Long-time strength athletes will be familiar with the old school approach to creatine use that begins with a loading phase of 20 grams a day for 5 days before switching to a 5 gram daily maintenance dose. Endurance athletes have been known to glycogen load with carbs in the lead up to a long-distance event. A study published in the journal Medicine & Science in Sports & Exercise looks at the effects of both techniques on muscle mass.
The body composition of 18 experience male cyclists was measured before and after loading with creatine and/or carbohydrates for 5 days. Glycogen loading with creatine resulted in an estimate of 3.1% greater leg muscle mass. The amount was 2.6% more mass with glycogen loading alone. After a glycogen-depleting exercise protocol, leg muscle mass decreased an average of 1.4%.