Vastus lateralis and rectus femoris echo intensity fail to reflect knee extensor specific tension in middle-school boys

2017 ◽  
Vol 38 (8) ◽  
pp. 1529-1541 ◽  
Author(s):  
Jacob A Mota ◽  
Matt S Stock ◽  
Brennan J Thompson
Keyword(s):  
Middle School ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Rectus Femoris ◽  
Echo Intensity ◽  
Specific Tension

scholarly journals Regional and muscle-specific adaptations in knee extensor hypertrophy using flywheel versus conventional weight-stack resistance exercise

2019 ◽  
Vol 44 (8) ◽  
pp. 827-833 ◽  
Author(s):  
Tommy R. Lundberg ◽  
Maria T. García-Gutiérrez ◽  
Mirko Mandić ◽  
Mats Lilja ◽  
Rodrigo Fernandez-Gonzalo
Keyword(s):  
Resistance Exercise ◽  
Muscle Hypertrophy ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Rectus Femoris ◽  
Knee Extension ◽  
Knee Extensors ◽  
Cross Sectional ◽  
Proximal Site ◽  
Before And After

This study compared the effects of the most frequently employed protocols of flywheel (FW) versus weight-stack (WS) resistance exercise (RE) on regional and muscle-specific adaptations of the knee extensors. Sixteen men (n = 8) and women (n = 8) performed 8 weeks (2–3 days/week) of knee extension RE employing FW technology on 1 leg (4 × 7 repetitions), while the contralateral leg performed regular WS training (4 × 8–12 repetitions). Maximal strength (1-repetition maximum (1RM) in WS) and peak FW power were determined before and after training for both legs. Partial muscle volume of vastus lateralis (VL), vastus medialis (VM), vastus intermedius (VI), and rectus femoris (RF) were measured using magnetic resonance imaging. Additionally, quadriceps cross-sectional area was assessed at a proximal and a distal site. There were no differences (P > 0.05) between FW versus WS in muscle hypertrophy of the quadriceps femoris (8% vs. 9%), VL (10% vs. 11%), VM (6% vs. 8%), VI (5% vs. 5%), or RF (17% vs. 17%). Muscle hypertrophy tended (P = 0.09) to be greater at the distal compared with the proximal site, but there was no interaction with exercise method. Increases in 1RM and FW peak power were similar across legs, yet the increase in 1RM was greater in men (31%) than in women (20%). These findings suggest that FW and WS training induces comparable muscle-specific hypertrophy of the knee extensors. Given that these robust muscular adaptations were brought about with markedly fewer repetitions in the FW compared with WS, it seems FW training can be recommended as a particularly time-efficient exercise paradigm.

Knee angle-dependent oxygen consumption during isometric contractions of the knee extensors determined with near-infrared spectroscopy

2005 ◽  
Vol 99 (2) ◽  
pp. 579-586 ◽  
Author(s):  
C. J. de Ruiter ◽  
M. D. de Boer ◽  
M. Spanjaard ◽  
A. de Haan
Keyword(s):  
Oxygen Consumption ◽  
Near Infrared ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Rectus Femoris ◽  
Knee Extensors ◽  
Isometric Contractions ◽  
Knee Angle ◽  
Extensor Muscles ◽  
Knee Extensor Muscles

Fatigue resistance of knee extensor muscles is higher during voluntary isometric contractions at short compared with longer muscle lengths. In the present study we hypothesized that this would be due to lower energy consumption at short muscle lengths. Ten healthy male subjects performed isometric contractions with the knee extensor muscles at a 30, 60, and 90° knee angle (full extension = 0°). At each angle, muscle oxygen consumption (mV̇o2) of the rectus femoris, vastus lateralis, and vastus medialis muscle was obtained with near-infrared spectroscopy. mV̇o2 was measured during maximal isometric contractions and during contractions at 10, 30, and 50% of maximal torque capacity. During all contractions, blood flow to the muscle was occluded with a pressure cuff (450 mmHg). mV̇o2 significantly ( P < 0.05) increased with torque and at all torque levels, and for each of the three muscles mV̇o2 was significantly lower at 30° compared with 60° and 90° and mV̇o2 was similar ( P > 0.05) at 60° and 90°. Across all torque levels, average (± SD) mV̇o2 at the 30° angle for vastus medialis, rectus femoris, and vastus lateralis, respectively, was 70.0 ± 10.4, 72.2 ± 12.7, and 75.9 ± 8.0% of the average mV̇o2 obtained for each torque at 60 and 90°. In conclusion, oxygen consumption of the knee extensors was significantly lower during isometric contractions at the 30° than at the 60° and 90° knee angle, which probably contributes to the previously reported longer duration of sustained isometric contractions at relatively short muscle lengths.

Alternate muscle activity observed between knee extensor synergists during low-level sustained contractions

2002 ◽  
Vol 93 (2) ◽  
pp. 675-684 ◽  
Author(s):  
Motoki Kouzaki ◽  
Minoru Shinohara ◽  
Kei Masani ◽  
Hiroaki Kanehisa ◽  
Tetsuo Fukunaga
Keyword(s):  
Muscle Activity ◽  
Vastus Lateralis ◽  
Force Production ◽  
Knee Extensor ◽  
Rectus Femoris ◽  
Quadriceps Muscle ◽  
Knee Extension ◽  
Voluntary Contraction ◽  
Low Level ◽  
Integrated Emg

To determine quantitatively the features of alternate muscle activity between knee extensor synergists during low-level prolonged contraction, a surface electromyogram (EMG) was recorded from the rectus femoris (RF), vastus lateralis (VL), and vastus medialis (VM) in 11 subjects during isometric knee extension exercise at 2.5% of maximal voluntary contraction (MVC) for 60 min ( experiment 1). Furthermore, to examine the relation between alternate muscle activity and contraction levels, six of the subjects also performed sustained knee extension at 5.0, 7.5, and 10.0% of MVC ( experiment 2). Alternate muscle activity among the three muscles was assessed by quantitative analysis on the basis of the rate of integrated EMG sequences. In experiment 1, the number of alternations was significantly higher between RF and either VL or VM than between VL and VM. Moreover, the frequency of alternate muscle activity increased with time. In experiment 2, alternating muscle activity was found during contractions at 2.5 and 5.0% of MVC, although not at 7.5 and 10.0% of MVC, and the number of alternations was higher at 2.5 than at 5.0% of MVC. Thus the findings of the present study demonstrated that alternate muscle activity in the quadriceps muscle 1) appears only between biarticular RF muscle and monoarticular vasti muscles (VL and VM), and its frequency of alternations progressively increases with time, and 2) emerges under sustained contraction with force production levels ≤5.0% of MVC.

scholarly journals Comparison of quadriceps muscle activation in exercises with different duration of concentric and eccentric contractions

2020 ◽  
Vol 37 (5) ◽  
pp. 291-297
Author(s):  
G Freire da Silva ◽  
F Douglas Tourino ◽  
RC Ribeiro Diniz ◽  
L Túlio de Lacerda ◽  
HC Martins Costa ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Muscle Activation ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Rectus Femoris ◽  
Quadriceps Muscle ◽  
Knee Extension ◽  
Muscle Action ◽  
Emg Signal ◽  
Knee Extension Exercise

Aim: The objective of the present study was to compare the amplitude of the electromyographic (EMG) signal of the quadriceps muscle portions vastus medialis (VM), vastus lateralis (VL) and rectus femoris (RF) and the activation ratio (VM/VL, VM/RF and VL/RF) in protocols with different durations of concentric and eccentric muscular actions. Material and method: Twelve female volunteers performed the knee extensor exercise with two different protocols [1s for concentric muscle action and 5s for eccentric muscle action (1:5); 5s of concentric muscle action and 1s of eccentric muscle action (5:1)] and 3 sets of 6 repetitions, 180s of pause between each sets and a intensity of 50% of 1RM. The root mean square of the amplitude of the normalized EMG signal was calculated for each repetition in each series. Results: it was observed an increase in the activation of the VM and VL portions in equivalent repetitions of each series and for the VL portion, the 1: 5 protocol provided greater activation compared to the other protocol. No differences were found for muscles activation ratios VM/RF and VL/RF, being that for the VM/VL ratio there was only change at one repetition. Conclusion: The results suggest that the portions of the quadriceps muscle may present different EMG responses in similar protocols, but this fact may not interfere in the synergism between them. The reduced degrees of freedom of the knee extension exercise and the characteristics of the protocols adopted may be the elements that contributed to the limited alterations that occurred in the present study.

scholarly journals The effect of 10 weeks of strength training on the electromyographic response of quadriceps portions

2020 ◽  
Vol 22 ◽  
Author(s):  
Frank Douglas Tourino ◽  
Lucas Túlio de Lacerda ◽  
André Gustavo Pereira de Andrade ◽  
Rodrigo César Ribeiro Diniz ◽  
Mauro Heleno Chagas ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Vastus Lateralis ◽  
Training Session ◽  
Knee Extensor ◽  
Rectus Femoris ◽  
Vastus Medialis ◽  
Repetition Maximum ◽  
Emg Signal ◽  
Group 3 ◽  
Group 5

Abstract This study investigate the effect of 10-week strenght training on the amplitude of the electromyographic (EMG) signal of vastus medialis, vastus lateralis and rectus Femoris. Twenty three untrained volunteers performed 3-5 sets (3 sets - weeks 1 and 2; 4 series - weeks 3 and 4; 5 series weeks 5 to 10) with 6 repetitions, intensity of 50% of 1 repetition maximum (1RM), 3 min rest between sets and 6 s repetition duration at the knee extensor exercise. One group (5:1) performed concentric action of 5 s and eccentric of 1 s and the other (3:3) performed concentric of 3 s and eccentric of 3 s. The VM, VL and RF EMG (RMS) activities were recorded in each repetition of the three series at the first training session and the first three series at the last session. The protocol 5:1 led to EMG reduction in all portions, with a greater number of repetitions presenting differences at the VL and RF. VM and RF presented similar results at Group 3:3. It was verified that all the differences occurred in the second half of the series. It was also verified differences in EMG ratios just in group 3:3 and only in VM/VL and VM/RF. These results suggest that the coordination was not affected when equivalent repetitions of series were compared. It was also suggested that these results were influenced by the reduced degrees of freedom of the exercise and the training load progression adopted.

The Rectus Femoris Flap for Groin Reconstruction

2019 ◽  
pp. 817-822
Author(s):  
Peter C. Neligan
Keyword(s):  
Vastus Lateralis ◽  
Muscle Flap ◽  
Knee Extensor ◽  
Rectus Femoris ◽  
Pedicled Flap ◽  
Skin Paddle ◽  
Rectus Femoris Muscle ◽  
Alt Flap ◽  
Femoris Muscle ◽  
Lower Abdominal Wall

The rectus femoris muscle is an important but expendable knee extensor. It is a bipennate muscle with a dense and strong fascia on its undersurface. This feature makes it extremely attractive for the repair of defects of the lower abdominal wall and groin as a pedicled flap. It is centrally located between the vastus medialis and vastus lateralis muscles. It is generally used as a pedicled muscle and usually taken as a muscle flap without a skin paddle. The muscle is then grafted. Following harvest, the extensor tendons need to be centralized and repaired for a distance of 6–8 cm above the knee. In many situations this flap has been superseded by the ALT flap.

Variability in Lateral Positioning of Surface EMG Electrodes

2009 ◽  
Vol 25 (4) ◽  
pp. 396-400 ◽  
Author(s):  
Taija Finni ◽  
Sulin Cheng
Keyword(s):  
Cross Correlation ◽  
Vastus Lateralis ◽  
Knee Extensor ◽  
Rectus Femoris ◽  
Surface Emg ◽  
Careful Consideration ◽  
Electrode Location ◽  
Close Proximity ◽  
Lateral Positioning ◽  
Emg Electrodes

The positions of EMG electrodes over the knee extensor muscles were examined in 19 healthy men using MR images; electrodes were placed according to the SENIAM (surface electromyography for non-invasive assessment of muscles) guidelines. From axial images, the medial and lateral borders of the muscles were identified, and the arc length of the muscle surface was measured. The electrode location was expressed as a percentage value from the muscle’s medial border. EMGs were recorded during isometric maximal contraction, squat jumps, and countermovement jumps and analyzed for cross-correlation. The results showed that variations in lateral positioning were greatest in vastus medialis (47% SD 11) and rectus femoris (68% SD 15). In vastus lateralis, the electrode was usually placed close to the rectus femoris (19% SD 6). The peak cross-correlation coefficient varied between 0.15 and 0.68, but was not associated with electrode location. It is recommended that careful consideration is given to the medial-lateral positioning of the vastus lateralis electrodes especially, so that the electrodes are positioned over the mid-muscle rather than in close proximity to rectus femoris.

scholarly journals Fast-Velocity Eccentric Cycling Exercise Causes Greater Muscle Damage Than Slow Eccentric Cycling

2020 ◽  
Vol 11 ◽  
Author(s):  
Hisashi Ueda ◽  
Yosuke Tsuchiya ◽  
Eisuke Ochi
Keyword(s):  
Muscle Damage ◽  
Muscle Soreness ◽  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Muscle Stiffness ◽  
Echo Intensity ◽  
Thigh Circumference ◽  
Cycling Exercise ◽  
Significant Difference ◽  
Slow Velocity

This study aims to investigate muscle damage occurring in the early and recovery phases after fast-velocity and slow-velocity eccentric cycling. Eleven untrained men (age, 20.0 ± 1.7 years; height, 171.3 ± 6.8 cm; weight, 61.8 ± 7.7 kg; and %body fat, 13.2 ± 2.9%) performed slow-velocity maximal isokinetic eccentric cycling (slow-velocity; 30°/s) with one leg and fast-velocity (fast-velocity; 210°/s) isokinetic eccentric cycling with the other leg. Changes in maximal voluntary isokinetic concentric contraction (MVCC) torque at velocities of 30 and 210°/s, range of motion (ROM), and muscle soreness were assessed by pressure using a digital muscle stiffness instrument; thigh circumference, muscle echo intensity, and muscle stiffness were assessed before exercise, and immediately after exercise, 1 day, and 4 days after exercise. Comparing with the results obtained for slow-velocity cycling (post: 215.9 ± 32.3 Nm, day 1: 192.9 ± 47.4 Nm, day 4: 184.3 ± 47.2 Nm) and before exercise, MVCC after fast-velocity cycling significantly decreased at immediately (160.4 ± 43.5 Nm), 1 day (143.6 ± 54.1 Nm), and 4 days (150.1 ± 44.5 Nm) after exercise (p &lt; 0.05). Significant increase in muscle soreness for vastus lateralis was observed after fast-velocity cycling (41.2 ± 16.9 mm) compared with slow-velocity cycling (23.7 ± 12.2 mm) 4 days after exercise (p &lt; 0.05). However, no significant difference in muscle soreness was observed for rectus femoris and vastus medialis at any time points after exercise. In addition, no significant differences were observed in the ROM, thigh circumference, muscle echo intensity, and muscle stiffness. In conclusion, fast-velocity eccentric cycling causes a decrease in muscle strength and an increase in soreness as compared to slow-velocity eccentric cycling.

scholarly journals Declines in skeletal muscle quality vs. size following two weeks of knee joint immobilization

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8224 ◽  
Author(s):  
Rob J. MacLennan ◽  
Michael Sahebi ◽  
Nathan Becker ◽  
Ethan Davis ◽  
Jeanette M. Garcia ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Knee Joint ◽  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Cross Sectional Area ◽  
Muscle Quality ◽  
Muscle Size ◽  
Sectional Area ◽  
Echo Intensity ◽  
Cross Sectional

Background Disuse of a muscle group, which occurs during bedrest, spaceflight, and limb immobilization, results in atrophy. It is unclear, however, if the magnitude of decline in skeletal muscle quality is similar to that for muscle size. The purpose of this study was to examine the effects of two weeks of knee joint immobilization on vastus lateralis and rectus femoris echo intensity and cross-sectional area. Methods Thirteen females (mean ± SD age = 21 ± 2 years) underwent two weeks of left knee joint immobilization via ambulating on crutches and use of a brace. B-mode ultrasonography was utilized to obtain transverse plane images of the immobilized and control vastus lateralis and rectus femoris at pretest and following immobilization. Effect size statistics and two-way repeated measures analyses of variance were used to interpret the data. Results No meaningful changes were demonstrated for the control limb and the rectus femoris of the immobilized limb. Analyses showed a large increase in vastus lateralis echo intensity (i.e., decreased muscle quality) for the immobilized limb (p = .006, Cohen’s d = .918). For vastus lateralis cross-sectional area, no time × limb interaction was observed (p = .103), but the effect size was moderate (d = .570). There was a significant association between the increase in vastus lateralis echo intensity and the decrease in cross-sectional area (r =  − .649, p = .016). Conclusion In female participants, two weeks of knee joint immobilization resulted in greater deterioration of muscle quality than muscle size. Echo intensity appears to be an attractive clinical tool for monitoring muscle quality during disuse.

scholarly journals Analysis of the Response Speed of Musculature of the Knee in Professional Male and Female Volleyball Players

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
D. Rodríguez-Ruiz ◽  
I. Diez-Vega ◽  
D. Rodríguez-Matoso ◽  
M. Fernandez-del-Valle ◽  
R. Sagastume ◽  
...  
Keyword(s):  
Vastus Lateralis ◽  
Knee Extensor ◽  
Rectus Femoris ◽  
Response Speed ◽  
Biceps Femoris ◽  
Vastus Medialis ◽  
Male And Female ◽  
Functional Differences ◽  
Volleyball Players ◽  
Specific Position

The aim of this study was to evaluate the normalized response speed (Vrn) of the knee musculature (flexor and extensor) in high competitive level volleyball players using tensiomyography (TMG) and to analyze the muscular response of the vastus medialis (VM), rectus femoris (RF), vastus lateralis (VL), and biceps femoris (BF) in accordance with the specific position they play in their teams. One hundred and sixty-six players (83 women and 83 men) were evaluated. They belonged to eight teams in the Spanish women’s superleague and eight in the Spanish men’s superleague. The use of Vrn allows avoiding possible sample imbalances due to anatomical and functional differences and demands. We found differences between Vrn in each of the muscles responsible for extension (VM, RF, and VL) and flexion (BF) regardless of the sex. Normalized response speed differences seem to be larger in setters, liberos and outside players compared to middle blockers and larger in males when compared to females. These results of Vrn might respond to the differences in the physical and technical demands of each specific position, showing an improved balance response of the knee extensor and flexor musculature in male professional volleyball players.

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