Determination of the contractility of children's bladders from isometric contractions

A new method of determining the contractility of the urinary bladder was applied to children. The method consists in the calculation of the force-velocity relation of the detrusor muscle from isometric contractions. These were measured by urodynamic equipment connected to a remote computer via a telephone line. The resulting force and velocity parameters are satisfactorily reproducible. The velocity parameter is comparable to that given by the stop test, a more direct but in practice more complicated method of assessing contractility. We found that boys' bladders can generate more force and higher contraction velocities than girls', and confirmed that obstructed bladders can generate more force than unobstructed ones. Some differences in the parameters found in enuretic children, and between stable and unstable bladders, are also discussed.