Write a question from the passage such that it identifies a character (a person or a thing) in the passage.

For active people, regular training is as important part of maintaining and increasing fitness. About the only real downside to regular exercise is the transient toll it takes on the body after a hard training session. The pain and soreness after training needs sufficient time to recover from before another hard session can be performed.
A very plausible theory pushed for many years is that the post-exercise oxidative stress in the body is the primary cause of the muscle damage and fatigue experienced. If you could reduce this oxidative stress, then it would allow quicker recovery, and then more time spent training. What this theory ignores though is that oxidative damage is a natural part of how the body adapts to stressful exercise, allowing the body to repair and grow stronger to allow higher levels of performance in the future.
A small scale study has previously found that trained and untrained individuals who dose up on antioxidant supplements impair important exercise training adaptations such as improved insulin sensitivity and production of oxidative stress defence proteins. Now researchers have extended this study by looking at the effect of antioxidants in trained female runners, and published their findings in the European Journal of Sports Science.
Twenty-three well trained female runners took part in three separate 3-week training blocks where they took either 1 gram of vitamin C, blackcurrant juice, or a placebo drink for each of the training blocks. Each of the dietary interventions involved drinking a similar volume of fruit drink of a total of half a litre per day split over the morning and evening.
The training performance of each runner was carefully measured at the beginning and end of each 3-week treatment period. The runners stuck to a set training schedule which allowed a more accurate assessment of any changes in performance over the training period.
Who had different drinks for a training study?