Relationship between duty factor and external forces in slow recreational runners

Abstract

ObjectivesRecreational runners show a large interindividual variation in spatiotemporal characteristics. This research focused on slow runners and intended: (1) to document the variance in duty factor (DF) between runners in a real-life running setting and (2) examine whether the interindividual variation in DF and stride frequency (SF) relates to differences in external loading parameters between runners.MethodsSpatiotemporal characteristics of 23 slow runners (ie, <2.6 m/s) were determined during a 5.2 km running event. To relate the interindividual variation in DF and SF to differences in external forces between runners (maximal vertical ground reaction force (FzMax), peak braking force (PBF) and vertical instantaneous loading rate (VILR)), 14 of them were invited to the lab. They ran at 1.9 m/s on a treadmill while ground reaction forces were recorded. A multiple linear regression analysis was conducted to investigate the effect of DF and SF on external force measures.ResultsDF between slow runners varied from 42.50% to 56.49% in a recreational running event. DF was found to be a significant predictor of FzMax (R²=0.755) and PBF (R²=0.430). SF only improved the model for PBF, but to a smaller extent than DF (R² change=0.191). For VILR, neither DF nor SF were significant predictors.ConclusionExternal forces are lower in recreational runners that run with higher DFs and slightly lower SFs. These findings may be important for injury prevention purposes, especially directed to recreational runners that are more prone to overuse injuries.

Examination of running pattern consistency across speeds

“…Indeed, DF and t f are related to the average vertical ground reaction force during t f (Beck et al, 2020) and effective vertical impulse during t f (Dorn et al, 2012), respectively. Both the average vertical ground reaction force during t f and effective vertical impulse during t f are proportional to the peak vertical ground reaction force, as supports the sine wave model of the vertical ground reaction force (Morin et al, 2005) and experimental data (Bonnaerens et al, 2021). The present study reported lower association between relative t c and DF values (correlations were moderate to high; Table 3 and Figure 4) than relative t c to DF values.…”

Effect of Running Exercise on Brain Functional Magnetic Resonance Characteristics of College Students with Depression

“…In recent years, it has received extensive attention as a nondrug antidepressant treatment. Studies have shown that running exercise 3 times a week for at least 8 weeks can achieve a therapeutic effect on patients with severe depression, and the intensity of the effect is about moderate to high; it was also found in animal experiments that running exercise can effectively improve the depression-like or anxiety-like behavior of experimental animals [ 4 ]. However, some people have put forward the opposite conclusion, they believe that running exercise has no antidepressant effect, and in the follow-up study of patients with depression, there is no significant improvement in the quality of life and disease severity of patients with depression [ 5 ].…”

Using statistical parametric mapping to assess the association of duty factor and step frequency on running kinetic

“…In addition, SF was shown to be more variable in novice than expert runners, independently of the running speed (10 and 15 km/h) (Fadillioglu et al, 2022). Furthermore, Bonnaerens et al (2021) demonstrated that external forces were lower in recreational runners that run with higher DF and SF values (although non-significant for SF).…”