Two Components of Motor Time: The Tension Lag and the Tension-Developing Phase

1984 ◽  
Vol 59 (3) ◽  
pp. 907-912 ◽  
Author(s):  
R. Nakamura ◽  
H. Nagasaki ◽  
I. Tsuji
Keyword(s):  
Early Phase ◽  
Rapid Development ◽  
Rectus Femoris ◽  
Knee Extension ◽  
Isometric Tension ◽  
Lag Phase ◽  
Motor Time ◽  
Normal Men ◽  
Rectus Femoris Muscle ◽  
Femoris Muscle

Motor time (MT) of the rectus femoris muscle for knee extension under loading on the leg with different weights and latency of isometric tension from the onset of electromyographic activities of the muscle were examined in 7 normal men. MT was linearly related to weights-loaded, indicating that the rate of rapid development of tension was almost linear even in its early phase. MT without a load obtained by calculation using the regression equation and the estimated weight of the leg and foot coincided with latency of isometric tension. It is assumed that MT is composed of two consecutive phases, a tension-lag phase and a rapid tension-developing phase.

scholarly journals Neuromuscular efficiency of the knee joint muscles in the early-phase of strength training: effects of antagonist’s muscles pre-activation

Motricidade ◽  
2018 ◽  
Vol 14 (4) ◽  
pp. 24-32
Author(s):  
Euler Alves Cardoso ◽  
Frederico Ribeiro Neto ◽  
Wagner Rodrigues Martins ◽  
Martim Bottaro ◽  
Rodrigo Luiz Carregaro
Keyword(s):  
Knee Flexion ◽  
Controlled Trial ◽  
Rectus Femoris ◽  
Training Group ◽  
Knee Extension ◽  
Effect Sizes ◽  
Randomized Controlled ◽  
Knee Extension Exercise ◽  
Rectus Femoris Muscle ◽  
Femoris Muscle

It was our objective tTo compare the neuromuscular efficiency (NME) adaptations between resistance exercise methods (with and without pre-activation of the antagonist’s muscles) after six-weeks training. This randomized controlled trial assigned forty-nine men (mean age 20.9 ± 2.2 years; height 1.80 ± 0.1 m; body mass 75.0 ± 8.2 kg) into two groups: 1) Reciprocal Training group (RT, concentric knee flexion immediately followed by concentric knee extension at 60°.s-1); and Conventional Training (CT, concentric knee extension exercise). Both training adopted three sets, 10 repetitions at 60°.s-1, 2 days/week for 6 weeks. NME of knee extension and flexion were assessed pre and post-training. The groups were similar at baseline, for all variables. We found significant effects on NME only for the rectus femoris muscle in the RT group (ES = 0.31; 95%CI [0.30-0,92]; p<0.01). There were no significant differences at NME pre- and post-training in CT and Total Work did not differ between groups. Reciprocal training provided better neuromuscular efficiency, but effects were limited to the rectus femoris muscle. The small effect sizes suggest caution in the results.

scholarly journals One Session Effects of Knee Motion Visualization Using Immersive Virtual Reality in Patients with Hemophilic Arthropathy

2021 ◽  
Vol 10 (20) ◽  
pp. 4725
Author(s):  
Roberto Ucero-Lozano ◽  
Raúl Pérez-Llanes ◽  
José Antonio López-Pina ◽  
Rubén Cuesta-Barriuso
Keyword(s):  
Muscle Activation ◽  
Vastus Lateralis ◽  
Joint Damage ◽  
Rectus Femoris ◽  
Quadriceps Muscle ◽  
Knee Extension ◽  
Post Intervention ◽  
Specific Protocol ◽  
Rectus Femoris Muscle ◽  
Femoris Muscle

(1) Background: Hemophilic knee arthropathy is characterized by a loss of muscle mass and decreased strength of the quadriceps muscle. The visualization of movement aims to favor the recruitment of the motor system in the same premotor and parietal areas, as would happen with the active execution of the observed action. The aim was to evaluate changes in quadriceps activation in patients with hemophilic knee arthropathy following immersive VR visualization of knee extension movements. (2) Methods: We recruited 13 patients with severe hemophilia A and knee arthropathy. Patients underwent a 15 min session of immersive VR visualization of knee extension movements. The quadriceps muscle activation was evaluated by surface electromyography. (3) Results: After the intervention, there were no changes in the muscle activation of vastus medialis, vastus lateralis, or rectus femoris muscles. There was a large effect size of changes in rectus femoris muscle activation. Age and knee joint damage did not correlate with changes in quadriceps activation. Dominance, inhibitor development, and type of treatment were not related with post-intervention muscle activation. (4) Conclusions: A session of immersive VR visualization of knee extension movement does not modify quadriceps muscle activation. A specific protocol for patients with hemophilic knee arthropathy may be effective in improving the activation of the rectus femoris muscle.

scholarly journals Electromyographic Analysis of Traditional and Nontraditional Abdominal Exercises: Implications for Rehabilitation and Training

2006 ◽  
Vol 86 (5) ◽  
pp. 656-671 ◽  
Author(s):  
Rafael F Escamilla ◽  
Eric Babb ◽  
Ryan DeWitt ◽  
Patrick Jew ◽  
Peter Kelleher ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Latissimus Dorsi ◽  
Rectus Femoris ◽  
Rectus Abdominis ◽  
Oblique Muscle ◽  
Emg Activity ◽  
Internal Oblique ◽  
Rectus Femoris Muscle ◽  
Femoris Muscle ◽  
Roll Out

Abstract Background and Purpose. Performing nontraditional abdominal exercises with devices such as abdominal straps, the Power Wheel, and the Ab Revolutionizer has been suggested as a way to activate abdominal and extraneous (nonabdominal) musculature as effectively as more traditional abdominal exercises, such as the crunch and bent-knee sit-up. The purpose of this study was to test the effectiveness of traditional and nontraditional abdominal exercises in activating abdominal and extraneous musculature. Subjects. Twenty-one men and women who were healthy and between 23 and 43 years of age were recruited for this study. Methods. Surface electromyography (EMG) was used to assess muscle activity from the upper and lower rectus abdominis, external and internal oblique, rectus femoris, latissimus dorsi, and lumbar paraspinal muscles while each exercise was performed. The EMG data were normalized to maximum voluntary muscle contractions. Differences in muscle activity were assessed by a 1-way, repeated-measures analysis of variance. Results. Upper and lower rectus abdominis, internal oblique, and latissimus dorsi muscle EMG activity were highest for the Power Wheel (pike, knee-up, and roll-out), hanging knee-up with straps, and reverse crunch inclined 30 degrees. External oblique muscle EMG activity was highest for the Power Wheel (pike, knee-up, and roll-out) and hanging knee-up with straps. Rectus femoris muscle EMG activity was highest for the Power Wheel (pike and knee-up), reverse crunch inclined 30 degrees, and bent-knee sit-up. Lumbar paraspinal muscle EMG activity was low and similar among exercises. Discussion and Conclusion. The Power Wheel (pike, knee-up, and roll-out), hanging knee-up with straps, and reverse crunch inclined 30 degrees not only were the most effective exercises in activating abdominal musculature but also were the most effective in activating extraneous musculature. The relatively high rectus femoris muscle activity obtained with the Power Wheel (pike and knee-up), reverse crunch inclined 30 degrees, and bent-knee sit-up may be problematic for some people with low back problems.

Ultrasonographic Morphologic Changes of the Central Aponeurosis of the Rectus Femoris Muscle in Individuals With Knee Osteoarthritis

2016 ◽  
Vol 32 (3) ◽  
pp. 241-246
Author(s):  
Yusuke Takahashi ◽  
Kyoji Okada ◽  
Akira Saito ◽  
Isao Saito ◽  
Kazuo Kinoshita ◽  
...  
Keyword(s):  
Knee Osteoarthritis ◽  
Rectus Femoris ◽  
Rectus Femoris Muscle ◽  
Femoris Muscle ◽  
Morphologic Changes
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