Influence of Curve Sharpness on Torsional Loading of the Tibia in Running

Abstract

The purpose of this study was to test quantitatively the hypothesis that, as runners run along a more sharply curved track, greater torsional moments act on their tibiae. Six male participants were asked to run along a straight track and along counterclockwise curved tracks with turn radii of 15 m (gentle) and 5 m (sharp) at 3.5 m s–1. Data were collected using two high-speed cameras and force platforms. Each participant’s left (corresponding to the inside of the curves) foot and tibia were modeled as a system of coupled rigid bodies. For analysis, net axial moments acting on both ends of the tibia were calculated using free-body analysis. The torsional moment acting on the tibia was determined from the quasi-equilibrium balance of the tibial axial moments based on the assumption that the rate of change of the angular momentum about the tibial axis was negligible. The results showed that the torsional moments, which were in the direction of external rotational loading of the proximal tibiae, increased as the track curvature became sharper. Furthermore, the mean value of the maximum torsional moments, while running on a sharply curved track (28.5 Nm), was significantly higher than the values obtained while running on a straight track (11.0 Nm, p < .01) and on a gently curved track (12.2 Nm, p < .01). In conclusion, the present study has quantitatively confirmed that as runners run along a more sharply curved track, greater torsional moments act on their tibiae. The findings imply that athletes prone to tibial running injuries such as stress fractures should avoid repetitive running on sharply curved paths.

The Impact of Circular Exercise Diameter on Bone and Joint Health of Juvenile Animals

“…The sharpness of a turn is also found to impact horses and human runners. A sharply curved track (5-m radius) leads to greater torsion on the inside tibia of humans, compared to running on a gently curved track (15-m) or straight line [ 9 ]. When running around a curve, the inside and outside limbs of human subjects are not biomechanically symmetrical.…”

Compensations for increased rotational inertia during human cutting turns

“…Performance depends on morphology, behavior and motor control (Aerts et al, 2003;Alexander, 2002;Carrier et al, 2001;Dial et al, 2008;Eilam, 1994;Jindrich et al, 2006;Jindrich and Full, 1999;Jindrich et al, 2007;Van Damme and van Dooren, 1999). For humans, turns alone comprise up to 50% of walking steps during daily living (Glaister et al, 2007), and can cause injuries directly by increasing the forces and moments experienced by the legs, and indirectly by decreasing stability and causing falls (Besier et al, 2001;Colby et al, 2000;Cross et al, 1989;Kawamoto et al, 2002;McLean et al, 2004;Stacoff et al, 1996). Maneuvering performance reflects dynamic interactions among mechanics, musculoskeletal physiology and motor control (Biewener and Daley, 2007;Dickinson et al, 2000;Full et al, 2002;Jindrich and Qiao, 2009).…”

Stress Fracture / Stress Reaction of the Lower Leg and Foot

“…Similarly, running on a sharply curved track has been shown to elevate tibial loads over running on a track with a more gentle curvature (Kawamoto et al 2002).…”