• Title/Summary/Keyword: Maximal voluntary contraction

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Effect of Close kinetic chain and Open kinetic chain Position on Proprioceptive Neuromuscular Facilitation Applied to the Unilateral Upper Extremity on the Muscle Activation of Lower Extremity (닫힌사슬과 열린사슬 자세에서 편측상지에 적용된 PNF가 양측 하지의 근 활성도에 미치는 영향)

  • Han, Hyang-Wan;Kim, Sang-Soo
    • PNF and Movement
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    • v.7 no.3
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    • pp.17-27
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    • 2009
  • The purpose of this study was to investigate the effect of close kinetic chain(CKC) and open kinetic chain(OKC) posion on proprioceptive neuromuscular facilitation applied to the unilateral upper extremity on the muscle activation of lower extremity. All subjects were randomly assigned to two groups: open kinetic chain group(n=5),closed kinetic chain group(n=5). All participants were PNF patterns applied on the unilateral upper extremity in all subjects were the kinetic chain(CKC) and open kinetic chain(OKC) posion on flexion/abduction/external rotation. The hold and approximation techniques for the irradiation were applied to end range. All measurements for each subject took the following tests: pre-test, post - test in 4weeks, post-testin 8weeks. EMG data was collected from the vastus medialis, tibialis anterior, biceps femoris, and gastrocnemius muscle of both lower extreamity using surface EMG system, Each EMG value in individual muscle was normalized for maximal voluntary contraction. The data were analyzed using Two-way analysis of variance(ANOVA) with repeated measures to determine the statistical significances. The results of this study are summarized as follows. First, during for close kinetic chain(CKC) and open kinetic chain(OKC) posion on PNF pattern application, all of the %MVIC values of close kinetic chain and open kinetic chain posion increased sign ificantly compared(p<0.05). Second, The close kinetic chain(CKC) and open kinetic chain(OKC) posion on PNF pattern application was significantly increased with in the intervention period(p<.05). Third, there was a no significant open kinetic chain posion on PNF pattern application of sing muscle group with in the intervention period.(p<0.05) there was a significant close kinetic chain posion on PNF pattern application of sing muscle group with with in the intervention period(p<0.05). Forth, interaction of the exercise position and muscle was also significant. Post-hoc tests revealed that the activation levels of vastus medialis muscle and tibialis anterior muscle was higher in the closed kinetic chain position(p<.05). that the activation levels of vastus medialis and gastrocnemius muscle was higher in the open kinetic chain position(p<.05). In conclusion, it was found that the application of PNF patterns to the unilateral upper extremity effect on the muscle activation of lower extremity and both open kinetic chain exercise and closed kinetic chain exercise was significantly increased muscle activity. Further studies are needed to analyzed long term effects and subjects resulting from these changed.

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Comparison of Kinematics and Myoelectrical Activity during Deadlift, with and without Variable Banded Resistance, in Healthy, Trained Athletes

  • Everett B. Lohman;Mansoor Alameri;Fulden Cakir;Chih Chieh Chia;Maxine Shih;Owee Mulay;Kezia Marceline;Simran Jaisinghani;Gurinder Bains;Michael DeLeon;Noha Daher
    • Physical Therapy Rehabilitation Science
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    • v.13 no.1
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    • pp.53-70
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    • 2024
  • Background: The conventional deadlift is a popular exercise for enhancing trunk, core, and lower extremity strength. However, its use in sports medicine is constrained by concerns of lumbar injuries, despite evidence supporting its safety and rehabilitative benefits. To optimize muscle activation using resistive bands in variable resistance therapy, we explored their feasibility in the deadlift. Design: Comparative experimental design Methods: Surface electromyography recorded muscle activity in the trunk and lower extremities during lifting, with normalization to the isometric Floor Lift using Maximal Voluntary Contraction. Kinematics were measured using inclinometer sensors to track hip and trunk sagittal plane angles. To prevent fatigue, each subject only used one of the three pairs of bands employed in the study. Results: Our study involved 45 healthy subjects (mean age: 30.4 ± 6.3 years) with similar baseline characteristics, except for years of lifting and strength-to-years-of-lifting ratio. Various resistance band groups exhibited significantly higher muscle activity than conventional deadlifts during different phases. The minimal resistance band group had notably higher muscle activity in the trunk, core, and lower extremity muscles, particularly in the end phase. The moderate resistance band group showed increased muscle activity in the mid-and end-phases. The maximum resistance band group demonstrated greater muscle activity in specific muscles during the early phase and overall higher activity in all trunk and lower extremity muscles in the mid and end phases of the deadlift (p<0.05). Conclusion: Our findings provide valuable insights into muscle activation with various resistance bands during deadlift exercise in clinical and gym settings. There appears to be a dose-response relationship between increased resistance bandwidth, external load, myoelectric activation, and range.

Assessment of Effect of Pulmonary Rehabilitation on Skeletal Muscle Metabolism by $^{31}P$ Magnetic Resonance Spectroscopy (호흡재활치료 전후 $^{31}P$ 자기공명분석법을 이용한 골격근대사의 변화에 관한 연구)

  • Cho, Won-Kyung;Kim, Dong-Soon;Choe, Kang-Hyeon;Park, Young-Joo;Lim, Tae-Hwan;Shim, Tae-Sun;Lim, Chae-Man;Lee, Sang-Do;Koh, Youn-Suck;Kim, Woo-Sung;Kim, Won-Dong
    • Tuberculosis and Respiratory Diseases
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    • v.44 no.5
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    • pp.1040-1050
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    • 1997
  • Pulmonary rehabilitation has been known to improve dyspnea and exercise tolerance in patients with chronic lung disease, although it does not improve pulmonary function. The mechanism of this improvement is not clearly explained till now; however some authors suggested that the improvement in the skeletal muscle metabolism after the rehabilitation could be a possible mechanism. The metabolc changes in skeletal muscle in patients with COPD are characterized by impaired oxidative phosphorylation which causes early activation of anaerobic glycolysis and excess lactate production with exercise. In order to evaluate the change in the skeletal muscle metabolism as a possible cause of the improvement in the exercise tolerance after the rehabilitation, noninvasive $^{31}P$ magnetic resonance spectroscopy(MRS) of the forearm flexor muscle was performed before and after the exercise training in nine patients with chronic lung disease who have undertaken intensive pulmonary rehabilitation for 6 weeks. 31p MRS was studied during the sustained isometric contraction of the dominant forearm flexor muscles up to the exhaustion state and the recovery period. Maximal voluntary contraction(MVC) force of the muscle was measured before the isometric exercise, and then 30% of MVC force was constantly loaded to each patient during the isometric exercise. After the exercise training, exercise endurance of upper and lower extremities and 6 minute walking distance were significantly increased(p<0.05). There were no differences of baseline intracellular pH (pHi) and inorganic phosphate/phosphocreatine(Pi/PCr). After rehabilitation pHi at the exercise and the exhaustion state showed a significant increase($6.91{\pm}0.1$ to $6.99{\pm}0.1$ and $6.76{\pm}0.2$ to $6.84{\pm}0.2$ respectively, p<0.05). Pi/PCr at the exercise and the recovery rate of pHi and Pi/PCr did not show significant differences. These results suggest that the delayed intracellular acidosis of skeletal muscle may contribute to the improvement of exercise endurance after pulmonary rehabilitation.

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Assessment of Abnormality in Skeletal Muscle Metabolism in Patients with Chronic Lung Desease by $^{31}P$ Magnetic Resonance Spectroscopy ($^{31}P$ 자기 공명분석법을 이용한 만성 폐질환 환자에서의 골격근대사 이상에 관한 연구)

  • Cho, Won-Kyoung;Kim, Dong-Soon;Lim, Tae-Hwan;Lim, Chae-Man;Lee, Sang-De;Koh, Youn-Suck;Kim, Woo-Sung;Kim, Won-Dong
    • Tuberculosis and Respiratory Diseases
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    • v.44 no.3
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    • pp.583-591
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    • 1997
  • The functional derangement of skeletal muscles which may be attributed to chronic hypoxia has been accepted as a possible mechanism of exercise impairment in patients with chronic obstructive pulmonary disease (COPD). The metabolic changes in skeletal muscle in patients with COPD are characterized by impaired oxidative phosphorylation, early activation of anaerobic glycolysis and excessive lactate and hydrogen ion production with exercise. But the cause of exercise limitation in patients with chronic lung disease without hypoxia has not been known. In order to evaluate the change in the skeletal muscle metabolism as a possible cause of the exercise limitation in chronic lung disease patients without hypoxia, we compared the muscular metabolic data of seven male patients which had been derived from noninvasive $^{31}P$ magnetic resonance spectroscopy(MRS) with those of five age-matched normal male control persons. $^{31}P$ MRS was studied during the sustained isometric contraction of the dominant forearm flexor muscles up to the exhaustion state and the recovery period. Maximal voluntary contraction(MVC) force of the muscle was measured before the isometric exercise, and the 30% of MVC force was constantly loaded to each patient during the isometric exercise. There were no differences of intracellular pH (pHi) and inorganic phosphate/phosphocreatine(Pi/PCr) at baseline, exhaustion state and recovery period between two groups. But pHi during the exercise was lower in patients group than the control group (p < 0.05). Pi/PCr during the exercise did not show significant difference between two groups. These results suggest that the exercise limitation in chronic lung disease patients without hypoxia also could be attributed to the abnormalities in the skeletal muscle metabolism.

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