At 8.00 am, following an overnight fast, subjects will arrive at the laboratory by car or public transportation. Subject will rest in a supine position and a Teflon catheter will be inserted into an antecubital vein for intravenous stable isotope infusion. A second Teflon catheter will be inserted in a heated dorsal hand vein of the contralateral arm and placed in a hot-box (60C) for arterialized blood sampling. Following basal blood collection (8 mL; t=-210 min), the plasma phenylalanine, leucine, tyrosine pools will be primed with a single intravenous dose of tracers. Subsequently, a blood sample will be obtained (t=-200) and a continuous tracer infusion will commence. Arterialized blood samples (8 mL) will be drawn at t= -185, -170, -120, -60, -30 min and a muscle biopsy will be collected from the vastus lateralis muscle (t=-30 min). This muscle biopsy will allow us to determine basal muscle protein synthetic rates. Following the collection of the muscle biopsy, subjects will perform knee extension exercise on a guided-motion exercise machine for 4 sets at a load they can lift for 10 - 12 repetitions. Subjects will be allowed to rest 2 minutes in between each exercise set and the load will be adjusted to maintain the desired 10-12 repetitions. Immediately after the exercise bout subjects will return to the resting supine position and arterialized blood sample will be drawn. Afterwards, a muscle biopsy will be collected (t= -5 min) from the opposite leg of the muscle biopsy obtained at t= -30. Subjects will then receive a minced beef meal containing 35 g of protein or an equivalent protein dose provided as dairy milk (t= 0). Arterialized blood samples (8 ml) will be collected at t= 15, 30, 45, 60, 90 and 120 min during the postprandial (fed) period. The third muscle biopsy will be taken from the same leg as the last biopsy and from the same incision. Subsequently, arterialized blood samples (8 ml) will be collected at t=150, 180, 210, 240, 270, 300 min. Finally, at 300 min a fourth muscle biopsy will be taken from the same incision as the last biopsies (t= -0.5 and 120 min). In total, four muscle biopsies will be taken through two separate incisions during each trial. The second and third muscle biopsy (immediately after and 2 h after exercise) will allow us to measure temporal muscle protein synthetic responses between the different consumed protein sources (milk vs. meat) after exercise. It is generally assumed that 'peak' stimulation of muscle protein synthesis rates is more meaningful in predicting phenotypic outcomes (muscle hypertrophy). However, peak muscle protein synthesis rates may appear at different time points depending on the protein source consumed. Obtaining a muscle biopsy at 2 h post-exercise will allow us to determine peak muscle protein synthesis rates between the different consumed protein sources. However, resistance exercise-induced muscle protein synthesis rates can extend beyond this 2 h time point and thus obtaining an fourth muscle biopsy at 5 h will also allow us to obtain physiological relevant information with regards to the anabolic response of resistance exercise.