Subjects
Eight well-trained male tennis players volunteered to par- ticipate in this study (age 26.0 ± 5.7 years; height 1.84 ± 0.70 m; body mass 82 ± 11 kg). The major inclusion criteria were as follows: men aged 18 – 35 years with a body mass index ≥ 18.5 kg.m−2 and < 26 kg.m−2, nonsmoking or con- suming less than 5 cigarettes per day, reporting a moderate caffeine intake (1–2 cups of coffee or equivalent per day), stable weight for at least one month before the beginning of the study, training at least twice a week, being involved in tennis-based training for at least three months prior to the beginning of the study, and figuring in the regional ranking tables drawn up by French Tennis Federation. Fur- thermore, participants also needed to have stable eating patterns during the month preceding the beginning of the protocol and had to agree to maintain these dietary habits throughout the study. Principal exclusion criteria included high-level sporting activities other than tennis and those necessary for their training, injury during the three months prior to the beginning of the study, diabetes, whether treated or detected at the inclusion visit, vegetarians and vegans, subjects with extreme eating habits and/or with a significant history of anorexia nervosa, bulimia or other eating disorders, a history of diseases that could disrupt our tests or subjects taking diuretics or other medications that we felt might interfere with our tests, and subjects consuming more than two alcoholic beverages per day (every day). Each candidate selected was fully informed of the purpose and risks associated with the procedures, and their written informed consent was obtained.