Mechanical work as predictor of force enhancement and force depression
2009 (English)In: Journal of Biomechanics, ISSN 0021-9290, E-ISSN 1873-2380, Vol. 42, no 11, 1628-1634 p.Article in journal (Refereed) Published
The steady-state force following active muscle shortening or stretch differs from the maximum isometric force associated with the final length. This phenomenon proves that the isometric force production is not only dependent on current muscle length and length time derivative, but depends on the preceding contraction history. Isolated extensor digitorum longus and soleus muscles from mice (NMRI strain) were used to investigate the force produced by a muscle, and some parameters hypothetically influencing this history-dependent force modification. The muscles were pre-stimulated at a fixed length, then different stretch/shortening episodes were introduced, whereafter changes of the active force were recorded while the muscles were held isometrically to approach a steady-state force before de-stimulation. The mechanical work during active stretch and shortening was evaluated by integrating the product of force and ramp velocity over the length-varying period. The results show a negative linear correlation between the force modification and the mechanical work produced on or by the muscle, continuous between shortening and stretch. A corresponding modification of the passive force component following each stimulation was also observed. The conclusion is that the isometric force attained after stretch or shortening is well described by an asymptotic force which is determined by the mechanical work.
Place, publisher, year, edition, pages
2009. Vol. 42, no 11, 1628-1634 p.
Mouse skeletal muscles, Transient-length contractions, Stretch-shortening cycle, Force depression, Force enhancement, History, dependence, Muscular work, frog-muscle fibers, cat soleus muscle, skeletal-muscle, length, relationship, isometric force, descending-limb, stretch, tension, simulations, contraction
IdentifiersURN: urn:nbn:se:kth:diva-18709DOI: 10.1016/j.jbiomech.2009.04.028ISI: 000269269800009PubMedID: 19486981ScopusID: 2-s2.0-67651155777OAI: oai:DiVA.org:kth-18709DiVA: diva2:336756
QC 201005252010-08-052010-08-052012-05-25Bibliographically approved