What impact does cycling have on reducing absenteeism and presenteeism, particularly in the context of workplace wellness initiatives, and are there any notable studies or case studies that demonstrate a correlation between increased cycling participation and improved employee attendance and productivity? How do factors such as bike-to-work schemes, on-site bike storage, and shower facilities influence employee cycling habits and subsequent absenteeism rates? Can cycling be effectively integrated into existing employee wellness programs, and what types of metrics or data would be most useful for evaluating the success of such initiatives?