Purpose: The aim of this research was the effect of 4 weeks of interval training and Inspiratory Muscle Training (IMT) on the initial recovery of respiratory muscle strength in inactive people. Method: This research was semi-experimental. The statistical sample of this research consisted of 30 healthy and inactive students of Shahrood University of Technology with an average age of 30±10 years. Subjects were randomly divided into 3 groups (IMT, Interval and Sham exercises). The parametric test of one-way analysis of variance with repeated measurement and dependent t-test with 95% confidence was used with SPSS 26 softwar. Results: Inspiratory muscle strength showed a significant increase in IMT and interval training groups (P<0.05). Also, the time to return to the initial state of respiratory muscle strength decreased significantly in all three groups (P>0.05), the largest decrease was related to the IMT and sham exercise groups, and the interval exercise group experienced a smaller decrease than the other two groups. Conclusions: It seems that IMT training is more effective than interval training in increasing the strength of respiratory muscles and improving the return to the initial state of the strength of these muscles.