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Titolo:
Facilitation of quadriceps activation following a concentrically controlled knee flexion movement: The influence of transition rate
Autore:
Jeon, HS; Trimble, MH; Brunt, D; Robinson, ME;
Indirizzi:
Univ Florida, Dept Phys Therapy, Gainesville, FL 32610 USA Univ Florida Gainesville FL USA 32610 Therapy, Gainesville, FL 32610 USA Univ Florida, Inst Brain, Gainesville, FL USA Univ Florida Gainesville FLUSA Florida, Inst Brain, Gainesville, FL USA Univ Florida, Dept Clin & Hlth Psychol, Gainesville, FL USA Univ Florida Gainesville FL USA Clin & Hlth Psychol, Gainesville, FL USA
Titolo Testata:
JOURNAL OF ORTHOPAEDIC & SPORTS PHYSICAL THERAPY
fascicolo: 3, volume: 31, anno: 2001,
pagine: 122 - 129
SICI:
0190-6011(200103)31:3<122:FOQAFA>2.0.ZU;2-T
Fonte:
ISI
Lingua:
ENG
Soggetto:
MAXIMAL VOLUNTARY CONTRACTIONS; STRETCH-SHORTENING CYCLE; ELASTIC ENERGY; ISOKINETIC DYNAMOMETRY; EXTENSION TORQUE; FORCE-VELOCITY; MUSCLE; EXERCISE; OUTPUT;
Keywords:
exercise; muscle training; proprioceptive neuromuscular facilitation; quadriceps;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Citazioni:
28
Recensione:
Indirizzi per estratti:
Indirizzo: Trimble, MH Univ Florida, Dept Phys Therapy, POB 100154 HSC, Gainesville, FL 32610 USA Univ Florida POB 100154 HSC Gainesville FL USA 32610 32610 USA
Citazione:
H.S. Jeon et al., "Facilitation of quadriceps activation following a concentrically controlled knee flexion movement: The influence of transition rate", J ORTHOP SP, 31(3), 2001, pp. 122-129

Abstract

Study Design: Single group repeated measures design. Objective: To determine ii the rate of transition between knee flexion andextension influences the subsequent concentric activation of the quadriceps and knee extension torque during reciprocal movements. Background: Preloading a muscle by stretching, a prior isometric or eccentric muscle action, or a prior movement controlled concentrically by the antagonist muscle group increases the maximal torque-generating capability of the agonist. We hypothesized that the rate of transition from the prior movement may be the critical factor that influences the degree of muscle facilitation and torque potentiation. Rapid reversal of antagonistic movements has been postulated as a potential facilitatory mechanism. Methods: Knee extension torque and electromyographic (EMG) amplitude (dependent variables) from 2 of the vasti muscles were recorded while subjects (N = 20; 12 men, 8 women, mean age, 28.5 +/- 2.68 years) maximally activatedtheir quadriceps at 3 constant angular velocities, 100 degrees /s, 200 degrees /s, and 300 degrees /s, and 2 preload conditions, SLOW and RAPID (independent variables). In the SLOW transition condition, subjects actively flexed their knee to 110 degrees from an extended position, paused in this position for 3 seconds, and then extended to 0 degrees. In the RAPID transition condition, the same movement from knee flexion to extension was performedwithout a pause. Results: Peak torque, the root-mean-square (RMS) average, peak (peak rectified and smoothed), and initial (100 milliseconds prior to torque onset) EMC amplitudes were all significantly greater during the RAPID transition condition. Peak torque decreased with increasing movement velocity. There wereno interactions between the preload conditions and angular velocity on peak torque or the EMG amplitude variables. There was also no influence of velocity on the EMC amplitude variables. Conclusions: The effect of preloading the quadriceps by prior concentric activation of the hamstrings is dependent on the rate of transition between the flexion and extension movements and is due primarily to neural facilitation.

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Documento generato il 14/08/20 alle ore 16:45:17