The energy cost of metalliferous mining operations in relation to the aerobic capacity of Indian miners

Background: Individuals post-stroke walk slower than their able-bodied peers, which limits participation. This might be attributed to neurological impairments, but could also be caused by a mismatch between aerobic capacity and aerobic load of walking. Research question: What is the potential impact of aerobic capacity and aerobic load of walking on walking ability post-stroke? Methods: In a cross-sectional study, forty individuals post-stroke (more impaired N=21; preferred walking speed (PWS)<0.8m/s, less impaired N=19), and 15 able-bodied individuals performed five, 5-minute treadmill walking trials at 70%, 85%, 100%, 115% and 130% of PWS. Energy expenditure (mlO2/kg/min) and energy cost (mlO2/kg/m) were derived from oxygen uptake (VO2). Relative load was defined as energy expenditure divided by peak aerobic capacity (%VO2peak) and by VO2 at ventilatory threshold (%VO2-VT). Relative load and energy cost at PWS were compared between groups with one-way ANOVAs. The effect of speed on these parameters was modeled with GEE. Results: Both more and less impaired individuals post-stroke showed lower PWS than able-bodied controls (0.44[0.19-0.76] and 1.04[0.81-1.43] vs 1.36[0.89-1.53] m/s) and higher relative load at PWS (50.2±14.4 and 51.7±16.8 vs 36.2±7.6 %VO2 peak and 101.9±20.5 and 97.0±27.3 vs 64.9±13.8 %VO2-VT). No differences in relative load were found between stroke groups. Energy cost at PWS of more impaired (0.30[.19-1.03] mlO2/kg/m) was higher than less-impaired (0.19[0.10-0.24] mlO2/kg/m) and able-bodied (0.15[0.13-0.18] mlO2/kg/m). For post-stroke individuals, increasing walking speed above PWS decreased energy cost, but resulted in a relative load above endurance threshold. Significance: Individuals post-stroke seem to reduce walking speed to prevent unsustainably high relative aerobic loads at the expense of reduced economy. When aiming to improve walking ability in individuals post-stroke, it is important to consider training aerobic capacity.

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Energy Cost of Walking and Functional Aerobic Capacity During Moderate Intensity Exercise in Adults with Obstructive Sleep Apnea: A Cross-Sectional Study

10.21203/rs.3.rs-91456/v1 ◽

2020 ◽

Author(s):

Monira Ibrahim Aldhahi ◽

Shipra Puri ◽

Vivek Jain ◽

Jeffrey E. Herrick

Keyword(s):

Obstructive Sleep Apnea ◽

Sleep Apnea ◽

Aerobic Capacity ◽

Energy Cost ◽

Cross Sectional Study ◽

Sectional Study ◽

Cross Sectional ◽

Obstructive Sleep ◽

Walking Economy ◽

Energy Cost Of Walking

Abstract Background: Autonomic dysregulation associated with obstructive sleep apnea (OSA) may limit cardiopulmonary responses to exercise which, in turn, may impair functional aerobic capacity (FAC) and walking economy. We aimed to characterize walking economy and FAC in OSA patients compared with healthy adults (non-OSA) and examine their relationship with OSA severity (apnea-hypopnea index [AHI]). Participants: In this cross-sectional study, a total of 26 adults (OSA: n=13; non-OSA: n=13) participated in the study. In this study, the participants with OSA were adults between the ages of 25 and 60 with a body mass index between 25 kg/m2 and 39 kg/m2 who had undergone a recent third-party sleep study with an AHI of 5 or greater. Methods: Participant completed a maximal integrated cardiopulmonary exercise test, three separate exercise bouts of a constant work rate (CWR) treadmill test at 85% of anaerobic threshold (AT), and a 10-minute walk test (10MWT). Multiple linear regression corrected for weight, age, and BMI was conducted to examine the associations. Results: There were significant differences between OSA and Non-OSA participants in VO2peak (29.7±5.6mL/kg/min vs. 37.5±6.5mL/kg/min, p=0.03) and in Net VO2 during CWR (12.7±5 vs.19±6mL/kg/min, p=0.02). The 10MWT speed, distance, and energy expenditure were significantly lower in the OSA group (all p<0.001). The AHI scores associated with 10MWT distance (R2=0.85, p<0.001), energy cost of walking (R2=87, p<0.001), VO2 at anaerobic threshold (R2=0.92, p<0.001). Conclusions: The findings of this study show that patients with OSA have reduced FAC and have a higher energy cost of walking. AHI explained 87% of the variance in the energy cost of walking during the 10MWT. The results suggest that individuals with more severe obstructive sleep apnea experience greater impairment in functional performance.

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Energetics of Locomotion

10.1093/oso/9780198743156.003.0003 ◽

2018 ◽

Keyword(s):

Aerobic Capacity ◽

Energy Cost ◽

Energy Use ◽

Explanatory Models ◽

Endurance Capacity ◽

Energetic Costs ◽

Terrestrial Locomotion ◽

Resistive Forces ◽

The Cost ◽

Land Water

The energetic costs of terrestrial locomotion are placed in the context of the fuel sources that animals use for generating adenosine triphosphate (ATP) and how these fuel sources affect an animal’s capacity for sustainable aerobic metabolism. Aerobic capacity and energy use are closely linked to an animal’s thermoregulatory strategy. Patterns of energy use across terrestrial gaits, sloped substrates and level ground are examined alongside explanatory models. The energetics of terrestrial locomotion is compared with the energetics of swimming and flight. Whereas the support of an animal’s weight against gravity dominates the cost of moving on land and through air, overcoming resistive forces of drag strongly affects the energy cost of movement through water and air. The physical properties of land, water and air influence how energy use changes with the speed of movement. Given these energetic considerations, animals use different locomotor strategies and mechanisms to avoid fatigue and increase endurance capacity.

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Aerobic Capacity, Heart Rate and Estimated Energy Cost during Women's Competitive Basketball

Research Quarterly American Association for Health Physical Education and Recreation ◽

10.1080/10671188.1971.10615055 ◽

1971 ◽

Vol 42 (2) ◽

pp. 178-186 ◽

Cited By ~ 1

Author(s):

William D. McArdle ◽

John R. Magel ◽

Lucille C. Kyvallos

Keyword(s):

Heart Rate ◽

Aerobic Capacity ◽

Energy Cost

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Energy Cost of Locomotion in Blind Adolescents

Adapted Physical Activity Quarterly ◽

10.1123/apaq.6.1.58 ◽

1989 ◽

Vol 6 (1) ◽

pp. 58-67 ◽

Cited By ~ 10

Author(s):

Gisela Kobberling ◽

Louis W. Jankowski ◽

Luc Leger

Keyword(s):

Oxygen Consumption ◽

Aerobic Capacity ◽

Energy Cost ◽

Sports Medicine ◽

Visually Impaired ◽

Energy Costs ◽

Same Sex ◽

Norm Values ◽

Cost Of Locomotion ◽

Energy Cost Of Locomotion

The oxygen consumption (VO2) of 30 (10 females, 20 males) legally blind adolescents and their sighted controls were compared for treadmill walking (3 mph, 4.8 km/h) and running (6 mph, 9.6 km/h). The VO2 of the visually impaired subjects averaged 24.4% and 10.8% higher than those of their same-sex age-matched controls, and 42.8% and 11.2% higher than the American College of Sports Medicine (ACSM) norms for walking (p<.01) and running (p<.05), respectively. The normal association between aerobic capacity and locomotor energy costs was evident among the sighted controls (r= .44, p<.05) but insignificant (r=.35, p>.05) for the visually impaired subjects. The energy costs of both walking and running were highest among the totally blind subjects, and decreased toward normal as a function of residual vision among the legally blind subjects. The energy costs of walking and running for blind adolescents are higher than both those of sighted controls and the ACSM norm values.

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Efficacy of downhill running training for improving muscular and aerobic performances

Applied Physiology Nutrition and Metabolism ◽

10.1139/apnm-2017-0538 ◽

2018 ◽

Vol 43 (4) ◽

pp. 403-410 ◽

Cited By ~ 6

Author(s):

Junichi Toyomura ◽

Hisashi Mori ◽

Kota Tayashiki ◽

Masayoshi Yamamoto ◽

Hiroaki Kanehisa ◽

...

Keyword(s):

Oxygen Uptake ◽

Aerobic Capacity ◽

Maximal Oxygen Uptake ◽

Energy Cost ◽

Knee Extension ◽

Target Heart Rate ◽

Running Training ◽

Leg Extension ◽

Young Males ◽

Change Of Direction

This study investigated effects of downhill (DR) versus level (LR) running training on various muscular and aerobic performances. Eighteen healthy young males conducted either DR (DR group (DRG), n = 10: –10% slope) or LR (LR group (LRG), n = 8) training at a target heart rate (HR) associated with lactate threshold (LT) for 20 min·session−1, 3 sessions·week−1, for 5 weeks. Before and after the interventions, the following variables were measured: knee extension torque (–150, –30, 0, 30, 150°·s−1), leg extension power (simultaneous hip and knee extension: 0.8 m·s−1), squat and countermovement jump height, rebound jump index (jump height·contact time−1), 20-m linear sprint and change-of-direction (Pro-agility and V-cut tests) time, and aerobic capacity (maximal oxygen uptake, energy cost at LT, and velocity at maximal oxygen uptake and LT) on a level surface. Throughout the training sessions, HR during running did not differ between the groups (DRG: 77.7% ± 4.6% vs LRG: 76.4% ± 4.6% of maximal HR; average across all sessions), while velocity was significantly higher for DRG (14.5 ± 1.1 vs 12.0 ± 1.9 km·h−1). After the training, DRG significantly improved knee extension torque at all angular velocities (9%–24%) and change-of-direction time for both tests (2%–3%), with no changes in other parameters. LRG significantly improved maximal oxygen uptake (5%), energy cost at LT (3%), and velocity at maximal oxygen uptake (7%), without changes in others. These results suggest that DR training has a greater potential to improve the knee extension strength and change-of-direction ability, but has little effect on the aerobic capacity, compared with HR-matched LR training.

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