Multidirectional basketball activities load different regions of the tibia: A subject-specific muscle-driven finite element study

Abstract

The tibia is a common site for bone stress injuries, which are believed to develop from microdamage accumulation to repetitive sub-yield strains. There is a need to understand how the tibia is loaded in vivo to understand how bone stress injuries develop and design exercises to build a more robust bone. Here, we use subject-specific, muscle-driven, finite element simulations of 11 basketball players to calculate strain and strain rate distributions at the midshaft and distal tibia during six activities: walking, sprinting, lateral cut, jumping after landing, changing direction from forward-to-backward sprinting, and changing direction while side shuffling. Maximum compressive strains were at least double maximum tensile strains during the stance phase of all activities. Sprinting and lateral cut had the highest compressive (-2,862 ± 662 με and -2,697 ± 495 με, respectively) and tensile (973 ± 208 με and 942 ± 223 με, respectively) strains. These activities also had the highest strains rates (peak compressive strain rate = 64,602 ± 19,068 με/s and 37,961 ± 14,210 με/s, respectively). Compressive strains principally occurred in the posterior tibia for all activities; however, tensile strain location varied. Activities involving a change in direction increased tensile loads in the anterior tibia. These observations may guide preventative and management strategies for tibial bone stress injuries. In terms of prevention, the strain distributions suggest individuals should perform activities involving changes in direction during growth to adapt different parts of the tibia and develop a more fatigue resistant bone. In terms of management, the greater strain and strain rates during sprinting than jumping suggests jumping activities may be commenced earlier than full pace running. The greater anterior tensile strains during changes in direction suggest introduction of these types of activities should be delayed during recovery from an anterior tibial bone stress injury, which have a high-risk of healing complications.

Keywords: Bone; Exercise; Physical activity; Running; Stress fracture.

Figure 1:

Diagrammatic representation of the experimental procedures. A) Biomechanics data of college-level basketball players (n=11) performing different activities were collected along with CT images of the lower limbs. B) Data were used to create muscle-driven FE models to investigate loading at the mid-tibia and distal tibia. Nodal surfaces (shown in red) were defined for each muscle insertion area over which muscle forces were distributed. C) For each task, the maximum and minimum principal strains during the stance phase were calculated per subject and D) used to analyze the spatial distribution of the principal strains between activities.

Figure 2:

(A) Maximum tensile (upper images and graphs) and compressive (lower images and graphs) strains at the mid-tibia during the stance phase of each activity. Bounds represent distribution across all subjects and vertical line indicates time of maximum strain. Inset figures of the tibial cross-sections show the distributions of strain at the time of maximum strain during stance. (B) Regions of significantly increased strain relative to Walk.

Figure 3:

Maximum tensile (upper images and graphs) and compressive (lower images and graphs) strain rates at the mid-tibia during the stance phase of each activity. Bounds represent distribution across all subjects and vertical line indicates time of maximum strain rate. Inset figures of the tibial cross-sections show the distributions of strain rates at the time of maximum strain rate during stance.