Protein supplementation after exercise may reduce the time required to recover glycogen stores (Ivy, 2002 2). Intact proteins, however, often have a slow stomach passage, and protein hydrolysates have a very bad taste. Using specific enzymes, a casein hydrolysate (PeptoPro) was produced having a good taste, and containing peptides that are readily absorbed. The objective of present study was to compare the effect of a carbohydrate drink, additionally or not containing PeptoPro, on post-recovery performance in well-trained male volunteers. Study Design In a randomized, double-blind, cross over designed experiment, 12 well trained athletes participated in 2 experimental trials in which a carbohydrate rich drink (CHO) or a carbohydrate rich drink + PeptoPro (CHO + PRO) was tested. The tests were separated by at least 2 weeks. After an overnight fast (8 hours) subjects reported to the laboratory. The study comprised three united phases. Phase 1 – Glycogen depletion To induce muscular glycogen depletion the athletes underwent an “all out” interval protocol until exertion. Phase 2 – Glycogen repletion period (recovery phase) During 5 hours, athletes were in supine rest. In this period, they consumed 350 ml of the test drink each 30, starting at t = , and were blood samples taken ever 15. Phase 3 – Time trial At the end of the repletion period a time trial was performed as performance outcome parameter. This time trial consists of 20 minutes of cycling at the highest speed possible. Results Eleven athletes completed the time trial. Their performance was 5% higher after ingestion of PeptoPro drink (P=0.14) then after consuming the CHO-drink. When results of one athlete, showing a very large difference between test periods, was excluded the effect was 2.3% (P=0.21; Figure 1) Conclusions Post-recovery performance in a 20-minutes time trial was 2.1% higher after consuming the PeptoPro containing CHO+PRO drink, than after consuming the CHO-drink. 1 This experiment was performed in 2003 at the Masstricht University, Department of Movement Sciences, by Eric van Breda, HanzKeizer (Nutrim University) of Masstricht. 2. Ivy, J.L, H.W. Goforth, B.M. Damon, T.R. McCauley, E.C. Parstons and T.B. Price, 2002. Early postexercise muscle glycogen recovery is enhanced with a carbohydrate-protein supplement. J. Appl Physiol 93: 1337-1344 <