Uphill Gradients Research Articles

The Soft Prefabricated Orthopedic Insole Decreases Plantar Pressure during Uphill Walking with Heavy Load Carriage.

This study aimed to investigate the effect of varying the hardness of prefabricated orthopedic insoles on plantar pressure and muscle fatigue during uphill walking with a heavy backpack. Fifteen healthy male recreational athletes (age: 20.4 ± 1.0 years, height: 176.9 ± 5.7 cm, weight: 76.5 ± 9.0 kg) wore prefabricated orthopedic insoles with foot arch support; a heel cup with medium (MI), hard (HI), and soft (SI) relative hardnesses; and flat insoles (FI). They performed treadmill walking on uphill gradients with 25 kg backpacks. The plantar pressure and surface electromyographic activity were recorded separately, in 30 s and 6 min uphill treadmill walking trials, respectively. The HI, MI, and SI significantly decreased peak plantar pressure in the lateral heel compared to FI. The MI and SI significantly decreased the peak plantar pressure in the fifth metatarsal compared to FI. The MI significantly reduced the pressure-time integral in the lateral heel compared to FI. The HI significantly increased the peak plantar pressure and pressure-time integral in the toes compared to other insoles, and decreased the contact area in the metatarsal compared to SI. In conclusion, a prefabricated orthopedic insole made of soft material at the fore- and rearfoot, with midfoot arch support and a heel cup, may augment the advantages of plantar pressure distribution during uphill weighted walking.

Gait and neuromuscular dynamics during level and uphill walking carrying military loads

ABSTRACT The neuromuscular system responds to perturbation and increasing locomotor task difficulty by altering the stability of neuromuscular output signals. The purpose of this study was to determine the effects of two different military load carriage systems on the dynamic stability of gait and muscle activation signals. 14 army office cadets (20 ± 1 years) performed 4-minute treadmill walking trials on level (0%) and uphill (10%) gradients while unloaded, and with 11 kg backpack and 11 kg webbing loads while the activity of 6 leg and trunk muscles and the motion of the centre of mass (COM) were recorded. Loaded and uphill walking decreased stability and increased magnitude of muscle activations compared to loaded and level gradient walking. Backpack loads increased the medio-lateral stability of COM and uphill walking decreased stability of vertical COM motion and increased stride time variability. However, there was no difference between the two load carriage systems for any variable. The reduced stability of muscle activations in loaded and uphill conditions indicates an impaired ability of the neuromuscular control systems to accommodate perturbations in these conditions which may have implications on the operational performance of military personnel. However, improved medio-lateral stability in backpack conditions may indicate that participants were able to compensate for the loads used in this study, despite the decreased vertical stability and increased stride time variability evident in uphill walking. This study did not find differences between load carriage systems however, specific load carriage system effects may be elicited by greater load carriage masses.

Effect of shod walking on plantar pressure with varying uphill gradients

Background: Uphill walking is biomechanically stressful. Changes in plantar pressure, is one of the important predictors of this stress and increased risk of foot injuries. It has been reported that civilians as well as different occupational workers have to walk over uphill gradient with footwear which may cause changes in plantar pressure. Till date published data on plantar pressure is not available of Indian population during shod walking with uphill gradients.
 Aims and Objective: The present study was aimed to generation of data base on plantar pressure and find out the effect of shod walking (wearing occupational boot) on plantar pressure at different uphill gradients.
 Materials and Methods: Twenty healthy male participated in this study. Plantar pressure was recorded using the pressure measurement system during walking at 4 km/hr speed on treadmill at level and different uphill gradients.
 Results: It was observed that the PP at all the five regions of both right and left foot (Forefoot, Mid-foot, Medial, Lateral, Heel and Overall) increased gradually along with the increase in gradients. There was significant increase of 8.94%, 9.93%, 18.22%, 16.06%, 10.27%, 12.92% respectively at left forefoot, mid-foot, heel, medial, lateral and overall regions at 10% gradient compared to level walking. Similarly, in right foot the increase was observed 8.20%, 10.82%, 14.28%, 13.75%, 8.27%, 10.88% in respective foot regions compared to level walking.
 Conclusion: Observations of the present study stated that with increasing gradient plantar pressure at various foot regions increased in both feet in comparison to level walking, maximum plantar pressure observed in heel region in both feet in comparison to other studied regions. This data will be considered as normal planter pressure value of adults at level and uphill gradients shod walking and may be utilized for prognosis of foot disorders and efficacy of treatment modalities of population comparable with studied individuals (for similar age, height and weight).

Sex-based differences in sub-technique selection during an international classical cross-country skiing competition.

The purpose of this study was to compare speed, sub-technique selection and temporal patterns between world-class male and female cross-country (XC) skiers and to examine the combined associations of sex and speed on sub-technique selection. Thirty-three XC skiers performed an international 10-km (women; n = 8) and 15-km (men; n = 25) time-trial competition in the classical style (with the first 10 km of the race being used for analyses). An integrated GNSS/IMU system was used to continuously track position speed and automatically classify sub-techniques and temporal patterns (i.e. cycle length and–rate). When comparing the eight highest ranked men and women, men spent less time than women (29±2 vs. 45±5% of total time) using diagonal stride (DIA), more time (44±4 vs. 31±4%) using double poling (DP) and more time (23±2 vs. 19±3%) using tucking and turning (all P < .01). Here, men and women used these sub-techniques at similar temporal patterns within the same speed-intervals; although men employed all sub-techniques at steeper uphill gradients (all P < .05). In subsequent analyses including all 33 skiers, adjustment for average racing speed did not fully attenuate the observed sex differences in the proportion of time using DIA (CI95% [-10.7, -1.6]) and DP (CI95% [0.8, 9.3]). Male world-class XC skiers utilized less DIA and more DP compared to women of equal performance levels. Although these differences coincided with men’s higher speed and their ability to use the various sub-techniques at steeper uphill gradients, sexual dimorphism in the proportional use of DIA and DP also occurred independently of these speed-differences.

Biomechanical and metabolic aspects of backward (and forward) running on uphill gradients: another clue towards an almost inelastic rebound

PurposeOn level, the metabolic cost (C) of backward running is higher than forward running probably due to a lower elastic energy recoil. On positive gradient, the ability to store and release elastic energy is impaired in forward running. We studied running on level and on gradient to test the hypothesis that the higher metabolic cost and lower efficiency in backward than forward running was due to the impairment in the elastic energy utilisation.MethodsEight subjects ran forward and backward on a treadmill on level and on gradient (from 0 to + 25%, with 5% step). The mechanical work, computed from kinematic data, C and efficiency (the ratio between total mechanical work and C) were calculated in each condition.ResultsBackward running C was higher than forward running at each condition (on average + 35%) and increased linearly with gradient. Total mechanical work was higher in forward running only at the steepest gradients, thus efficiency was lower in backward running at each gradient.ConclusionEfficiency decreased by increasing gradient in both running modalities highlighting the impairment in the elastic contribution on positive gradient. The lower efficiency values calculated in backward running in all conditions pointed out that backward running was performed with an almost inelastic rebound; thus, muscles performed most of the mechanical work with a high metabolic cost. These new backward running C data permit, by applying the recently introduced ‘equivalent slope’ concept for running acceleration, to obtain the predictive equation of metabolic power during level backward running acceleration.

On the simple calculation of walking efficiency without kinematic information for its convenient use

BackgroundSince walking is a daily activity not to require the maximal effort in healthy populations, a very few universal bio-parameters and/or methods have been defined to evaluate individual walking characteristics in those populations. A concept of “economy” is a potential candidate; however, walking economy highly depends on speed, so direct comparisons of economy values are difficult between studies. We investigated whether the vertical component of net walking “efficiency” (Effvert; %) is constant across speed. In that case, direct comparisons of Effvert will be possible between studies or individuals at any voluntary speed.MethodsThirty young male participants walked at eight speeds on the level or ± 5% gradients, providing vertical speeds (vvert). Differences in energy expenditure between level and uphill or downhill gradients (ΔEE) were calculated. The metabolic rate for vertical component (MRvert) was calculated by multiplying ΔEE with body mass (BM). The mechanical power output for vertical component (Pmech) was calculated by multiplying BM, gravitational acceleration, and vvert. Effvert was obtained from the ratio of Pmech to MRvert at each vvert. Delta efficiency (Delta-E; %) was also calculated from the inverse slope of the regression line representing the relationship of Pmech to MRvert.ResultsUpward Effvert was nearly constant at around 35% and downward Effvert ranged widely (49–80%). No significant differences were observed between upward Delta-E (35.5 ± 8.8%) and Effvert at any speeds, but not between downward Delta-E (44.9 ± 12.8%) and Effvert.ConclusionsUpward ΔEE could be proportional to vvert. Upward, but not downward, Effvert should be useful not only for healthy populations but also for clinical patients to evaluate individual gait characteristics, because it requires only two metabolic measurements on the level and uphill gradients without kinematic information at any voluntary speed.Trial registrationUMIN000017690 (R000020501; registered May 26th, 2015, before the first trial) and UMIN000031456 (R000035911; registered Feb. 23rd, 2018, before the first trial).

Effect of heavy load carriage on cardiorespiratory responses with varying gradients and modes of carriage

BackgroundThe present study was undertaken to determine the effect of different uphill and downhill gradients on cardiorespiratory and metabolic responses of soldiers while carrying heavy military loads in two different modes.MethodsEight physically fit male soldiers with a mean age 32.0 ± 2.0 years, a mean height of 169.5 ± 4.9 cm, and a mean weight of 63.8 ± 8.4 kg volunteered for this study. Each volunteer completed treadmill walking trials at a speed of 3.5 km/h while carrying no external load, 31.4 kg load in a distributed mode (existing load carriage ensembles) and compact mode (new back pack) over 5 different downhill and uphill gradients (− 5, − 10%, 0, 5, 10%) for 6 min at each gradient. During the walking trials, heart rate (HR), oxygen uptake (VO2), respiratory frequency (RF) and energy expenditure (EE) were determined by the process of breath-by-breath gas analysis using a K4b2 system. The average of the last 2 min data from each 6 min walking trial for each individual was subjected to statistical analysis.ResultsAll parameters (HR, VO2, RF, and EE) gradually increased with the change in gradient from downhill to level to uphill. The distributed mode showed higher values compared to compact mode for all gradients, e.g., for VO2, there was a 10.7, 7.4, 5.1, 28.2 and 18.7% increase in the distributed mode across the 5 different gradients.ConclusionIt can be concluded from the present study that the compact mode of load carriage is more beneficial than the distributed mode in terms of cardiorespiratory responses while walking on downhill and uphill surfaces with a 31.4 kg load.

Energy cost and lower leg muscle activities during erect bipedal locomotion under hyperoxia

BackgroundEnergy cost of transport per unit distance (CoT) against speed shows U-shaped fashion in walking and linear fashion in running, indicating that there exists a specific walking speed minimizing the CoT, being defined as economical speed (ES). Another specific gait speed is the intersection speed between both fashions, being called energetically optimal transition speed (EOTS). We measured the ES, EOTS, and muscle activities during walking and running at the EOTS under hyperoxia (40% fraction of inspired oxygen) on the level and uphill gradients (+ 5%).MethodsOxygen consumption left(dot{V}{mathrm{O}}_2right) and carbon dioxide output left(dot{V}{mathrm{CO}}_2right) were measured to calculate the CoT values at eight walking speeds (2.4–7.3 km h−1) and four running speeds (7.3–9.4 km h− 1) in 17 young males. Electromyography was recorded from gastrocnemius medialis, gastrocnemius lateralis (GL), and tibialis anterior (TA) to evaluate muscle activities. Mean power frequency (MPF) was obtained to compare motor unit recruitment patterns between walking and running.Results dot{V}{mathrm{O}}_2 , dot{V}{mathrm{CO}}_2 , and CoT values were lower under hyperoxia than normoxia at faster walking speeds and any running speeds. A faster ES on the uphill gradient and slower EOTS on both gradients were observed under hyperoxia than normoxia. GL and TA activities became lower when switching from walking to running at the EOTS under both FiO2 conditions on both gradients, so did the MPF in the TA.ConclusionsES and EOTS were influenced by reduced metabolic demands induced by hyperoxia. GL and TA activities in association with a lower shift of motor unit recruitment patterns in the TA would be related to the gait selection when walking or running at the EOTS.Trial registrationUMIN000017690 (R000020501). Registered May 26, 2015, before the first trial.

The effect of prolonged level and uphill walking on the postural control of older adults

Prolonged walking could alter postural control leading to an increased risk of falls in older adults. The aim of this study was to determine the effect of level and uphill prolonged walking on the postural control of older adults. Sixteen participants (64 ± 5 years) attended 3 visits. Postural control was assessed during quiet standing and the limits of stability immediately pre, post and post 15 min rest a period of 30 min walking on level and uphill (5.25%) gradients on separate visits. Each 30 min walk was divided into 3 10 min blocks, the limits of stability were measured between each block. Postural sway elliptical area (PRE: 1.38 ± 0.22 cm2, POST: 2.35 ± 0.50 cm2, p = .01), medio-lateral (PRE: 1.33 ± 0.03, POST: 1.40 ± 0.03, p = .01) and anterio-posterior detrended fluctuation analysis alpha exponent (PRE: 1.43 ± 0.02, POST: 1.46 ± 0.02, p = .04) increased following walking. Medio-lateral alpha exponent decreased between post and post 15 min’ rest (POST: 1.40 ± 0.03, POST15: 1.36 ± 0.03, p = .03). Forward limits of stability decreased between the second walking interval and post 15 min’ rest (Interval 2: 28.1 ± 1.6%, POST15: 25.6 ± 1.6%, p = .01) and left limits of stability increased from pre-post 15 min’ rest (PRE: 27.7 ± 1.2%, POST15: 29.4 ± 1.1%, p = .01). The neuromuscular alterations caused by prolonged walking decreased the anti-persistence of postural sway and altered the limits of stability in older adults. However, 15 min’ rest was insufficient to return postural control to pre-exercise levels.

Assessment of Muscular Fatigue with Electromyography on Lower Back and Leg Muscles during Continuous Uphill and Downhill Load Carriage Task

&lt;p&gt;Soldiers of Indian Army need to carry moderate to heavy load in complex terrain conditions as their routine activity, which may prove to be highly tiring for leg and back muscles. Soldiers’ regular movement at hilly area was simulated in a study consisting of a continuous uphill (UH) and downhill (DH) load carriage task to monitor state of fatigue at back and lower limb muscles. Twelve Indian soldiers walked at a fixed speed on five UH and five DH gradients with three loads (0, 10.7 kg and 21.4 kg). Electromyographic (EMG) recording was carried out throughout the experimentation on four groups of muscles- left and right Erector spinae (ESR and ESL), Vastus medialis (VMR and VML), Gastrocnemius medialis (GMR and GML), and Soleus (SOR and SOL) muscles. Median frequency (MDF) responses of tested muscles were derived from raw (EMG) data. Higher level of muscle fatigue was observed at highest UH inclination as the MDF response in GMR, GML and VMR was lowest at this point. The MDF response were found to be lower at DH gradients as the physical demand of that stage is less than the UH gradients.&lt;/p&gt;

The pendular mechanism does not determine the optimal speed of loaded walking on gradients

The pendular mechanism does not act as a primary mechanism in uphill walking due to the monotonic behavior of the mechanical energies of the center of mass. Nevertheless, recent evidence shows that there is an important minimization of energy expenditure by the pendular mechanism during walking on uphill gradients. In this study, we analyzed the optimum speed (OPT) of loaded human walking and the pendulum-like determining variables (Recovery R, Instantaneous pendular re-conversion Rint, and Congruity percentage %Cong). Ten young men walked on a treadmill at five different speeds and at three different treadmill incline gradients (0, +7 and +15%), with and without a load carried in their backpacks. We used indirect calorimetry and 3D motion analysis, and all of the data were analyzed by computational algorithms. Rint increased at higher speeds and decreased with increasing gradient. R and %Cong decreased with increasing gradient and increased with speed, independent of load. Thus, energy conversion by the pendular mechanism during walking on a 15% gradient is supported, and although this mechanism can explain the maintenance of OPT at low walking speeds, the pendular mechanism does not fully explain the energy minimization at higher speeds.

Effect of uphill walking with varying grade and speed during load carriage on muscle activity

Indian soldiers, while guarding the mountainous border areas, often carry loads in steep uphill gradients. This activity may predispose the risk of muscle injury. The present study aimed to examine the effects of an increasing load, speed and gradient during incremental uphill treadmill walking on different muscles. Twelve infantry soldiers walked on a treadmill at two speeds (2.5 and 4 km/h) with no load, and carrying 10.7, 17 and 21.4 kg loads at 0, 5, 10, 15, 20, 25% gradients. Electromyographic responses of erector spinae (>240%) and vastus medialis (>240%) were mostly affected, followed by soleus (>125%) and gastrocnemius medialis (>100%) at maximum speed, load and gradient combination compared to 0% gradient. Carrying 10.7 kg at 15% gradient and above was found to be highly strenuous and fatiguing with the risk of muscle injury. Uphill load carriage in slower speed is recommended for the maintenance of combat fitness of the individual at higher gradients.Practitioner Summary:The present article has evaluated the stress encountered by soldiers during load carriage at incremental uphill gradients while walking at different speeds by recording the muscular activities. Load carriage in steep uphill gradients is highly strenuous and may lead to muscle injury thus compromising the combat fitness.

Optimum load for carriage by Indian soldiers on different uphill gradients at specified walking speed

Physiological responses of soldiers while carrying different loads were studied to suggest maximum weight that can be carried by an Indian infantry soldier comfortably at different gradients at specific walking speed. Ten physically fit infantry soldiers walked at 4.5 km h−1 on treadmill (0%, 5%, 10% and 15% gradient) without and with loads of 4.4, 10.7, 17.0 and 21.4 kg. At each gradient, all the loads including without load were experimented for 10 min. Heart rate (HR), oxygen consumption (V˙O2), energy expenditure (EE), respiratory frequency (RF) and minute ventilation (V˙E) were determined using K4b2 system. A linear increase in HR, V˙O2, EE, RF and V˙E with increasing gradient and external load was observed. Based on physiological limit of 50%, 60% and 75% of V˙O2max and linear regression equations optimum loads are suggested as permissible for carriage on different gradients by Indian soldiers at above speed. This combination of weight and gradient would improve the combat readiness of soldiers while carrying load. Relevance to industryMost of the developing countries do not have load carriage standards, for either Industry or Military personnel and extrapolation of the data from developed countries do not seem feasible. Results of this study may be applicable in developing standards or in recommending optimal loads for similar populations under similar conditions.

Paleochannels, stream incision, erosion, topographic evolution, and alternative explanations of paleoaltimetry, Sierra Nevada, California

Geologic relationships in the Sierra Nevada, California, show negligible stream incision between Eocene and Late Miocene–Pliocene time. Stream incision of up to ∼1 km began at (from south to north) ca. 20 Ma in the Kern to Kings River drainages, between 6 and 10 Ma in the San Joaquin River drainage, 3.6–4 Ma in the Stanislaus and Mokelumne River drainages, and ca. 3 Ma in the American and Feather River drainages. These differences in incision timing greatly exceed the time of knickpoint retreat, based on the example of the North Fork Feather River, where the knickpoint may have retreated over 100 km in less than 300 k.y. based on ages of interfluve-capping andesites and an inset basalt flow. The knickpoint in the Stanislaus River may have retreated over 50 km in less than 400 k.y. based on somewhat looser constraints. Eocene paleochannels show lowest gradients parallel to the range axis, steepest ones perpendicular, and reaches with significant “uphill” gradients that rise in the paleo-downstream direction. Modern Sierran rivers lack this relationship. The azimuth-gradient relationships of paleochannels, especially the uphill gradients, require late Cenozoic tilting and uplift. Incision began in spite of decreasing discharge and increasing sediment load and must have resulted from steepening associated with tilting and uplift. Stable-isotope paleoaltimetry apparently records a profile similar to that of the modern range and areas east of it, in spite of significant vertical deformation that postdates the age of the sampled deposits, suggesting fairly recent reequilibration, in contrast to the published interpretations of closed-system behavior since the Oligocene or Eocene. Such apparent open-system behavior agrees with studies showing progressive hydration of volcanic glass and the correspondence between weathering and erosion rates. Northward-younging initiation of late Cenozoic uplift and stream incision suggests a relationship with triple-junction migration, possibly associated with slab window development, with a second uplift pulse related to delamination and limited to the southern Sierra (San Joaquin River drainage and southward). Basement features may have significantly influenced along- and across-strike differences in Cenozoic tectonics and geomorphic response.

Effects of trail gradient on leaf tissue transport and load size selection in leaf-cutter ants

Leaf-cutter ants in the genus Atta are frequent model organisms in studies of central-place foraging. Workers carry leaf fragments from the foraging site to the nest. Larger workers carry heavier loads, but it has been noted repeatedly that workers typically carry fragments lower in mass than appropriate to maximize leaf tissue transport. Here, we suggest and test a previously unconsidered explanation for this discrepancy. Previous calculations of rate-maximizing load sizes have been based on data from smooth, horizontal trails. However, foraging ants will in reality experience a variety of trail gradients, with implications for locomotion speeds of laden ants and consequently for rate-maximizing loads. In the field, we manipulated trail gradient for 389 laden Atta cephalotes workers and found that gradient had marked effects on leaf tissue transport rates, which were highest on downhill and horizontal gradients and considerably lower when ants carried loads uphill. In a captive colony where the whole length of the foraging trail was manipulated, ants apparently adjusted their loading ratios in response to gradient, carrying smaller loads relative to their mass on uphill gradients. Significantly higher loading ratios were recorded for ants carrying loads vertically downhill, perhaps because ants use gravity to reduce the energetic costs of carrying heavy loads. Our results suggest that optimal loads will differ markedly under differing trail conditions and that leaf-cutter ants show previously unsuspected plasticity in load size selection, allowing them to maintain foraging efficiency under a range of trail conditions. Key words: Atta, central-place foraging, gradient, leaf-cutting ants, loading, slope. [Behav Ecol]

GPS-Based Prediction Of Energy Expenditure For Outdoor Walking On Downhill, Level, And Uphill Gradients

GPS-Based Prediction Of Energy Expenditure For Outdoor Walking On Downhill, Level, And Uphill Gradients

Case-control investigation of the factors affecting the risk of horses falling during steeplechase racing in the UK

A concurrent case-control study of 12 UK racecourses was made between March 1, 2000, and August 31, 2001, to identify and quantify the factors associated with the risk of horses...

Congested traffic states in empirical observations and microscopic simulations

We present data from several German freeways showing different kinds of congested traffic forming near road inhomogeneities, specifically lane closings, intersections, or uphill gradients. The states are localized or extended, homogeneous or oscillating. Combined states are observed as well, like the coexistence of moving localized clusters and clusters pinned at road inhomogeneities, or regions of oscillating congested traffic upstream of nearly homogeneous congested traffic. The experimental findings are consistent with a recently proposed theoretical phase diagram for traffic near on-ramps [D. Helbing, A. Hennecke, and M. Treiber, Phys. Rev. Lett. 82, 4360 (1999)]. We simulate these situations with a continuous microscopic single-lane model, the "intelligent driver model," using empirical boundary conditions. All observations, including the coexistence of states, are qualitatively reproduced by describing inhomogeneities with local variations of one model parameter. We show that the results of the microscopic model can be understood by formulating the theoretical phase diagram for bottlenecks in a more general way. In particular, a local drop of the road capacity induced by parameter variations has essentially the same effect as an on-ramp.

The oxygen consumption associated with unloaded walking and load carriage using two different backpack designs.

The purpose of this study was to assess the energy expenditure associated with load carriage using both a traditional rucksack and a new rucksack design, the AARN rucksack, which incorporates front balance pockets. Nine volunteers walked at 3 km h(-1) at various uphill and downhill gradients on a treadmill without a load and carrying a load of 25.6 kg in each of the rucksacks. The oxygen consumption associated with both of the loading conditions was significantly (P < 0.001) higher than that associated with unloaded walking at all downhill gradients tested, although there was no significant difference between the two loading conditions. During the uphill gradients the oxygen consumption associated with the AARN pack was significantly (P < 0.05) lower than that associated with the traditional pack at the 0%, 5%, 10% and 20% gradients. The mean (%) differences at these gradients, expressed in ml x kg(-1) x min(-1) were 1.18 (9%), 1.45 (8%), 1.76 (8%) and 1.88 (6%), respectively. On average for the whole protocol, the oxygen consumption associated with the AARN rucksack was 5% lower than that associated with the traditional rucksack [mean (SD) 17.28 (7.46) ml x kg(-1) x min(-1) for the AARN pack and 18.20 (7.84) ml x kg(-1) x min(-1) for the traditional pack]. The findings of the present study suggest that a load carriage system that allows the load to be distributed between the back and font of the trunk is more appropriate for carrying relatively heavy loads than a system that loads the back only.

The Chicama-Moche Intervalley Canal: Social Explanations and Physical Paradigms

Antithetical premises of a static versus dynamic Andean landscape produce contradictory interpretations of the Chicama-Moche Intervalley Canal. On a static landscape, inoperable canal gradients must be explained by social parameters such as poor surveying or construction techniques. The paradigm of Plate Tectonics and evidence of ongoing crustal convergence support an alternative premise of continuous, gradual landscape alteration and ground slope change. This premise provides a physical explanation for why abandoned canals often exhibit uphill gradients and ancient monuments are frequently not level. However, this premise also requires that complex methods in the engineering analysis of slope-altered structures be made explicit. Assessment of landscape alteration utilizes basic principles of physical geology, but their application to a particular study area must take local conditions into consideration. Similarly, analysis of the hydraulic properties of an irrigation canal utilizes basic principles of fluid dynamics, but local conditions must be considered in deciding which formulas to use and how to apply them. Improper application of geological principles and hydraulic equations has led our critics to incorrect results.