Search results for "Eccentric contractions"
showing 4 items of 4 documents
Effects of a trail running competition on muscular performance and efficiency in well-trained young and master athletes
2010
International audience; To determine the acute effects of a trail running competition and the age-dependent differences between young and master athletes, 23 subjects [10 young (30.5 ± 7 years), 13 master (45.9 ± 5.9 years)] participated in a 55-km trail running competition. The study was conceived as an intervention study compromising pre, post 1, 24, 48 and 72 h measurements. Measurements consisted of blood tests, ergometer cycling and maximal isometric voluntary contractions (MVC). Parameters monitored included MVC, twitch-and M-wave properties, EMG (RMS) of the vastus lateralis, two locomotion efficiency calculations and muscle damage markers in the blood (CK, LDH). Results indicate pos…
Alterations of mechanical characteristics of human skeletal muscle during strength training
1983
To investigate the influence of strength training on the mechanical characteristics of human skeletal muscle, 14 male subjects went through training of combined heavy concentric and eccentric contractions three times a week for 16 weeks. The strength training program consisted mainly of dynamic exercises for leg extensors with loads of 80 to 120% of one maximum repetition. The force-time curves produced during various vertical jumps were the basis for calculation of various mechanical parameters. In addition to a great increase (p less than 0.001) in maximal isometric force, heavy resistance strength training also caused significant (p less than 0.05-0.01) increases in heights and in variou…
Activation of human quadriceps femoris during isometric, concentric, and eccentric contractions.
2001
Maximal and submaximal activation level of the right knee-extensor muscle group were studied during isometric and slow isokinetic muscular contractions in eight male subjects. The activation level was quantified by means of the twitch interpolation technique. A single electrical impulse was delivered, whatever the contraction mode, on the femoral nerve at a constant 50° knee flexion (0° = full extension). Concentric, eccentric (both at 20°/s velocity), and isometric voluntary activation levels were then calculated. The mean activation levels during maximal eccentric and maximal concentric contractions were 88.3 and 89.7%, respectively, and were significantly lower ( P < 0.05) with respe…
Mechanical and electrical behavior of human muscle during maximal concentric and eccentric contractions
1974
The force-velocity relationships of human muscle (e.g., Asmussen, Hansen, and Lammert, 1965; Komi, 1973a) characterize the main mechanical differences in concentric and eccentric work. Some information also has been reported on the interrelationship between neural input and mechanical output during submaximal concentric and eccentric contractions. The slope of the regression line representing the relationship between IEMG and muscle tension is greater when muscle shortens at a constant velocity than when it lengthens at the same velocity (Bigland and Lippold, 1954). When recordings were made with a greater number of velocities, then a family of curves was obtained, a result which emphasizes…