scholarly journals Uneven substrates constrain walking speed in ants through modulation of stride frequency more than stride length

2020 ◽  
Vol 7 (3) ◽  
pp. 192068 ◽  
Author(s):  
G. T. Clifton ◽  
D. Holway ◽  
N. Gravish
Keyword(s):  
Stride Length ◽  
Field Experiments ◽  
Walking Speed ◽  
Stride Frequency ◽  
Mixed Effect ◽  
Uneven Terrain ◽  
Flat Substrate ◽  
Walking Performance ◽  
Kinematic Mechanisms ◽  
Walking Speeds

Natural terrain is rarely flat. Substrate irregularities challenge walking animals to maintain stability, yet we lack quantitative assessments of walking performance and limb kinematics on naturally uneven ground. We measured how continually uneven 3D-printed substrates influence walking performance of Argentine ants by measuring walking speeds of workers from laboratory colonies and by testing colony-wide substrate preference in field experiments. Tracking limb motion in over 8000 videos, we used statistical models that associate walking speed with limb kinematic parameters to compare movement over flat versus uneven ground of controlled dimensions. We found that uneven substrates reduced preferred and peak walking speeds by up to 42% and that ants actively avoided uneven terrain in the field. Observed speed reductions were modulated primarily by shifts in stride frequency instead of stride length (flat R 2 : 0.91 versus 0.50), a pattern consistent across flat and uneven substrates. Mixed effect modelling revealed that walking speeds on uneven substrates were accurately predicted based on flat walking data for over 89% of strides. Those strides that were not well modelled primarily involved limb perturbations, including missteps, active foot repositioning and slipping. Together these findings relate kinematic mechanisms underlying walking performance on uneven terrain to ecologically relevant measures under field conditions.

scholarly journals Rough substrates constrain walking speed in ants through modulation of stride frequency and not stride length

2019 ◽  
Author(s):  
G.T. Clifton ◽  
D. Holway ◽  
N. Gravish
Keyword(s):  
Stride Length ◽  
Field Experiments ◽  
Walking Speed ◽  
Stride Frequency ◽  
Rough Terrain ◽  
Flat Substrate ◽  
Walking Performance ◽  
Natural Terrain ◽  
Kinematic Mechanisms ◽  
Walking Speeds

AbstractNatural terrain is rarely flat. Substrate irregularities challenge walking animals to maintain stability, yet we lack quantitative assessments of walking performance and limb kinematics on naturally rough ground. We measured how continually rough 3D-printed substrates influence walking performance of Argentine ants by measuring walking speeds of workers from lab colonies and by testing colony-wide substrate preference in field experiments. Tracking limb motion in over 8,000 videos, we used statistical models that associate walking speed with limb kinematic parameters to compare movement over flat versus rough ground. We found that rough substrates reduced preferred and peak walking speeds by up to 42% and that ants actively avoided rough terrain in the field. Observed speed reductions were modulated primarily by shifts in stride frequency and not stride length, a pattern consistent across flat and rough substrates. Modeling revealed that walking speeds on rough substrates were accurately predicted based on flat walking data for over 89% of strides. Those strides that were not well modeled primarily involved limb perturbations, including missteps, active foot repositioning, and slipping. Together these findings relate kinematic mechanisms underlying walking performance on rough terrain to ecologically-relevant measures under field conditions.

scholarly journals Vision does not impact walking performance in Argentine ants

2020 ◽  
Vol 223 (20) ◽  
pp. jeb228460
Author(s):  
Glenna T. Clifton ◽  
David Holway ◽  
Nicholas Gravish
Keyword(s):  
Vision Loss ◽  
Obstacle Detection ◽  
Argentine Ant ◽  
Tactile Sensing ◽  
Long Distance ◽  
Uneven Terrain ◽  
Approach Speed ◽  
Close Range ◽  
Walking Performance ◽  
Walking Speeds

ABSTRACTMany walking insects use vision for long-distance navigation, but the influence of vision on rapid walking performance that requires close-range obstacle detection and directing the limbs towards stable footholds remains largely untested. We compared Argentine ant (Linepithema humile) workers in light versus darkness while traversing flat and uneven terrain. In darkness, ants reduced flat-ground walking speeds by only 5%. Similarly, the approach speed and time to cross a step obstacle were not significantly affected by lack of lighting. To determine whether tactile sensing might compensate for vision loss, we tracked antennal motion and observed shifts in spatiotemporal activity as a result of terrain structure but not illumination. Together, these findings suggest that vision does not impact walking performance in Argentine ant workers. Our results help contextualize eye variation across ants, including subterranean, nocturnal and eyeless species that walk in complete darkness. More broadly, our findings highlight the importance of integrating vision, proprioception and tactile sensing for robust locomotion in unstructured environments.

A Comparison of Algorithms for Body-Worn Sensor-Based Spatiotemporal Gait Parameters to the GAITRite Electronic Walkway

2012 ◽  
Vol 28 (3) ◽  
pp. 349-355 ◽  
Author(s):  
Barry R. Greene ◽  
Timothy G. Foran ◽  
Denise McGrath ◽  
Emer P. Doheny ◽  
Adrian Burns ◽  
...  
Keyword(s):  
Concurrent Validity ◽  
Stride Length ◽  
Walking Speed ◽  
Heel Strike ◽  
Gait Parameters ◽  
Stance Time ◽  
The Mean ◽  
Walking Speeds ◽  
Analysis Platform ◽  
Good Agreement

This study compares the performance of algorithms for body-worn sensors used with a spatiotemporal gait analysis platform to the GAITRite electronic walkway. The mean error in detection time (true error) for heel strike and toe-off was 33.9 ± 10.4 ms and 3.8 ± 28.7 ms, respectively. The ICC for temporal parameters step, stride, swing and stance time was found to be greater than 0.84, indicating good agreement. Similarly, for spatial gait parameters—stride length and velocity—the ICC was found to be greater than 0.88. Results show good to excellent concurrent validity in spatiotemporal gait parameters, at three different walking speeds (best agreement observed at normal walking speed). The reported algorithms for body-worn sensors are comparable to the GAITRite electronic walkway for measurement of spatiotemporal gait parameters in healthy subjects.

scholarly journals Contrasting the realized and fundamental niche of the arboreal walking performance of neotropical rodents

2015 ◽  
Vol 97 (1) ◽  
pp. 155-166 ◽  
Author(s):  
Nícholas F. Camargo ◽  
Nayara Y. Sano ◽  
Juliana F. Ribeiro ◽  
Emerson M. Vieira
Keyword(s):  
Stride Length ◽  
Performance Metrics ◽  
Strong Association ◽  
Ecological Factors ◽  
Relevant Information ◽  
Stride Frequency ◽  
Fundamental Niche ◽  
Terrestrial Species ◽  
Walking Performance ◽  
Neotropical Rodents

Abstract Evaluation of the fundamental niche under controlled conditions can provide relevant information about physiological, evolutionary, and ecological aspects of an organism, without the influence of external factors. We investigated how allometric, phylogenetic, and adaptive components contribute to arboreal walking performance by 7 sigmodontine rodents of the Brazilian savanna (Cerrado). We captured the rodents in the field and evaluated their performances by measuring stride length, stride frequency, and velocity on 5 horizontal supports: flat board and cylindrical plastic tubes with diameters of 5.0, 3.5, 2.5, and 2.0cm. Arboreal rodents exhibited higher velocities than terrestrial species by increasing stride frequency and decreasing stride length on supports with smaller diameters. However, terrestrial species decreased both stride frequency and stride length or tended to maintain stride length and vary stride frequency. Our results reveal a strong association between realized arboreal walking performances (as inferred by proportion of arboreal captures) and stride length and frequency. However, performance metrics were weakly related to body mass and exhibited no phylogenetic effects. Our results are consistent with the hypothesis that dynamically stable arboreal walking is facilitated by increased velocity. Arboreal walking performance is likely related to ecological factors rather than phylogenetic constraints. A avaliação do nicho fundamental por meio de condições controladas pode fornecer informações relevantes sobre aspectos fisiológicos, evolutivos e ecológicos de diferentes organismos, excluindo a influência de fatores externos. Considerando tal abordagem, nós investigamos como componentes alométricos, filogenéticos e adaptativos podem contribuir para a habilidade de locomoção arborícola em sete espécies de roedores sigmodontíneos do Cerrado. Os roedores foram capturados no campo e tiveram suas performances avaliadas por meio de medidas de tamanho de passos, frequência de passos e velocidade em cinco suportes horizontais distintos: tábua, e tubos cilíndricos de plástico com diâmetros de 5,0, 3,5, 2,5 e 2,0cm. Nossos resultados revelaram que roedores arborícolas apresentaram maiores velocidades em comparação com roedores mais terrestres. Adicionalmente, as espécies arborícolas mantiveram ou aumentaram a velocidade em suportes com menores diâmetros, enquanto que os roedores terrestres tenderam a reduzir a velocidade. Para as espécies arborícolas, tais velocidades foram obtidas por meio do aumento da frequência de passos e diminuição do tamanho dos passos. Entretanto, espécies primariamente terrestres diminuíram tanto a frequência quanto o tamanho dos passos, ou tenderam a manter a o tamanho de passos e variar a frequência de passos. Nossos resultados revelaram uma forte associação entre capturas acima do solo e o tamanho e frequência de passos. Contudo, tais aspectos da habilidade de locomoção tiveram fraca relação com a massa corporal e não tiveram relação com a filogenia das espécies analisadas. Nossos resultados corroboram a hipótese de que roedores necessitam aumentar velocidade como forma de manter a locomoção arborícola dinamicamente estável. Entretanto, a habilidade de locomoção é provavelmente mais relacionada com fatores ecológicos do que com restrições filogenéticas.

Gait Abnormalities in Elderly Fallers

2003 ◽  
Vol 11 (1) ◽  
pp. 40-52 ◽  
Author(s):  
Bernard Auvinet ◽  
Gilles Berrut ◽  
Claude Touzard ◽  
Laurent Moutel ◽  
Nadine Collet ◽  
...  
Keyword(s):  
Stride Length ◽  
Walking Speed ◽  
Stride Frequency ◽  
Routine Practice ◽  
Risk Of Falling ◽  
Risk Of Falls ◽  
S Period ◽  
Analysis System ◽  
Gait Abnormalities ◽  
Underlying Pathology

The objective of this study was to measure gait abnormalities in elderly fallers with the Locometrix™ gait-analysis system. This accelerometric device provided the following gait variables: walking speed and stride frequency, length, symmetry, and regularity. The variables were analyzed over a 20-s period of stable walking on a flat track of 40 m. Participants were 20 elderly patients hospitalized for falls (mean age 80.8 ± 5.0 years) and 33 older adults living at home (mean age 77.2 ± 6.5 years). All gait variables were found to be significantly lower in the faller group (p< .05). The lower gait speed, stride length, and stride frequency were previously recognized as nonrelevant in predicting the risk of falling, whereas lower stride symmetry was related to an underlying pathology and lower stride regularity was correlated to the risk of falls. The Locometrix appears to be well suited to measure gait regularity in routine practice.

scholarly journals Vision does not impact walking performance in Argentine ants

2020 ◽  
Author(s):  
G.T. Clifton ◽  
D. Holway ◽  
N. Gravish
Keyword(s):  
Vision Loss ◽  
Argentine Ant ◽  
Tactile Sensing ◽  
Long Distance ◽  
Argentine Ants ◽  
Uneven Terrain ◽  
Approach Speed ◽  
Close Range ◽  
Walking Performance ◽  
Walking Speeds

AbstractMany walking insects use vision for long-distance navigation, but the influence of vision in detecting close-range obstacles and directing the limbs to maintain stability remains largely untested. We compared Argentine ant workers in light versus darkness while traversing flat and uneven terrain. In darkness, ants reduced flat-ground walking speeds by only 5%. Similarly, neither the approach speed nor the time to cross a step obstacle was affected by lighting. To determine if tactile sensing might compensate for vision loss, we tracked antennal motion and observed shifts in spatiotemporal activity due to terrain structure but not illumination. Together, these findings suggest that vision does not impact walking performance in Argentine ant workers. Our results help contextualize eye variation across ants, including subterranean, nocturnal, and eyeless species that walk in complete darkness. More broadly, our findings highlight the importance of integrating vision, proprioception, and tactile sensing for robust locomotion in unstructured environments.

scholarly journals Limb swinging in elephants and giraffes and implications for the reconstruction of limb movements and speed estimates in large dinosaurs

Fossil Record ◽  
1999 ◽  
Vol 2 (1) ◽  
pp. 81-90 ◽  
Author(s):  
A. Christian ◽  
R. H. G. Müller ◽  
G. Christian ◽  
H. Preuschoft
Keyword(s):  
Detailed Analysis ◽  
Driving Force ◽  
Stride Length ◽  
Stride Frequency ◽  
Limb Movements ◽  
Eine Analyse ◽  
Fast Walking ◽  
Shoulder Joints ◽  
Walking Mechanism ◽  
Walking Speeds

Abstract. Speeds of walking dinosaurs that left fossil trackways have been estimated using the stride length times natural pendulum frequency of the limbs. In a detailed analysis of limb movements in walking Asian elephants and giraffes, however, distinct differences between actual limb movements and the predicted limb movements using only gravity as driving force were observed. Additionally, stride frequency was highly variable. Swing time was fairly constant, but especially at high walking speeds, much shorter than half the natural pendulum period. An analysis of hip and shoulder movements during walking showed that limb swinging was influenced by accelerations of hip and shoulder joints especially at high walking speeds. These results suggest an economical fast walking mechanism that could have been utilised by large dinosaurs to increase maximum speeds of locomotion. These findings throw new light on the dynamics of large vertebrates and can be used to improve speed estimates in large dinosaurs. Geschwindigkeiten gehender Dinosaurier, die fossile Fährten hinterlassen haben, wurden als Produkt aus Schrittlänge und natürlicher Pendelfrequenz der Beine abgeschätzt. Eine detaillierte Analyse der Beinbewegungen von gehenden Asiatischen Elefanten und Giraffen offenbarte allerdings klare Unterschiede zwischen den tatsächlichen Extremitätenbewegungen und den Bewegungen, die zu erwarten wären, wenn die Gravitation die einzige treibende Kraft darstellte. Zudem erwies sich die Schrittfrequenz als hochgradig variabel. Die Schwingzeit der Gliedmaßen war recht konstant, aber besonders bei hohen Gehgeschwindigkeiten viel kürzer als die halbe natürliche Pendelperiode der Extremitäten. Eine Analyse der Bewegungen der Hüft- und Schultergelenke während des Gehens zeigte, daß das Schwingen der Gliedmaßen durch Beschleunigungen dieser Gelenke beeinflußt wurde, insbesondere bei hohen Gehgeschwindigkeiten. Die Resultate legen einen ökonomischen Mechanismus für schnelles Gehen nahe, der von großen Dinosauriern zur Erhöhung der Höchstgeschwindigkeiten eingesetzt worden sein könnte. Die Ergebnisse werfen neues Licht auf die Dynamik großer Wirbeltiere. Sie können zu Verbesserungen in den Schätzungen der Fortbewegungsgeschwindigkeiten großer Dinosaurier eingesetzt werden. doi:10.1002/mmng.1999.4860020105

scholarly journals Comparison of Different Microprocessor Controlled Knee Joints on the Energy Consumption during Walking in Trans-Femoral Amputees: Intelligent Knee Prosthesis (IP) Versus C-Leg

2006 ◽  
Vol 30 (1) ◽  
pp. 73-80 ◽  
Author(s):  
Takaaki Chin ◽  
Katsuhiro Machida ◽  
Seishi Sawamura ◽  
Ryouichi Shiba ◽  
Hiroko Oyabu ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Knee Joint ◽  
Energy Efficient ◽  
Walking Speed ◽  
Knee Prosthesis ◽  
Knee Joints ◽  
Significant Difference ◽  
Walking Performance ◽  
In Trans ◽  
Walking Speeds

The purpose of this study was to investigate the characteristic differences between the IP and C-Leg by making a comparative study of energy consumption and walking speeds in trans-femoral amputees. The subjects consisted of four persons with traumatic trans-femoral amputations aged 17 – 33 years who had been using the IP and were active in society. Fourteen able-bodied persons served as controls. First the energy consumption at walking speeds of 30, 50, 70, and 90 m/min was measured when using the IP. Then the knee joint was switched to the C-Leg. The same energy consumption measurement was taken once the subjects were accustomed to using the C-Leg. The most metabolically efficient walking speed was also determined. At a walking speed of 30 m/min using the IP and C-Leg, the oxygen rate (ml/kg/min) was, on average, 42.5% and 33.3% higher ( P<0.05) than for the able-bodied group. At 50 m/min, the equivalent figures were 56.6% and 49.5% ( P<0.05), while at 70 m/min the figures were 57.8% and 51.2% ( P<0.05), and at 90 m/min the figures were 61.9% and 55.2% ( P<0.05%). Comparing the oxygen rates for the subjects using the IP and C-Leg at walking speeds of 30 m/min and 90 m/min it was found that subjects who used C-Leg walked somewhat more efficiently than those who used IP. However, there was no significant difference between the two types at each walking speed. It was also determined that the most energy-efficient walking speed for subjects using the IP and C-Leg was the same as for the controls. Although the subjects in this study walked with comparable speed and efficiency whether they used the IP or C-Leg, the subjects' energy consumption while walking with the IP and C-Leg at normal speeds were much lower than previously reported. This study suggested that the microprocessor controlled knee joints appeared to be valid alternative for improving walking performance of trans-femoral amputees.

scholarly journals Myofascial Release of the Hamstrings Improves Physical Performance—A Study of Young Adults

Healthcare ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 674
Author(s):  
Keisuke Itotani ◽  
Kanta Kawahata ◽  
Wakana Takashima ◽  
Wakana Mita ◽  
Hitomi Minematsu ◽  
...  
Keyword(s):  
Young Adults ◽  
Physical Performance ◽  
Walking Speed ◽  
Quadriceps Muscle ◽  
Lower Limbs ◽  
Joint Movement ◽  
Myofascial Release ◽  
Functional Reach Test ◽  
Hamstring Flexibility ◽  
Walking Speeds

Physical performance is mainly assessed in terms of gait speed, chair rise capacity, and balance skills, and assessments are often carried out on the lower limbs. Such physical performance is largely influenced by the strength of the quadriceps and hamstrings muscles. Flexibility of the hamstrings is important because quadriceps muscle activity influences the hip flexion angle. Therefore, hamstring flexibility is essential to improve physical performance. In this study, Myofascial Release (MFR) was applied to the hamstrings to evaluate its effects. MFR on the hamstrings was performed on 17 young adults. Physical function and physical performance were measured before, immediately after, and 5 days after the MFR intervention: finger floor distance (FFD), range of motion (ROM) of the straight leg raising test (SLR), standing long jump (SLJ), squat jump (SJ), functional reach test (FRT), comfortable walking speeds (C-walking speed), and maximum walking speeds (M-walking speed). The results of the analysis show a significant increase in FFD (−2.6 ± 8.9 vs. 0.4 ± 9.4 vs. 2.4 ± 8.9, p < 0.01), SLJ (185.6 ± 44.5 vs. 185.0 ± 41.8 vs. 196.6 ± 40.1, p < 0.01), and M-walking speed (2.9 ± 0.6 vs. 3.0 ± 0.6 vs. 3.3 ± 0.6, p < 0.01). This study has shown that MFR for hamstrings not only improves flexibility but also increases M-walking speed and physical performance of the SLJ. As MFR is safe and does not involve joint movement, it may be useful for maintaining and improving performance and flexibility during inactivity and for stretching before exercise.

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