Muscle recovery is one of the most critical factors in endurance sports, and nutrition plays a massive role. Specifically, food within the first 1-4 hours after training is crucial.

Post-exercise carbohydrate and protein consumption are critical, and carbohydrate fueling strategies are nothing new. During exercise, carbohydrates provide energy to fuel movements and cellular processes. They’re so essential because they burn up so quickly that athletes don’t have enough fuel to run, cycle, swim, or do anything else.

This study aimed to assess how carbohydrates alone or carbohydrate and protein supplementation affect endurance capacity and muscle damage.

This study was designed to determine which formulation strategies were most effective in improving the performance of a small cohort of runners (carbohydrate-only or carbohydrate-plus-protein).

The average endurance athlete spends hours doing a continuous activity, whether running 40-60 miles a week, cycling 150 miles a week, or swimming hundreds of laps. The sheer volume of training, combined with a few resistance-training sessions a week, means endurance athletes must carefully pay attention to their diet and supplementation.

It takes a great deal of time to train for endurance activities and to prepare and eat nutrient-dense foods to replenish energy. If that wasn’t enough, you quickly run out of hours in the day as you prepare and eat nutrient-dense foods to replenish energy.

The purpose of endurance runners’ supplementation is to improve exercise performance and promote post-exercise muscle recovery. Several studies have found that consuming carbohydrates and proteins after exercise improves performance better than carbohydrates alone. 

Ten recreationally active male runners (VO2max: 53.61 ± 3.86 ml/kg·min) completed the run-to-exhaustion test three times with different intakes of intervention drinks. Each trial started with 60 minutes of running at 70% VO2max (phase 1), followed by an endurance capacity test: time-to-exhaustion running at 80% VO2max (phase 2). 

All subjects ingested carbohydrate (CHO) 1.2 g/kg BM during phase 1, and blood samples were obtained before, immediately, and 24 h after exercise for measurements of alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatine kinase (CK), and myoglobin (MB).

The protein was whey protein isolate, and the carbohydrate was maltodextrin. Protein was supplied at 1.2 grams per kilogram of body weight, while carbs came in at 0.4 grams per kilogram.

Each participant consumed one of the supplement interventions 30 minutes before the test and warmed up with a treadmill run at 70% of their VO2 max for one hour. After taking the second supplement, they ran to exhaustion at 80% VO2 max for one hour. 

Additionally, they provided blood samples at baseline and after test completion, along with urine samples. There was a 7-day washout period between the tests.

Results of the Study

Researchers examined blood samples for alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatine kinase (CK), and myoglobin (MB), all of which are associated with muscle damage caused by exercise. In the time to exhaustion test, none of the interventions significantly affected the subjects’ endurance.

Researchers discovered that both approaches of adding protein – well before exercise or as an acute intervention during exercise – helped quell inflammation markers better than carbohydrates alone.

In summary, carbohydrate and protein supplementation can reduce muscle damage caused by endurance exercise, but they do not improve endurance exercise performance.

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