Among adult skeletal muscles, AMPD1 is expressed at high levels and produces the myoadenylate deaminase isoform M. People with the rs17602729 mutation have extremely low AMPD1 activities, those with one normal allele and one mutant allele have intermediate AMPD1 activities, and those with two normal alleles have high AMPD1 activities. Performance during sprints/strength exercises may be adversely affected by AMPD1 deficiency.