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Titolo:
Alterations in contractile properties of human skeletal muscle induced by joint immobilization
Autore:
Seki, K; Taniguchi, Y; Narusawa, M;
Indirizzi:
Int Budo Univ, Dept Exercise Physiol, Chiba 29952, Japan Int Budo Univ Chiba Japan 29952 ept Exercise Physiol, Chiba 29952, Japan
Titolo Testata:
JOURNAL OF PHYSIOLOGY-LONDON
fascicolo: 3, volume: 530, anno: 2001,
pagine: 521 - 532
SICI:
0022-3751(20010201)530:3<521:AICPOH>2.0.ZU;2-L
Fonte:
ISI
Lingua:
ENG
Soggetto:
MOTOR UNITS; DIFFERENT LENGTHS; HINDLIMB IMMOBILIZATION; SARCOPLASMIC-RETICULUM; TRICEPS SURAE; RAT EXTENSOR; FATIGABILITY; DISUSE; NERVE; CAT;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
45
Recensione:
Indirizzi per estratti:
Indirizzo: Seki, K Univ Washington, Dept Physiol & Biophys, 357290, Seattle, WA 98195USA Univ Washington 357290 Seattle WA USA 98195 Seattle, WA 98195 USA
Citazione:
K. Seki et al., "Alterations in contractile properties of human skeletal muscle induced by joint immobilization", J PHYSL LON, 530(3), 2001, pp. 521-532

Abstract

1. The effects of joint immobilization on the contractile properties of human skeletal muscle were examined using the first dorsal interosseous (FDI)muscle.2. The middle finger, index finger and thumb were immobilized for a periodof 6 weeks, and the contractile properties of FDI were tested before immobilization, after 3 and 6 weeks of immobilization, and after a 6 week recovery period.3. Twitch and tetanic contractions of FDI were evoked by per-cutaneous electrical stimulation. The peak twitch tension (Pt), contraction time (CT) and half-relaxation time (1/2RT) were measured from twitch contractions, while the stimulus frequency-force relationship was obtained from the tetanic contractions (2 s) evoked using various frequencies of stimulation (10-100 Hz). The fatigability of FDI was tested using Burke's fatigue protocol.4. Pt was significantly increased after 6 weeks of immobilization (P < 0.05) but little alteration was observed in CT or 1/2RT. No change was noted in the FDI fatigue index throughout the immobilization period.5. The stimulus frequency-force relationship was shifted to the left by immobilization, indicating that a larger percentage of maximal force was evoked by the lower rates of stimulation. Indeed, the tetanic force evoked by astimulus frequency of 10 Hz was enhanced after immobilization (P < 0.05). On the other hand, the force evoked by frequencies above 50 Hz, including maximal tetanic tension, was decreased (P < 0.05). As a result, the twitch/tetanus ratio was increased (P < 0.01) after immobilization.6. The changes induced by immobilization in the FDI twitch/tetanus ratio and the estimated maximal firing rate of FDI motoneurones showed a significant correlation (r = 0.80, P < 0.05).7. It is suggested that the changes in the contractile properties of the FDI muscle seen after joint immobilization are causally linked to the changes in firing rate modulation of FDI motoneurones.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/09/20 alle ore 19:45:52