
Craig P McGowanUniversity of Idaho | UID · Department of Biological Sciences
Craig P McGowan
PhD, Harvard University
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65
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Introduction
Publications
Publications (65)
The single leg squat (SLS), forward step down (FSD), and lateral step down (LSD) are
clinically reliable movement screens for identifying motion imbalances. The current understanding for the kinematic profiles of each task is limited to discrete time points such as peak knee flexion. However, analyses of the entire movement would better aid clinic...
Body size is a key factor that influences antipredator behavior. For animals that rely on jumping to escape from predators, there is a theoretical trade-off between jump distance and acceleration as body size changes at both the inter- and intraspecific levels. Assuming geometric similarity, acceleration will decrease with increasing body size due...
Synopsis
Although tails are common and versatile appendages that contribute to evolutionary success of animals in a broad range of ways, a scientific synthesis on the topic is yet to be initiated. For our Society for Integrative and Comparative Biology (SICB) symposium, we brought together researchers from different areas of expertise (e.g., roboti...
Synopsis
Tails are widespread in the animal world and play important roles in locomotor tasks, such as propulsion, maneuvering, stability, and manipulation of objects. Kangaroo rats, bipedal hopping rodents, use their tail for balancing during hopping, but the role of their tail during the vertical evasive escape jumps they perform when attacked by...
Background and Objectives
Increased fall risk in older adults is associated with declining balance. Previous work showed that brief postural instructions can affect balance control in older adults with Parkinson’s disease. Here, we assessed the effects of brief instructions on static and dynamic balance in healthy older adults.
Research Design and...
This study assesses the functional morphology of the ankle extensor muscle-tendon units of the springhare Pedetes capensis, an African bipedal hopping rodent, to test for convergent evolution with the Australian bipedal hopping macropods. We dissect and measure the gastrocnemius, soleus, plantaris, and flexor digitorum longus in ten adult springhar...
The derivative of force with respect to time does not have a standard term in physics. As a consequence, the quantity has been given a variety of names, the most closely related being 'rate of force development'. The lack of a proper name has made it difficult to understand how different structures and processes within the sensorimotor system respo...
Bipedal hopping is an efficient form of locomotion, yet it remains relatively rare in the natural world. Previous research has suggested that the tail balances the angular momentum of the legs to produce steady state bipedal hopping. In this study, we employ a 3D physics simulation engine to optimize gaits for an animat whose control and morphologi...
Abstract Tendons must be able to withstand the forces generated by muscles and not fail. Accordingly, a previous comparative analysis across species has shown that tendon strength (i.e., failure stress) increases for larger species. In addition, the elastic modulus increases proportionally to the strength, demonstrating that the two properties co-v...
The combined force–length (F–L) properties of a muscle group acting synergistically at a joint are determined by several aspects of the F–L properties of the individual musculotendon units. Namely, misalignment of the optimal lengths of the individual muscles will affect the group F–L properties. This misalignment, which we named \(M_{\text{opt}}^{...
A fundamental aspect of animal ecology is the ability to avoid getting eaten. Catching prey and avoiding depredation involves a dynamic interplay between forward and lateral acceleration. Success at these tasks depends on achieving sufficient performance. In turn, performance is determined by biomechanics. After observing several kangaroo rats util...
Kangaroo rats are small bipedal desert rodents that use erratic vertical jumps to escape predator strikes. In this study we examined how individual hind limb joints of desert kangaroo rats (Dipodomys deserti) power vertical jumps across a range of heights. We hypothesized that increases in net work would be equally divided across hind limb joints w...
Predation is an important factor that shapes prey’s fitness. Kangaroo rats (D. deserti) are bipedal hoppers that use vertical jumps to evade their attacker (i.e., snakes and owls). Reported jumps of this animal can reach more than 1 meter, which is over 20 times hip height. The ankle extensors are the primary muscles involved in plantar flexion, an...
Many cursorial and large hopping species are extremely efficient locomotors with various morphological adaptations believed to reduce mechanical demand and improve movement efficiency, including elongated distal limb segments. However, despite having elongated limbs, small hoppers such as desert kangaroo rats (Dipodomys deserti) are less efficient...
Bipedal hopping is a specialized mode of locomotion that has arisen independently in at least five groups of mammals. We review the evolutionary origins of these groups, examine three of the most prominent hypotheses for why bipedal hopping may have arisen, and discuss how this unique mode of locomotion influences the behavior and ecology of modern...
The majority of terrestrial locomotion studies have focused on parasagittal motion and paid less attention to forces or movement in the frontal plane. Our previous research has shown that grizzly bears produce higher medial ground reaction forces (lateral pushing from the animal) than would be expected for an upright mammal, suggesting frontal plan...
There has been limited biomechanical research on plantigrade species, despite the fact that this posture is ancestral and retained in many species. Within Carnivora, eleven of fourteen families are plantigrade or semi-plantigrade. Bears (family Ursidae) are a group of large, quadrupedal, plantigrade animals, which makes them unique. Our previous wo...
The regulation of whole-body angular momentum is important for maintaining dynamic balance during human walking, which is particularly challenging in the frontal plane. Whole-body angular momentum is actively regulated by individual muscle forces. Thus, understanding which muscles contribute to frontal plane angular momentum will further our unders...
During the ground contact phase of running, the body's mass is rapidly decelerated resulting in forces that propagate through the musculoskeletal system. The repetitive attenuation of these impact forces is thought to contribute to overuse injuries. Modern running shoes are designed to reduce impact forces, with the goal to minimize running related...
The majority of locomotion studies have focused on parasagittal motion and all but ignored any forces or movement in the frontal plane. Our previous research has shown that grizzly bears produce higher medial ground reaction forces (lateral pushing from the animal) than would be expected for an upright mammal, suggesting frontal plane movement is a...
Locomotion of plantigrade generalists has been relatively little studied compared to more specialised postures even though plantigrady is ancestral among quadrupeds. Bears (Ursidae) are a representative family for plantigrade carnivorans, they have the majority of the morphological characteristics identified for plantigrade species, and they have t...
Barefoot running has been associated with decreased stride length and switching from a rearfoot strike (RFS) pattern to a mid/forefoot strike (M/FFS) pattern. However, some individuals naturally contact the ground on their mid/forefoot, even when wearing cushioned running shoes. The purpose of this study was to determine if the mechanics of barefoo...
Morphometrics have been used for decades to answer functional morphology questions, especially with regards to skeletal structures. Many studies used linear measurements, although landmark based geometric morphometric datasets are becoming more common. However, even with this approach, a large amount of variation is missed due to the complex three...
Trotting, bipedal running, and especially hopping have long been considered the principal bouncing gaits of legged animals. We use the radial-leg spring constant [Formula: see text] to quantify the stiffness of the physical leg during bouncing gaits. The radial-leg is modeled as an extensible strut between the hip and the ground and [Formula: see t...
It is as yet unknown how large plantigrade quadrupeds move in their surroundings. Bears are the only group of such mammals in the world. However, they are relatively understudied in the areas of biomechanics and locomotion. This study represents one of the first to investigate the gait mechanics of grizzly bears (Ursus arctos horribilis). We used t...
A number of interventions and technique changes have been proposed to attempt to improve performance and reduce the number of running related injuries. Running shoes, barefoot running and alterations in spatio-temporal parameters (stride frequency and stride length) have been associated with significant kinematic and kinetic changes, which may have...
Bears are the only group of large, plantigrade, quadrupedal mammals in the world. However, they are relatively understudied in the areas of biomechanics and locomotion. This study represents one of the first to investigate the gaits mechanics used by grizzly bears (Ursus arctos horribilis). We used three high speed cameras and a custom built forcep...
Patellofemoral Pain Syndrome (PFPS) is pervasive and debilitating in the sport of cycling. Currently, little is known about the underlying mechanism causing patellofemoral pain in cyclists.
The purpose of this study was to determine if temporal differences in the muscle activity of the vastus medialis (VM), vastus lateralis (VL), semitendinosus (ST...
Bipedal hopping has evolved as a mode of terrestrial locomotion
in relatively few mammalian species. Despite large
differences in body size, habitat use, and having evolved independently,
all species that use bipedal hopping have remarkably
similar limb morphology and posture. In addition,
these species all have relatively long tails, presumably to...
The muscle work required to sustain steady-speed locomotion depends largely upon the mechanical energy needed to redirect the centre of mass and the degree to which this energy can be stored and returned elastically. Previous studies have found that large bipedal hoppers can elastically store and return a large fraction of the energy required to ho...
Most musculoskeletal models used to analyze human movement utilize Hill-type muscle models that account for state dependent intrinsic muscle properties (e.g., force-length-velocity relationships), but rarely do these models include history dependent effects (e.g., force depression or enhancement). While the relationship between muscle shortening an...
The regulation of whole-body angular momentum is essential for maintaining dynamic balance during human walking and appears to be tightly controlled during normal and pathological movement (e.g., [1, 2]). The primary mechanism to regulate angular momentum is muscle force generation, which accelerates the body segments and generates ground reaction...
Running-specific prostheses (RSF) are designed to replicate the spring-like nature of biological legs (bioL) during running. However, it is not clear how these devices affect whole leg stiffness characteristics or running dynamics over a range of speeds. We used a simple spring-mass model to examine running mechanics across a range of speeds, in un...
Walking is a complex dynamic task that requires the regulation of whole-body angular momentum to maintain dynamic balance while performing walking subtasks such as propelling the body forward and accelerating the leg into swing. In human walking, the primary mechanism to regulate angular momentum is muscle force generation. Muscles accelerate body...
Walking is a complex dynamic task that requires the generation of whole-body angular momentum to maintain dynamic balance and perform a wide range of locomotor tasks. Previous studies have shown that controlling angular momentum is essential to maintaining dynamic balance and preventing falls during walking [1] and recovering from a trip [2]. Other...
to the editor: We thank the authors of the comments for their time and ideas. Drs. Buckley and Cavagna (see Ref. [3][1]) raise important points regarding how leg spring stiffness affects running speed. It is well established that biological leg stiffness remains nearly constant across slow to
Running-specific prostheses (RSP) emulate the spring-like behaviour of biological limbs during human running, but little research has examined the mechanical means by which amputees achieve top speeds. To better understand the biomechanical effects of RSP during sprinting, we measured ground reaction forces (GRF) and stride kinematics of elite unil...
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Studies have suggested that the nervous system may adopt a control scheme in which synergistic muscle groups are controlled by common excitation patters, or modules, to simplify the coordination of movement tasks such as walking. A recent computer modeling and simulation study of human walking using experimentally derived modules as the control inp...
History-dependent effects on muscle force development following active changes in length have been measured in a number of experimental studies. However, few muscle models have included these properties or examined their impact on force and power output in dynamic cyclic movements. The goal of this study was to develop and validate a modified Hill-...
Complex musculoskeletal models and computer simulations can provide critical insight into muscle mechanical work output during locomotion. Simulations provide both a consistent mechanical solution that can be interrogated at multiple levels (muscle fiber, musculotendon, net joint moment, and whole-body work) and an ideal framework to identify limit...
Walking is the most common type of physical activity prescribed for the treatment of obesity. The net metabolic rate during level walking (W/kg) is approximately 10% greater in obese vs. normal weight adults. External mechanical work (W(ext)) is one of the primary determinants of the metabolic cost of walking, but the effects of obesity on W(ext) h...
The recent competitive successes of a bilateral, transtibial amputee sprint runner who races with modern running prostheses has triggered an international controversy regarding the relative function provided by his artificial limbs. Here, we conducted three tests of functional similarity between this amputee sprinter and competitive male runners wi...
Muscle mechanical output such as force and power are governed by highly nonlinear intrinsic muscle properties associated with different muscle fiber types and are influenced by training and age. Many of the interactions between these properties pose trade-offs such that an individual's anthropometrics and muscle morphology may allow an athlete to e...
A number of studies have examined the functional roles of individual muscles during normal walking, but few studies have examined which are the primary muscles that respond to changes in external mechanical demand. Here we use a novel combination of experimental perturbations and forward dynamics simulations to determine how muscle mechanical outpu...
The ankle plantar flexor muscles, gastrocnemius (Gas) and soleus (Sol), have been shown to play important roles in providing body support and forward propulsion during human walking. However, there has been disagreement about the relative contributions of Gas and Sol to these functional tasks. In this study, using independent manipulations of body...
Hindlimb musculoskeletal anatomy and steady speed over ground hopping mechanics were compared in two species of macropod marsupials, tammar wallabies and yellow-footed rock wallabies (YFRW). These two species are relatively closely related and are of similar size and general body plan, yet they inhabit different environments with presumably differe...
The aim of this study was to examine hind limb scaling of the musculoskeletal system in the Macropodoidea, the superfamily containing wallabies and kangaroos, to re-examine the effect of size on the locomotor mechanics and physiology of marsupial hopping. Morphometric musculoskeletal analyses were conducted of 15 species and skeletal specimens of 2...
We examined the functional role of two major proximal leg extensor muscles of tammar wallabies during level and inclined hopping (12 degrees, 21.3% grade). Previous in vivo studies of hopping wallabies have revealed that, unlike certain avian bipeds, distal hindlimb muscles do not alter their force-length behavior to contribute positive work during...
The goal of this study was to test whether the contractile patterns of two major hindlimb extensors of guinea fowl are altered by load-carrying exercise. We hypothesized that changes in contractile pattern, specifically a decrease in muscle shortening velocity or enhanced stretch activation, would result in a reduction in locomotor energy cost rela...
The goal of our study was to explore the mechanical power requirements associated with jumping in yellow-footed rock wallabies and to determine how these requirements are achieved relative to steady-speed hopping mechanics. Whole body power output and limb mechanics were measured in yellow-footed rock wallabies during steady-speed hopping and movin...
Differential pressure measurements offer a new approach for studying the aerodynamics of bird flight. Measurements from differential pressure sensors are combined to form a dynamic pressure map for eight sites along and across the wings, and for two sites across the tail, of pigeons flying between two perches. The confounding influence of accelerat...
Measurements of joint work and power were determined using inverse dynamics analysis based on ground reaction force and high-speed video recordings of tammar wallabies as they decelerated and accelerated while hopping over a force platform on level ground. Measurements were obtained over a range of accelerations ranging from -6 m s(-2) to 8 m s(-2)...
The goal of our study was to examine whether the in vivo force-length behavior, work and elastic energy savings of distal muscle-tendon units in the legs of tammar wallabies (Macropus eugenii) change during level versus incline hopping. To address this question, we obtained measurements of muscle activation (via electromyography), fascicle strain (...