Walking Legs Research Articles

Development and validation of a prognostic score integrating remote heart failure symptoms and clinical variables for mortality risk prediction after myocardial infarction. The PragueMi score

Abstract Background While heart failure (HF) symptoms are associated with adverse prognosis after myocardial infarction (MI), they are not routinely used for patients’ stratification. Purpose The primary objective of this study was to develop and validate a score to predict mortality risk after MI, combining remotely recorded HF symptoms and clinical risk factors, and to compare it against the guideline-recommended GRACE score. Methods A cohort study design using prospectively collected data from consecutive patients hospitalized for MI at a large tertiary heart centre between June 2017 and September 2022 was used. Results Data from 1,135 patients (aged 64±12 years, 26.7% women), were split into derivation (70%) and validation cohort (30%). Components of the 23-item Kansas City Cardiomyopathy Questionnaire (KCCQ) questionnaire and clinical variables were used as possible predictors. The best model included the following variables – age, heart failure history, admission creatinine and heart rate, ejection fraction at hospital discharge, and HF symptoms 1 month after discharge including walking impairment, leg swelling, and change in HF symptoms. Based on these variables, the PragueMi score was developed. In the validation cohort, the PragueMi score showed superior discrimination to the GRACE score for 6 months (AUC 90.1, 95% CI 81.8-98.4 vs. 77.4, 95% CI 62.2-92.5, p=0.04) and 1-year risk prediction (AUC 89.7, 95% CI 83.5-96.0 vs. 76.2, 95% CI 64.7-87.7, p=0.004). Conclusion The PragueMi score combining heart failure symptoms and clinical variables performs better than the currently recommended GRACE score.

Putative Nociceptive Responses in a Decapod Crustacean: The Shore Crab (Carcinus maenas)

Nociceptors are receptors that detect injurious stimuli and are necessary to convey such information from the periphery to the central nervous system. While nociception has been extensively studied in various taxa, there is relatively little electrophysiological evidence for the existence of nociceptors in decapod crustaceans. This study investigated putative nociceptive responses in the shore crabs, specifically their response to mechanical and noxious chemical stimuli. Extracellular multi-unit electrophysiological recordings were conducted from the anterior ganglion and the circumesophageal connective ganglia to assess nociceptive responses. Soft tissues at the joints of the chelae, antennae, and walking legs were stimulated using acetic acid (noxious stimulus) and von Frey hairs (mechanical stimulus), while nearby ganglion activity was recorded. The results indicate the existence of nociceptors in the tested areas, with mechanical stimuli eliciting shorter, more intense neural activity compared with acetic acid. Although acetic acid triggered responses in all areas, the antennae and antennules did not respond to mechanical stimuli. Though we acknowledge the challenges of conducting in vivo electrophysiological recordings, future research should focus on further characterizing nociceptor activity because the results suggest the presence of nociceptors.

Interlimb coordination is not strictly controlled during walking

In human walking, the left and right legs move alternately, half a stride out of phase with each other. Although various parameters, such as stride frequency and length, vary with walking speed, the antiphase relationship remains unchanged. In contrast, during walking in left-right asymmetric situations, the relative phase shifts from the antiphase condition to compensate for the asymmetry. Interlimb coordination is important for adaptive walking and we expect that interlimb coordination is strictly controlled during walking. However, the control mechanism remains unclear. In the present study, we derived a quantity that models the control of interlimb coordination during walking using two coupled oscillators based on the phase reduction theory and Bayesian inference method. The results were not what we expected. Specifically, we found that the relative phase is not actively controlled until the deviation from the antiphase condition exceeds a certain threshold. In other words, the control of interlimb coordination has a dead zone like that in the case of the steering wheel of an automobile. It is conjectured that such forgoing of control enhances energy efficiency and maneuverability. Our discovery of the dead zone in the control of interlimb coordination provides useful insight for understanding gait control in humans.

A new species of xanthid crab, Palapedia schubarti n. sp. (Decapoda, Brachyura, Xanthoidea), from Socotra, northwestern Indian Ocean

Abstract Palapedia schubarti n. sp. is the third species of the genus Palapedia, described from the northwestern Indian Ocean. Two species, P. persica and P. apeli, had already been recorded from the Persian Gulf, and the new species is described from farther south in Socotra Island. Palapedia persica has appendages markedly ornamented with large denticles, while P. apeli has distinctly smooth appendages. Compared to the two above-mentioned species, the new species has an intermediate position regarding the spination, with small denticles on the upper margin of the palm, fingers and anterior margin of walking legs. The morphology of the first male gonopod of P. schubarti n. sp. is very close to P. rastripes, described from Ceylon, and P. truncatifrons described from Japan. The new species, however, is easily distinguishable from those two congeners in having a spade form ending and several other characteristics of chelipeds and carapace.

Percutaneous unilateral vertebro-stentoplasty for painful osteoporotic compression fracture of lumbar vertebra

Osteoporosis is one of the common diseases in the elderly population which can cause compression fracture of the vertebral body due to loss of microarchitecture, loss of density, and deterioration of bone tissue leading to chronic pain, kyphotic deformity of the vertebra, and neurological complications. We report the case of a 68-year-old female, who presented to us with severe midback region pain for one year, which was increased over two months along with numbness in the right leg and difficulty in walking. The radiological investigation and magnetic resonance imaging spine revealed chronic compression fracture with the reduction in height of the L1 vertebra, which is seen with anterior wedging. The patient underwent vertebro-stentoplasty (VS) with bone cement, polymethyl-methacrylate. The patient was discharged well on third day of surgery. The VS for compression fracture of the lumbar vertebra demonstrated better results with improvement in pain and radiological finding in our patient.

Confirmation of Ostracotheres H. Milne Edwards, 1853 from Southeast Asia in a new species from Singapore and Indonesia (Crustacea: Decapoda: Brachyura)

A new species of the pinnotherid crab genus Ostracotheres H. Milne Edwards, 1853 described from Singapore and Indonesia is the third species in the genus, previously represented by O. cynthiae Nobili, 1906 and O. tridacnae (Rüppell, 1830) (type species), both known only from the Red Sea and western Gulf of Aden. Therefore, the new species represents the first confirmed record of the Ostracotheres outside of the western Indian Ocean and the twelfth species and ninth genus of pinnotherid to be recorded from Singapore. The new species is closest to O. cynthiae, differing in details of the epistome, ornamentation of the walking leg dactyli and proportional lengths of the walking legs. A key to the species of Ostracotheres is provided.

Prevalence, intensity, and attachment sites of larval mites (Acari: Erythraeidae) infesting Erginulus clavotibialis, a Neotropical harvestman (Opiliones: Cosmetidae) from Belize

Larval erythraeid mites of the genus Leptus Latreille, 1796 are common ectoparasites of terrestrial arthropods, including harvestmen (Order Opiliones). In this study, we investigated sexual, ontogenetic, and geographic variation in infestations of the Neotropical cosmetid harvestmen Erginulus clavotibialis (Cambridge, 1904) by larval mites across multiple sampling locations in Belize. We did not observe any significant differences in the prevalence or intensity of mite infestation with respect to sex of the host or between juveniles and adults. However, there was significant variation in the prevalence of infestation between field sites, varying from 18-71%. The overall mean intensity of infestation was 3.2 mites/host. Larval mites exhibited a non-random distribution with respect to attachment sites, with significantly more mites occurring on femur IV. Larval mites were absent from the tarsi of the walking legs and were rarely observed attached to the pedipalps or chelicerae of the harvestmen. Of the ten mites attached to hosts that were examined with SEM, six larvae were found in close association to abandoned attachment cones.

Pedestrian Walking Speed Analysis: A Systematic Review

(1) Background: Almost all trips include a walking leg. Pedestrian flow dynamics are an essential input to infrastructure design as well as efficient and safe operations. Pedestrian walking speed is the most influential traffic flow variable. This study examines the factors influencing pedestrian walking speed, categorizing them into pedestrian flow characteristics, pedestrian attributes, layout configuration, ambient conditions, and pedestrian behavioral patterns. (2) Methods: A comprehensive literature review was conducted, aggregating studies that investigate pedestrian walking speed across various environments and conditions. The identified factors were systematically categorized, and a meta-analysis was employed to synthesize the results. (3) Results: Speed measurements seem to be dependent on the method and technique employed, with experiments systematically overestimating speed and video recordings systematically underestimating it. Pedestrian density strongly influences speed as in motorized traffic. Being female, being of older age, walking in a group, engaging in social interactions or phone-related tasks, and moving under noise conditions are reported to have a negative impact on walking speed. Carrying baggage and moving under adverse weather conditions are also reported to have a statistically significant impact, but the direction of the impact is not always the same and seems to be very context dependent. (4) Conclusions: The findings highlight the significance of physiological, psychological, and environmental elements in shaping pedestrian behavior and thus speed. Valuable insights from this review can assist researchers, designers, and operators in providing safer, more inclusive, and reliable infrastructures for pedestrians. Future investigations should broaden the scope of data collection methods, particularly indoors.

Influence of the sagittal spinal profile type on the long-term outcome of patients with symptomatic lumbar spinal stenosis after microsurgical decompression

OBJECTIVE Microsurgical decompression for patients with symptomatic lumbar spinal stenosis (LSS) has demonstrated long-term improvement concerning pain and function. Nonetheless, a considerable proportion of these patients do not experience satisfactory alleviation of symptoms. Previous studies have not found a direct influence of single sagittal parameters on patient outcomes. However, recent research indicates that a composite of parameters, presented in specific sagittal profile types (SPTs) that were defined by Roussouly and colleagues, may affect these outcomes. This study aims to investigate the impact of SPT on long-term outcomes of patients with LSS following microsurgical decompression. METHODS This study is a prospective clinical observation. Patients with symptomatic LSS, who underwent microsurgical treatment and had long-term follow-up data for at least 36 months, were included. Patients with spinal deformity, fractures, or significant instability were excluded. Outcomes were measured using the numeric rating scale for pain, 36-Item Short Form Health Survey for quality of life, walking distance, Oswestry Disability Index, Roland-Morris Disability Questionnaire, and Odom’s criteria. SPT was determined in blinded fashion by using preoperative long standing radiographs. RESULTS The initial population of this observational study consisted of 128 patients, with long-term results available for 87 individuals, including 24 patients with SPT1, 20 with SPT2, 27 with SPT3, and 16 with SPT4. The average age was 70 years, with a slight male majority (56.3%) and a mean BMI of 27.9 kg/m2. After a median follow-up of 48 months, all groups showed significant improvement in walking distance, leg pain, and disability. Overall, 75% reported satisfaction with the surgery. However, patients with SPT1, which is characterized by low sacral slope and specific spinal curvatures, experienced significantly less improvement in back pain (p = 0.018) and related disability (p = 0.030), and lower satisfaction compared to other SPT groups (p = 0.008). CONCLUSIONS The sagittal spinal type is influencing the long-term outcome of patients suffering from symptomatic LSS. Patients with a combination of a flat sacral slope and a low overall lumbar lordosis with a high lordosis in the lower lumbar spine (i.e., spinal SPT1) showed worse outcome concerning back pain and had decreased satisfaction with surgery than comparable subjects from other SPT groups. Consequently, the authors recommend the assessment of sagittal spinal types in patients diagnosed with symptomatic spinal stenosis prior to decompression surgery. Inclusion of SPT in the preoperative consultation process can provide valuable insights, potentially guiding practitioners to more tailored patient counseling.

The Rediscovery of a Relict Unlocks the First Global Phylogeny of Whip Spiders (Amblypygi).

Asymmetrical rates of cladogenesis and extinction abound in the tree of life, resulting in numerous minute clades that are dwarfed by larger sister groups. Such taxa are commonly regarded as phylogenetic relicts or "living fossils" when they exhibit an ancient first appearance in the fossil record and prolonged external morphological stasis, particularly in comparison to their more diversified sister groups. Due to their special status, various phylogenetic relicts tend to be well-studied and prioritized for conservation. A notable exception to this trend is found within Amblypygi ("whip spiders"), a visually striking order of functionally hexapodous arachnids that are notable for their antenniform first walking leg pair (the eponymous "whips"). Paleoamblypygi, the putative sister group to the remaining Amblypygi, is known from Late Carboniferous and Eocene deposits but is survived by a single living species, Paracharon caecusHansen (1921), that was last collected in 1899. Due to the absence of genomic sequence-grade tissue for this vital taxon, there is no global molecular phylogeny for Amblypygi to date, nor a fossil-calibrated estimation of divergences within the group. Here, we report a previously unknown species of Paleoamblypygi from a cave site in Colombia. Capitalizing upon this discovery, we generated the first molecular phylogeny of Amblypygi, integrating ultraconserved element sequencing with legacy Sanger datasets and including described extant genera. To quantify the impact of sampling Paleoamblypygi on divergence time estimation, we performed in silico experiments with pruning of Paracharon. We demonstrate that the omission of relicts has a significant impact on the accuracy of node dating approaches that outweighs the impact of excluding ingroup fossils, which bears upon the ancestral range reconstruction for the group. Our results underscore the imperative for biodiversity discovery efforts in elucidating the phylogenetic relationships of "dark taxa," and especially phylogenetic relicts in tropical and subtropical habitats. The lack of reciprocal monophyly for Charontidae and Charinidae leads us to subsume them into one family, Charontidae, new synonymy.

Mechanical Properties, Tissue Structure, and Elemental Composition of the Walking Leg Tips of Coconut Crabs

The coconut crab, Birgus latro, has black protrusions on the tops of its walking legs and claw fingers. In addition, there are regularly aligned small black protrusions on parts of the exoskeleton surface of the claws and leg. In this study, the elemental composition, crystal structure, tissue structure, and mechanical properties of these protrusions were studied using a materials science approach, and the results were compared with those of mineralized cuticle. These leg tips were found to be a non-calcified fibrous tissue of α-chitin connected to the mineralized cuticle. The tip of the second walking leg was elongated and had a pointed shape with an oval cavity at its center that was more than 1000 times larger than the pore tubes (100–350 nm) of the mineralized cuticle. It was very soft, with a hardness of 0.4 GPa, corresponding to 11–12% of the hardness of the hard exocuticle and 55–57% of the hardness of the soft endocuticle. The elastic modulus of 8.0 GPa obtained by means of nanoindentation testing was consistent with that of α-chitin fibers of shrimp shells obtained by means of tensile testing. These soft protrusions provide a secure grip on the surfaces of trees or rocks and protect the claw fingertips. It was concluded that the black protrusions are related to a unique ecological (engaging in vertical movements, entering and exiting limestone caves, and escape behavior) aspect of the coconut crab, the largest terrestrial crustacean.

Integrated Modular Neural Control for Versatile Locomotion and Object Transportation of a Dung Beetle-Like Robot.

Dung beetles can effectively transport dung pallets of various sizes in any direction across uneven terrain. While this impressive ability can inspire new locomotion and object transportation solutions in multilegged (insect-like) robots, to date, most existing robots use their legs primarily to perform locomotion. Only a few robots can use their legs to achieve both locomotion and object transportation, although they are limited to specific object types/sizes (10%-65% of leg length) on flat terrain. Accordingly, we proposed a novel integrated neural control approach that, like dung beetles, pushes state-of-the-art insect-like robots beyond their current limits toward versatile locomotion and object transportation with different object types/sizes and terrains (flat and uneven). The control method is synthesized based on modular neural mechanisms, integrating central pattern generator (CPG)-based control, adaptive local leg control, descending modulation control, and object manipulation control. We also introduced an object transportation strategy combining walking and periodic hind leg lifting for soft object transportation. We validated our method on a dung beetle-like robot. Our results show that the robot can perform versatile locomotion and use its legs to transport hard and soft objects of various sizes (60%-70% of leg length) and weights (approximately 3%-115% of robot weight) on flat and uneven terrains. The study also suggests possible neural control mechanisms underlying the dung beetle Scarabaeus galenus' versatile locomotion and small dung pallet transportation.

Development and validation of a prognostic score integrating remote heart failure symptoms and clinical variables in mortality risk prediction after myocardial infarction: the PragueMi score.

While heart failure (HF) symptoms are associated with adverse prognosis after myocardial infarction (MI), they are not routinely used for patients' stratification. The primary objective of this study was to develop and validate a score to predict mortality risk after MI, combining remotely recorded HF symptoms and clinical risk factors, and to compare it against the guideline-recommended Global Registry of Acute Coronary Events (GRACE) score. A cohort study design using prospectively collected data from consecutive patients hospitalized for MI at a large tertiary heart centre between June 2017 and September 2022 was used. Data from 1135 patients (aged 64 ± 12 years, 26.7% women), were split into derivation (70%) and validation cohort (30%). Components of the 23-item Kansas City Cardiomyopathy Questionnaire and clinical variables were used as possible predictors. The best model included the following variables: age, HF history, admission creatinine and heart rate, ejection fraction at hospital discharge, and HF symptoms 1 month after discharge including walking impairment, leg swelling, and change in HF symptoms. Based on these variables, the PragueMi score was developed. In the validation cohort, the PragueMi score showed superior discrimination to the GRACE score for 6 months [the area under the receiver operating curve (AUC) 90.1, 95% confidence interval (CI) 81.8-98.4 vs. 77.4, 95% CI 62.2-92.5, P = 0.04) and 1-year risk prediction (AUC 89.7, 95% CI 83.5-96.0 vs. 76.2, 95% CI 64.7-87.7, P = 0.004). The PragueMi score combining HF symptoms and clinical variables performs better than the currently recommended GRACE score.

Factors associated with changes in walking performance in individuals 3 months after stroke or TIA: secondary analyses from a randomised controlled trial of SMS-delivered training instructions in Sweden

ObjectivesThis study aimed to identify factors related to changes in walking performance in individuals 3 months after a stroke or TIA.DesignCross-sectional study with post hoc analysis of a randomised controlled...

Three new interstitial species of the genus Neonesidea (Bairdioidea: Podocopida: Ostracoda) from the infralittoral zone in Japan.

This study is the first to report on interstitial species of the genus Neonesidea: Neonesidea arenalocus sp. nov. from the Pacific coast of central Japan, Neonesidea alyamanai sp. nov. from the Pacific coast of south-western Japan, and Neonesidea alwakasaensis sp. nov. from the Sea of Japan coast of western Japan. All three species share a smaller carapace size than that of the epiphytic Neonesidea species; in particular, the carapace width and valve thickness are significantly less. Furthermore, the terminal claws on the walking legs are more linear than those of the epiphytic Neonesidea species. However, these three new species share a feature in the apical portion of the terminal claw on the males second antennae and asymmetric brush-shaped organs, which are common to this genus. In addition, the results of our field survey indicate that all three new species occur in coarse-grained sediments (coarse sand to pebbles) in the upper infralittoral zone, particularly on Miho-Masaki Beach, which contains an optimum zone for N. arenalocus sp. nov.

Prevalence, clinical presentation, and risk factors of chronic venous disease in Cameroon: A general population-based study.

Chronic venous disease is a global public health problem, with high morbidity and economic distress. There is scarcity of data on this disease in sub-Saharan Africa. We conducted the first population-based study over a period of 20months from 1st February 2020 to 30th September 2021 in the 10 regions of Cameroon. A stratify sampling method was chose to select study site. Socio-demographic data, personal and family history, anthropometric parameters, clinical signs, illustrative images, CEAP (Clinical-Etiological-Anatomical-Pathophysiological) classification revised in 2004, VCSS (venous Clinical Severity Score) and risk factor assessment score were used to construct the survey form. Chi-squared test and Fischer exact test were used to compare the prevalence of chronic venous disease across different potential risk factors (sex, age category, previous history of deep vein thrombosis, hypertension, diabetes, smoking status, obesity). Simple and multiple logistic regression models were used to obtain crude and adjusted odds ratio for risk factors associated with chronic venous insufficiency. Statistical analyses were done with R version 4.2 for Linux and the threshold for statistical significance was 0.05. A total of 6578 participants were included in the study, with a mean age of 41.09 ± 16.02years with female predominance (54.3%). The prevalence of chronic venous disease was 21.8% (95% CI: 20.8-22.9) and the prevalence of chronic venous insufficiency (C3-C6) was 7.02% (n = 462). Night cramps (43.2%), oedema (21.7%), lower limbs pain (20.4%) mostly worsens by walking and heavy legs (16.2%) were more common symptoms. The mean total venous clinical severity score was 0.69 ± 1.76 and this score had a significant positive correlation with C classification (p < .001). In the multivariate analysis, the following factors were independently associated with CVD: Male gender (aOR: 1.27; 95%CI: 1.04-1.56; p = .021), retired people (aOR: 46.9; 95% CI: 12.6-174.5; p < .001), hypertension (aOR: 289.5; 95%CI: 169.69-493.1; p < .001), diabetes (aOR: 2.19; 95% CI: 1.21-3.96; p = .009), obesity (aOR: 10.22; 95%CI: 7.67-13.62; p < .001). Smoking appears as a protective factor (aOR: 0.18; 95%CI: 0.10-0.30; p < .001). Chronic venous disease is frequent in Cameroon and main traditional cardiovascular risk factors are associated to this condition. Systematic screening of the CVD in these specific groups could reduce the burden of the disease and its economic impact.

A Parallel Compliant Leg for energy efficient walking of exoskeleton–walker systems

Lower limb exoskeletons have garnered significant attention for their effectiveness in gait training for paraplegic patients. For patients with insufficient trunk or upper limb strength to maintain balance, employing an unpowered robotic walker with an exoskeleton for gait training is an effective approach. The energy efficiency of the actuation system is a pivotal consideration in the design of the exoskeleton–walker system due to its significant influence on the system’s durability and service efficiency. The main contribution of this paper is the development of a Parallel Compliant Leg (PCL) for the exoskeleton–walker system. The PCL consists of both powered legs of the exoskeleton and a passive flexible mechanism within the walker. This integration allows for the storage and release of energy during cyclic walking, resulting in reduced system energy consumption. To enhance energy efficiency, the support force optimization of the flexible mechanism is established. Based on this optimization, a design scheme and parameter optimization for the flexible mechanism are proposed. The effectiveness of the proposed flexible mechanism is verified through simulations on a robot simulation platform. Experimental results demonstrate a remarkable 67.6% reduction in system energy consumption achieved by the optimized mechanism.

Ecomorphological convergence in the walking leg dactyli of two clades of ascidian- and mollusc-associated shrimps (Decapoda: Caridea: Palaemonidae).

Symbiotic species, living within or on the surface of host organisms, may evolve a wide range of adaptations as a result of various selection pressures, host specificity of the symbiont and the nature of the symbiosis. In tropical marine coral reef ecosystems, palaemonid shrimps (Crustacea: Decapoda: Caridea) live in association with at least five different invertebrate phyla. Host switches between (distantly) related host groups, and the thereby associated selection pressures were found to play a major role in the diversification of these shrimp lineages, giving rise to various host-specific adaptations. Two lineages of palaemonid shrimp, which have switched from an ectosymbiotic association towards endosymbiosis, are studied for their morphological diversification and possible convergence. Special attention is given to the between-phyla host switches involving ascidian and bivalve hosts, which are characteristic for these lineages. Using landmark-based (phylo)morphospace analyses and Scanning Electron Microscopy, the walking leg dactylus shape and the microstructures on these dactyli are studied. No specific bivalve- or ascidian-associated morphotypes were found, but morphological convergence in dactylus morphology was found in various species within the two studied clades with similar host groups. In addition, multiple lineages of bivalve-associated species appear to be morphologically diverging more than their ascidian-associated relatives, with 'intermediate' morphotypes found near host-switching events.

Walking leg regeneration in the sea spider Nymphon brevirostre Hodge, 1863 (Pycnogonida)

Regeneration is widespread across all animal taxa, but patterns of its distribution and key factors determining regeneration capabilities stay enigmatic. A comparative approach could shed light on the problem, but its efficacy is limited by the fact that data is only available on a few species from derived taxa. Pycnogonida are nested basally within the Chelicerata. They can shed and replace their walking legs and have a high regeneration capacity. In this work, we carried careful observation on leg appendotomy and regeneration processes in a sea spider under laboratory settings. The limb structure and in vivo observation reveal autotomy as the most likely appendotomy mechanism. High regeneration capabilities were ascertained: an anatomically normal but small leg appeared in a single molting cycle and the full functionality regained in 2–3 cycles. Wound closure after appendotomy in N. brevirostre primarily relies on hemolymph coagulation, which apparently differs from both xiphosurans and crustaceans. Regeneration is provided by proliferation in the leg cutpiece. Regenerative morphogenesis resembles the normal ontogenetic morphogenesis of a walking leg, but accelerated. Unlike in most arthropods, in N. brevirostre, regeneration does not necessarily correspond to the molting cycle, inferring a plesiomorphic state.

Development of a model for a walking robot made of Desai mechanism using ANN and regression approach

The study focuses on computing the optimized foot profile for a walking leg mechanism using artificial neural network (ANN), genetic algorithm, and regression approaches. The technique adopted in this work is the benchmark approach and acts as a tool for complex problems. A mathematical model using regression and ANN is developed for the 8-link coplanar mechanism. Optimum link lengths are obtained to minimize the objective function (error). The output response is the foot length with a minimum foot height of 124 mm for obstacle clearance. A neural network is designed with seven neurons (one neuron/link) in the input layer. Optimum neurons in the hidden layer are determined based on the output obtained through simulation. A single neuron is used to represent the foot profile length at the output layer. The foot lengths obtained from the regression model and ANN are compared and validated with a genetic algorithm for the data sets of 100, 200, 300, 400, and 500. Simulation studies of the walking leg mechanism revealed a difference of 19%, 22.4%, and 5.23% in the foot profile by ANN and mathematical, ANN and regression model, and mathematical and regression approach respectively. This paper reveals that different approaches viz., ANN, mathematical and regression models generate dissimilar foot profiles.