Search results for "Eccentric"

Molecular adaptations of voltage-gated sodium ion channel related proteins after fatiguing stretch-shortening cycle exercise

2008

Dystrophin associated protein alpha-syntrophin is known to interact with voltage-gated sodium ion channel (NaCh). Dystrophin is known to be sensitive to eccentric muscle actions. For this reason, the function of the NaChs might also be affected. Molecular adaptations of dystrophin, alpha-syntrophin and NaChs were investigated after fatiguing stretch-shortening cycle (SSC) exercise, which consisted of unilateral jumps on a sledge apparatus. Muscle biopsies were taken from the vastus lateralis muscle of eight healthy subjects immediately after (IA) and 2 days after (2D) the exercise to analyze mRNA levels and immunohistochemical staining patterns. SSC exercise resulted in decreased isometric …

2021

Sports-related pain and injury is directly linked to tissue inflammation, thus involving the autonomic nervous system (ANS). In the present experimental study, we disable the sympathetic part of the ANS by applying a stellate ganglion block (SGB) in an experimental model of delayed onset muscle soreness (DOMS) of the biceps muscle. We included 45 healthy participants (female 11, male 34, age 24.16 ± 6.67 years [range 18–53], BMI 23.22 ± 2.09 kg/m2) who were equally randomized to receive either (i) an SGB prior to exercise-induced DOMS (preventive), (ii) sham intervention in addition to DOMS (control/sham), or (iii) SGB after the induction of DOMS (rehabilitative). The aim of the study was t…

Revisión bibliográfica sobre la eficacia del ejercicio excéntrico como tratamiento para la tendinopatía del tendón de Aquiles

2020

Resumen Introducción: las tendinopatías son consecuencia de cargas excesivas en el tendón, por lo que son frecuentes en el ámbito laboral debido a movimientos repetitivos y posturas forzadas. La tendinopatía de Aquiles se caracteriza por una respuesta de curación desorganizada, asociada a cierto grado de neovascularización, siendo el tratamiento conservador la estrategia inicial. Objetivos realizar una revisión bibliográfica para analizr la efectividad de los tratamientos utilizados en la tendinopatía aquilea a partir de los estudios incluidos. Material y métodos: revisión bibliográfica de artículos científicos consultando las bases de datos PubMed y The Cochrane Library utilizando las pala…

Effects of combined electromyostimulation and gymnastics training in prepubertal girls.

2011

This study investigated the effects of a 6-week combined electromyostimulation (EMS) and gymnastic training program on muscle strength and vertical jump performance of prepubertal gymnasts. Sixteen young women gymnasts (age 12.4 ± 1.2 yrs) participated in this study, with 8 in the EMS group and the remaining 8 as controls. EMS was conducted on knee extensor muscles for 20 minutes 3 times a week during the first 3 weeks and once a week during the last 3 weeks. Gymnasts from both groups underwent similar gymnastics training 5-6 times a week. Isokinetic torque of the knee extensors was determined at different eccentric and concentric angular velocities ranging from -60 to +240° per second. Jum…

Plyometric muscular action tests in judo- and non-judo athletes

2011

The majority of explosive actions during the Judo fight occur when the athlete is trying to overcome his/her adversary via rapid execution(s) of (isolated or chained) technical manoeuvres. The aim of this study was to compare the results of two plyometric muscular action tests (i.e., Squat Jump – SJ, and Countermovement Jump – CMJ) between judoand non-judoathletes. The investigation involved a cross-sectional examination of 102 subjects (age, 21.9 ± 3.4 years) divided into 3 performance groups: a) Senior top elite judo athletes (n = 50), b) Junior elite judo athletes (n = 26) and c) Adult non-judo athletes (n = 26). Thirteen biomechanical variables (including jump height, velocity, power, f…

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…

2021

The aim of this study was to investigate whether recovery from eccentric squat exercise varies depending on age and to assess whether the use of a mixed-method recovery (MMR) consisting of cold water immersion and compression tights benefits recovery. Sixteen healthy and resistance-trained young (age, 22.1±2.1years; N=8) and master male athletes (age, 52.4±3.5years; N=8), who had a similar half squat 1-repetition maximum relative to body weight, completed two identical squat exercise training sessions, separated by a 2-week washout period. Training sessions were followed by either MMR or passive recovery (PR). Internal training loads [heart rate and blood lactate concentration (BLa)] were r…

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…

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.