 Subjects: Fifty males and females between the ages of 18 - 35 will be recruited to participate in this study. Subject will be randomized to one of three groups: a control group CTL, an HIIT only group HIIT or a group which will take the amino acid metabolite HMB and perform HIIT HMB-HIIT. Individuals assigned to CTL will undergo baseline testing. They will then be asked to continue their normal exercise routine for 4 weeks and will undergo post-testing after this time period. 