Effects of the Etna uphill ultramarathon on energy cost and mechanics of running.

PURPOSE: To investigate the effects of an extreme uphill marathon on the mechanical parameters that are likely to affect the energy cost of running (Cr).

METHODS: Eleven runners (27-59 y) participated in the Etna SuperMarathon (43 km, 0-3063 m above sea level). Anthropometric characteristics, maximal explosive power of the lower limb (Pmax), and maximal oxygen uptake were determined before the competition. In addition, before and immediately after the race, Cr, contact (tc) and aerial (ta) times, step frequency (f), and running velocity were measured at constant self-selected speed. Then, peak vertical ground-reaction force (Fmax), vertical downward displacement of the center of mass (Δz), leg-length change (ΔL), and vertical (kvert) and leg (kleg) stiffness were calculated.

RESULTS: A direct relationship between Cr, measured before the race, and race time was shown (r=.61, P<.001). Cr increased significantly at the end of the race by 8.7%. Immediately after the race, the subjects showed significantly lower ta (-58.6%), f (-11.3%), Fmax (-17.6%), kvert (-45.6%), and kleg (-42.3%) and higher tc (+28.6%), Δz (+52.9%), and ΔL (+44.5%) than before the race. The increase of Cr was associated with a decrement in Fmax (r=-.45), kvert (r=-.44), and kleg (r=-.51). Finally, an inverse relationship between Pmax measured before the race and ΔCr during race was found (r=-.52).

CONCLUSIONS: Lower Cr was related with better performance, and athletes characterized by the greater Pmax showed lower increases in Cr during the race. This suggests that specific power training of the lower limbs may lead to better performance in ultraendurance running competition.