scholarly journals Himalayan porter's specialization: metabolic power, economy, efficiency and skill

2006 ◽  
Vol 273 (1602) ◽  
pp. 2791-2797 ◽  
Author(s):  
Alberto E Minetti ◽  
Federico Formenti ◽  
Luca P Ardigò
Keyword(s):  
Motor Skills ◽  
Lower Cost ◽  
The Body ◽  
Metabolic Power ◽  
Oscillation Pattern ◽  
Load Carrying ◽  
Heavy Loads ◽  
Adaptation To Altitude ◽  
Real Challenge ◽  
Loaded Walking

Carrying heavy loads in the Himalayan region is a real challenge. Porters face extreme ranges in terrain condition, path steepness, altitude hypoxia and climate for 6–8 h a day, many months a year, since they were boys. It has been previously shown that, when carrying loads on level terrain, porters' metabolic economy is higher than in Caucasians but the reasons are still unknown. We monitored Nepalese porters both during 90 km trekking in Khumbu Valley and at two different altitudes (3490 and 5050 m above sea-level), where they were compared to Caucasian mountaineers during (22%) gradient walking. Both subject groups carried a load of up to 90% body mass. The remarkably higher performance of porters during uphill locomotion (+60% in speed, +39% mechanical power) is only partly explained by the lower cost of loaded walking (−20%), being also the result of a better cardio-circulatory adaptation to altitude, which generates a higher mass-specific metabolic power (+30%). Consequently, Nepalese porters show higher efficiency, both during uphill and downhill loaded walking. Their higher economy on steep paths cannot be ascribed to a better exchange between potential and kinetic energy, as in our experiments the body centre of mass travelled monotonically uphill (or downhill). A different oscillation pattern of the loaded head–trunk segment, together with the analysis of the different components of the mechanical work during load carrying, suggests that achieved motor skills in balancing the loaded body segment above the hip could play a role in determining the better economy of porters.

Design of Compliant Bamboo Poles for Carrying Loads

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Karna Potwar ◽  
Jeffrey Ackerman ◽  
Justin Seipel
Keyword(s):  
Low Cost ◽  
Material Design ◽  
The Body ◽  
Load Carriage ◽  
Design Parameters ◽  
Beam Model ◽  
Load Carrying ◽  
Predictive Design ◽  
Force Reduction ◽  
Heavy Loads

Carriage of heavy loads is common in developing countries and can impart large repetitive forces on the body that could lead to musculoskeletal fatigue and injury. Compliant bamboo poles have been used to carry heavy loads in Asia for generations and could be a low-cost, sustainable, and culturally acceptable way to minimize the forces acting on the body during load carriage. Experimental evidence of running with a 15 kg load suspended from a pair of compliant poly(vinyl chloride), or PVC, poles shows that the poles act as a vibration-isolating suspension, which can reduce the peak forces on the body during locomotion. However, it is currently not well-understood how to design and optimize poles for load carrying such that the peak forces on the body are minimized during carrying. Further, current users of bamboo poles do not have a reliable way to measure forces on the body and so cannot empirically optimize their poles for force reduction. Our objective is to determine the geometric and material design parameters that optimize bamboo poles for load carriage and to develop recommendations that could make it easier for load carriers to fabricate well-suited poles. Our approach is to synthesize a predictive model of walking and running from the field of biomechanics, which can predict the peak forces on the body as a function of pole stiffness, with a bending beam model of the bamboo pole that relates pole geometry and material to the effective pole stiffness. We first check our model's ability to predict the experimental results from a well-established study with PVC poles. We then extend the predictive design study to include a wider range of stiffness values and pole geometries that may be more effective and realistic for practical load carrying situations. Based on stiffness, deflection, strength, and pole mass design constraints, we specify an appropriate range of dimensions for selecting bamboo poles to carry a 15 kg load. The design methodology presented could simplify the selection and design of bamboo carrying poles in order to reduce the likelihood of musculoskeletal injury.

How to Carry Loads Economically: Analysis Based on a Predictive Biped Model

2019 ◽  
Vol 142 (4) ◽  
Author(s):  
Tong Li ◽  
Qingguo Li ◽  
Tao Liu ◽  
Jingang Yi
Keyword(s):  
Relative Motion ◽  
Energy Cost ◽  
Interaction Force ◽  
The Body ◽  
Additional Energy ◽  
Load Carrying ◽  
Walking Motion ◽  
Carrier Interaction ◽  
Heavy Loads ◽  
And Control

Abstract Carrying heavy loads costs additional energy during walking and leads to fatigue of the user. Conventionally, the load is fixed on the body. Some recent studies showed energy cost reduction when the relative motion of the load with respect to the body was allowed. However, the influences of the load's relative motion on the user are still not fully understood. We employed an optimization-based biped model, which can generate human-like walking motion to study the load–carrier interaction. The relative motion can be achieved by a passive mechanism (such as springs) or a powered mechanism (such as actuators), and the relative motion can occur in the vertical or fore-aft directions. The connection between the load and body is added to the biped model in four scenarios (two types × two directions). The optimization results indicate that the stiffness values affect energy cost differently and the same stiffness value in different directions may have opposite effects. Powered relative motion in either direction can potentially reduce energy cost but the vertical relative motion can achieve a higher reduction than fore-aft relative motion. Surprisingly, powered relative motion only performs marginally better than the passive conditions at similar peak interaction force levels. This work provides insights into developing more economical load-carrying methods and the model presented may be applied to the design and control of wearable load-carrying devices.

scholarly journals Hovering performance of Anna's hummingbirds ( Calypte anna ) in ground effect

2014 ◽  
Vol 11 (98) ◽  
pp. 20140505 ◽  
Author(s):  
Erica J. Kim ◽  
Marta Wolf ◽  
Victor Manuel Ortega-Jimenez ◽  
Stanley H. Cheng ◽  
Robert Dudley
Keyword(s):  
Wing Length ◽  
Ground Effect ◽  
The Body ◽  
Plane Angle ◽  
Metabolic Power ◽  
Wingbeat Frequency ◽  
Body Angle ◽  
Induced Flow ◽  
Induced Velocity ◽  
Calypte Anna

Aerodynamic performance and energetic savings for flight in ground effect are theoretically maximized during hovering, but have never been directly measured for flying animals. We evaluated flight kinematics, metabolic rates and induced flow velocities for Anna's hummingbirds hovering at heights (relative to wing length R = 5.5 cm) of 0.7 R , 0.9 R , 1.1 R , 1.7 R , 2.2 R and 8 R above a solid surface. Flight at heights less than or equal to 1.1 R resulted in significant reductions in the body angle, tail angle, anatomical stroke plane angle, wake-induced velocity, and mechanical and metabolic power expenditures when compared with flight at the control height of 8 R . By contrast, stroke plane angle relative to horizontal, wingbeat amplitude and wingbeat frequency were unexpectedly independent of height from ground. Qualitative smoke visualizations suggest that each wing generates a vortex ring during both down- and upstroke. These rings expand upon reaching the ground and present a complex turbulent interaction below the bird's body. Nonetheless, hovering near surfaces results in substantial energetic benefits for hummingbirds, and by inference for all volant taxa that either feed at flowers or otherwise fly close to plant or other surfaces.

The problem of studying motor skills in connection with the peculiarities of the body and psyche

1927 ◽  
Vol 23 (6-7) ◽  
pp. 735-740
Author(s):  
I. N. Zhilin
Keyword(s):  
Motor Skills ◽  
Motor Behavior ◽  
The Body ◽  
Motor Functions ◽  
Mental Structure ◽  
General Pathology ◽  
Mental Diseases

Kretschmer's doctrine of the correlation between physique and character overlooks a question that lies in the plane of similar correlations, namely, that of the correlation between motor functions and the mental structure of personality. This question attracts much attention these days and must occupy the most legitimate place among other problems included in the study of personality, both healthy and sick. In the latter case, it is worth remembering at least the instructions of Wernicke (2), who opined that "the general pathology of mental diseases consists in nothing else than in peculiarities of motor behavior".

scholarly journals Load carriage, human performance, and employment standards

2016 ◽  
Vol 41 (6 (Suppl. 2)) ◽  
pp. S131-S147 ◽  
Author(s):  
Nigel A.S. Taylor ◽  
Gregory E. Peoples ◽  
Stewart R. Petersen
Keyword(s):  
Work Performance ◽  
Human Performance ◽  
Performance Testing ◽  
The Body ◽  
Load Carriage ◽  
Physical Endurance ◽  
Physiological Strain ◽  
Employment Standards ◽  
Heavy Loads ◽  
External Loads

The focus of this review is on the physiological considerations necessary for developing employment standards within occupations that have a heavy reliance on load carriage. Employees within military, fire fighting, law enforcement, and search and rescue occupations regularly work with heavy loads. For example, soldiers often carry loads >50 kg, whilst structural firefighters wear 20–25 kg of protective clothing and equipment, in addition to carrying external loads. It has long been known that heavy loads modify gait, mobility, metabolic rate, and efficiency, while concurrently elevating the risk of muscle fatigue and injury. In addition, load carriage often occurs within environmentally stressful conditions, with protective ensembles adding to the thermal burden of the workplace. Indeed, physiological strain relates not just to the mass and dimensions of carried objects, but to how those loads are positioned on and around the body. Yet heavy loads must be borne by men and women of varying body size, and with the expectation that operational capability will not be impinged. This presents a recruitment conundrum. How do employers identify capable and injury-resistant individuals while simultaneously avoiding discriminatory selection practices? In this communication, the relevant metabolic, cardiopulmonary, and thermoregulatory consequences of loaded work are reviewed, along with concomitant impediments to physical endurance and mobility. Also emphasised is the importance of including occupation-specific clothing, protective equipment, and loads during work-performance testing. Finally, recommendations are presented for how to address these issues when evaluating readiness for duty.

scholarly journals KAPASITAS PERKEMBANGAN KEMAMPUAN MOTORIK PADA ANAK USIA TAMAN KANAK-KANAK

2019 ◽  
Vol 7 (2) ◽  
pp. 26-37
Author(s):  
Ahadin Ahadin
Keyword(s):  
Motor Skills ◽  
Motor Development ◽  
The Body ◽  
Power Balance ◽  
Motor Behaviour ◽  
Motor Ability ◽  
Community Environment ◽  
Child Interaction ◽  
Individual Capacity ◽  
Integrated Or

Motor ability is an individual capacity to develop the ability of the skills that are possessed in an effort to heighten or accelerate the mastery of a skill. Individual capacities that are motor capability consist of: speed (speed), agility, power, balance (balance), flexibility (flexibility), and coordination (coordination). Motor development is a change in motor behaviour that occurs because of maturity and child interaction with the environment. Maturity is a change that occurs in the body within a period of time. While the environment consists of: family, friends play, and community environment. The function of motor capability for children in kindergarten is to promote labor, facilitate, accelerate in the mastery of various motor skills studied. Motor skills are a child's ability to display or demonstrate a skill. Motor capability occurs or is acquired through an integrated or associated process along with an exercise or enhancement through experience. Motor capability will occur with a change from time to time relatively permanent in the capacity to showcase a skilled motor skill.

scholarly journals Morphological characteristics and motor skills of young students with different levels of engagement in physical activities (Características morfológicas y habilidades motrices de estudiantes jóvenes con diferentes niveles de participación en actividad

Retos ◽  
2017 ◽  
pp. 58-62
Author(s):  
Maja Batez ◽  
Branko Krsmanović ◽  
Milena Mikalački ◽  
Nebojša Čokorilo ◽  
Marijana Simić ◽  
...  
Keyword(s):  
Physical Activity ◽  
Motor Skills ◽  
Physical Activity Level ◽  
Morphological Characteristics ◽  
Research Problem ◽  
Physical Activities ◽  
The Body ◽  
Activity Level ◽  
Los Grupos ◽  
Shuttle Run

The overall orientation of the research problem is focused on the physical activity level of the participants from the aspect of different intensities of motor engagement and their impact on morphological characteristics and motor skills with an intention of determining whether there are statistically significant differences between groups. In a sample of 103 students, aged between 18 and 20 years (18.9 ± 0.4), the female students were divided into three subsamples according to the level of physical activity: highly active, active and inactive. The study which was conducted had a transversal character. The data obtained in the survey were analysed using the univariate (ANOVA) and multivariate (MANOVA) statistical methods. The motor skills mere monitored by the use of the Eurofit Test Battery (wide-angle seated forward bend, standing long jump, pull-up endurance, 10 x 5m shuttle run and endurance shuttle run- beep test). The following morphological characteristics were considered: height, weight, body mass index, percentage of muscular mass and fat mass, as well as waist circumference. The obtained results indicate the existence of statistically significant differences between the % body muscle mass´ groups (p < 0.05) and motor skills parameters (sit and reach, p<0.01; standing broad jump, bent arm hang, 10x5m shuttlerun, beep test, p<0.001) of participants according to physical activity level. In conclusion, participants with a high level of physical activities have higher average values than the participants with light level of physical activities when considering the variables for assessing pliability, strength and agility.Resumen. La orientación general del problema de investigación se centra en el nivel de actividad física de las participantes desde el aspecto de diferentes intensidades de compromiso motor y su impacto en las características morfológicas y habilidades motrices con la intención de determinar si existen diferencias estadísticamente significativas entre los grupos. En una muestra de 103 alumnas, con edades comprendidas entre los 18 y 20 años (18,9 ± 0,4), las estudiantes fueron divididas en tres grupos de acuerdo con el nivel de actividad física de cada uno: muy activas, activas e inactivas. El estudio llevado a cabo tuvo un carácter transversal. Los datos obtenidos mediante cuestionarios fueron analizados utilizando un análisis de la varianza (ANOVA) y un análisis multivariante de la varianza (MANOVA). Las habilidades fueron controladas mediante la batería Eurofit y para las características morfológicas, se midió la altura, peso, índice de masa corporal, porcentaje de masa muscular, masa grasa y la circunferencia de la cintura. Los resultados obtenidos indican la existencia de diferencias entre los grupos estudiados respecto al % de masa muscular (p <0.05) y las habilidades motrices (flexibilidad-inclinación hacia adelante, p<0.01; salto de longitud a pie, fuerza resistencia mediante flexión de brazos, 10 x 5 m carrera de ida y vuelta y Beep Test, p<0.001) de los participantes según el nivel de actividad física. En conclusión, las participantes con alto nivel de actividad física tienen mayores valores de habilidad motriz que las participantes que el resto en función de las variables flexibilidad, capacidad aeróbica, fuerza y agilidad.

scholarly journals THE ROLE OF PHYSICAL THERAPY IN EDUCATING A CORRECT BODY POSTURE IN SCHOOL CHILDREN

GYMNASIUM ◽  
2017 ◽  
Vol XVII (1) ◽  
Author(s):  
Alina Mihaela Cristuță
Keyword(s):  
Physical Therapy ◽  
Motor Skills ◽  
School Children ◽  
The Body ◽  
Body Posture ◽  
Intervention Programs ◽  
Intervention Measures ◽  
Specific Assessment ◽  
External Stimuli

Posture expresses the way in which the body receives external stimuli and gets ready to react, constantly adapting to the demands, according to the difficulty and to the individual's motor skills. The aim of this study is to educate the correct body posture through specific physical therapy means. The hypotheses presume that: by performing a specific assessment, one can spot the bad postures that are frequently adopted by school children; through specific intervention programs, one can educate, correct, and form a correct posture reflex. The objectives were to: assess the school children in order to spot physical deficiencies; to educate a correct posture and to form a correct posture reflex. The research methods were established according to the objectives. In the end, it can be concluded that this research  regarding the education of posture in school children has contributed to the prevention of instalment of physical deficiencies and to their correction, and the intervention measures were effective in educating the correct body posture.

scholarly journals THE SIGNIFICANCE OF ORIENTATION OF BLIND PUPILS TO THEIR BODY IN REGARD TO MOBILITY AND SPACE ORIENTATION

2018 ◽  
Vol 8 (1) ◽  
pp. 10-16
Author(s):  
Amela Teskeredžić ◽  
Keyword(s):  
Motor Skills ◽  
Test Methods ◽  
The Body ◽  
Children And Youth ◽  
Blind And Visually Impaired ◽  
Final Measurement ◽  
Orientation And Mobility ◽  
Impaired Children ◽  
Visually Impaired Children ◽  
Blind Students

Independent and safe movement includes the development of motor skills, the acquisition of basic concepts, the awareness of oneself and the awareness of the environment. The aim of the research was to determine the influence and significance of the orientation to the body of blind students, on orientation and mobility. The sample consisted of 30 blind students aged 7 to 15, placed in the internal accommodation of the Center for Children and Youth with Developmental Disabilities "Budućnost" in Derventa and the Center for Blind and Visually Impaired Children and Youth in Sarajevo. The research used an instrument for assessing the ability of the mobility of the blind, which established the initial and final levels of development of the ability to orientate towards one's own body and the mobility of blind students. For statistical data processing, descriptive statistics and t-test methods were used. The results are in favor of the final measurement, that is, after the treatment was carried out, the improvement of the orientation towards the body was determined, which influenced the orientation and mobility of the blind pupils.

scholarly journals Theoretical-Methodological Considerations Regarding the Formation and Strengthening of Motor Skills in Military Physical Education

2016 ◽  
Vol 22 (2) ◽  
pp. 496-500
Author(s):  
Robert Stănciulescu
Keyword(s):  
Physical Education ◽  
Motor Skills ◽  
The Body ◽  
Advanced Level ◽  
State Of Mind ◽  
Level Of Training ◽  
Methodological Considerations ◽  
The Military

Abstract The programme of training in the field of military physical education is directed towards developing an efficient motor capacity by ensuring superior development gauges for basic motor skills and for the motor skills and aptitudes specific to the military system, as well as towards developing the body resilience to stress, enhancing productivity and the mental alarm state of mind, elements playing an important role in improving the combat capacity. In the economy of the formative process, the basic motor and utility-applicable skills represent the essence of an advanced level of training in the field of physical education, so that their development, strenghening and improvement will always be a constant priority objective of training.

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