Muscular Performance, Muscular Performance Online, Muscular Systems
Within working muscle, development of conditions that directly influence exercise performance is dependent on many factors, including: intensity and duration of exercise, type of skeletal muscle fibres recruited, cardiovascular support to the working fibres and the inherent metabolic characteristics of the contracting fibres. In general, it is possible to identify factors that seem to alter exercise performance only at relatively intense exercise conditions. During prolonged moderately intense exercise (e.g. 70-80% maximal oxygen consumption for at least 60-90 min) decline in performance is related to the depletion of glycogen within
the working muscle. Although the cause of muscle performance decline during very intense exercise is not known, an extreme acidosis is found, especially in fast-twitch muscle, which could significantly disrupt normal metabolic and contractile processes. During fatigue caused by intense contraction conditions, ATP content decreases and there is a stoichiometric production of IMP and ammonia in fast-twitch muscle. This loss in adenine nucleotide content is dependent on the severity of the contraction conditions relative to the functional aerobic capacity of the muscle fibre, since fast-twitch red (high mitochondria, high blood flow) and fast-twitch white (low mitochondria, low blood flow) muscles respond differently. In contrast, during similarly intense contraction conditions, rat slow-twitch muscle fibres maintain their ATP content and do not produce significant amounts of IMP. Indirect evidence suggests that a similar contrast between fibres occurs in humans during maximal exercise. Thus, there seems to be a fundamental difference between fast- and slow-twitch muscles in the management of their adenine nucleotide contents during intense contraction conditions. Whether this is related to the known differences in the fatigue process between these fibre types is not known. The point is that knee extensions will make your quads stronger during knee-extension workouts, but they may not make your quads more powerful during a 10K or marathon, when the actual contractions of the quads are of a different magnitude and frequency, and the quads are forced to act in concert with the other muscles in the legs. If you carry out knee extensions, knee flexions, leg presses, and other isolated exercises in hopes of improving your running, you're as foolish as the symphony-orchestra conductor who works with the percussion, horns, woodwinds, and strings separately during rehearsals but never asks the various elements to play together before an important concert. Since traditional resistance routines are of doubtful value because of their lack of similarity to running, what kind of strength training should you employ? To answer this question, it's important to remember that all competitive running events require the development and maintenance of speed over a specified period of time. Running speed is largely dependent on the amount of force applied to the ground during each foot strike - and me time over which that force is applied. The greater the force of a foot strike and the shorter its period of application, the higher the power of an individual step - and the faster the speed of a runner. By increasing the power exerted during each step, runners raise the speed of their workouts and races. The power requirements for a marathon are lower (and running speeds slower), compared to a 5000-metre race, but both events require optimal power production during each foot strike. A lot of the power produced during running depends on the mechanical 'energy-return' properties of a runner's feet and legs. The muscles and tendons of the lower extremities act like springs during running, mainly by storing energy just before and during the compression associated with foot strike and then releasing ('returning') this energy during take-off. This return of energy is influenced by both the elasticity of the muscles and tendons and by nerve cells which control muscle and tendon stretchiness. Overall, the strength-building triad carries little risk of injury, takes little of your time, and is very specific to the actual act of running. The three exercises will improve both your coordination and leg-muscle power, and after several weeks you'll notice that your legs feel much stronger and that your stride length and frequency have improved. You'll move quickly and aggressively from one foot to the other as you run, and you'll reach the finish lines of your races in faster and faster times.For More Details:http://www.muscularperformanceonline.com
the working muscle. Although the cause of muscle performance decline during very intense exercise is not known, an extreme acidosis is found, especially in fast-twitch muscle, which could significantly disrupt normal metabolic and contractile processes. During fatigue caused by intense contraction conditions, ATP content decreases and there is a stoichiometric production of IMP and ammonia in fast-twitch muscle. This loss in adenine nucleotide content is dependent on the severity of the contraction conditions relative to the functional aerobic capacity of the muscle fibre, since fast-twitch red (high mitochondria, high blood flow) and fast-twitch white (low mitochondria, low blood flow) muscles respond differently. In contrast, during similarly intense contraction conditions, rat slow-twitch muscle fibres maintain their ATP content and do not produce significant amounts of IMP. Indirect evidence suggests that a similar contrast between fibres occurs in humans during maximal exercise. Thus, there seems to be a fundamental difference between fast- and slow-twitch muscles in the management of their adenine nucleotide contents during intense contraction conditions. Whether this is related to the known differences in the fatigue process between these fibre types is not known. The point is that knee extensions will make your quads stronger during knee-extension workouts, but they may not make your quads more powerful during a 10K or marathon, when the actual contractions of the quads are of a different magnitude and frequency, and the quads are forced to act in concert with the other muscles in the legs. If you carry out knee extensions, knee flexions, leg presses, and other isolated exercises in hopes of improving your running, you're as foolish as the symphony-orchestra conductor who works with the percussion, horns, woodwinds, and strings separately during rehearsals but never asks the various elements to play together before an important concert. Since traditional resistance routines are of doubtful value because of their lack of similarity to running, what kind of strength training should you employ? To answer this question, it's important to remember that all competitive running events require the development and maintenance of speed over a specified period of time. Running speed is largely dependent on the amount of force applied to the ground during each foot strike - and me time over which that force is applied. The greater the force of a foot strike and the shorter its period of application, the higher the power of an individual step - and the faster the speed of a runner. By increasing the power exerted during each step, runners raise the speed of their workouts and races. The power requirements for a marathon are lower (and running speeds slower), compared to a 5000-metre race, but both events require optimal power production during each foot strike. A lot of the power produced during running depends on the mechanical 'energy-return' properties of a runner's feet and legs. The muscles and tendons of the lower extremities act like springs during running, mainly by storing energy just before and during the compression associated with foot strike and then releasing ('returning') this energy during take-off. This return of energy is influenced by both the elasticity of the muscles and tendons and by nerve cells which control muscle and tendon stretchiness. Overall, the strength-building triad carries little risk of injury, takes little of your time, and is very specific to the actual act of running. The three exercises will improve both your coordination and leg-muscle power, and after several weeks you'll notice that your legs feel much stronger and that your stride length and frequency have improved. You'll move quickly and aggressively from one foot to the other as you run, and you'll reach the finish lines of your races in faster and faster times.For More Details:http://www.muscularperformanceonline.com
