5′-UMP inhibited muscle atrophy due to detraining: a randomized, double-blinded, placebo-controlled, parallel-group comparative study

Purpose A short period of disuse of 1-2 weeks due to factors such as illness or injury can lead to muscle atrophy, affecting both athletic performance and health. Recent research has shown that uridine 5 '-monophosphate (5 '-UMP) can counteract disuse-induced muscle atrophy by increasing PGC-1 alpha expression and inhibiting atrogin-1 expression. However, the effect of 5 '-UMP on disuse muscle atrophy in humans remains unknown. Therefore, the aimed of this study was to explore the effects of 5 '-UMP supplementation during detraining on short-term disuse muscle atrophy in healthy men.Methods Following a 6-week resistance training program on upper arm, healthy men were randomized to either a UMP group (n = 11) or a placebo group (n = 10), taking their respective supplements during the 2-week detraining period. Muscle thickness, an indicator of muscle hypertrophy and atrophy, was measured at 3 positions (MT50, MT60, and MT70) at baseline, 1 week, and 2 weeks after detraining.Results Both groups showed a significant decrease in muscle thickness at MT70. The relative decrease was greater in the placebo group (2.4 +/- 2.8%) than in the UMP group (0.0 +/- 2.0%), significantly (p = 0.034) at 1 week. However, no significant difference was observed at MT50 and MT60.Conclusion After the hypertrophy, 5 '-UMP may prevent muscle atrophy due to the detraining within the first week.