Acute effect of different minimalist shoes on foot strike pattern and kinematics in rearfoot strikers during running

Abstract

Despite the growing interest in minimalist shoes, no studies have compared the efficacy of different types of minimalist shoe models in reproducing barefoot running patterns and in eliciting biomechanical changes that make them differ from standard cushioned running shoes. The aim of this study was to investigate the acute effects of different footwear models, marketed as "minimalist" by their manufacturer, on running biomechanics. Six running shoes marketed as barefoot/ minimalist models, a standard cushioned shoe and the barefoot condition were tested. Foot-/shoe-ground pressure and three-dimensional lower limb kinematics were measured in experienced rearfoot strike runners while they were running at 3.33 m · s −1 on an instrumented treadmill. Physical and mechanical characteristics of shoes (mass, heel and forefoot sole thickness, shock absorption and flexibility) were measured with laboratory tests. There were significant changes in foot strike pattern (described by the strike index and foot contact angle) and spatio-temporal stride characteristics, whereas only some among the other selected kinematic parameters (i.e. knee angles and hip vertical displacement) changed accordingly. Different types of minimalist footwear models induced different changes. It appears that minimalist footwear with lower heel heights and minimal shock absorption is more effective in replicating barefoot running.

Redistribution of Mechanical Work at the Knee and Ankle Joints During Fast Running in Minimalist Shoes

“…They suggested that minimalist shoes with a smaller heelstack height (7À13 mm) were more likely to change running biomechanics than minimalist shoes with a greater stack height (22À26 mm) because the latter provides more protection for the heel and allows a more comfortable RF. 5 However, contrary to this finding, the minimalist shoes in our study had a heel-stack height of 22 mm and still caused runners to alter the strike index and ankle angle. Therefore, the effects of minimalist shoes on foot-strike pattern may not be explained solely by differences in heel-stack height.…”

“…Fourth, we investigated only 1 type of minimalist shoe. The shoe mass, heel drop, and stack height of the racing flat used in our study were equivalent to those of several other minimalist shoes ( 5 Nonetheless, racing flats have been used by runners for many years and can be considered representative of the running footwear used before the introduction of modern conventional running shoes. 11,17 Therefore, racing flats are well suited to investigations of minimalist footwear.…”

“…Differences across studies may have resulted from heterogeneity in minimalist footwear and participant training status. Indeed, in a recent study involving 6 different types of minimalist shoes, Squadrone et al 5 observed different effects on the strike index and ankle angle at initial contact across shoes. They suggested that minimalist shoes with a smaller heelstack height (7À13 mm) were more likely to change running biomechanics than minimalist shoes with a greater stack height (22À26 mm) because the latter provides more protection for the heel and allows a more comfortable RF.…”

“…Sample size was based on studies in which researchers 5,17 compared running biomechanics between minimalist and conventional shoes. We included only participants who were 18 to 40 years old, trained with conventional running shoes, were habitual RF runners (typical of 89% of runners), 18 had a weekly training distance of 15 km or more, and had no experience with running in minimalist shoes.…”

“…11 Results from a recent 5-km fun-run event showed that the upper 25th percentile of the 472 race finishers had average race speeds of 15 to 20 km/h. 14 These average speeds were faster than the running speeds used in most studies of minimalist shoes, [4][5][6][7]12,13 and at speeds greater than 15 km/ h, runners are more likely to run with a midfoot or forefoot foot strike, irrespective of the shoes worn. 15 Therefore, minimalist shoes may have reduced effects on running gait at faster speeds.…”