摘要
Itiswellacknowledgedthatmusclesthatareelongatedwhileactivated（i.e.,eccentricmuscleaction）arestrongerandrequirelessenergy（perunitofforce）thanmusclesthatareshortening（i.e.,concentriccontraction）orthatremainataconstantlength（i.e.,isometriccontraction）.Althoughthecross-bridgetheoryofmusclecontractionprovidesagoodexplanationfortheincreaseinforceinactivemusclelengthening,itdoesnotexplaintheresidualincreaseinforcefollowingactivelengthening（residualforceenhancement）,orexceptwithadditionalassumptions,thereducedmetabolicrequirementofmuscleduringandfollowingactivestretch.Asidefromthecross-bridgetheory,2otherprimaryexplanationsforthemechanicalpropertiesofactivelystretchedmuscleshaveemerged：（1）theso-calledsarcomerelengthnonuniformitytheoryand（2）theengagementofapassivestructuralelementtheory.Inthisarticle,thesetheoriesarediscussed,anditisshownthatthelastofthese—theengagementofapassivestructuralelementineccentricmuscleaction—offersasimpleandcompleteexplanationformanyhithertounexplainedobservationsinactivelylengtheningmuscle.Althoughbynomeansfullyproven,thetheoryhasgreatappealforitssimplicityandbeauty,andevenifovertimeitisshowntobewrong,itneverthelessformsausefulframeworkfordirecthypothesistesting.
出版日期
2018年03月13日（中国期刊网平台首次上网日期，不代表论文的发表时间）
