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Lower limb muscle co contraction

A D Wibawa, N Verdonschot, J P K Halbertsma, J G M Burgerhof, R L Diercks, G J Verkerke
This study focused on comparing muscle activities predicted by the Musculoskeletal Modeling System with EMG from ten healthy subjects who performed normal walking, one-legged forward hopping and side jumping. Eight EMG electrodes measured the activity of eight right leg muscles. Specific thresholds per muscle were applied on the EMG prior comparison. These thresholds were determined by equalizing the duration of EMG to AMS muscle activity. Three graph variables, number of onsets, offsets and hills were used to quantify the level of agreement by using Cohen׳s kappa analysis...
October 6, 2016: Journal of Biomechanics
Charlotte Apps, Thorsten Sterzing, Thomas O'Brien, Mark Lake
Unstable shoes (US) continually perturb gait which can train the lower limb musculature, but muscle co-contraction and potential joint stiffness strategies are not well understood. A shoe with a randomly perturbing midsole (IM) may enhance these adaptations. This study compares ankle and knee joint stiffness, and ankle muscle co-contraction during walking and running in US, IM and a control shoe in 18 healthy females. Ground reaction forces, three-dimensional kinematics and electromyography of the gastrocnemius medialis and tibialis anterior were recorded...
September 20, 2016: Journal of Electromyography and Kinesiology
Jean-Philippe Ehny, Yoshimasa Sagawa, Laurent Tatu, Ludivine Chamard, Bernard Parratte, Pierre Decavel
OBJECTIVE: Hereditary spastic paraplegia (HSP) designates a rare genetic disorder characterized by the existence of a pyramidal syndrome and/or paresis of the lower limbs, resulting in locomotor disorders. The objective of this study was to investigate the HSP patients walking characteristics during a comfortable walking speed, to determinate the most deleterious impairments and their evolutivity during a prolonged standardized walk. A second goal was to study the co-contraction of targeted muscles during these two walking conditions...
September 2016: Annals of Physical and Rehabilitation Medicine
Antônio Padilha L Bó, Lucas O da Fonseca, Ana Carolina C de Sousa
Control systems for human movement based on Functional Electrical Stimulation (FES) have shown to provide excellent performance in different experimental setups. Nevertheless, there is still a limited number of such applications available today on worldwide markets, indicating poor performance in real settings, particularly for upper limb rehabilitation and assistance. Based on these premises, in this paper we explore the use of an alternative control strategy based on co-activation of antagonist muscles using FES...
August 8, 2016: Medical Engineering & Physics
Louise M Thoma, Michael P McNally, Ajit M Chaudhari, David C Flanigan, Thomas M Best, Robert A Siston, Laura C Schmitt
Increased muscle co-contraction during gait is common in individuals with knee pathology, and worrisome as it is known to amplify tibiofemoral compressive forces. While knees with articular cartilage defects (ACD) are more vulnerable to compressive forces, muscle co-contraction has never been reported in this population. The purpose of this study was to evaluate the extent to which individuals with ACDs in the knee demonstrate elevated quadriceps to hamstrings muscle co-contraction on the involved limb during gait compared to the uninvolved limb and to healthy controls...
July 2016: Gait & Posture
Kota Tayashiki, Sumiaki Maeo, Seiji Usui, Naokazu Miyamoto, Hiroaki Kanehisa
PURPOSE: It is unknown whether maximal voluntary co-contraction of abdominal muscles, called abdominal bracing, can be a training maneuver for improving strength and power of trunk and lower limb muscles. The present study aimed to elucidate this. METHODS: Twenty young adult men (23.3 ± 1.8 years) were allocated to training (TG, n = 11) or control (CG, n = 9) group. TG conducted an 8-week training program (3 days/week) consisting of 2-s maximal abdominal bracing followed by 2-s muscle relaxation (5 × 10 repetitions/day)...
September 2016: European Journal of Applied Physiology
P C Raffalt, T Alkjaer, E B Simonsen
We investigated muscle activity, intra-subject variability in muscle activity and co-contraction during vertical jumps and landings in children and adults. Ten male children and 10 male adults completed 10 countermovement jumps (CMJ), 10 drop jumps (DJ) from 30 cm, 10 low and high landings from 30 and 60 cm for the children and 60 and 90 cm for the adults. The adults also performed ten DJ from 60 cm. EMG was recorded from nine lower limb muscles in the right leg and normalized to isometric MVC. Statistical parametric mapping was used to reveal differences in the muscle activity and intra-subject variability in the muscle activity...
April 25, 2016: Scandinavian Journal of Medicine & Science in Sports
R Babina, P P Mohanty, M Pattnaik
BACKGROUND: Altered respiratory function has been found to be associated with back pain. Limited chest excursion in subjects with chronic low back pain (CLBP) may be due to co-contraction or bracing of erector spinae and abdominal muscles; their flexed spinal posture; and/or their compromised spinal stability resulting from dysfunctional transversus abdominis. OBJECTIVE: To check for the effects of thoracic mobilization on respiratory parameters in subjects with chronic non-specific low back pain...
February 19, 2016: Journal of Back and Musculoskeletal Rehabilitation
Sue Peters, S Jayne Garland, Kimberly J Miller, Christopher K Cochrane, Tanya D Ivanova, Michael A Hunt
OBJECTIVES: To determine the characteristics of motor planning surrounding initial contact during gait through examination of thigh muscle timing, amplitude, and co-contraction of the paretic and nonparetic limbs in people poststroke, and to investigate whether muscle timing, amplitude, and clinical performance measures of balance and mobility differ based on the level of co-contraction. DESIGN: Observational study. SETTING: University-based research laboratory...
April 2016: Archives of Physical Medicine and Rehabilitation
Yuji Matsuda, Masami Hirano, Yosuke Yamada, Yasushi Ikuta, Teruo Nomura, Hiroaki Tanaka, Shingo Oda
The purpose of this study was to examine the difference in muscle activation pattern and co-contraction of the rectus and biceps femoris in flutter-kick swimming between competitive and recreational swimmers, to better understand the mechanism of repetitive kicking movements during swimming. Ten competitive and 10 recreational swimmers swam using flutter kicks at three different velocities (100%, 90%, and 80% of their maximal velocity) in a swimming flume. Surface electromyographic signals (EMG) were obtained from the rectus (RF) and biceps femoris (BF), and lower limb kinematic data were obtained at the same time...
February 2016: Human Movement Science
Roya Khanmohammadi, Saeed Talebian, Mohammad Reza Hadian, Gholamreza Olyaei, Hossein Bagheri
It is thought that gait initiation (GI) might be an optimal task for identifying postural control deficiencies. Thus, the aim of this study was to clarify the strategies adopted by older subjects during this task. 16 healthy younger and 15 healthy older adults participated in the study. Subjects were instructed to begin forward stepping with their dominant limb in response to an auditory stimulus. The mean muscle activity, co-contraction index, and intra-subject coefficients of variation (intra-subject CVs) of dominant limb muscles in different phases of GI were measured...
January 2016: Gait & Posture
Valentina Agostini, Francesco Lo Fermo, Giuseppe Massazza, Marco Knaflitz
BACKGROUND: Texting on a smartphone while walking has become a customary task among young adults. In recent literature many safety concerns on distracted walking have been raised. It is often hypothesized that the allocation of attentional resources toward a secondary task can influence dynamic stability. In the double task of walking and texting it was found that gait speed is reduced, but there is scarce evidence of a modified motor control strategy compromising stability. The aim of this study is twofold: 1) to comprehensively examine the gait modifications occurring when texting while walking, including the study of the lower limb muscle activation patterns, 2) to specifically assess the co-contraction of ankle antagonist muscles...
2015: Journal of Neuroengineering and Rehabilitation
Rachel C Drew, Cheryl A Blaha, Michael D Herr, Sean D Stocker, Lawrence I Sinoway
Low-dose aspirin inhibits thromboxane production and augments the sensitivity of carotid baroreflex (CBR) control of heart rate (HR) during concurrent muscle mechanoreflex and metaboreflex activation in healthy young humans. However, it is unknown how aging affects this response. Therefore, the effect of low-dose aspirin on carotid-cardiac baroreflex sensitivity during muscle mechanoreflex with and without metaboreflex activation in healthy older humans was examined. Twelve older subjects (6 men and 6 women, mean age: 62 ± 1 yr) performed two trials during two visits preceded by 7 days of low-dose aspirin (81 mg) or placebo...
October 2015: American Journal of Physiology. Heart and Circulatory Physiology
Rebecca Shultz, Amy Silder, Maria Malone, Hillary Jane Braun, Jason Logan Dragoo
BACKGROUND: Increasing quadriceps:hamstring muscular co-contraction at the knee may reduce the risk of anterior cruciate ligament (ACL) injury. The purpose of this investigation was to examine muscle activation in the quadriceps and hamstrings and peak kinematics of the knee, hip, and trunk when performing a single-leg drop (SLD) on to a Bosu ball (unstable surface) compared with on to the floor (stable surface). HYPOTHESES: (1) The SLD on an unstable surface would lower the quadriceps to hamstrings electromyographic (EMG) activation ratio (Q:H EMG activation ratio) compared with being performed on the floor...
March 2015: Sports Health
Andrew J T Stevenson, Ernest N Kamavuako, Svend S Geertsen, Dario Farina, Natalie Mrachacz-Kersting
KEY POINTS: The present study is the first to show short-latency crossed-spinal reflexes in the human upper leg muscles following mechanical rotations to the ipsilateral knee (iKnee) joint. The short-latency reflex in the contralateral biceps femoris (cBF) was inhibitory following iKnee extension perturbations, and facilitatory following iKnee flexion perturbations. The onset latency was 44 ms, indicating that purely spinal pathways mediate the cBF reflexes. The short-latency cBF inhibitory and facilitatory reflexes followed the automatic gain control principle, becoming larger as the level of background contraction in the cBF increased...
August 15, 2015: Journal of Physiology
Georgios Bouchouras, Glykeria Patsika, Vassilia Hatzitaki, Eleftherios Kellis
BACKROUND: The purpose of this study was to compare joint kinematics, knee and trunk muscle activation and co-activation patterns during a sit-to-stand movement in women with knee osteoarthritis and age-matched controls. METHODS: Eleven women with knee osteoarthritis (mean and standard deviation, age: 66.90, 4.51 years, height: 1.63, 0.02 m, mass: 77.63, 5.4 kg) and eleven healthy women (mean and standard deviation, age: 61.90, 3.12 years, height: 1.63 m, 0.03, mass: 78...
July 2015: Clinical Biomechanics
Zachary Barrett-O'Keefe, Joshua F Lee, Amanda Berbert, Melissa A H Witman, Jose Nativi-Nicolau, Josef Stehlik, Russell S Richardson, D Walter Wray
To better understand the mechanisms responsible for exercise intolerance in heart failure with reduced ejection fraction (HFrEF), the present study sought to evaluate the hemodynamic responses to small muscle mass exercise in this cohort. In 25 HFrEF patients (64 ± 2 yr) and 17 healthy, age-matched control subjects (64 ± 2 yr), mean arterial pressure (MAP), cardiac output (CO), and limb blood flow were examined during graded static-intermittent handgrip (HG) and dynamic single-leg knee-extensor (KE) exercise...
November 15, 2014: American Journal of Physiology. Heart and Circulatory Physiology
Chang Ho Yu, Ui Ryeong Kim, Tae Kyu Kwon
In this study, we assessed indoor horse riding exercise's effects on basal physical exercise and activities of daily living (ADL) function using horse riding equipment, involving elderly test subjects (in their sixties). The participants were 20 people with no impediment to activity. They participated in experiments that lasted 60 min per day, 3 days per week, over 8 weeks, using the "SRider" (Rider Co. and Chonbuk National University Korea).We measured trunk flexion, sit-up, whole-body reaction, leg strength, and maximal oxygen uptake as basal physical fitness parameters...
2014: Bio-medical Materials and Engineering
Federico Quinzi, Valentina Camomilla, Francesco Felici, Alberto Di Mario, Paola Sbriccoli
PURPOSE: Age-related neuromuscular control adaptations have been investigated mainly in untrained populations, where higher antagonist activation in adults was observed with respect to children. In elite athletes age-related differences in neuromuscular control have scarcely been investigated. Therefore, this study aims at investigating differences in co-activation about the knee joint in two groups of karate athletes belonging to the Junior (JK) and Senior (SK) age categories, performing the roundhouse kick (RK)...
January 2015: European Journal of Applied Physiology
L Zollo, N Zaccheddu, A L Ciancio, M Morrone, M Bravi, F Santacaterina, M Laineri Milazzo, E Guglielmelli, S Sterzi
BACKGROUND: Ankle-foot-orthoses (AFOs) are frequently prescribed for hemiparetic patients to compensate for the foot drop syndrome. However, there is not a systematic study either on the effectiveness of AFOs in the gait recovery process or pointing out the therapeutic differences among the various types of AFOs available on the market. AIM: To perform a comparative evaluation of solid and dynamic Ankle-Foot-Orthoses (AFOs) on hemiparetic patients affected by foot drop syndrome by means of spatio-temporal, kinematic and electromyographic indicators...
April 2015: European Journal of Physical and Rehabilitation Medicine
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