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Athletic footwear does not alter in-shoe hindfoot kinematics during overground running
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2013 ASICS Conference / Journal of Science and Medicine in Sport 16S (2013) e2–e38
7 Athletic footwear does not alter in-shoe hindfoot kinematics during overground running C. Bishop ∗ , J. Arnold University of South Australia, Australia Background: Heel counters are added to most athletic shoes under the premise that they control excessive hindfoot motion. However, it is often questioned whether this premise has any scientific evidence. Although previous studies have described hindfoot kinematics during running, they have often used external shoe markers to infer in-shoe foot motion which is not a valid technique. The aim of this study was to compare hindfoot kinematics during running both barefoot and in typical running shoes. We hypothesised that running shoes would not alter hindfoot eversion motion but would reduce the rate at which it occurs (angular velocity). Methodology: Eighteen adults participated in this study (mean age 21.2 ± 2.0 years, height 1.73 ± 0.08 m, body mass 70.8 ± 8.3 kg). Each participant completed five running trials both barefoot and wearing shoes (Asics Gel-Pulse 3). Kinematic data were acquired with a 12 camera VICON MXF-20 motion capture system (Vicon Motion Systems Ltd., Oxford, UK) at 100 Hz. Variables of interest were the hindfoot eversion angle at initial contact and peak loading (15% stance), as well as the ROM and peak angular velocity during loading response (0–15% stance). Differences between conditions were compared using paired t-tests. Effect sizes (Cohen’s d) were also computed. Results: During running, footwear did not significantly reduce eversion of the hindfoot at initial contact (−7.59 ± 5.69∞ vs. −6.15 ± 5.59∞ , p = >.05, ES = 0.26) or peak loading (−13.91 ± 4.63∞ vs. −13.24 ± 6.15∞ , p = >.05, ES = 0.12), nor did it decrease the amount of eversion during loading response (6.88 ± 2.63∞ vs. 7.21 ± 1.99∞ , p = >.05, ES = 0.14). No difference in eversion angular velocity was identified between barefoot and shod running (−175.46 ± 100.52∞ /s vs. −151.73 ± 70.73∞ /s, p = >.05, ES = 0.27). Conclusion: In this study, footwear did not change hindfoot eversion at initial contact or peak loading, nor significantly reduce the amount of eversion or the peak eversion velocity occurring during loading. These results suggest hindfoot kinematics were not altered by the shoe used in this study. We found no evidence that design features in the heel (i.e. heel counter) provide motion control benefits (i.e. decrease hindfoot eversion) to the foot during stance phase of running. It is possible that the purported feature of running shoe heel counters of ‘motion control’ with reference to the hindfoot require re-evaluation. http://dx.doi.org/10.1016/j.jsams.2013.10.011 8 Dynamic function of the plantar intrinsic foot muscles during walking and running L. Kelly ∗ , G. Lichtwark, A. Cresswell School of Human Movement Studies, The University of Queensland, Australia Introduction: During the stance phase of gait the longitudinal arch (LA) of the foot deforms and recoils in a spring-like manner. It is thought that the elastic plantar aponeurosis is the primary structure responsible for this spring-like foot function. However, given that the plantar intrinsic foot muscles have muscle-tendon units (MTU) that span the length of the LA they could potentially contribute to actively stiffen the LA during the stance phase of gait.
Therefore, we sought to test the hypothesis that the plantar intrinsic foot muscles actively lengthen and shorten during the stance phase of gait and that recruitment of these muscles is regulated in response to the magnitude of the ground reaction force and MTU deformation. Methods: 8 healthy male participants volunteered to participate in the study which involved walking (4.5 and 6 km/h) and running (8, 10 and 12 km/h) on a force instrumented treadmill, while intramuscular electromyography (EMGi) signals were recorded from the right foot abductor hallucis (AH), flexor digitorum brevis (FDB) and quadratus plantae (QP). A 3D motion capture system recorded foot and ankle motion according to a multi-segment foot model. MTU length of the AH, FDB and QP were determined based on a geometrical model according to the kinematics. Ground reaction forces (GRF) were recorded from the treadmill. A repeated-measures ANOVA was used to test for differences in EMGi, MTU length and GRF with increasing gait velocity. Results: Muscles were activated from the end of swing phase until toe off with the peak EMGi value occurring in mid-stance. Mean stance and swing phase EMGi root mean square amplitude increased with gait velocity (all P ≤ 0.05). MTU length increased for all muscles during the first half of stance phase, followed by rapid recoil occurring prior to propulsion. Peak MTU lengths increased with increasing gait velocity for all muscles (all P ≤ 0.05), corresponding to increases in both EMGi and GRF (P ≤ 0.05). Discussion: We have provided the first in vivo evidence that the plantar intrinsic foot MTU’s are actively lengthening and shortening during the stance phase of gait and thus are capable of contributing to the stiffness of the LA. We have also shown evidence of late swing phase and stance activation of these muscles, which may be an important mechanism to stiffen the LA in preparation for high deformation forces associated with running. http://dx.doi.org/10.1016/j.jsams.2013.10.012 9 Fatigue impact on non-contact ACL injury risk associated with multi-directional jumping and landing in female athletes: A systematic review C. McMaster Catherine McMaster, Australia Introduction: This paper reviews current research regarding the impact of fatigue and multi-directional landings on non-contact anterior cruciate ligament (NC-ACL) injury risk in female athletes. It focuses on knee and hip biomechanical outcomes associated with NC-ACL injury, covering all three planes of movement. Fatigue is considered to be an NC-ACL injury risk factor because an athlete appears to be at greatest risk towards the end of half time, end of the game and end of the season. Focusing on multi-directional landings moves research closer to sports like ‘high risk’ scenarios. Methods: The criterion for article selection includes a fatigue protocol, and at least one biomechanical outcome from the first multi-directional landing. Studies are evaluated for quality using a modified Downs and Black checklist. Analysis between studies focuses on identified hip and knee NC-ACL biomechanical risk factors. Effect size and Forest plots are used to compare study results. Results: The keyword search yielded 105 articles on SCOPUS and 12 on Web Of Science. Eight articles were selected for this review after checking against the criteria for inclusion. All studies include a priori power calculation ensuring meaningful results. A total of 132 female participants are evaluated. Five studies include elite female soccer players. One study includes elite athletes from soccer, volleyball and basketball. Two studies include participants
2013 ASICS Conference / Journal of Science and Medicine in Sport 16S (2013) e2–e38
7 Athletic footwear does not alter in-shoe hindfoot kinematics during overground running C. Bishop ∗ , J. Arnold University of South Australia, Australia Background: Heel counters are added to most athletic shoes under the premise that they control excessive hindfoot motion. However, it is often questioned whether this premise has any scientific evidence. Although previous studies have described hindfoot kinematics during running, they have often used external shoe markers to infer in-shoe foot motion which is not a valid technique. The aim of this study was to compare hindfoot kinematics during running both barefoot and in typical running shoes. We hypothesised that running shoes would not alter hindfoot eversion motion but would reduce the rate at which it occurs (angular velocity). Methodology: Eighteen adults participated in this study (mean age 21.2 ± 2.0 years, height 1.73 ± 0.08 m, body mass 70.8 ± 8.3 kg). Each participant completed five running trials both barefoot and wearing shoes (Asics Gel-Pulse 3). Kinematic data were acquired with a 12 camera VICON MXF-20 motion capture system (Vicon Motion Systems Ltd., Oxford, UK) at 100 Hz. Variables of interest were the hindfoot eversion angle at initial contact and peak loading (15% stance), as well as the ROM and peak angular velocity during loading response (0–15% stance). Differences between conditions were compared using paired t-tests. Effect sizes (Cohen’s d) were also computed. Results: During running, footwear did not significantly reduce eversion of the hindfoot at initial contact (−7.59 ± 5.69∞ vs. −6.15 ± 5.59∞ , p = >.05, ES = 0.26) or peak loading (−13.91 ± 4.63∞ vs. −13.24 ± 6.15∞ , p = >.05, ES = 0.12), nor did it decrease the amount of eversion during loading response (6.88 ± 2.63∞ vs. 7.21 ± 1.99∞ , p = >.05, ES = 0.14). No difference in eversion angular velocity was identified between barefoot and shod running (−175.46 ± 100.52∞ /s vs. −151.73 ± 70.73∞ /s, p = >.05, ES = 0.27). Conclusion: In this study, footwear did not change hindfoot eversion at initial contact or peak loading, nor significantly reduce the amount of eversion or the peak eversion velocity occurring during loading. These results suggest hindfoot kinematics were not altered by the shoe used in this study. We found no evidence that design features in the heel (i.e. heel counter) provide motion control benefits (i.e. decrease hindfoot eversion) to the foot during stance phase of running. It is possible that the purported feature of running shoe heel counters of ‘motion control’ with reference to the hindfoot require re-evaluation. http://dx.doi.org/10.1016/j.jsams.2013.10.011 8 Dynamic function of the plantar intrinsic foot muscles during walking and running L. Kelly ∗ , G. Lichtwark, A. Cresswell School of Human Movement Studies, The University of Queensland, Australia Introduction: During the stance phase of gait the longitudinal arch (LA) of the foot deforms and recoils in a spring-like manner. It is thought that the elastic plantar aponeurosis is the primary structure responsible for this spring-like foot function. However, given that the plantar intrinsic foot muscles have muscle-tendon units (MTU) that span the length of the LA they could potentially contribute to actively stiffen the LA during the stance phase of gait.
Therefore, we sought to test the hypothesis that the plantar intrinsic foot muscles actively lengthen and shorten during the stance phase of gait and that recruitment of these muscles is regulated in response to the magnitude of the ground reaction force and MTU deformation. Methods: 8 healthy male participants volunteered to participate in the study which involved walking (4.5 and 6 km/h) and running (8, 10 and 12 km/h) on a force instrumented treadmill, while intramuscular electromyography (EMGi) signals were recorded from the right foot abductor hallucis (AH), flexor digitorum brevis (FDB) and quadratus plantae (QP). A 3D motion capture system recorded foot and ankle motion according to a multi-segment foot model. MTU length of the AH, FDB and QP were determined based on a geometrical model according to the kinematics. Ground reaction forces (GRF) were recorded from the treadmill. A repeated-measures ANOVA was used to test for differences in EMGi, MTU length and GRF with increasing gait velocity. Results: Muscles were activated from the end of swing phase until toe off with the peak EMGi value occurring in mid-stance. Mean stance and swing phase EMGi root mean square amplitude increased with gait velocity (all P ≤ 0.05). MTU length increased for all muscles during the first half of stance phase, followed by rapid recoil occurring prior to propulsion. Peak MTU lengths increased with increasing gait velocity for all muscles (all P ≤ 0.05), corresponding to increases in both EMGi and GRF (P ≤ 0.05). Discussion: We have provided the first in vivo evidence that the plantar intrinsic foot MTU’s are actively lengthening and shortening during the stance phase of gait and thus are capable of contributing to the stiffness of the LA. We have also shown evidence of late swing phase and stance activation of these muscles, which may be an important mechanism to stiffen the LA in preparation for high deformation forces associated with running. http://dx.doi.org/10.1016/j.jsams.2013.10.012 9 Fatigue impact on non-contact ACL injury risk associated with multi-directional jumping and landing in female athletes: A systematic review C. McMaster Catherine McMaster, Australia Introduction: This paper reviews current research regarding the impact of fatigue and multi-directional landings on non-contact anterior cruciate ligament (NC-ACL) injury risk in female athletes. It focuses on knee and hip biomechanical outcomes associated with NC-ACL injury, covering all three planes of movement. Fatigue is considered to be an NC-ACL injury risk factor because an athlete appears to be at greatest risk towards the end of half time, end of the game and end of the season. Focusing on multi-directional landings moves research closer to sports like ‘high risk’ scenarios. Methods: The criterion for article selection includes a fatigue protocol, and at least one biomechanical outcome from the first multi-directional landing. Studies are evaluated for quality using a modified Downs and Black checklist. Analysis between studies focuses on identified hip and knee NC-ACL biomechanical risk factors. Effect size and Forest plots are used to compare study results. Results: The keyword search yielded 105 articles on SCOPUS and 12 on Web Of Science. Eight articles were selected for this review after checking against the criteria for inclusion. All studies include a priori power calculation ensuring meaningful results. A total of 132 female participants are evaluated. Five studies include elite female soccer players. One study includes elite athletes from soccer, volleyball and basketball. Two studies include participants