Contraction

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Contraction

In a business cycle, the time between the peak and the bottom. That is, a contraction occurs between the end of economic growth and the end of the subsequent recession. Contractions are characterized by layoffs, a decline in GDP, and other negative factors. However, historically, contractions have tended not to last as long as expansions.
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In the trained group, the mean muscle power generated during concentric contractions of the triceps brachii at a load of 75% of the subject's 1RM was significantly higher during the DS than during the RDS (Figure 3).
Predominantly concentric contractions (running uphill), seem to be the most efficient way of increasing the HSP70 concentrations in the different tissues, followed by eccentric contraction (downhill) and lastly the concentric-eccentric cycle (horizontal).
Therefore, the greater concentric contraction of the quadriceps at a lower angular velocity would compromise the isokinetic tests more significantly in participants with symptomatic PT.
The prestretch allows a greater amount of muscular force to develop during the concentric contraction.
If the motor neuron pool is also inhibited during maximal eccentric contraction, as previous studies have suggested, the attenuation of Ia afferents due to the application of prolonged vibration stimulation might not affect or have less of an effect on the recruitment of high threshold motor units as compared with concentric contraction.
The submaximal elbow flexion elicited neuromuscular activity up to 95% of the maximum RMS value during the phase 3 of the concentric contraction for the IDC and DBC protocols.
Hence, in the initial downward motion, the longer eccentric contraction of hip joint extensors in elderly may increase concentric contraction of flexors at the knee joint, which would not significantly decrease angular displacement of the knee joint.
Concentric contractions are directly involved in daily human movement (1), and it is well reported in the literature that fatigue generated by CC causes a decrease in torque, muscle strength, electromyographic activity, and higher metabolic cost (8).
HTS seems to take advantage of both resistance exercise (anaerobic exercise) by electrical eccentric contractions and aerobic exercise at a low exercise intensity by voluntary concentric contractions.
The trials consisted of: 1, isometric contractions at angles of 80[degrees], 90[degrees], and 100[degrees] of plantar flexion; 2, peak torque and power at six isokinetic angular velocities at 60[degrees], 90[degrees], 120[degrees], 180[degrees], 240[degrees], and 300[degrees] per second; and 3, a fatigue test consisting of 30 maximal concentric contractions at 300[degrees] per second, where the amount of work produced and the percentage of decline in work produced was measured.
Force in eccentric contractions is generally greater than in isometric or concentric contractions (Griffin, 1987; Walmsley, Pearson, & Stymiest, 1986).
The extent of muscle hypertrophy is dependent upon protein degradation and synthesis, which may be enhanced through high intensity, high volume eccentric and concentric contractions.