One hundred marathons in 100 days: Unique biomechanical signature and the evolution of force characteristics and bone density
Authors: Bastiaan Breine
Dirk De Clercq
Ella Haeck
Pieter Van den Berghe
Journal: Journal of Sport and Health Science (2021)
Discipline: CLINICAL MEDICINE
Keywords: Bone; Gait analysis; Ground reaction force; Load; Running.
Affiliations: Department of Movement and Sports Sciences, Ghent University, Ghent 9000, Belgium. Electronic address: ., Department of Movement and Sports Sciences, Ghent University, Ghent 9000, Belgium.

Abstract:  Background: An extraordinary long-term running performance may benefit from low dynamic loads and a high load-bearing tolerance. An extraordinary runner (age = 55 years, height = 1.81 m, mass = 92 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. Methods: Overground 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. Results: The case's peak vertical loading rate (Δx̄ = -61.9 body weight (BW)/s or -57%), peak vertical ground reaction force (Δx̄ = -0.38 BW or -15%), and peak braking force (Δx̄ = -0.118 BW or -31%) were remarkably lower (p &lt; 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 = -9.16 watt/kg or -48%) and ankle generation (Δx̄ = -3.17 watt/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. Conclusion: The remarkable pattern of the high-mileage runner may be useful in developing or evaluating load-shifting strategies in distance running. 

Retracted: No

PubPeer comments:
 ABSTRACT Background: An extraordinary long-term running performance may benefit from low dynamic loads and a high load-bearing tolerance. An extraordinary runner (ageu202f=u202f55 years, heightu202f=u202f1.81 m, massu202f=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. Methods: Overground 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. Results: The case s peak vertical loading rate (u0394xu0304u202f=u202fu201361.9 BW s or u201357%), peak vertical ground reaction force (u0394xu0304u202f=u202fu20130.38 BW or u201315%), and peak braking force (u0394xu0304u202f=u202fu20130.118 BW or u201331%) were remarkably lower (p 0.05) than the control group at u223c3.3 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 (29.5u00b0) 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 (u0394xu0304u202f=u202fu20139.16 W kg or u201348%) and ankle generation (u0394xu0304u202f=u202fu20133.17 W kg or u201330%). The bone mineral density increased to 1.245 g cmu00b2 (+2.98%) near completion of the challenge, whereas the force characteristics showed no statistically significant change. Conclusion: The remarkable pattern of the high-mileage runner may be useful in developing or evaluating load-shifting strategies in distance running. Questions and comments are welcome. PVdB ,