The aim of this study was to use bone-anchored markers to determine the bone movement of calcaneal adduction, eversion and tibial rotation in a global coordinate system and to describe the relationship of calcaneal adduction to tibial rotation. Furthermore, the amount of overall intra-foot motion in the transverse plane (metatarsal I relative to calcaneus) and its relationship to calcaneal adduction were quantified. Three male participants were assessed during slow running. A 10-camera motion analysis system was used for kinematic data capture of global bone orientations in 3D space for all bones of the foot and ankle complex. For the description of intrinsic articulations within the foot, the skeletal motion relative to the adjacent proximal segment in the transverse plane was calculated. Furthermore, the time of occurrence of maximum values was determined. The findings showed that calcaneal adduction of all participants amounted to 7.8 ± 4.8°, which exceeded the magnitude of calcaneal eversion (4.7 ± 3.1°). Although the inter-participant variability was high, considerable overall intra-foot motion in the transverse plane of the metatarsal I relative to the calcaneus was found to be 4.7 ± 4.6° and could be qualitatively related to calcaneal adduction. The present data provide evidence that next to calcaneal eversion, calcaneal adduction seems related to tibial rotation. Furthermore, overall intra-foot motion in the transverse plane seems related to calcaneal adduction. Controlling calcaneal adduction and overall intra-foot motion in the transverse plane may be a mechanism to control excessive tibial rotation in runners who suffer from overuse knee injuries. These findings could be used to provide an additional approach for future motion-control footwear design to control rearfoot adduction or overall within-foot motion.
An increase in training intensity and the number of active participants and competitors in figure skating has been accompanied by an increasing frequency of injuries. The aim of this study was to investigate whether different brands of skates as well as the usage of the skates modify the kinetics and kinematics of the landing impact from a jump. New Graf Edmonton (NG), old used Graf Edmonton (OG) and new Edea Concerto (NE) skates were compared. Twelve participants completed six jump trials from 30 cm and 50 cm high boxes, respectively in all three skates and landed on a section of artificial ice placed on a laboratory floor. Landing kinematics (Oqus4 system, Qualisys, Sweden) and kinetics (force plate: Kistler, Switzerland; insoles: Pedar, Novel, Germany) were examined. Each participant acted as their own control for statistical comparison between the skates. The results confirmed that the kinetics and kinematics of the landing are affected by wearing different skates. During landing impacts in NG, participants had significantly greater dorsiflexion at initial contact (IC) and peak dorsiflexion of the ankle, peak flexion of the knee and also greater in-skate plantar forces (PF) than in NE, which may increase the risk of injury. In OG, participants had significantly greater peak flexion of knee and longer time from IC to first peak dorsiflexion (TP) of the ankle than in NG. The differences observed may be due to the different construction designs, such as height of the heel, used materials, and stiffness of the skates, which may affect injury occurrence.
Current frameworks on running-related injury (RRI) aetiology emphasise the relation between exposure to training load, internal tissue loads, and tissue capacity; with tissue load exceeding its capacity being the key biological mechanism in the development of RRI. Despite this, runners and clinicians commonly attribute improper prescription of running shoes as a primary causative factor for RRI. A likely contributor to this belief may be the marketing produced by the footwear industry, which often is not supported by scientific evidence. The purpose of this study was to examine the beliefs of running shoe salespersons and physiotherapy students regarding the influence of running shoes and foot pronation on RRI. A questionnaire was distributed to 275 physiotherapy students at three different Swedish universities and to 219 running shoe salespersons of 35 different running shoe stores. A total of 270 students and 89 salespersons responded to the questionnaire. Salespersons rated their knowledge of running shoes (r = ?0.56), foot pronation (r = ?0.55) and RRI (r = ?0.34) higher than students did (p < .001). A minority of students (32.4%) and salespersons (14.1%) reported training errors to be the main contributing cause of RRI. A majority of salespersons (52.5%), but not students (15.3%), reported more expensive shoes to be better at preventing RRI than cheaper shoes. Most salespersons (51.9%), but not students (39.0%), would recommend uninjured runners to change their current running shoe type despite runners being satisfied with their current shoes. Despite salespersons being more confident in their knowledge of running shoes and foot pronation with relation to RRI development than students, both populations hold beliefs that do not align well with current frameworks on RRI aetiology.