evidence:  outcome
  Significantly more patients treated with hydrotherapy (40/46, 87%) felt much better or very much better than the patients treated with land exercise (19/40, 47.5%), p < 0.001 Fisher's exact test
intervention: receive a weekly 30-minute session of hydrotherapy for 6 weeks
comparator: similar exercises on land for 6 weeks
outcome: Ten-metre walk time