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Titolo:
Performance of plantar flexor muscles with eccentric and isometric contractions in intact rats
Autore:
Willems, MET; Stauber, WT;
Indirizzi:
W Virginia Univ, Dept Physiol, Morgantown, WV 26506 USA W Virginia Univ Morgantown WV USA 26506 Physiol, Morgantown, WV 26506 USA
Titolo Testata:
MEDICINE AND SCIENCE IN SPORTS AND EXERCISE
fascicolo: 7, volume: 32, anno: 2000,
pagine: 1293 - 1299
SICI:
0195-9131(200007)32:7<1293:POPFMW>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
SKELETAL-MUSCLE; INDUCED INJURY; LENGTHENING CONTRACTIONS; MECHANICAL-PROPERTIES; SOLEUS MUSCLE; IN-VIVO; EXERCISE; DAMAGE; MOTIONS; CALCIUM;
Keywords:
skeletal muscle; muscle injury; muscle force; velocity; ankle; dynamometer;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
29
Recensione:
Indirizzi per estratti:
Indirizzo: Stauber, WT W Virginia Univ, Dept Physiol, POB 9229, Morgantown, WV 26506 USA W Virginia Univ POB 9229 Morgantown WV USA 26506 WV 26506 USA
Citazione:
M.E.T. Willems e W.T. Stauber, "Performance of plantar flexor muscles with eccentric and isometric contractions in intact rats", MED SCI SPT, 32(7), 2000, pp. 1293-1299

Abstract

Purpose: To examine the changes in performance of active plantar flexor muscles of rats by controlled dorsiflexion (i.e., stretching of muscles) at two angular velocities. Methods: Repeated stretches (30) at two velocities of ankle rotation [slow stretch (0.87 rad.s(-1) (i.e., 50 degrees.s(-1))), fast stretch (10.47 rad.s(-1) (i.e., 600 degrees s(-1)))] were superimposed on maximally active muscles from an ankle position of 1.57 rad to 0.70 rad (i.e., from 90 degrees to 40 degrees). Repeated isometric contractions (30)of the same duration (1900 ms) and rest interval (3 min) were performed at1.13 rad (i.e., 65 degrees). Performance was assessed by measuring the isometric torque at ankle positions of 1.57 and 0.70 rad, work during concentric contractions [range of motion 1.22 rad (i.e., 70 degrees)], and the timeto produce 50% of the maximal isometric torque. Results: Thirty isometric contractions resulted in a linear reduction in torque (total deficit of 13.8% at 1.57 rad), whereas for slow and fast stretches, half of the total, nonlinear deficit at 1.57 rad (about 30%) was completed after six stretches. Increases in half contraction times were larger for stretches than for isometric contractions. Reductions in isometric torque were greater at an ankleposition of 1.57 rad than at 0.70 rad. One hour of rest after the repeatedstretches and isometric contractions did not restore muscle performance. Conclusions: Isometric contractions of skeletal muscle can create a torque deficit which is much less than that after stretches. Repeated fast and slowstretches resulted in similar torque deficits which did not recover after a rest period of 1 h.

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Documento generato il 03/04/20 alle ore 06:52:34