Browsing by Subject "Foot"

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    ItemOpen Access
    A Model of the Foot and Ankle in Running
    (2011-05-11) Waggoner, Bo
    We present several variations on a model and simulation of the foot and ankle during the course of one running stride. We summarize the motivation behind the model and similar work in the field, then describe the model and the results obtained. In the model, the shin and foot are each represented by thin rods, while two major muscle groups are modeled as exponential springs. The ground is modeled as a network of points connected by damped linear springs. Results on ground impact forces and physiological parameters are presented. In particular, we find that heel striking tends to produce higher peak impact forces than forefoot striking, we search for foot parameters producing the most effective foot strike, we compare force-time data obtained to experimental results, and we compare the effects of different ground and shoe properties on foot strike.
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    ItemOpen Access
    FOOT ALIGNMENT IN SYMPTOMATIC NATIONAL FOOTBALL LEAGUE (NFL) ATHLETES: A WEIGHTBEARING CT ANALYSIS.
    (Acta ortopedica brasileira, 2021-05) Bernasconi, Alessio; Cesar, Cesar DE; Roberts, Lauren; Lintz, François; Godoy-Santos, Alexandre Leme; O'Malley, Martin Joseph

    Objective

    Our aim was to describe the foot alignment in National Football League (NFL) players with different symptomatic foot and ankle pathologies using weightbearing cone-beam computed tomography (WBCBCT), comparing them to normally aligned feet as control group.

    Methods

    41 feet (36 active NFL players) were assessed using WBCBCT and compared to 20 normally aligned controls from a normal population. Measurements included: Foot and Ankle Offset (FAO); Calcaneal Offset (CO); Hindfoot Alignment Angle (HAA); angle between inferior and superior facets of the talus (Inftal-Suptal); angle between inferior facet of the talus and the horizontal/floor (Inftal-Hor); Forefoot Arch Angle (FAA); navicular- and medial cuneiform-to-floor distance.

    Results

    NFL athletes showed a neutrally aligned hindfoot when compared to controls (FAO: 1% vs 0.5%; CO: 2.3 mm vs 0.8 mm; HAA: 2.9° vs 0.8° in two groups, with all p > 0.05) and a normal morphology of the subtalar joint (no difference in Inftal-Suptal and Inftal-Hor angles). Conversely, in athletes we found a decreased medial longitudinal arch (FAA: 15° vs 18.3°, p = 0.03) with smaller navicular (38.2 mm vs 42.2 mm, p = 0.03) and medial cuneiform (27 mm vs 31.3 mm, p = 0.01) mean distances to the floor when compared to controls.

    Conclusion

    In our series, NFL players presented a lower medial longitudinal arch than controls but a neutrally aligned hindfoot. WBCBCT may help shed light on anatomical risk factors for injuries in professional players. Level of Evidence III, Retrospective comparative study.
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    Foot for Thought: Identifying Causes of Foot and Leg Pain in Rural Madagascar to Improve Musculoskeletal Health
    (2018-04-25) Tasnim, Noor
    Incidence of musculoskeletal health disorders is increasing in Madagascar. Foot pain in the Malagasy may be related to daily occupational activities or foot shape and lack of footwear. Our study tests hypotheses concerning the cause of foot pain in male and female Malagasy populations and its effects on gait kinematics. The study was conducted in Mandena, Madagascar. We obtained 89 participants’ height, mass, and age from a related study (n male = 41, n female = 48). We collected self-report data on daily activity and foot and lower limb pain. A modified Revised Foot Function Index (FFI-R) assessed pain, difficulty, and limitation of activities because of reported foot pain (total score = 27). We quantified ten standard foot shape measures. Participants walked across a force platform at self-selected speeds while being videorecorded at 120 fps. Females reported higher FFI-R scores (p = 0.029), spending more hours on their feet (p = 0.0184), and had larger BMIs (p = 0.0001) than males. Strong linear relationships were examined between participants’ self-selected speed and force curve peaks and loading rates. No significant differences were found in force curve parameters between participants with foot/ankle/knee pain and lack thereof. Males showed higher values of force curve parameters and steeper slopes when relating velocity to the same parameters. The higher foot pain and lower force peaks in females may be related to the combination of higher BMI, small feet relative to BMI, and the amount of time they are on their feet. Results suggest that a combination of BMI, foot size, and occupational factors influence foot pain in this community leading to long term injury and limitations on work. These results will help guide future interventions that promote engagement in leisure/work activities.
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    Footprint evidence of early hominin locomotor diversity at Laetoli, Tanzania.
    (Nature, 2021-12) McNutt, Ellison J; Hatala, Kevin G; Miller, Catherine; Adams, James; Casana, Jesse; Deane, Andrew S; Dominy, Nathaniel J; Fabian, Kallisti; Fannin, Luke D; Gaughan, Stephen; Gill, Simone V; Gurtu, Josephat; Gustafson, Ellie; Hill, Austin C; Johnson, Camille; Kallindo, Said; Kilham, Benjamin; Kilham, Phoebe; Kim, Elizabeth; Liutkus-Pierce, Cynthia; Maley, Blaine; Prabhat, Anjali; Reader, John; Rubin, Shirley; Thompson, Nathan E; Thornburg, Rebeca; Williams-Hatala, Erin Marie; Zimmer, Brian; Musiba, Charles M; DeSilva, Jeremy M
    Bipedal trackways discovered in 1978 at Laetoli site G, Tanzania and dated to 3.66 million years ago are widely accepted as the oldest unequivocal evidence of obligate bipedalism in the human lineage1-3. Another trackway discovered two years earlier at nearby site A was partially excavated and attributed to a hominin, but curious affinities with bears (ursids) marginalized its importance to the paleoanthropological community, and the location of these footprints fell into obscurity3-5. In 2019, we located, excavated and cleaned the site A trackway, producing a digital archive using 3D photogrammetry and laser scanning. Here we compare the footprints at this site with those of American black bears, chimpanzees and humans, and we show that they resemble those of hominins more than ursids. In fact, the narrow step width corroborates the original interpretation of a small, cross-stepping bipedal hominin. However, the inferred foot proportions, gait parameters and 3D morphologies of footprints at site A are readily distinguished from those at site G, indicating that a minimum of two hominin taxa with different feet and gaits coexisted at Laetoli.
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    Hand and foot pressures in the aye-aye (Daubentonia madagascariensis) reveal novel biomechanical trade-offs required for walking on gracile digits.
    (J Exp Biol, 2010-05) Kivell, Tracy L; Schmitt, Daniel; Wunderlich, Roshna E
    Arboreal animals with prehensile hands must balance the complex demands of bone strength, grasping and manipulation. An informative example of this problem is that of the aye-aye (Daubentonia madagascariensis), a rare lemuriform primate that is unusual in having exceptionally long, gracile fingers specialized for foraging. In addition, they are among the largest primates to engage in head-first descent on arboreal supports, a posture that should increase loads on their gracile digits. We test the hypothesis that aye-ayes will reduce pressure on their digits during locomotion by curling their fingers off the substrate. This hypothesis was tested using simultaneous videographic and pressure analysis of the hand, foot and digits for five adult aye-ayes during horizontal locomotion and during ascent and descent on a 30 degrees instrumented runway. Aye-ayes consistently curled their fingers during locomotion on all slopes. When the digits were in contact with the substrate, pressures were negligible and significantly less than those experienced by the palm or pedal digits. In addition, aye-ayes lifted their hands vertically off the substrate instead of 'toeing-off' and descended head-first at significantly slower speeds than on other slopes. Pressure on the hand increased during head-first descent relative to horizontal locomotion but not as much as the pressure increased on the foot during ascent. This distribution of pressure suggests that aye-ayes shift their weight posteriorly during head-first descent to reduce loads on their gracile fingers. This research demonstrates several novel biomechanical trade-offs to deal with complex functional demands on the mammalian skeleton.