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Katie A Ewing, Justin W Fernandez, Rezaul K Begg, Mary P Galea, Peter V S Lee
Anterior cruciate ligament (ACL) injury can be a painful, debilitating and costly consequence of participating in sporting activities. Prophylactic knee bracing aims to reduce the number and severity of ACL injury, which commonly occurs during landing maneuvers and is more prevalent in female athletes, but a consensus on the effectiveness of prophylactic knee braces has not been established. The lower-limb muscles are believed to play an important role in stabilizing the knee joint. The purpose of this study was to investigate the changes in lower-limb muscle function with prophylactic knee bracing in male and female athletes during landing...
October 3, 2016: Journal of Biomechanics
Nathaniel T Pickle, Alena M Grabowski, Arick G Auyang, Anne K Silverman
Sloped walking is biomechanically different from level-ground walking, as evidenced by changes in joint kinematics and kinetics. However, the changes in muscle functional roles underlying these altered movement patterns have not been established. In this study, we developed a total of 273 muscle-actuated simulations to assess muscle functional roles, quantified by induced body center-of-mass accelerations and trunk and leg power, during walking on slopes of 0°, ±3°, ±6°, and ±9° at 1.25m/s. The soleus and gastrocnemius both provided greater forward acceleration of the body parallel to the slope at +9° compared to level ground (+126% and +66%, respectively)...
October 3, 2016: Journal of Biomechanics
Richard R Neptune, Craig P McGowan
The regulation of whole-body angular momentum is important for maintaining dynamic balance during human walking, which is particularly challenging in the frontal plane. Whole-body angular momentum is actively regulated by individual muscle forces. Thus, understanding which muscles contribute to frontal plane angular momentum will further our understanding of mediolateral balance control and has the potential to help diagnose and treat balance disorders. The purpose of this study was to identify how individual muscles and gravity contribute to whole-body angular momentum in the frontal plane using a muscle-actuated forward dynamics simulation analysis...
September 6, 2016: Journal of Biomechanics
Marjolein Margaretha van der Krogt, Lynn Bar-On, Thalia Kindt, Kaat Desloovere, Jaap Harlaar
BACKGROUND: Increased resistance in muscles and joints is an important phenomenon in patients with cerebral palsy (CP), and is caused by a combination of neural (e.g. spasticity) and non-neural (e.g. contracture) components. The aim of this study was to simulate instrumented, clinical assessment of the hamstring muscles in CP using a conceptual model of contracture and spasticity, and to determine to what extent contracture can be explained by altered passive muscle stiffness, and spasticity by (purely) velocity-dependent stretch reflex...
2016: Journal of Neuroengineering and Rehabilitation
Ryosuke Ando, Aya Tomita, Kohei Watanabe, Hiroshi Akima
We compared vasti muscle electromyograms for two knee joint angles during fatiguing tetanic contractions. Tetanic contraction of the knee extensors was evoked for 70 s by electrical stimulation of the femoral nerve at knee joint angles of 60° (extended, with 0° indicating full extension) and 110° (flexed) in eight healthy men. Surface electromyography was recorded from the vastus intermedius (VI), vastus lateralis (VL) and vastus medialis (VM) muscles. Knee extension force and M-wave amplitudes and durations were calculated every 7 s, which were normalized by the initial value...
May 19, 2016: Clinical Physiology and Functional Imaging
Sarah H Ward, Alan Pearce, Kim L Bennell, Brian Peitrosimone, Adam L Bryant
BACKGROUND: Altered quadriceps corticomotor excitability has been demonstrated following anterior cruciate ligament (ACL) injury and reconstruction, however only the single joint vasti muscles have been assessed. There is no current data on rectus femoris corticomotor excitability following ACL injury, the biarticular quadriceps muscle also critical for force attenuation and locomotion. The purpose of this study was to examine rectus femoris corticomotor excitability, intracortical inhibition and cortical motor representation in individuals with and without an ACL injury...
August 2016: Knee
Maria Fonte Petruzzelli, Maria Pia Vasti, Francesco Tramacere, Maria Patrizia D'Errico, Emilio A L Gianicolo, Maria Grazia Andreassi, Eugenio Picano, Maurizio Portaluri
BACKGROUND AND PURPOSE: Breast cancer patients exposed to doses of radiation after radiotherapy could develop toxicity to lung. Lung ultrasound (LUS) is able to detect interstitial lung disease by the evaluation of B-lines. The aim of our study was to assess the number of B-lines to diagnose lung involvement after chest radiotherapy. MATERIALS AND METHODS: We measured LUS B-lines in the treated and contralateral lung of 20 breast cancer patients, 1-3 months after the end of radiotherapy and 1 year after previous LUS...
September 2016: Echocardiography
Prasanna Sritharan, Yi-Chung Lin, Sara E Richardson, Kay M Crossley, Trevor B Birmingham, Marcus G Pandy
This study quantified the contributions by muscles, gravity and inertia to the tibiofemoral compartment forces in the symptomatic (SYM) and asymptomatic (ASYM) limbs of varus mal-aligned medial knee osteoarthritis (OA) patients, and compared the results with healthy controls (CON). Muscle forces and tibiofemoral compartment loads were calculated using gait data from 39 OA patients and 15 controls aged 49 ± 7 years. Patients exhibited lower knee flexion angle, higher hip abduction and knee adduction angles, lower internal knee flexion torque but higher external knee adduction moment...
April 18, 2016: Journal of Orthopaedic Research: Official Publication of the Orthopaedic Research Society
Ryoichi Ema, Masanori Sakaguchi, Ryota Akagi, Yasuo Kawakami
PURPOSE: This study aimed to examine whether muscle activation of the quadriceps femoris differs between single- and multi-joint exercises, and to explore the factors resulting in muscle and exercise specificity in activation. METHODS: Eleven adults developed isometric hip extension torque gradually while maintaining submaximal isometric knee extension torque (Experiment 1). In Experiment 2, 15 men performed knee extension and leg press separately at intensities of 20, 40, 60 and 80 % of their one repetition maximum (1RM) load, and 14 men conducted leg press at intensities of 40 and 80 % of 1RM until exhaustion (Experiment 3)...
May 2016: European Journal of Applied Physiology
Alireza Motealleh, Elham Gheysari, Esmaeil Shokri, Sobhan Sobhani
OBJECTIVE: To evaluate the immediate effect of lubmopelvic manipulation on EMG activity of vastus medialis, vastus lateralis and gluteus medius as well as pain and functional performance of athletes with patellofemoral pain syndrome. DESIGN: Randomized placebo-controlled trial. METHODS: Twenty eight athletes with patellofemoral pain syndrome were randomly assigned to two groups. One group received a lubmopelvic manipulation at the side of the involved knee while the other group received a sham manipulation...
April 2016: Manual Therapy
K Grob, T Ackland, M S Kuster, M Manestar, L Filgueira
The quadriceps femoris is traditionally described as a muscle group composed of the rectus femoris and the three vasti. However, clinical experience and investigations of anatomical specimens are not consistent with the textbook description. We have found a second tensor-like muscle between the vastus lateralis (VL) and the vastus intermedius (VI), hereafter named the tensor VI (TVI). The aim of this study was to clarify whether this intervening muscle was a variation of the VL or the VI, or a separate head of the extensor apparatus...
March 2016: Clinical Anatomy
Taku Wakahara, Ryoichi Ema, Naokazu Miyamoto, Yasuo Kawakami
The purpose of this study was to examine whether inter- and intramuscular differences in hypertrophy induced by resistance training correspond to differences in muscle activation during the first training session. Eleven young men completed 12 weeks of training intervention for knee extension. Before and after the intervention, T1-weighted magnetic resonance (MR) images were recorded to determine the volume and anatomical cross-sectional area (CSA) along the length of the individual muscles of the quadriceps femoris...
November 17, 2015: Clinical Physiology and Functional Imaging
Christopher M Laine, Eduardo Martinez-Valdes, Deborah Falla, Frank Mayer, Dario Farina
UNLABELLED: Neural control of synergist muscles is not well understood. Presumably, each muscle in a synergistic group receives some unique neural drive and some drive that is also shared in common with other muscles in the group. In this investigation, we sought to characterize the strength, frequency spectrum, and force dependence of the neural drive to the human vastus lateralis and vastus medialis muscles during the production of isometric knee extension forces at 10 and 30% of maximum voluntary effort...
September 2, 2015: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Elva C Chávez-Hernández, Naholi D Alejandri-Ramírez, Vasti T Juárez-González, Tzvetanka D Dinkova
Maize somatic embryogenesis (SE) is induced from the immature zygotic embryo in darkness and under the appropriate hormones' levels. Small RNA expression is reprogrammed and certain miRNAs become particularly enriched during induction while others, characteristic to the zygotic embryo, decrease. To explore the impact of different environmental cues on miRNA regulation in maize SE, we tested specific miRNA abundance and their target gene expression in response to photoperiod and hormone depletion for two different maize cultivars (VS-535 and H-565)...
2015: Frontiers in Plant Science
Tannaz Moin, Kristyn Ertl, Jessica Schneider, Elena Vasti, Fatima Makki, Caroline Richardson, Kathryn Havens, Laura Damschroder
BACKGROUND: Diabetes prevention is a national goal and particularly important in the Veterans Health Administration (VHA) where 1 in 4 veterans has diabetes. There is growing evidence to support the use of Web-based diabetes prevention program (DPP) interventions, shown to be as effective and often more feasible than in-person interventions. OBJECTIVE: Our primary objective was to qualitatively explore women veterans' early experiences with a Web-based DPP intervention...
2015: Journal of Medical Internet Research
Jacob E Earp, Robert U Newton, Prue Cormie, Anthony J Blazevich
INTRODUCTION: Previous studies have reported inhomogeneous changes in quadriceps femoris (QF) cross-sectional area (CSA) in response to strength training. It is assumed that these differential changes in muscle shape influence the muscle's functional capacity during high-force and high-power movements. The purpose of the current study was to compare intermuscular and intramuscular QF adaptations to high-load strength training and fast-speed power training. METHODS: Thirty-six non-strength-trained men were randomly assigned to four groups and completed 8 wk of parallel-depth heavy squat-lift training (HS-P), parallel-depth jump squat training (JS-P), volitional-depth jump squat training (JS-V), or no training (C)...
November 2015: Medicine and Science in Sports and Exercise
Jari-Joonas Eskelinen, Ilkka Heinonen, Eliisa Löyttyniemi, Virva Saunavaara, Anna Kirjavainen, Kirsi A Virtanen, Jarna C Hannukainen, Kari K Kalliokoski
We tested the hypothesis that sprint interval training (SIT) causes larger improvements in glucose and free fatty acid uptake (FFAU) in lower and upper body muscles than moderate-intensity training (MIT). Twenty-eight healthy, untrained, middle-aged men were randomized into SIT (n = 14, 4-6 × 30 s of all-out cycling/4 min recovery) and MIT groups [n = 14, 40-60 min cycling at 60% of peak O2 uptake (V̇o2 peak)] and completed six training sessions within 2 wk. Pre- and postmeasurements included V̇o2 peak, whole body (M-value), muscle-specific insulin-stimulated glucose uptake (GU), and fasting FFAU measured with positron emission tomography in thigh [quadriceps femoris (QF) and hamstrings] and upper body (deltoids, biceps, and triceps brachii) muscles...
May 1, 2015: Journal of Applied Physiology
S Shiozawa, R P Hirata, J B Jeppesen, T Graven-Nielsen
BACKGROUND: Anticipatory postural adjustments (APAs) are motor responses generated to stabilize balance prior to voluntary movement. This study investigated how infrapatellar fat pad pain induces reorganization of APAs during reaction time tasks. It has been hypothesized that knee pain may cause insufficient APAs, thereby impairing the balance. METHODS: While standing, 12 healthy men performed two reaction time tasks (shoulder flexion of the dominant side and bilateral heel lift, respectively) before, during and after experimental infrapatellar fat pad pain induced in the dominant side by injections of hypertonic saline...
October 2015: European Journal of Pain: EJP
Nicholas J Napoli, Anthony R Mixco, Jorge E Bohorquez, Joseph F Signorile
High-speed resistance training is used to increase power; however, momentum can reduce the effectiveness of high-speed (HS) training when using weight-stack (WS) machines. This study used a non-linear scaled wavelet analysis to assess differences between pneumatic (P) and WS during seven HS or controlled speed (CS) repetitions. Vastus medialis (VM) and lateralis (VL), and rectus femoris (RF) EMG data were collected during leg extension exercises performed by five regular weight-trainers (mean age ± SD, 23...
April 2015: Human Movement Science
Yi-Chung Lin, Laurence A Fok, Anthony G Schache, Marcus G Pandy
Stair ambulation is more physically demanding than level walking because it requires the lower-limb muscles to generate greater net joint moments. Although lower-limb joint kinematics and kinetics during stair ambulation have been extensively studied, relatively little is known about how the lower-limb muscles accelerate the whole-body center of mass (COM) during stair ascent and descent. The aim of the current study was to evaluate differences in muscle contributions to COM accelerations between level walking and stair ambulation in 15 healthy adults...
January 21, 2015: Journal of Biomechanics
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