AbstractThe aim of the study is to identify the effects of Mobile Altitude Device on Cardiopulmonary and Metabolic function during High Intensity Interval Training among Trained Soccer Players.A quantitative true experimental research design was selected to answer six objective and hypothesis.There parameters were tested in the study,Maximal Oxygen Consumption(VO_ max),Haemoglobin level (HB) and Heart Rate Variability (HRV).Thirty (n=30) trained soccer players were chosen as a sample by using non-random convenience sampling.Data analysis using one-way ANOVA series using the software programme Statistical Package for the Social Sciences (SPSS).The result showed a significant difference in the effect of HIIT on VO2 max (P- 0.003) and HRV(P-0.009) in the pre-test and post-test Trained Soccer Players,with no significant difference in the effect on HB (P-0.157).Furthermore,this study found that there is a significant effect of HIIT using MAD on cardiopulmonary and metabolic function among Trained S.....