A New Paradigm of Muscle Contraction Video) Event as iCalendar


16 August 2016

4 - 5pm

Venue: Ground Floor Seminar Room (G10)

Location: 70 Symonds Street, Auckland Central


An ABI seminar by Professor Walter Herzog, Faculties of Kinesiology, Engineering and Medicine and Co-Director, Human Performance Laboratory, University of Calgary.




Since the discovery of the sliding filament and cross-bridge theories of muscle contraction more than half a century ago, force production and contraction in skeletal muscles have been associated exclusively with the contractile filaments actin and myosin. Recently, the structural protein titin, has emerged as a third filament contributing to active force regulation and contraction. In the past decade, we have attempted to identify the role of titin in force regulation during eccentric contraction and found that titin can regulate its stiffness upon activation and active, actin-myosin based force production. Likely, titin’s force regulatory role occurs in two ways: (i) by binding calcium upon activation and thus becoming stiffer, and (ii) by attaching its proximal segments to actin, thereby shortening its free spring length and thus become stiffer and stronger in active compared to passive eccentric contractions. Modeling titin’s role in conjunction with the regular cross-bridge mechanism of muscle contraction allows for the first time to explain the extra force observed experimentally following eccentric contractions, the increase in efficiency of force production in eccentric compared to isometric and concentric contractions, and the stability of sarcomeres on the descending limb of the force-length relationship.