Skyscraper running

Running uphill on steep stairs is a sport that has recently become an interesting activity for physiologists/biomechanists. This is due to the apparently simple mechanical paradigm of locomotion (no elastic contribution, only positive external work to lift the body centre of mass) and the consequent possibility to ‘easily’ link energetics to mechanics. We recently reviewed races occurred in many skyscrapers around the globe and measured a group of athletes during a competition on the Pirelli building in Milano. We noticed that the vertical speed showed a sudden drop at a given altitude, different for each subject. The phenomenon can be speculatively explained by some fatigue of upper limbs, the additional engine to propel by pushing on handrails. Another potential explanation is related to biochemical factors deriving from anaerobic metabolism affecting aerobic pathways. The analysis of other records on skyscrapers showed a relationship between the (minimum) mechanical power and the event duration qualitatively resembling the equation proposed by Wilkie about the maximum mechanical power provided as a function of time. The vertical distance between the two curves is likely to be due by: the internal mechanical work of locomotion (which can be different depending on the speed and stride frequency adopted), and by the use of upper limbs to assist propulsion. These topics will be discussed during the presentation.