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• pp.21-28
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• 2010

Purpose: The purpose of this study was to evaluate the electromyographic (EMG) activity of vastus medialis oblique (VMO) and vastus lateralis (VL) muscles on foot position and knee angle for hemiplegia patients. Methods: Ten stroke subjects (10 males) participated in the study. Subjects were all right-hemiplegic patients. All subjects did $0^{\circ},\;20^{\circ}$ and $40^{\circ}$ knee flexion while maintaining the foot in a neutral position, or at $30^{\circ}$ adduction or at $30^{\circ}$ abduction. Surface EMG data were collected for VMO and VL muscles on the non-hemiplegic side and hemiplegic side. Collected data were analyzed using two-way ANOVA. Results: VMO and VL activities for the non-hemiplegic and the hemiplegic sides were highest for $40^{\circ}$ knee flexion while maintaining the three foot positions. There were no significant differences in EMG activity of the VMO and VL muscles with different foot positions. There were significant differences between VMO and VL activity for knee flexion angle while maintaining the foot in neutral (p<0.05), at $30^{\circ}$ adduction (p<0.05), or at $30^{\circ}$ abduction (p<0.05). Conclusion: Foot position does not influence VMO and VL activities. But, knee flexion exercise in a closed chain can increase VMO and VL muscle activity for hemiplegic patients. In particular, VMO and VL activities for both the non-hemi side and the hemi side were highest for $40^{\circ}$ knee flexion.

• 한국축산식품학회지
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• 제40권1호
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• pp.34-43
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• 2020

The objectives of this study was to compare palatability changes of the longissimus thoracis (LT) and vastus lateralis (VL) muscles of Hanwoo steers from different beef quality grades (1⁺ and 1) during 28 d of wet-aging in order to improve the utilization of the VL muscle as a steak. The VL muscle showed a higher collagen content and a lower intramuscular fat content than the LT muscle (p<0.05). As expected, the Warner-Bratzler shear force value was greater in the LT 1 grade (LT-1) muscle than the LT-1⁺ muscle (p<0.05); whereas no difference was observed between the grades in the VL muscle at 24 h postmortem. Compared to 0 d of aging, tenderness scores significantly increased after 14 and 21 d of aging in the LT and VL muscles, respectively (p<0.05). Additionally, there was no difference in tenderness score between the VL-1⁺ aged for 21 d and the LT-1 at 24 h postmortem, although tenderness score was greater in the LT than the VL at each period (p<0.05). Moreover, the VL-1⁺ steak exhibited a higher tenderness score than the VL-1 steak at 21 and 28 d of aging (p<0.05). On the other hand, the effect of aging time on juiciness and flavor in the VL muscle was somewhat limited unlike the LT muscle. Taken together, the VL muscle requires a longer aging time than the LT muscle to improve consumer preference. Considering the tenderness, using a higher quality grade for aging is more useful in the VL muscle.

• 대한물리의학회지
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• 제13권4호
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• pp.9-17
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• 2018

PURPOSE: This study was conducted to compare the effects of the Graston-based massage method and microcurrent application on muscle fatigue after causing muscle fatigue of the quadriceps femoris by applying high-intensity exercise. METHODS: Study subjects (56 healthy subjects in their 20s) were randomized into a microcurrent group (MG), Graston group (GG), and control group (CG). To induce fatigue of the quadriceps femoris, the subjects performed squats 100 times without a break within about 5 minutes. Muscle fatigue was measured immediately after performing squats and 15 minutes after intervention. To measure muscle fatigue, surface electromyogram (EMG) was used to obtain and compare the median frequency. Microcurrent or Graston massage was applied to their quadriceps muscles 15 minutes after performing the squats. RESULTS: Muscle fatigue increased significantly in the vastus lateralis before and after intervention in the Graston group (p<.05), while no significant difference was observed in the rectus femoris and vastus medialis (p>.05). There were also no significant differences in the microcurrent group or the control group. CONCLUSION: Both the microcurrent group and Graston group showed a tendency for increasing median frequency values compared to the control group, but there was no significant difference except in the vastus lateralis treated with the Graston technique. Although there was no significant difference, the Graston technique could be utilized to reduce the occurrence of DOMS by preventing muscle fatigue in clinical practice or sports medicine.

• 한국운동역학회지
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• 제17권2호
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• pp.239-245
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• 2007

The purpose of this study was to compare the electromyography signal's power spectrum mean and median tendencies appearing in the lower extremity during walking while wearing roller shoes. 9 male subjects volunteered who have no experience riding inline-skate or roller-skate, and have no record of musculoskeletal disorder. Subjects walked on treadmill twice for an hour (Once a week, one trial with the roller on and the other without roller, Walking velocity = 1.39 m/s). Electromyography was measured every 15 minute (0, 15, 30, 45, 60 minutes). Surface electrode sticked muscle at rectus femoris(R.F.), vastus lateralis(V.L.), vastus medialis(V.M.), biceps femoris(B.F.), tibialis anterior(T.A.), gastrocnemius lateralis(G.L.), gastrocnemius medialis(G.M.). At Rectus femoris, Vastus Lateralis, Vastus medialis, and Biceps femoris showed no statistically significant decrease of median frequency or mean edge frequency as time passes. Also, between two treatments (wearing the roller shoes vs not wearing the roller shoes), no statistically significant difference. After 60 minutes, mean edge frequency showed statistically significant decrease at tibalis anterior and after 45 minutes, mean edge frequency showed statistically significant decrease compared to wearing roller shoes without the wheels at gastrocnemius lateralis. At gastrocnemius medialis after 30 minutes, median frequency showed statistically significant decrease, and showed statistically significant difference compared to the control group. Wearing the roller shoes with wheels for a long time resulted in statistically significant decrease of mean edge frequency and median frequency in lower extremity, especially in shank muscles. Increase of wearing time of roller shoes and walking on a bumpy road wearing roller shoes with wheels result fatigue and thus, danger of injury.

• International journal of advanced smart convergence
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• 제12권4호
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• pp.426-433
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• 2023

The purpose of this study was to investigate the muscle activity of the lower extremity during driver swing in three-foot positions (Feet Open Stance, Feet Straight Stance, Lead Foot Open Stance). The electromyograms of gastrocnemius, tibialis anterior, and vastus lateralis during swing were measured and analyzed in three sections (take away - back swing, back swing - down swing, and down swing - follow swing). There was no significant difference in muscle activity according to foot position. Muscle activity according to phase was significantly higher in right gastrocnemius and tibialis anterior, and the left and right vastus lateralis in down swing - follow swing. In conclusion, the difference in muscle activity according to foot position is insignificant, and it is considered that the muscle activity to maintain the balance of the body increases toward the end of swing.

• 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.

• 대한물리의학회지
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• 제7권4호
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• pp.541-550
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• 2012

PURPOSE: The purpose of this study was compare quadriceps femoris muscle activity while performing wall slide squats of four methods. METHODS: Forty subjects, with no history of patellofemoral pain, quadriceps injury, or other knee injury volunteered for this study. Muscle activation of the vastus medialis obliquus, rectus femoris, vastus lateralis muscles were recorded while subjects performed 10 consecutive wall slide squats. Subjects performed the wall slide squats during four different methods: (1) basic wall slide squat, (2) keep back upright against fitness ball, (3) standing of unstable surface, (4) squeezing ball between both knees. Statistical analysis were accomplished by utilizing the one-way ANOVA(Bonferroni's post-hoc test) by SPSS 20.0 program. Significance level was set at p<.05. RESULTS: Muscle activations induced wall slide squats of four methods compared and results showed that there was significant difference only in vastus medialis obliquus and rectus femoris but there was no significant difference in vastus lateralis. The vastus medialis obliquus was significantly different only keep back upright against fitness ball at post-hoc test. The rectus femoris was significantly different keep back upright against fitness ball and standing of unstable surface at post-hoc test. CONCLUSION: Based on these results, we conclude that quadriceps femoris muscle activations are differenced by performing wall slide squats of four different methods in healthy subjects. These data suggest that for quadriceps muscle strengthening, exercise professionals can perform the wall slide squats by altering several task variables. Further research is needed to determine the exact mechanism by which quadriceps function is altered.

• PNF and Movement
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• 제18권1호
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• pp.35-44
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• 2020

Purpose: The purpose of this study was to investigate the effect of the simultaneous abdominal drawing-in maneuver (ADIM) on the muscle activity of the ipsilateral trunk and leg during proprioceptive neuromuscular facilitation (PNF) leg flexion, adduction, and external rotation with knee flexion (D1) patterns. Methods: The participants were 20 healthy adult males and females (18 males and 2 females). The maneuvers were performed by a physical therapist who fully understands the PNF leg patterns (D1) and their application in clinical practice. The participants were trained and allowed to practice for 15 minutes prior to applying ADIM, to ensure adequate learning as evidenced by the pressure biofeedback unit. In this study, we measured the muscle activity of the trunk and leg when the PNF leg pattern (D1) was performed by the physical therapist either sustaining or releasing the ADIM. Muscle activity was measured on the right transverse abdominis muscle (TRA), the external abdominal oblique muscle (EO), the internal abdominal oblique muscle (IO), the erector spinae muscle (ES), the vastus medialis oblique muscle (VMO), the vastus lateralis oblique muscle (VLO), and the tibialis anterior muscle (TA) and compared using the mean values from averaging three repeated measurements. Results: The muscle activity of the transversus abdominis, the external abdominal oblique, the internal abdominal oblique, the vastus medialis oblique, and the vastus lateralis oblique was significantly greater (p < 0.05), and the muscle activity of the erector spinae was significantly less (p < 0.05) during PNF leg pattern (D1) when the ADIM contraction was sustained compared to when it was not. Conclusion: These results suggest that sustaining ADIM during PNF leg pattern (D1) training increases the trunk and leg muscle activity, resulting in more effective training.

• PNF and Movement
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• 제21권1호
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• pp.107-117
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• 2023

Purpose: The aim of this study is to compare the immediate effects of weight-assisting methods on vastus medialis oblique (VMO) and vastus lateralis (VL) muscle activation, on the VMO/VL muscle activation ratio, and on muscle onset time in healthy subjects when ascending stairs. Methods: Healthy participants were randomly assigned to the belt group (n = 11), hand group (n = 11), and control group (n = 11). In the belt group, a belt was wrapped around the sacrum and pulled forward with both hands, moving the center of weight forward, while ascending stairs. The hand group grasped the hips with both hands and climbed stairs, assisting their weight from the rear and moving the center of weight backward, and the control group climbed the stairs without any intervention. Results: Muscle activation of the VMO decreased significantly after the intervention in the belt and hand groups, and activation of the VL muscle in both groups showed a greater decrease than that of the VMO muscle. Further, the VMO/VL muscle activation ratio increased significantly, with an improvement shown in the order of the belt group, hand group, and control group, while muscle onset time also improved in the order of the belt group, hand group, and control group. Conclusion: The belt group demonstrated the greatest effect across all dependent variables, confirming that in clinical practice, these two weight-assisting methods are more effective interventions during stair ascent for patients with knee joint instability, pain, and imbalance than no assistance.

• 대한정형도수물리치료학회지
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• 제19권2호
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• pp.55-60
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• 2013

Background: The purpose of this study was to determine if there is a difference in activation of the rectus femoris, vastus medialis oblique, vastus lateralis, semitendinosus, and biceps femoris when performing normal free squat with standinding position and free squat with $30^{\circ}$ flexed hip joint. Methods: Electromyograph surface electrodes were placed on the rectus femoris, vastus medialis oblique, vastus lateralis, semitendinosus, and biceps femoris of 19 healthy college students. The participants performed standing bilateral squats and standing bilateral squats with $30^{\circ}$ flexed hip joint with EMG measures taken upon initiation of muscle activity as confirmed by an electronic goniometer. Participants completed one trial with the EMG time measurements on each type. Results: There was a significant difference between normal squats(standing squats) and normal squats with $30^{\circ}$ flexed hip joint. The normal squat exercise was statistically higer than normal squat exercise with $30^{\circ}$ flexed trunk except for semitendinosus and biceps femoris that shown slightly high. Conclusions: As a result of this study, there were increases of muscle activity in both ways. In particular, it may be more beneficial for knee joint stabilization to perform normal squat exercise with standing position relatively.