RESUMO
Purpose of the study: The effect of free loaded and after loaded condition in mammalian skeletal musclecontraction can be studied using an in-situ nerve-muscle preparation in rat. The experimental setup mimicsthe physiological conditions very closely unlike the classical in vitro frog nerve-muscle preparation andhence could be considered as an effective practical module to demonstrate the work done in a skeletalmuscle in both free loaded and after loaded condition.Methodology: A simple, feasible and novel practical is designed in which muscle twitch is recorded in anin-situ nerve-muscle preparation of an anaesthetized rat under free loaded and after loaded condition atdifferent weights using an isotonic transducer. Work done was calculated under free loaded and after loadedcondition and compared.Main finding: Difference was observed with respect to displacement and work done during free loaded andafter loaded condition. Work done was higher in free loaded condition.Conclusion: We propose a simple and novel practical to demonstrate the effect of free loaded and afterloaded condition in muscle twitch for undergraduate teaching in physiology.