Residual force enhancement and depression of human single muscle fibres

Residual force depression (rFD) and residual force enhancement (rFE) are intrinsic contractile properties of skeletal muscle. To date, there have been no investigations of rFD and rFE in human fibres. Thus, the purpose of this study was to determine whether rFD and rFE occur at the single muscle fibre level in humans. Isometric steady-state force was lower following active shortening and higher following active lengthening, as compared to the reference isometric contractions (ISO). We demonstrated rFD and rFE in human single fibres which is consistent with previous animal models.