Compared Effect of a Fruit Milk Shake With a Protein-Carbohydrate Supplement on Recovery After Resistance Exercise

The aim of this study is to assess the effect of ingesting a commercial carbohydrate and protein dietary supplement in powder form (P-CHO supplement) or a milk shake with skimmed milk, strawberries and banana (MS), after resistance exercise, in muscle damage, oxidative stress, inflammation and functional recovery. It is hypothesised if the ingestion of a milk shake with skimmed milk and fruit (strawberry and banana) has the same impact on markers of muscle damage, oxidative stress, inflammation and functional recovery induced by resistance exercise, as the intake of a commercial powder with the same CHO and protein amounts. Fifteen adult athletes from the Portuguese Athletic Federation will complete 2 trials separated at least by 2 weeks. Alternate legs and drinks will be used in each trial and participants will be overnight-fasted. This study will have a single-blind, randomized, crossover, repeated-measures experimental design. In each trial, after warm-up, the eccentric peak torque of the knee joint extensors will be determined using an isokinetic dynamometer. After this, participants will complete an isokinetic exercise until exhaustion at a constant angular velocity of 60° • s-1. After the exhaustion protocol, athletes will perform again the peak torque determination. Immediately after, participants will drink the P-CHO supplement or MS during the first 2 h. Both drinks will contain 0.8-1.2 g carbohydrates • kg-1 • h-1 and 0.2-0.4 g protein • kg-1 • h-1. Twenty four and 48 h after the exhaustion protocol participants will return to the laboratory to repeat the peak torque determination. Blood samples will be collected before warming-up, immediately and 2 h after the last peak torque determination and 24 h and 48 h after. Serum samples will be analyzed for creatine kinase, lactate dehydrogenase, interleukine-6, protein carbonyls and total antioxidant status. The delayed onset muscle soreness, using a visual analogue scale, and girths will be measured at the sam