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Voluntary rate of torque development is impaired after a voluntary versus tetanic conditioning contraction
Author(s) -
Smith Cameron B.,
Allen Matti D.,
Rice Charles L.
Publication year - 2014
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.23888
Subject(s) - isometric exercise , long term potentiation , contraction (grammar) , conditioning , muscle contraction , turnover , medicine , chemistry , physical medicine and rehabilitation , anesthesia , mathematics , statistics , receptor , management , economics
: Both voluntary and evoked conditioning contractions will potentiate muscle twitch contractile properties. The response of a voluntary contraction to each condition type is not well understood but it may be a more functional model than evoked twitch potentiation. Methods : Baseline measurements from tibialis anterior included: maximal isometric twitch torque and rate of torque development (RTD); maximal evoked 50‐H z torque; and maximal voluntary ballistic RTD. Potentiation was induced by a 10‐s voluntary or tetanic contraction (∽78% MVC), followed by 2 twitches and 2 ballistic contractions. Results : Twitch properties (torque and RTD) were potentiated equally after each conditioning contraction. Ballistic RTD was greater post‐tetanus (390.2 ± 59.3 Nm/s) than post‐voluntary (356.4 ± 69.1 Nm/s), but both were reduced from baseline (422.0 ± 88.9 Nm/s). Conclusions : Twitch potentiation was similar between conditioning contraction types, but ballistic RTD was lower after post‐tetanus than post‐voluntary. The results indicate central inhibition or fatigue concurrent with peripheral potentiation. Muscle Nerve 49 : 218–224, 2014