Abstract
The movement patterns produced during a basketball game result in frequent acceleration followed by almost immediate deceleration. Therefore, players require strategies to attenuate the muscle damage which occurs from the mechanical and metabolic stress of having to continually overcome inertia. Strategies which could reduce such stressors during exercise could have a positive influence on performance towards the end of exercise and improve post-exercise recovery in preparation for the next exercise bout. One such strategy which has recently gained interest is a preventative approach; pre-exercise protein and carbohydrate (PRO/CHO) co-ingestion. Combining protein and carbohydrate intake pre-exercise has been found to inhibit muscle protein degradation during and following exercise, however, very few studies have shown any improvement in performance. Previous studies have administered meals several times throughout study protocols, and therefore exactly where the benefits of PRO/CHO co-ingestion have occurred cannot be pinpointed.
The present study aimed to add to the scientific knowledge surrounding PRO/CHO co-ingestion by isolating ingestion to pre-exercise only, and uniquely using a sport-specific exercise protocol to simulate basketball game play. Ten well-trained male basketball players volunteered to participate in this randomised, cross-over study. Participants consumed either 2g carbohydrate/kg bm (CHO), or 1g protein/kg bm with 1g carbohydrate/kg bm (PRO/CHO) 90 minutes before completing a standardised warm-up immediately followed by an 87-minute exercise protocol. This protocol consisted of circuits of the Basketball Exercise Simulation Test (BEST), free throws, suicide runs and rest periods structured to represent a full basketball game. Blood, saliva and urine samples were collected at baseline, post-exercise and at 24-hours post-baseline. Performance measures were taken throughout the exercise protocol and questionnaires inquiring about gastrointestinal (GI) symptoms, muscle soreness (MS) and ratings of perceived exertion (RPE) were completed at baseline, pre-exercise, half-time, post-exercise and 24-hours post-baseline.
Following PRO/CHO co-ingestion, the increase in creatine kinase (CK) concentration from baseline to post-exercise was attenuated compared to CHO (p=0.018). Blood glucose concentration was also higher during and post-exercise with PRO/CHO compared to CHO (p<0.05 for both time points), and free throw shooting accuracy increased in the fourth quarter following the PRO/CHO meal (p=0.027). A tendency for faster sprint times in the final quarter was also found during the PRO/CHO trial (p=0.093). However, an increase in nausea during (p=0.007) and post-(p=0.039) exercise was found following PRO/CHO co-ingestion, as well as an increase in cortisol post-exercise (p=0.038) and RPE in the final quarter (p=0.017).
In conclusion, PRO/CHO co-ingestion attenuated the rise in creatine kinase, suggestive of a decrease in muscle damage during basketball-specific exercise compared to CHO alone. The higher blood glucose concentration throughout exercise following the PRO/CHO meal could explain the maintenance of shooting accuracy in the final quarter. It is likely that the increase in post-exercise cortisol was in response to the nausea participants were experiencing during the PRO/CHO trial. Therefore, although findings showed an attenuation of CK, unfamiliarity with the dosage of protein provided may have caused nausea to increase during exercise, and this may have limited the ability to see an improvement in more performance measures.