www.englishpractice.com/improve/omission-articles-cases-articles/
The articles are not used:
In certain phrases made up of a preposition + noun:
Examples are: on foot, at school, from top to bottom, at home, in bed, by train, by car, in debt, in hand, on earth, at noon, on board, in jest, at best, at worst etc.
артикля здесь вообще не надо. а когда с запятыми беда, но выступить сильно хочется - лучше идти кататься)
tazhate