Preparatory co-activation of the ankle muscles may prevent ankle inversion injuries

Abstract

Ankle inversion sprains are the most frequent acute musculoskeletal injuries occurring in physical activity. Interventions that retrain muscle coordination have helped rehabilitate injured ankles, but it is unclear which muscle coordination strategies, if any, can prevent ankle sprains. The purpose of this study was to determine whether coordinated activity of the ankle muscles could prevent excessive ankle inversion during a simulated landing on a 30-degree incline. We used a set of musculoskeletal simulations to evaluate the efficacy of two strategies for coordinating the ankle evertor and invertor muscles during simulated landing scenarios: planned co-activation and stretch reflex activation with physiologic latency (60-millisecond delay). A full-body musculoskeletal model of landing was used to generate simulations of a subject dropping onto an inclined surface with each coordination condition. Within each condition, the intensity of evertor and invertor co-activity or stretch reflexes were varied systematically. The simulations revealed that strong preparatory co-activation of the ankle evertors and invertors prior to ground contact prevented ankle inversion from exceeding injury thresholds by rapidly generating eversion moments after initial contact. Conversely, stretch reflexes were too slow to generate eversion moments before the simulations reached the threshold for inversion injury. These results suggest that training interventions to protect the ankle should focus on stiffening the ankle with muscle co-activation prior to landing. The musculoskeletal models, controllers, software, and simulation results are freely available online at http://simtk.org/home/ankle-sprains, enabling others to reproduce the results and explore new injury scenarios and interventions.

Number of Segments Within Musculoskeletal Foot Models Influences Ankle Kinematics and Strains of Ligaments and Muscles

“…It should still be noted, however, that in each case the 2MFM overestimated ligament strains compared to the other models, which may lead to erroneous conclusions about the risk of ligamentous injury based on choice of MFM. Although risks of ankle ligament injury were investigated by a number of studies in the literature, many studies simply estimate injury risk indirectly from assessment of ankle joint kinematics, such as the subtalar joint angle with a threshold angle such as 30° inversion . Given that ankle ligament strains are affected by sagittal and frontal plane motions, musculoskeletal modeling provides a more direct estimation of ligament strains than estimation from subtalar joint kinematics in only one plane of motion.…”

“…Although risks of ankle ligament injury were investigated by a number of studies in the literature, many studies simply estimate injury risk indirectly from assessment of ankle joint kinematics, such as the subtalar joint angle with a threshold angle such as 30°inversion. 39 Given that ankle ligament strains are affected by sagittal and frontal plane motions, musculoskeletal modeling provides a more direct estimation of ligament strains than estimation from subtalar joint kinematics in only one plane of motion. The current findings about the effects of the number of foot segments in MFM on ligament strains of the ATFL and CTL imply that the decision about the number of segments in MFMs impacts not only the simple ankle kinematics but also composite ankle ligament strains.…”

The Difference Between Countermovement and Squat Jump Performances: A Review of Underlying Mechanisms With Practical Applications

“…Specifically, the athlete does not have time to perform a large countermovement when there is timepressure, and pretension is therefore the only effective solution to minimize muscle slack and to successfully complete the movement under time-pressure. Unstable loads and surfaces may cause perturbations in the movement, and when there is very little time for correction of these perturbations, reflexes may be too slow, and pretension is then the only adequate solution to minimize these perturbations because of the preflex effect (21,80). It should be therefore noted that unstable load and surface training is likely not effective when there is plenty of time to correct the perturbations such as during traditional balance training.…”

Fixed and mobile-bearing total ankle prostheses: Effect on tibial bone strain

“…We might indeed observe other stress and strain patterns for more complex loading. However, very few models are using more complex loading (Arnold et al 2010;Leardini et al 2014;Wang et al 2016;DeMers et al 2017), and the comparison with our results remains difficult since bone strain is rarely analyzed (Reggiani et al 2006;Jay Elliot et al 2014). Besides, since we had no information about the donor, we applied the same loading to all tibias, which is certainly not fully consistent with real life.…”