Methods for improving physical exercise performance

A method of increasing blood lactate concentration during physical exercise in a human subject, comprising orally administering to the human subject, less than six hours before the exercise, a composition comprising an effective amount of (i) sulforaphane, (ii) glucoraphanin and myrosinase, (iii) sulforaphane and myrosinase, or (iv) sulforaphane, glucoraphanin and myrosinase, with the proviso that when the composition comprises glucoraphanin it further comprises myrosinase;

• wherein, at a matched workload, the human subject's blood lactate concentration is higher relative to when the same human subject performs the exercise without having been administered the composition.