Search results for "ETC"

Changes in neural drive to calf muscles during steady submaximal contractions after repeated static stretches

2021

Key points: Repeated static-stretching interventions consistently increase the range of motion about a joint and decrease total joint stiffness, but findings on the changes in muscle and connective-tissue properties are mixed. The influence of these stretch-induced changes on muscle function at submaximal forces is unknown. To address this gap in knowledge, the changes in neural drive to the plantar flexor muscles after a static-stretch intervention were estimated. Neural drive to the plantar flexor muscles during a low-force contraction increased after repeated static stretches. These findings suggest that adjustments in motor unit activity are necessary at low forces to accommodate reduct…

Fatigue effects of marathon running on neuromuscular performance

2007

Nine experienced endurance runners performed individual marathon runs that involved several tests of neuromuscular performance before, during and after the marathon. The tests were performed with special force platform and dynamometer techniques. The results showed an overall decrease in performance from the marathon. The maximal sprint velocity decreased parabolically during the marathon, reaching the final value of 84% of the pre-marathon one. Similarly, the other test results after marathon indicated that maximal isometric knee extension torque was 78%, the performance in a special rebound test (drop jump) 84% and the 5-jump performance 92% of the pre-marathon values. These reductions we…

2019

Muscle architecture is an important component of muscle function, and recent studies have shown changes in muscle architecture with fatigue. The stretch-shortening cycle is a natural way to study human locomotion, but little is known about how muscle architecture is affected by this type of exercise. This study investigated potential changes in medial gastrocnemius (MG) muscle architecture after exhaustive stretch-shortening cycle exercise. Male athletes (n = 10) performed maximal voluntary contractions (MVC) and maximal drop jump (DJ) tests before and after an exercise task consisting of 100 maximal DJs followed by successive rebound jumping to 70% of the initial maximal height. The exerci…

The function of neuromuscular system in maximal stretch-shortening cycle exercises: Comparison between power- and endurance-trained athletes.

1994

Abstract Differences in neuromuscular function between power athletes ( n = 10) and endurance athletes ( n = 10) were investigated in six different experimental conditions. In drop jumps and in stretch-shortening cycle (SSC) exercises on the sledge (sledge jumps), the subjects performed about 10 maximal jumps from the optimum dropping height (O) as well as from the dropping height of optimum −40 cm (O − 40) and optimum +40 cm (O + 40). The five to six best jumps were taken for further analysis. In every condition the power group had better physical performance compared to their endurance counterparts. During the pre-activity, the rate of electromyographic (EMG) development of the power athl…

The Stretch-Shortening Cycle

2006

Neuromuscular fatigue has traditionally been examined using isolated forms of either isometric, concentric or eccentric actions. However, none of these actions are naturally occurring in human (or animal) ground locomotion. The basic muscle function is defined as the stretch-shortening cycle (SSC), where the preactivated muscle is first stretched (eccentric action) and then followed by the shortening (concentric) action. As the SSC taxes the skeletal muscles very strongly mechanically, its influence on the reflex activation becomes apparent and very different from the isolated forms of muscle actions mentioned above. The ground contact phases of running, jumping and hopping etc. are example…

Effects of power training on neuromuscular performance and mechanical efficiency

2007

Effects of power training with stretch-shortening cycle (SSC) exercises on mechanical efficiency (ME) were investigated with 9 young women who trained 3 times a week for 4 months. The training included various types of jumping exercises. Before and after the training as well as after the detraining (2 months) the subjects performed 6 different submaximal exercises with a special sledge apparatus. Each exercise involved 60 muscle actions lasting for a total of 3 min per testing condition. The work intensities were determined individually according to the recordings of distance obtained during the single maximal concentric exercises. The training caused the greatest changes of ME in condition…

Carboxytherapy in dermatology.

2022

Abstract Carboxytherapy is a medical technique during which a sterile gas—carbon dioxide—is injected into the subdermal tissue. The utility of carbon dioxide injections has enhanced the practical relevance of carboxytherapy as a method for the management of multiple disorders. We have evaluated its use in the treatment of dermatologic conditions by searching electronic databases (ie, MEDLINE and PubMed) for contributions in the English language through January 2021. Carboxytherapy provides an attractive aesthetic option in skin rejuvenation, atrophic scars, striae distensae (stretch marks), cellulite-fibrolipodystrophy adhesions after liposuction, and certain types of alopecia. We discuss t…

Interaction between muscle stiffness and stretch reflex sensitivity after long-term stretch-shortening cycle exercise

1998

The short latency stretch-reflex component (M1) and its interactions with muscle stiffness and with muscle performance were investigated before and after long-term stretch-shortening cycle (SSC) exercise. Dramatic fatigue induced reduction in maximal SSC performance capability, and electromyographic activity was accompanied by a consistent decrease in the M1 reflex component and eccentric peak stiffness of the muscle. It can be suggested, therefore, that the decreased muscle performance is not simply a direct effect of central or peripheral fatigue, but is partly due to impairment of the ability to utilize stiffness-related elastic energy.

Production and characterization of the recombinant Sphingomonas chlorophenolica pentachlorophenol 4-monooxygenase.

2001

Abstract Pentachlorophenol 4-monooxygenase (PCP4MO) from Sphingomonas chlorophenolica is a flavoprotein that hydroxylates PCP in the presence of NADPH and oxygen. In order to investigate the structure and function of active site, recombinant PCP4MO (rePCP4MO) was produced in Escherichia coli as a glutathione S-transferase (GST) fusion protein. Moreover, a tobacco etch virus (TEV) protease cleavage site (EKLYFQG) was introduced into GST-PCP4MO and a his-tagged TEV protease was employed. Hence, a two-step purification protocol was developed which allowed obtaining 15–20 mg of rePCP4MO from 1 L culture. The rePCP4MO revealed identity with native enzyme by SDS–PAGE and N-terminal sequence analy…

Avaliando o caso da dengue na Argentina em 2009: discriminação e medo

2010

Após quase uma década, a reaparição da Dengue na Argentina causou pânico e medo. Diferente da Bolívia, do Brasil e do Paraguai, onde as políticas de prevenção têm sido seguidas, o futuro da dengue fica incerto para a Argentina; este trabalho não tem qualquer afiliação política, mas destaca o papel da mídia de massa na cobertura das epidemias. A questão de se um jornal ou corporação de mídia de massa deveria manter um mínimo de objetividade é extensa demais para ser resolvida neste artigo curto. Entretanto, temos apresentado um modelo que ajudará outros pesquisadores a interpretarem temas desta natureza no futuro. Nos momentos de desordem, incerteza ou desastre, as sociedades passam por uma …