Half of the 2-hour practice is for running and weightlifting, so the time for running and weight lifting is 1/2 * 2 hours = <<2*1/2=1>>1 hour.
If the time he lifts weights is x, then the time he runs is 2x.
So the time for running and weight lifting is x + 2x = 3x = 1 hour
Thus 3x = 60 minutes
Thus x = 60/3 = <<60/3=20>>20 minutes spent weight lifting.
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