scholarly journals Dynamic multivoxel-localized31P MRS during plantar flexion exercise with variable knee angle

2018 ◽  
Vol 31 (6) ◽  
pp. e3905 ◽  
Author(s):  
Fabian Niess ◽  
Georg B. Fiedler ◽  
Albrecht I. Schmid ◽  
Elmar Laistler ◽  
Roberta Frass-Kriegl ◽  
...  
Keyword(s):  
Plantar Flexion ◽  
Knee Angle ◽  
Plantar Flexion Exercise

Ankle Angle but Not Knee Angle Influences Force Fluctuations During Plantar Flexion

2021 ◽  
Author(s):  
Georgios Trypidakis ◽  
Ioannis G. Amiridis ◽  
Roger Enoka ◽  
Irini Tsatsaki ◽  
Eleftherios Kellis ◽  
...  
Keyword(s):  
Knee Joint ◽  
Coefficient Of Variation ◽  
Discharge Rate ◽  
Dominant Role ◽  
Plantar Flexion ◽  
Motor Units ◽  
Medial Gastrocnemius ◽  
Knee Angle ◽  
Plantar Flexors ◽  
Ankle Angle

AbstractThe purpose of the study was to evaluate the influence of changes in ankle- and knee-joint angles on force steadiness and the discharge characteristics of motor units (MU) in soleus when the plantar flexors performed steady isometric contractions. Submaximal contractions (5, 10, 20, and 40% of maximum) were performed at two ankle angles (75° and 105°) and two knee angles (120° and 180°) by 14 young adults. The coefficient of variation of force decreased as the target force increased from 5 to 20% of maximal force, then remained unaltered at 40%. Independently of knee angle, the coefficient of variation for force at the ankle angle of 75° (long length) was always less (p<0.05) than that at 105° (shorter length). Mean discharge rate, discharge variability, and variability in neural activation of soleus motor units were less (p<0.05) at the 75° angle than at 105°. It was not possible to record MUs from medial gastrocnemius at the knee angle of 120° due to its minimal activation. The changes in knee-joint angle did not influence any of the outcome measures. The findings underscore the dominant role of the soleus muscle in the control of submaximal forces produced by the plantar flexor muscles.

scholarly journals Behavior of Aponeurosis and External Tendon of the Gastrocnemius Muscle During Dynamic Plantar Flexion Exercise

2005 ◽  
Vol 3 (Special_Issue_2) ◽  
pp. 235-244 ◽  
Author(s):  
Norihide Sugisaki ◽  
Hiroaki Kanehisa ◽  
Yasuo Kawakami ◽  
Tetsuo Fukunaga
Keyword(s):  
Gastrocnemius Muscle ◽  
Plantar Flexion ◽  
Plantar Flexion Exercise

MUSCLE OXYGENATION AND FEMORAL ARTERY FLOW DURING DYNAMIC PLANTAR FLEXION EXERCISE

1999 ◽  
Vol 31 (Supplement) ◽  
pp. S246
Author(s):  
V. Quaresima ◽  
S. Homma ◽  
K. Azuma ◽  
S. Shimizu ◽  
M. Ferrari ◽  
...  
Keyword(s):  
Femoral Artery ◽  
Plantar Flexion ◽  
Muscle Oxygenation ◽  
Artery Flow ◽  
Plantar Flexion Exercise

Effects of Respiratory Alkalosis on Phosphocreatine Kinetics During Moderate-Intensity Plantar Flexion Exercise

2006 ◽  
Vol 38 (Supplement) ◽  
pp. S520
Author(s):  
Sean C. Forbes ◽  
John M. Kowalchuk ◽  
R. Terry Thompson ◽  
Gregory D. Marsh ◽  
Donald H. Paterson
Keyword(s):  
Plantar Flexion ◽  
Respiratory Alkalosis ◽  
Moderate Intensity ◽  
Plantar Flexion Exercise

scholarly journals Enhanced muscle blood flow with intermittent pneumatic compression of the lower leg during plantar flexion exercise and recovery

2018 ◽  
Vol 124 (2) ◽  
pp. 302-311 ◽  
Author(s):  
K. A. Zuj ◽  
C. N. Prince ◽  
R. L. Hughson ◽  
S. D. Peterson
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Exercise Performance ◽  
Muscle Blood Flow ◽  
Plantar Flexion ◽  
Intermittent Pneumatic Compression ◽  
Muscle Pump ◽  
Intermittent Compression ◽  
Postexercise Recovery ◽  
Plantar Flexion Exercise

This study tested the hypothesis that intermittent compression of the lower limb would increase blood flow during exercise and postexercise recovery. Data were collected from 12 healthy individuals (8 men) who performed 3 min of standing plantar flexion exercise. The following three conditions were tested: no applied compression (NoComp), compression during the exercise period only (ExComp), and compression during 2 min of standing postexercise recovery. Doppler ultrasound was used to determine superficial femoral artery (SFA) blood flow responses. Mean arterial pressure (MAP) and cardiac stroke volume (SV) were assessed using finger photoplethysmography, with vascular conductance (VC) calculated as VC = SFA flow/MAP. Compared with the NoComp condition, compression resulted in increased MAP during exercise [+3.5 ± 4.1 mmHg (mean ± SD)] but not during postexercise recovery (+1.6 ± 5.9 mmHg). SV increased with compression during both exercise (+4.8 ± 5.1 ml) and recovery (+8.0 ± 6.6 ml) compared with NoComp. There was a greater increase in SFA flow with compression during exercise (+52.1 ± 57.2 ml/min) and during recovery (+58.6 ± 56.7 ml/min). VC immediately following exercise was also significantly greater in the ExComp condition compared with the NoComp condition (+0.57 ± 0.42 ml·min−1·mmHg−1), suggesting the observed increase in blood flow during exercise was in part because of changes in VC. Results from this study support the hypothesis that intermittent compression applied during exercise and recovery from exercise results in increased limb blood flow, potentially contributing to changes in exercise performance and recovery. NEW & NOTEWORTHY Blood flow to working skeletal muscle is achieved in part through the rhythmic actions of the skeletal muscle pump. This study demonstrated that the application of intermittent pneumatic compression during the diastolic phase of the cardiac cycle, to mimic the mechanical actions of the muscle pump, accentuates muscle blood flow during exercise and elevates blood flow during the postexercise recovery period. Intermittent compression during and after exercise might have implications for exercise performance and recovery.

Skeletal muscle oxidative metabolism in sedentary humans: 31P-MRS assessment of O2 supply and demand limitations

2004 ◽  
Vol 97 (3) ◽  
pp. 1077-1081 ◽  
Author(s):  
Luke J. Haseler ◽  
Alexander P. Lin ◽  
Russell S. Richardson
Keyword(s):  
Gastrocnemius Muscle ◽  
Supply And Demand ◽  
Plantar Flexion ◽  
Submaximal Exercise ◽  
Resonance Spectroscopy ◽  
O2 Supply ◽  
Sedentary Subjects ◽  
Mitochondrial Capacity ◽  
Oxidative Rate ◽  
Plantar Flexion Exercise

Previously, it was demonstrated in exercise-trained humans that phosphocreatine (PCr) recovery is significantly altered by fraction of inspired O2 (FiO2), suggesting that in this population under normoxic conditions, O2 availability limits maximal oxidative rate. Haseler LJ, Hogan ML, and Richardson RS. J Appl Physiol 86: 2013–2018, 1999. To further elucidate these population-specific limitations to metabolic rate, we used 31P-magnetic resonance spectroscopy to study the exercising human gastrocnemius muscle under conditions of varied FiO2 in sedentary subjects. To test the hypothesis that PCr recovery from submaximal exercise in sedentary subjects is not limited by O2 availability, but rather by their mitochondrial capacity, six sedentary subjects performed three bouts of 6-min steady-state submaximal plantar flexion exercise followed by 5 min of recovery while breathing three different FiO2 (0.10, 0.21, and 1.00). PCr recovery time constants were significantly longer in hypoxia (47.0 ± 3.2 s), but there was no difference between hyperoxia (31.8 ± 1.9 s) and normoxia (30.0 ± 2.1 s) (mean ± SE). End-exercise pH was not significantly different across treatments. These results suggest that the maximal muscle oxidative rate of these sedentary subjects, unlike their exercise-trained counterparts, is limited by mitochondrial capacity and not O2 availability in normoxia. Additionally, the significant elongation of PCr recovery in these subjects in hypoxia illustrates the reliance on O2 supply at the other end of the O2 availability spectrum in both sedentary and active populations.

scholarly journals Recovery kinetics of creatine in mild plantar flexion exercise using 3D creatine CEST imaging at 7 Tesla

2020 ◽  
Vol 85 (2) ◽  
pp. 802-817
Author(s):  
Dushyant Kumar ◽  
Ravi Prakash Reddy Nanga ◽  
Deepa Thakuri ◽  
Neil Wilson ◽  
Abigail Cember ◽  
...  
Keyword(s):  
Plantar Flexion ◽  
7 Tesla ◽  
Cest Imaging ◽  
Kinetics Of ◽  
Plantar Flexion Exercise

pH heterogeneity during exercise in localized spectra from single human muscles

1993 ◽  
Vol 265 (5) ◽  
pp. C1332-C1339 ◽  
Author(s):  
K. Vandenborne ◽  
G. Walter ◽  
J. S. Leigh ◽  
G. Goelman
Keyword(s):  
Steady State ◽  
Line Width ◽  
Maximal Exercise ◽  
Fiber Type ◽  
Plantar Flexion ◽  
Fiber Types ◽  
Lateral Gastrocnemius ◽  
Human Muscles ◽  
Metabolic Heterogeneity ◽  
Plantar Flexion Exercise

We investigated whether pH heterogeneity in skeletal muscle during exercise, observed with 31P nuclear magnetic resonance, represents muscle fiber type heterogeneity. Localized spectra were simultaneously acquired from the soleus, medial, and lateral gastrocnemius using a multivolume localization technique, the Hadamard spectroscopic imaging (HSI) technique. Contamination of nonselected regions to the localized volumes was < 5%. HSI-localized spectra were obtained from the calf muscles of untrained subjects and a small group of athletes. Two plantar flexion exercise protocols were implemented: a "maximal" high frequency protocol and a "steady-state" protocol at low contraction frequency (0.25 Hz). pH heterogeneity was observed in localized spectra of single muscles during both exercise protocols, as indicated by the large Pi line width. During maximal exercise the Pi line width was up to three times wider than the phosphocreatine line width, covering an entire pH unit. During the steady-state exercise, in three subjects the Pi peak clearly resolved into two distinct peaks, one at low pH and one at high pH. As pH heterogeneity was observed in localized spectra of single muscles during both exercise protocols, it most likely reflects the metabolic heterogeneity between fiber types.

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