According to the RBE research, a muscular adaptation may occur as early as 24 after the initial bout. These observations lead to the exclusion of two theories; the connective tissue theory and cellular adaptation theory (Morgan’s sarcomeres popping theory). Both of these theories suggested the structural change in muscle as the onset of the RBE. But the time required for structural remodeling discredits these theories bcos RBE is observed within a time frame of 24 hours. The neural adaptation theory was excluded after observation of RBE with electrical stimulation. Likewise, the dissipation of RBE if it were for structural components would take much longer. I has been observed though that an reduction in tendon compliance to be occurring following training. The reaserchers doubt this to be due to the strengthening of the cross bridges. I wont disagree considering this theory.
Bryan believes that RBE is a structural phenomena , like the sarcolemma getting tougher. But as you can see the RBE is is observed with 24 hrs or maybe even less time. There is not enough time for structural adaptation to appear nor even if it appears to cause any significant change in muscle function. I am assuming the 24 hrs is enough for enzymatic changes to appaear and therby cause the RBE. Not sure though. Structural adaptations do happen, but that can be classified as a chronic adaptation. Muscle getting decondtioned in very litlle time compared to the time it takes to get conditioned shows that the changes are more chemical than mechanical.