One hundred marathons in 100 days: Unique biomechanical signature and the evolution of force characteristics and bone density.

Abstract

BACKGROUND\nAn extraordinary long-term running performance may benefit from low dynamic loads and a high load-bearing tolerance. An extraordinary runner (age\u202f=\u202f55 years, height\u202f=\u202f1.81 m, mass\u202f=\u202f92 kg) scheduled a marathon a day for 100 consecutive days. His running biomechanics and bone density were investigated to better understand successful long-term running in the master athlete.\n\n\nMETHODS\nOverground running gait analysis and bone densitometry were conducted before the marathon-a-day challenge and near its completion. The case s running biomechanics were compared pre-challenge to 31 runners who were matched by a similar foot strike pattern.\n\n\nRESULTS\nThe case s peak vertical loading rate (Δx̄\u202f=\u202f-61.9 BW/s or -57%), peak vertical ground reaction force (Δx̄\u202f=\u202f-0.38 BW or -15%), and peak braking force (Δx̄\u202f=\u202f-0.118 BW or -31%) were remarkably lower (p < 0.05) than the control group at ∼3.3 m/s. The relatively low loading-related magnitudes were attributed to a remarkably high duty factor (0.41) at the evaluated speed. The foot strike angle of the marathoner (29.5°) was greater than that of the control group, affecting the peak vertical loading rate. Muscle powers in the lower extremity were also remarkably low in the case vs. controls: peak power of knee absorption (Δx̄\u202f=\u202f-9.16 W/kg or -48%) and ankle generation (Δx̄\u202f=\u202f-3.17 W/kg or -30%). The bone mineral density increased to 1.245 g/cm² (+2.98%) near completion of the challenge, whereas the force characteristics showed no statistically significant change.\n\n\nCONCLUSION\nThe remarkable pattern of the high-mileage runner may be useful in developing or evaluating load-shifting strategies in distance running.