Search results for "FLEXION"
showing 10 items of 113 documents
Afferent contribution to locomotor muscle activity during unconstrained overground human walking:an analysis of triceps surae muscle fascicles
2010
Plantar flexor series elasticity can be used to dissociate muscle–fascicle and muscle–tendon behavior and thus afferent feedback during human walking. We used electromyography (EMG) and high-speed ultrasonography concomitantly to monitor muscle activity and muscle fascicle behavior in 19 healthy volunteers as they walked across a platform. On random trials, the platform was dropped (8 cm, 0.9 g acceleration) or held at a small inclination (up to ±3° in the parasagittal plane) with respect to level ground. Dropping the platform in the mid and late phases of stance produced a depression in the soleus muscle activity with an onset latency of about 50 ms. The reduction in ground reaction force…
Superimposing hip extension on knee flexion evokes higher activation in biceps femoris than knee flexion alone.
2021
Hamstring muscle function during knee flexion has been linked to hamstring injury and performance. However, it is unclear whether knee flexion alone (KF) requires similar hamstring electromyography (EMG) activity pattern to simultaneous hip extension and knee flexion (HE-KF), a combination that occurs in the late swing phase of sprinting. This study examined whether HE-KF maximal voluntary isometric contraction (MVIC) evokes higher (EMG) activity in biceps femoris long head (BFlh) and semitendinosus (ST) than KF alone. Effects of shank rotation angles were also tested. Twenty-one males performed the above-mentioned MVICs while EMG activity was measured along ST and BFlh. Conditions were com…
Neural drive preservation after detraining following neuromuscular electrical stimulation training
2006
The purpose of the study was to investigate the behaviour of the central nervous system when 5 weeks of neuromuscular electrical stimulation (NMES) training was followed by 5 weeks of detraining. Nineteen males were divided into the neuromuscular electrostimulated group (EG, n=12) and the control group (CG, n=7). The training program consisted of 15 sessions of isometric NMES over a 5-week period. The EG subjects were tested before training (PRE), after 5 weeks of NMES training (POST) and after 5 weeks of detraining (DE) while CG subjects were only tested at PRE and at POST. Soleus (SOL) and gastrocnemii (GAS) maximal H-reflex and M-wave potentials were evoked at rest (i.e., H(max) and M(ma…
Effect of bike-fit in the perception of comfort, fatigue and pain
2016
The aim of this study was to assess the influence of different bike positions on the perception of fatigue, pain and comfort. Twenty cyclists underwent three tests that involved cycling for 45 min at their individual 50% peak aerobic power output while adopting different positions on the bike. Participants performed the cycling tests adopting three positions defined by two parameters (knee flexion angle [20°, 30°, 40°] and trunk flexion angle [35°, 45°, 55°]) in random order. Angles were measured using a 2D motion analysis system during cycling and applying Fonda's correction factor. Perceptions of comfort, fatigue and pain were reported before the end of each test. The combination of 40° k…
Neural Activation During Submaximal Contractions Seems More Reflective of Neuromuscular Ageing than Maximal Voluntary Activation
2016
International audience; This study aimed at testing the hypothesis that differences in neural activation strategy during submaximal but not maximal plantarflexions exist between young and older men. Eleven young men (YM, 26 +/- 4 years) and thirteen old men (OM, 76 +/- 3 years) volunteered for the investigation. Maximal voluntary torque (MVT) was 38.2%, lower (p < 0.001) in OM than in YM, while voluntary activation was equivalent (similar to 97%). The relationship between the interpolated twitch torque and the voluntary torque (IT-VT relationship) was composite (curvilinear + exponential) for both age-groups. However, the OM showed accentuated concavity, as attested by the occurrence of the…
The involvement of ankle muscles in maintaining balance in the upright posture is higher in elderly fallers
2016
International audience; The purpose of this study was to determine whether the mechanical contribution of ankle muscles in the upright stance differed among young adults (YA) (n = 10, age: similar to 24.3), elderly non-fallers (ENF) (n = 12, age: similar to 77.3) and elderly fallers (EF) (n = 20, age: similar to 80.7). Torque and electromyographic (EMG) activity were recorded on the triceps surae and tibialis anterior during maximum and submaximum contractions in the seated position. EMG activity was also recorded in subjects standing still. Plantar flexor (PF) and dorsal flexor (DF) torques generated in the upright posture were estimated from the torque-EMG relationship obtained during sub…
Tempo-controlled resistance training of the hip abductors and ankle dorsiflexors with light loads does not improve postural sway in older adults.
2022
The force steadiness capabilities of the hip abductors and ankle dorsiflexors can explain a significant amount of the variance in postural sway during four types of standing balance tests. Control over balance, as well as force steadiness, generally worsens with aging, although the latter can be improved with unique training interventions. The purpose of our study was to assess how tempo-controlled, light-load resistance training of the hip abductors and ankle dorsiflexors influences performance in clinical movement tests, postural sway, muscle strength, and force steadiness in older adults. Participants (n = 28, 70 +/- 7 years, 8 men) completed nine training sessions for either the hip abd…
Inter-and intra-tester reliability of a battery of cervical movement control dysfunction tests
2015
Abstract Background Apart from the cranio-cervical flexion test and the deep neck flexor endurance test, evidence related to reliability of cervical movement control dysfunction tests is lacking. Objectives This study investigated the inter- and intra-tester reliability of a battery of cervical movement control dysfunction tests and the effect of clinician experience on reliability in 15 patients with chronic neck pain and 17 non-neck pain controls. In addition, it explored whether impaired performance on this battery of tests was more frequently observed in the neck pain group. Design Inter and intra-tester reliability study. Method Participants were videotaped while performing a battery o…
Algunas reflexiones acerca de la stjue de 9 de julio de 2020 sobre los pactos novatorios en materia de cláusulas suelo
2021
The Sentence of the Court of Justice of the European Union of July 9, 2020 comes to answer the five questions that, in its preliminary question, the Court of First Instance and Instruction No. 3 of Teruel asks about the validity of the new agreements in the context of the floor clauses, establishing jurisprudential doctrine on this matter about which our Supreme Court had previously ruled in its Judgments of October 16, 2017, in the sense of considering the agreed floor clause null as a consequence of the novation agreement and, subsequently, those of April 11, 2018 and September 13, 2018 in the opposite direction, declaring that the novation agreement was valid. It is a long-awaited and in…
Intervención de José Vidal-Beneyto en el debate sobre “Difference in thinking today”
2002
Versión en inglés de las intervenciones de José Vidal-Beneyto en el debate "La diferencia hoy pensada : El comienzo de la historia" [En: Portella, Eduardo (Dir.) (2000). Caminos del pensamiento: hacia nuevos lenguajes (pp. 111-112 ; 125 ; 131-132; 135 ; 146-149; 294). París: Ediciones UNESCO - La biblioteca del filósofo.]. Disponible también la versión francesa en: En: Portella, Eduardo (Dir.) (2000). Chemins de la pensée : vers de nouveaux langages (pp. 111-112; 125-126; 132; 135; 147-149; 296). Paris: Éditions UNESCO - La bibliothèque du philosophe.