This data set was collected to assess the effect of ingesting of 30 g protein provided as quark on muscle protein synthesis rates at rest and during recovery from exercise in young and older males. In this parallel-group intervention trial, 14 young (18-35 y) and 15 older (65-85 y) males ingested 30 g protein provided as quark following a single-legged bout of resistance-type exercise on leg press and leg extension machines. Primed, continuous intravenous L-[ring-13C6]-phenylalanine infusions were combined with the collection of blood and muscle tissue samples to assess postabsorptive and 4-h postprandial muscle protein synthesis rates at rest and during recovery from exercise. Outcomes included baseline characteristics, body composition assessed with DEXA scan, plasma glucose/insulin/amino acid concentrations measured at frequent intervals before and after the nutrinial intervention, and measurements of postabsorptive (basal) and postprandial muscle protein synthesis rates both at rest and during recovery from exercise.