Search results for "shortening"

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…

Injury in elite women soccer and national women soccer in the lower extremity

2018

Purpose: Analyse the epidemiology of women's soccer harmful depending on the category of game. Materials and Methods: There were 26 participants (38 Super League and 32 National League women) with a mean age of 21.20 ± 4.64 years and body mass index (BMI) of 21.94 ± 1.79 kg/m2. There are several reasons why the health problems of the women’s soccer must be taken into account. Among these reasons, we think that the speed actions in this sport will have a great impact on the health of competitors. In addition, the women are more prone to overuse injuries due to the morphological characteristics. Results: Musculoskeletal injuries and pain were importance to women’s soccer of two levels. This w…

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…

Leg and joint stiffness in human hopping

2010

The present study investigated the regulation of leg and joint stiffness in hopping at different intensity levels. Eight male subjects performed bilateral hopping at various intensity levels that were determined by peak vertical ground reaction force (GRF). In addition to the GRF, the measurements included hopping kinematics and electromyography (EMG) of selected leg muscles. While the leg and ankle joint stiffness remained invariant, the knee joint stiffness increased significantly (P<0.01) with the hopping intensity. EMG analysis revealed a significant increase in averaged EMG for all the measured muscles before and during the early phase of ground contact (P<0.05-0.001) with increasing h…

Stretch reflex modulation during exercise and fatigue

2003

Muscle and joint stiffness regulation during normal and fatiguing stretch-shortening cycle exercise

2010

Gene expressions of SREBP-2, PPARδ, MYH7 and blood lipid changes induced by stretch-shortening cycle exercise

2011

The present study was to investigate whether the mRNA levels of the transcription factors, sterol regulatory element-binding protein-2 (SREBP-2), peroxisome proliferator-activated receptor-δ (PPARδ) as well as slow type myosin heavy chain (MYH7) gene are modulated after exhaustive exercise and if so, whether such alterations are related to the percentage of MHC isoforms. In particular, this study was undertaken to examine whether the level of selected blood parameters are influenced by fatiguing stretch-shortening cycle (SSC) exercise. Ten healthy men performed unilateral exhaustive repeated jumps on a special sledge. The maximal voluntary contraction (MVC) was examined before, immediately,…