The effect of load distribution within military load carriage systems on the kinetics of human gait

Military personnel carry their equipment in load carriage systems (LCS) which consists of webbing and a Bergen (aka backpack). In scientific terms it is most efficient to carry load as close to the body's centre of mass (CoM) as possible, this has been shown extensively with physiological studies. However, less is known regarding the kinetic effects of load distribution. Twelve experienced load carriers carried four different loads (8, 16, 24 and 32 kg) in three LCS (backpack, standard and AirMesh). The three LCS represented a gradual shift to a more even load distribution around the CoM. Results from the study suggest that shifting the CoM posteriorly by carrying load solely in a backpack significantly reduced the force produced at toe-off, whilst also decreasing stance time at the heavier loads. Conversely, distributing load evenly on the trunk significantly decreased the maximum braking force by 10%. No other interactions between LCS and kinetic parameters were observed. Despite this important findings were established, in particular the effect of heavy load carriage on maximum braking force. Although the total load carried is the major cause of changes to gait patterns, the scientific testing of, and development of, future LCS can modify these risks

The role of tibialis posterior fatigue on foot kinematics during walking

<p>Abstract</p> <p>Background</p> <p>The purpose of this study was to investigate the effect of localised tibialis posterior muscle fatigue on foot kinematics during walking. It was hypothesised that following fatigue, subjects would demonstrate greater forefoot and rearfoot motion during walking. It was also postulated that the magnitude of the change in rearfoot motion would be associated with standing anatomical rearfoot posture.</p> <p>Methods</p> <p>Twenty-nine subjects underwent an exercise fatigue protocol aimed at reducing the force output of tibialis posterior. An eight camera motion analysis system was used to evaluate 3D foot kinematics during treadmill walking both pre- and post-fatigue. The anatomical rearfoot angle was measured during standing prior to the fatigue protocol using a goniometer.</p> <p>Results</p> <p>Peak rearfoot eversion remained unchanged following the fatigue protocol. Although increases in rearfoot eversion excursion were observed following fatigue, these changes were of a magnitude of questionable clinical significance (<1.0°). The magnitude of the change in rearfoot eversion due to fatigue was not associated with the anatomical measurement of standing rearfoot angle. No substantial changes in forefoot kinematics were observed following the fatigue protocol.</p> <p>Conclusions</p> <p>These data indicate that reduced force output of the tibialis posterior muscle did not alter rearfoot and forefoot motion during gait. The anatomical structure of the rearfoot was not associated with the dependence of muscular activity that an individual requires to maintain normal rearfoot kinematics during gait.</p

Effect of thong style flip-flops on children’s barefoot walking and jogging kinematics

BACKGROUND: Thong style flip-flops are a popular form of footwear for children. Health professionals relate the wearing of thongs to foot pathology and deformity despite the lack of quantitative evidence to support or refute the benefits or disadvantages of children wearing thongs. The purpose of this study was to compare the effect of thong footwear on children’s barefoot three dimensional foot kinematics during walking and jogging. METHODS: Thirteen healthy children (age 10.3 ± 1.6 SD years) were recruited from the metropolitan area of Sydney Australia following a national press release. Kinematic data were recorded at 200 Hz using a 14 camera motion analysis system (Cortex, Motion Analysis Corporation, Santa Rosa, USA) and simultaneous ground reaction force were measured using a force platform (Model 9281B, Kistler, Winterthur, Switzerland). A three-segment foot model was used to describe three dimensional ankle, midfoot and one dimensional hallux kinematics during the stance sub-phases of contact, midstance and propulsion. RESULTS: Thongs resulted in increased ankle dorsiflexion during contact (by 10.9°, p; = 0.005 walk and by 8.1°, p; = 0.005 jog); increased midfoot plantarflexion during midstance (by 5.0°, p; = 0.037 jog) and propulsion (by 6.7°, p; = 0.044 walk and by 5.4°, p;= 0.020 jog); increased midfoot inversion during contact (by 3.8°, p;= 0.042 jog) and reduced hallux dorsiflexion during walking 10% prior to heel strike (by 6.5°, p; = 0.005) at heel strike (by 4.9°, p; = 0.031) and 10% post toe-off (by 10.7°, p; = 0.001). CONCLUSIONS: Ankle dorsiflexion during the contact phase of walking and jogging, combined with reduced hallux dorsiflexion during walking, suggests a mechanism to retain the thong during weight acceptance. Greater midfoot plantarflexion throughout midstance while walking and throughout midstance and propulsion while jogging may indicate a gripping action to sustain the thong during stance. While these compensations exist, the overall findings suggest that foot motion whilst wearing thongs may be more replicable of barefoot motion than originally thought

Ultrasound evaluation of the abductor hallucis muscle: Reliability study

© 2008 Cameron et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Obesity and foot muscle strength are associated with high dynamic plantar pressure during running

© 2020 Elsevier Ltd Obese people are often encouraged to lose body mass by exercise. The aim of the study was to determine the effect of body mass and ankle muscle strength on the dynamic foot-pressure distribution before and after running. Twenty-five normal weight (72.0 ± 5.3 kg), 25 overweight (80.8 ± 5.6 kg) and 25 obese (96.8 ± 6.5 kg) age- and height-matched male recreational runners joined the study. Before and after 30 min running, dynamic foot-pressure distribution during running, and ankle plantarflexor, dorsiflexor, invertor and evertor muscle strength were measured using a foot-scan pressure-plate and isokinetic dynamometer, respectively. Body mass index and percentage fat mass correlated positively to almost all components of foot-pressure distribution; this explantion was extracted from 14% (for toe 1) to 52% (for dynamic arch index) of peak foot pressure and between 21% (for metatarsal 1) to 48% (for midfoot) of the impulse underneath different foot zones. Only plantarflexor muscle strength significantly predicted plantar pressure and impulse underneath the T1, T2-5, midfoot area and the dynamic arch index. After running, plantarflexor and invertor muscle strength predicted from 30% (for metatarsal 2) to 58% (for metatarsal 1) of peak foot-pressure and impulse underneath the different foot zones. Obesity is associated with excessive plantar loading that is aggravated after running by fatigue-related reductions in plantar flexor and invertor muscle strength. To prevent foot pain and injuries related to excessive foot pressures, at the start of the weight control process non-weight bearing rather than weight-bearing exercise is advisable

The effects of the communicating branch between medial and lateral plantar nerves on the innervations of the foot lumbrical muscles

Bozer, Cuneyt (Trakya author) Donmez, Didem Parlak, MuhammedIntroduction: The communicating branches between the medial (MPN) and lateral (LPN) plantar nerves aren't frequently observed in relation to the innervation of the foot muscles in previous studies. In this study, the number and localization of the communicating branch on the innervations of foot muscles were evaluated to open a new sight considering the innervations of lumbrical muscles. Material and methods: 30 formalin-fixed feet (15 right-15 left feet), with an average age of 76 from the inventory of Trakya and Mersin University Anatomy Departments in 2015 were dissected. The innervations of the lumbricals and the communicating branches were revealed and then photographed. Results: In all feet, first lumbricals were observed to be innervated by MPN, while the remaining muscles were innervated by deep branches of LPN. In four cadaveric feet, communicating branches of MPN, LPN and deep branch of LPN were appeared but, in one of them, proximal to the branches of MPN and LPN to lumbricals, a communicating branch between MPN and deep branch of LPN were observed. Discussion: Data about the innervations of the lumbricals were found to be consistent with the previous studies. Taking into account the localization of the communicating branches between the MPN and LPN, it should be considered that nerve injuries during surgical procedures such as flexor tendon transfers, island flap surgery, treatment of hallux valgus or lesser toes deformity in the foot and ankle region may unexpectedly lead to different functional failures. (C) 2018 Anatomical Society of India. Published by Elsevier, a division of RELX India, Pvt. Ltd. All rights reserved