Conference PaperPDF Available

Variables Temporales Y Energética Del Galope Bípedo: Un Estudio Piloto

Authors:
Métodos
Dos voluntarios realizaron galope
sobre una cinta caminadora a 4
velocidades diferentes (4.0; 5.5; 7.0;
8.5 km/h). Se utilizaron foot-switches
(Delsys Trigno) para detectar
instantes de ‘heel-strike’ y ‘toe-off’,
y un metabolímetro portátil (Cosmed
K5) para analizar el CoT.
Posteriormente, se calculó duty factor
(DF) para la pierna delantera (DF
l
) y
trasera (DF
t
); y el tiempo de vuelo
(t
f
). Protocolo aprobado por el
Comité de Ética en Investigación
Institucional (UdelaR; Exp. N.
003065-000653-16). Los datos se
analizaron usando software Omnia
(Cosmed) y Matlab (Mathworks).
Variables temporales y energética del
galope bípedo: un estudio piloto
Germán Pequera1, Renata L. Bona2, Artur Bonezi2, Fernando López-Mangini3,
Patricia Polero2, Carlo M. Biancardi2
1.Departamento de Ingeniería Biológica, CENUR Litoral Norte, Universidad de la Republica, Uruguay;
2.Laboratorio de Investigación en Biomecánica y Análisis del Movimiento Humano, Cenur Litoral Norte,
Universidad de la Republica Uruguay; 3.Unidad de Investigación en Biomecánica de la Locomoción
Humana, Facultad de Medicina, Universidad de la Republica Uruguay.
Introducción
El galope bípedo es un patrón natural de
los cuadrúpedos y de algunos primates
escasamente utilizado por el hombre
debido al alto costo de transporte que
implica (1). Sin embargo en situaciones
particulares los adultos utilizan este
patrón, por ejemplo, al descender
escaleras o en condiciones de gravedad
reducida (misiones Apollo) (2, 3, 4). Estas
características hacen que el galope
humano sea un modelo interesante para
estudiar las determinantes del costo de
transporte durante la locomoción.
Objetivo
El objetivo de este estudio es evaluar
relaciones entre parámetros temporales y
el costo de transporte (CoT) que
caracterizan el galope bípedo.
XVII Congresso Brasileiro de Biomecânica, Porto Alegre 8-11/05/2017
Resultados y discusión
El CoT siguen las tendencias reportadas en otros trabajos (1,2,3), mostrando altos valores comparado con marcha y carrera (Fig. 1). El t
f
presentó
valores crecientes, mientras DF
l
y DF
t
decrecientes (Figs. 2 y 3). Además, correlaciones entre CoT y las variables temporales fueron significativas (P
< 0.01). DF
l
está en el rango de DF medidos en la marcha (> 0.5). DF
t
presenta valores mas bajos, comparables a los de la carrera (4,5,6). El CoT
excesivo podría ser determinado por la baja eficiencia en el intercambio de energía. La tendencia del t
f
y del DF en relación a la velocidad y al CoT
parece indicar que el rendimiento del mecanismo elástico puede ser un factor crítico en el galope. La asimetría entre DF
l
y DF
t
tiende a
incrementarse con el aumento de velocidad; en contra de lo reportado en caballos quienes utilizan el galope como modo de locomoción eficiente a
altas velocidades (7). Es sugerido que el aumento de asimetrías está asociado al alto CoT (8). Por tanto, la amplificación de diferencias entre DF
l
y
DF
t
podría ser un factor relevante para el CoT.
ID 12149
Referencias
1. Minetti AE. The biomechanics of skipping gaits: a third locomotion paradigm? P Roy Soc of Lond B Bio. 1998. 265(1402): 1227-1233.
2. Minetti AE, Pavei G, Biancardi CM. The energetics and mechanics of level and gradient skipping: Preliminary results for a potential gait of choice in low gravity environments. Planet Space Sci. 2012. 74(1): 142-145.
3. Pavei G, Biancardi CM, Minetti AE. Skipping vs. running as the bipedal gait of choice in hypogravity. J Appl Physiol. 2015. 119(1): 93-100.
4. Biancardi CM, Minetti AE. Biomechanical determinants of transverse and rotary gallop in cursorial mammals. J Exp Biol.. 2012. 215(23), 4144-4156.
5. Cappellini G, Ivanenko YP, Poppele RE, Lacquaniti F. Motor patterns in human walking and running. J Neurophysiol. 2006. 95(6): 3426-3437.
6. Gatesy SM, Biewener AA. Bipedal locomotion: effects of speed, size and limb posture in birds and humans. J Zool. 1991. 224(1): 127-147.
7. Witte TH, Knill K, Wilson AM. Determination of peak vertical ground reaction force from duty factor in the horse (Equus caballus). J Exp Biol. 2004. 207(21): 3639-3648.
8. Finley JM, Bastian AJ. Associations Between Foot Placement Asymmetries and Metabolic Cost of Transport in Hemiparetic Gait. Neurorehab and neural re. 2016.
Figs. Costo de transporte
(A), tiempo de vuelo (B),
Duty Factor (C) y
diferencia entre Duty
Factor de la pierna trasera
y Duty Factor de la pierna
delantera (D) en función de
la velocidad
Agradecimientos
Programa de Desarrollo de la Ciencia Básicas Contactos
gpequera@cup.edu.uy; biomecanica@cup.edu.uy
D
C
A
B
ResearchGate has not been able to resolve any citations for this publication.
Article
Full-text available
Stroke survivors often have a slow, asymmetric walking pattern. They also walk with a higher metabolic cost than healthy, age-matched controls. It is often assumed that spatial-temporal asymmetries contribute to the increased metabolic cost of walking poststroke. However, elucidating this relationship is made challenging because of the interdependence between spatial-temporal asymmetries, walking speed, and metabolic cost. Here, we address these potential confounds by measuring speed-dependent changes in metabolic cost and implementing a recently developed approach to dissociate spatial versus temporal contributions to asymmetry in a sample of stroke survivors. We used expired gas analysis to compute the metabolic cost of transport (CoT) for each participant at 4 different walking speeds: self-selected speed, 80% and 120% of their self-selected speed, and their fastest comfortable speed. We also computed CoT for a sample of age- and gender-matched control participants who walked at the same speeds as their matched stroke survivor. Kinematic data were used to compute the magnitude of a number of variables characterizing spatial-temporal asymmetries. Across all speeds, stroke survivors had a higher CoT than controls. We also found that our sample of stroke survivors did not choose a self-selected speed that minimized CoT, contrary to typical observations in healthy controls. Multiple regression analyses revealed negative associations between speed and CoT and a positive association between asymmetries in foot placement relative to the trunk and CoT. These findings suggest that interventions designed to increase self-selected walking speed and reduce foot-placement asymmetries may be ideal for improving walking economy poststroke.
Article
Full-text available
Seven species of ground-dwelling birds (body mass range: 0.045-90 kg) were filmed while walking and running on a treadmill. High-speed light films were also taken of humans to compare kinematic patterns of avian with human bipedalism. Consistent patterns of stride frequency, stride length, step length, duty factor and limb excursion were observed in all species, with most of the variation among species being due to differences in body size. In general, smaller bipeds have higher stride frequencies (αM−0.18), shorter stride lengths (αM0.38) and more limited ranges of speed within each gait than large bipeds. After normalizing for size (based on Froude number, after Alexander, 1977), remaining kinematic variation is largely due to interspecific differences in posture and relative limb segment lengths. For their size, smaller bipeds have greater step lengths, limb excursion angles and duty factors than large bipeds because of their more crouched posture and greater effective limb length. The most notable differences in limb kinematics between birds and humans occur at the walk-run transition and are maintained as running speed increases. Change of gait is smooth and difficult to discern in birds, but distinct in humans, involving abrupt decreases in step length and duty factor (time of contact) and a corresponding increase in limb swing time. These differences appear to reflect a spring-like run that is stiff in humans (favouring elastic energy recovery) but more compliant in birds (increasing time of ground contact). Differences between birds and humans in balance of the body's centre of mass not only affect femoral orientation and motion, but also affect pattern of limb excursion with speed.
Article
Full-text available
Skipping, a gait children display when they are about four- to five-years-old, is revealed to be more than a behavioural peculiarity. By means of metabolic and biomechanical measurements at several speeds, the relevance of skipping is shown to extend from links between bipedal and quadrupedal locomotion (namely galloping) to understanding why it could be a gait of choice in low-gravity conditions, and to some aspects of locomotion evolution (ground reaction forces of skipping seem to originate from pushing the walking gait to unnaturally high speeds). When the time-courses of mechanical energy and the horizontal ground reaction force are considered, a different locomotion paradigm emerges, enabling us to separate, among the bouncing gaits, the trot from the gallop (quadrupeds) and running from skipping (bipeds). The simultaneous use of pendulum-like and elastic mechanisms in skipping gaits, as shown by the energy curve analysis, helps us to understand the low cost of transport of galloping quadrupeds.
Article
Full-text available
Measurement of peak vertical ground reaction force (GRFz) from multiple limbs simultaneously during high-speed, over-ground locomotion would enhance our understanding of the locomotor mechanics of cursorial animals. Here, we evaluate the accuracy of predicting peak GRFz from duty factor (the proportion of the stride for which the limb is in contact with the ground). Foot-mounted uniaxial accelerometers, combined with UHF FM telemetry, are shown to be practical and accurate for the field measurement of stride timing variables, including duty factor. Direct comparison with the force plate produces a mean error of 2.3 ms and 3.5 ms for the timing of foot on and foot off, respectively, across all gaits. Predictions of peak GRFz from duty factor show mean errors (with positive values indicating an overestimate) of 0.8+/-0.04 N kg(-1) (13%; N=42; mean +/- S.E.M.) at walk, -0.3+/-0.06 N kg(-1) (3%; N=75) at trot, -2.3+/-0.27 N kg(-1) (16%; N=18) for the non-lead limb at canter and +2.1+/-0.7 N kg(-1) (19%; N=9) for the lead limb at canter. The substantial over- and underestimate seen at canter, in the lead and non-lead limbs, respectively, is attributed to the different functions performed by the two limbs in the asymmetrical gaits. The difference in load experienced by the lead and non-lead limbs decreased with increasing speed.
Article
Full-text available
Despite distinct differences between walking and running, the two types of human locomotion are likely to be controlled by shared pattern-generating networks. However, the differences between their kinematics and kinetics imply that corresponding muscle activations may also be quite different. We examined the differences between walking and running by recording kinematics and electromyographic (EMG) activity in 32 ipsilateral limb and trunk muscles during human locomotion, and compared the effects of speed (3-12 km/h) and gait. We found that the timing of muscle activation was accounted for by five basic temporal activation components during running as we previously found for walking. Each component was loaded on similar sets of leg muscles in both gaits but generally on different sets of upper trunk and shoulder muscles. The major difference between walking and running was that one temporal component, occurring during stance, was shifted to an earlier phase in the step cycle during running. These muscle activation differences between gaits did not simply depend on locomotion speed as shown by recordings during each gait over the same range of speeds (5-9 km/h). The results are consistent with an organization of locomotion motor programs having two parts, one that organizes muscle activation during swing and another during stance and the transition to swing. The timing shift between walking and running reflects therefore the difference in the relative duration of the stance phase in the two gaits.
Article
Hypogravity challenges bipedal locomotion in its common forms. However as previously theoretically and empirically suggested, humans can rely on 'skipping', a less common gait available as a functional analogue (perhaps a vestigium) of quadrupedal gallop, to confidently move when gravity is much lower than on Earth. We set up a 17 m tall cavaedium (skylight shaft) with a bungee rubber body-suspension system and a treadmill to investigate the metabolic cost and the biomechanics of low-gravity (Mars, Moon) locomotion. Although skipping is never more metabolically economical than running, the difference becomes marginal at lunar gravities, with both bouncing gaits approaching values of walking on Earth (cost ≈ 2 J/(kg m)). Non-metabolic factors may thus be allowed to dominate the choice of skipping on the Moon. Based on centre of pressure measurements and body segments kinetics, we can speculate that these factors may include a further reduction of mechanical work to move the limbs when wearing space suits and a more effective motor control during the ground (regoliths)-boot interaction. Copyright © 2014, Journal of Applied Physiology.
Article
Walking and running in low gravity cannot be used at useful speeds, while ‘skipping’, a gait displayed by kids and spontaneously adopted by astronauts of Apollo missions, proved to have the potential to become the gait of choice in that condition. In this paper the previous biomechanical and metabolic analysis of level skipping is extended to positive and negative gradients, in normal gravity. The results confirm at all gradients the higher (average) ground reaction force during the contact phase, with respect to running at the same speed, which would allow confidently facing the Lunar surface where the dust and regoliths affect, in addition to a lower gravity, the locomotion dynamics. Metabolic data, other gait variables related to the mechanical work done and the locomotor/respiratory coupling have also been investigated.
Article
Transverse and rotary gallop differ for the placement of the hind and fore leading feet: ipsilateral in the former, contralateral in the latter gait. 351-filmed sequences have been analysed to assess the gallop type of 89 investigated mammal species belonging to Carnivora, Artiodactyla and Perissodactyla orders. 23 biometrical, ecological and physiological parameters have been collected for each species both from literature data and from animal specimens. Most of the species showed only one kind of gallop: transverse (42%) or rotary (39%), while some species performed rotary gallop only at high speed (19%). In a factorial analysis the first principal component (PC), which accounted for 40% of the total variance, was positively correlated to the relative speed and negatively correlated to size and body mass. The second PC was correlated to the ratio between distal and proximal limb segments. Large size and longer proximal limb segments resulted associated to transverse gallop, while rotary and speed dependent species showed higher metacarpus/humerus and metatarsus/femur length ratio and faster relative speeds. The limb excursion angles resulted proportional to the square-root of the Froude number, and significantly higher in rotary galloper. The gait pattern analysis provided significant differences between transverse and rotary gallop in fore and hind duty factor (t-test; p < 0.001), and in duration of the fore contact (t-test; P = 0.045). Our results assessed that an exclusive gallop gait is adopted by a large number of mammal species, and indicated that the gallop pattern depends on diverse environmental, morphometrical and biomechanical characters.