<prompt> Isocapnic exercise is -Breathing for short duration against resistanceBreathing of decreased volume of ventilationBreathing of increased volume of ventilation for long periodBreathing of decreased volume for long period  <response>: Ans. is c i.e.. Breathing of increased volume of ventilation for long period o Specific training of respiratory muscles is generally carried out in one of two ways -Isocapnic hyperpnoea isocapnic exerciseIt requires the individual to breath at an increased volume of ventilation for an extended period.It primarily helps to develop respiratory muscle endurance.Threshold loadingIt requires the individual to breath for short durations against a resistance.It focuses on building respiratory muscles strength. 