scholarly journals Energetic costs of producing muscle work and force in a cyclical human bouncing task

2011 ◽  
Vol 110 (4) ◽  
pp. 873-880 ◽  
Author(s):  
Jesse C. Dean ◽  
Arthur D. Kuo
Keyword(s):  
Energy Expenditure ◽  
Human Subjects ◽  
Force Production ◽  
The Body ◽  
Triceps Surae ◽  
Metabolic Energy ◽  
Active Muscle ◽  
Series Elasticity ◽  
Muscle Work ◽  
Near Resonance

Muscles expend energy to perform active work during locomotion, but they may also expend significant energy to produce force, for example when tendons perform much of the work passively. The relative contributions of work and force to overall energy expenditure are unknown. We therefore measured the mechanics and energetics of a cyclical bouncing task, designed to control for work and force. We hypothesized that near bouncing resonance, little work would be performed actively by muscle, but the cyclical production of force would cost substantial metabolic energy. Human subjects ( n = 9) bounced vertically about the ankles at inversely proportional frequencies (1–4 Hz) and amplitudes (15–4 mm), such that the overall rate of work performed on the body remained approximately constant (0.30 ± 0.06 W/kg), but the forces varied considerably. We used parameter identification to estimate series elasticity of the triceps surae tendon, as well as the work performed actively by muscle and passively by tendon. Net metabolic energy expenditure for bouncing at 1 Hz was 1.15 ± 0.31 W/kg, attributable mainly to active muscle work with an efficiency of 24 ± 3%. But at 3 Hz (near resonance), most of the work was performed passively, so that active muscle work could account for only 40% of the net metabolic rate of 0.76 ± 0.28 W/kg. Near resonance, a cost for cyclical force that increased with both amplitude and frequency of force accounted for at least as much of the total energy expenditure as a cost for work. Series elasticity reduces the need for active work, but energy must still be expended for force production.

Effects of experimental weight perturbation on skeletal muscle work efficiency in human subjects

2003 ◽  
Vol 285 (1) ◽  
pp. R183-R192 ◽  
Author(s):  
Michael Rosenbaum ◽  
Krista Vandenborne ◽  
Rochelle Goldsmith ◽  
Jean-Aime Simoneau ◽  
Steven Heymsfield ◽  
...  
Keyword(s):  
Physical Activity ◽  
Skeletal Muscle ◽  
Body Weight ◽  
Energy Expenditure ◽  
Human Subjects ◽  
Cycle Ergometry ◽  
Resonance Spectroscopy ◽  
Work Efficiency ◽  
Initial Weight ◽  
Muscle Work

Maintenance of reduced or elevated body weight results in respective decreases or increases in energy expended in physical activity, defined as 24-h energy expenditure excluding resting energy expenditure and the thermic effect of feeding, beyond those attributable to weight change. We examined skeletal muscle work efficiency by graded cycle ergometry and, in some subjects, rates of gastrocnemius muscle ATP flux during exercise by magnetic resonance spectroscopy (MRS), in 30 subjects (15 males, 15 females) at initial weight and 10% below initial weight and in 8 subjects (7 males, 1 female) at initial weight and 10% above initial weight to determine whether changes in skeletal muscle work efficiency at altered body weight were correlated with changes in the energy expended in physical activity. At reduced weight, muscle work efficiency was increased in both cycle ergometry [mean (SD) change = +26.5 (26.7)%, P < 0.001] and MRS [ATP flux change = -15.2 (23.2)%, P = 0.044] studies. Weight gain resulted in decreased muscle work efficiency by ergometry [mean (SD) change = -17.8 (20.5)%, P = 0.043]. Changes in muscle efficiency at altered body weight accounted for 35% of the change in daily energy expended in physical activity.

scholarly journals Relatively Shorter Muscle Lengths Increase the Metabolic Rate of Cyclic Force Production

2021 ◽  
Author(s):  
Owen N. Beck ◽  
Jordyn N. Schroeder ◽  
Lindsey H. Trejo. ◽  
Jason R. Franz ◽  
Gregory S. Sawicki
Keyword(s):  
Energy Expenditure ◽  
Plantar Flexion ◽  
Force Production ◽  
Biological Tissues ◽  
Metabolic Energy ◽  
Fascicle Length ◽  
Leg Muscles ◽  
Muscle Fascicle ◽  
Length Relationship ◽  
Metabolic Energy Expenditure

AbstractDuring animal locomotion, force-producing leg muscles are almost exclusively responsible for the whole-body’s metabolic energy expenditure. Animals can change the length of these leg muscles by altering body posture (e.g.,joint angles), kinetics (e.g.,body weight), or the structural properties of their biological tissues (e.g.,tendon stiffness). Currently, it is uncertain whether relative muscle fascicle operating length has a measurable effect on the metabolic energy expenditure of cyclic locomotion-like contractions. To address this uncertainty, we measured the metabolic energy expenditure of human participants as they cyclically produce two distinct ankle moments at three separate ankle angles (90°, 105°, 120°) on a fixed-position dynamometer exclusively using their soleus. Overall, increasing participant ankle angle from 90° to 120° (more plantar flexion) reduced minimum soleus fascicle length by 17% (both moment levels, p<0.001) and increased metabolic energy expenditure by an average of 208% (both p<0.001). Across both moment levels, the increased metabolic energy expenditure was not driven by greater fascicle positive mechanical work (higher moment level, p=0.591), fascicle force rate (both p≥0.235), or active muscle volume (both p≥0.122); but it was correlated with average relative soleus fascicle length (r=-179, p=0.002) and activation (r=0.51, p<0.001). Therefore, the metabolic energy expended during locomotion can likely be reduced by lengthening active muscles that operate on the ascending-limb of their force-length relationship.

scholarly journals Molecular Mechanisms, Therapeutic Targets and Pharmacological Interventions: An Update

2021 ◽  
Author(s):  
Mohit Kwatra ◽  
Sahabuddin Ahmed ◽  
Samir Ranjan Panda ◽  
Vegi Ganga Modi Naidu ◽  
Nitika Gupta
Keyword(s):  
Skeletal Muscle ◽  
Energy Expenditure ◽  
Muscle Mass ◽  
Molecular Mechanisms ◽  
Human Subjects ◽  
Therapeutic Targets ◽  
The Body ◽  
Sirtuin 1 ◽  
Pharmacological Interventions ◽  
Ubiquitin Proteasome

Muscles are the enriched reservoir of proteins in the body. During any workout or exercise, the demand in the form of energy is essentially required by the muscle. Energy expenditure of skeletal muscle is more dependent on the type of demand. There is particular homeostasis within the body that avoid surplus energy expenditure and this prevents any muscle loss. Muscle atrophy is termed as the loss of skeletal muscle mass due to immobility, malnutrition, medications, aging, cancer cachexia, variety of injuries or diseases that impact the musculoskeletal or nervous system. Hence, atrophy within the skeletal muscle initiates further cause fatigue, pain, muscle weakness, and disability in human subjects. Therefore, starvation and reduced muscle mass further initiate numerous signaling pathways including inflammatory, antioxidant signaling, mitochondria bio-energetic failure, AMP-activated protein kinase (AMPK), Sirtuin 1(SIRT1), BDNF/TrkB/PKC, Autophagy, ubiquitin-proteasome systems, etc. Here, in this chapter, we will mention molecular mechanisms involved in therapeutic targets and available Pharmacological Interventions with the latest updates.

scholarly journals Muscle Actuators, Not Springs, Drive Maximal Effort Human Locomotor Performance

2021 ◽  
pp. 766-777
Author(s):  
Jeffrey M. McBride
Keyword(s):  
Motion Analysis ◽  
Force Plate ◽  
Triceps Surae ◽  
Active Muscle ◽  
Muscle Work ◽  
Triceps Surae Muscle ◽  
Muscle Fascicle ◽  
Muscle Complex ◽  
Muscle Actuators ◽  
Maximal Effort

The current investigation examined muscle-tendon unit kinematics and kinetics in human participants asked to perform a hopping task for maximal performance with variational preceding milieu. Twenty-four participants were allocated post-data collection into those participants with an average hop height of higher (HH) or lower (LH) than 0.1 m. Participants were placed on a customized sled at a 20º angle while standing on a force plate. Participants used their dominant ankle for all testing and their knee was immobilized and thus all movement involved only the ankle joint and corresponding propulsive unit (triceps surae muscle complex). Participants were asked to perform a maximal effort during a single dynamic countermovement hop (CMH) and drop hops from 10 cm (DH10) and 50 cm (DH50). Three-dimensional motion analysis was performed by utilizing an infrared camera VICON motion analysis system and a corresponding force plate. An ultrasound probe was placed on the triceps surae muscle complex for muscle fascicle imaging. HH hopped significantly higher in all hopping tasks in comparison to LH. In addition, the HH group concentric ankle work was significantly higher in comparison to LH during all of the hopping tasks. Active muscle work was significantly higher in HH in comparison to LH as well. Tendon work was not significantly different between HH and LH. Active muscle work was significantly correlated with hopping height (r = 0.97) across both groups and hopping tasks and contributed more than 50% of the total work. The data indicates that humans primarily use a motor-driven system and thus it is concluded that muscle actuators and not springs maximize performance in hopping locomotor tasks in humans.

Characteristics of circadian rhythms in rest-activity and energy expendi-ture in cancer in-patients

2015 ◽  
Vol 4 (6) ◽  
pp. 327-335
Author(s):  
Armiya Sultan ◽  
Vivek Choudhary ◽  
Arti Parganiha
Keyword(s):  
Circadian Rhythms ◽  
Energy Expenditure ◽  
Human Subjects ◽  
Average Energy ◽  
Metabolic Energy ◽  
Activity Count ◽  
Healthy Human ◽  
Control Subjects ◽  
And Gender ◽  
Rest Activity

  The objective of the current study was to assess the rest-activity (RA) and energy expenditure (EE) rhythms in cancer in-patients. Twenty chemothera-py receiving cancer in-patients (10 males and 10 females) and ten apparently healthy human subjects (5 males and 5 females) wore a non-invasive elec-tronic device – the Actical on their non dominant wrist. Data were recorded at 1-minute epoch for at least 3-4 consecutive days. Significant differences in RA and EE patterns were observed between cancer in-patients and control subjects, irrespective of gender. Control subjects showed absolute rhythm detection ratio in RA and EE, whereas, ratio was of low magnitude in cancer patients, especially with reference to EE. Statistically significant decrement in circadian amplitudes and advancement in circadian peaks of RA and EE were observed in cancer in-patients as compared to control subjects. Significant independent effects of factors, namely ‘disease’ and ‘gender’ on total activity count (TAC), average activity count (AAC), total energy expenditure (TEE) and average energy expenditure (AEE) were observed. TEE and AEE were signifi-cantly lower in cancer in-patients as compared to control subjects. Further, factors, ‘disease’ and ‘gender’ also produced significant effects on activity energy expenditure (AcEE), metabolic energy expenditure (MET) and resting energy expenditure (REE). In conclusion, the findings indicate disruption of the circadian rhythms in rest-activity and energy expenditure in cancer in-patients. This disruption is gauged from alterations in rhythm characteristics of RA and EE. However, additional studies involving more patients are re-quired for further validation of the present findings.

Effects of blood pressure on force production in cat and human muscle

1987 ◽  
Vol 63 (2) ◽  
pp. 834-839 ◽  
Author(s):  
S. F. Hobbs ◽  
D. I. McCloskey
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Arterial Pressure ◽  
Perfusion Pressure ◽  
Human Subjects ◽  
Muscle Fibers ◽  
Force Production ◽  
Human Muscle ◽  
Medial Gastrocnemius ◽  
Active Muscle

In anesthetized cats reducing local arterial pressure from 125 to 75 Torr decreased blood flow (53 +/- 5%) and force production (57 +/- 7%) in soleus and medial gastrocnemius. Force was produced in these muscles by aerobic, slowly fatiguing fibers. Similar reductions in arterial pressure did not affect force production in caudofemoralis, which contains mainly fast-fatiguing fibers. In human subjects the electromyogram produced by the ankle extensors during rhythmic constant-force contractions increased as the contracting muscles were raised above the heart during legs-up tilt. This suggests that force production of active muscle fibers at a given level of activation fell with muscle perfusion pressure, thus requiring augmentation of muscle activity to sustain the standard contractions. Because aerobic fibers contributed to these contractions, it appears that force production of human muscle fibers is sensitive to small changes in perfusion pressure and, presumably, blood flow. The critical dependence of developed muscular force on blood pressure is of importance to motor control and may also play a significant role in cardiovascular control during exercise.

scholarly journals The energetic basis for smooth human arm movements

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Jeremy D Wong ◽  
Tyler Cluff ◽  
Arthur D Kuo
Keyword(s):  
Energy Expenditure ◽  
Energy Cost ◽  
Muscle Force ◽  
Force Production ◽  
Metabolic Energy ◽  
Reaching Movements ◽  
Human Arm ◽  
The Central Nervous System ◽  
Muscle Force Production ◽  
Human Arm Movements

The central nervous system plans human reaching movements with stereotypically smooth kinematic trajectories and fairly consistent durations. Smoothness seems to be explained by accuracy as a primary movement objective, whereas duration seems to economize energy expenditure. But the current understanding of energy expenditure does not explain smoothness, so that two aspects of the same movement are governed by seemingly incompatible objectives. Here we show that smoothness is actually economical, because humans expend more metabolic energy for jerkier motions. The proposed mechanism is an underappreciated cost proportional to the rate of muscle force production, for calcium transport to activate muscle. We experimentally tested that energy cost in humans (N=10) performing bimanual reaches cyclically. The empirical cost was then demonstrated to predict smooth, discrete reaches, previously attributed to accuracy alone. A mechanistic, physiologically measurable, energy cost may therefore explain both smoothness and duration in terms of economy, and help resolve motor redundancy in reaching movements.

scholarly journals Muscle mechanics and energy expenditure of the triceps surae during rearfoot and forefoot running

2018 ◽  
Author(s):  
Allison H. Gruber ◽  
Brian R. Umberger ◽  
Ross H. Miller ◽  
Joseph Hamill
Keyword(s):  
Energy Expenditure ◽  
Elastic Energy ◽  
Reaction Force ◽  
Metabolic Cost ◽  
Running Economy ◽  
Mechanical Work ◽  
Triceps Surae ◽  
Metabolic Energy ◽  
Forefoot Running ◽  
Metabolic Energy Expenditure

ABSTRACTForefoot running is advocated to improve running economy because of increased elastic energy storage than rearfoot running. This claim has not been assessed with methods that predict the elastic energy contribution to positive work or estimate muscle metabolic cost. The purpose of this study was to compare the mechanical work and metabolic cost of the gastrocnemius and soleus between rearfoot and forefoot running. Seventeen rearfoot and seventeen forefoot runners ran over-ground with their habitual footfall pattern (3.33-3.68m•s−1) while collecting motion capture and ground reaction force data. Ankle and knee joint angles and ankle joint moments served as inputs into a musculoskeletal model that calculated the mechanical work and metabolic energy expenditure of each muscle using Hill-based muscle models with contractile (CE) and series elastic (SEE) elements. A mixed-factor ANOVA assessed the difference between footfall patterns and groups (α=0.05). Forefoot running resulted in greater SEE mechanical work in the gastrocnemius than rearfoot running but no differences were found in CE mechanical work or CE metabolic energy expenditure. Forefoot running resulted in greater soleus SEE and CE mechanical work and CE metabolic energy expenditure than rearfoot running. The metabolic cost associated with greater CE velocity, force production, and activation during forefoot running may outweigh any metabolic energy savings associated with greater SEE mechanical work. Therefore, there was no energetic benefit at the triceps surae for one footfall pattern or the other. The complex CE-SEE interactions must be considered when assessing muscle metabolic cost, not just the amount of SEE strain energy.

Energy intake and expenditure of improvised explosive device detection dogs

2015 ◽  
Vol 11 (4) ◽  
pp. 249-254 ◽  
Author(s):  
S. Pratt Phillips ◽  
J. Kutzner-Mulligan ◽  
M. Davis
Keyword(s):  
Energy Expenditure ◽  
Energy Intake ◽  
The Body ◽  
Metabolic Energy ◽  
Energy Requirements ◽  
Doubly Labelled Water ◽  
Improvised Explosive Device ◽  
Working Dogs ◽  
Explosive Device ◽  
Improvised Explosive

Improvised explosive device detection (IDD) dogs explore up to 40 km of land daily and therefore have energetic demands that may be above the National Research Council’s requirement for working dogs. This study was designed to quantify metabolic energy intake (MEI) and total energy expenditure (TEE) in a group of IDD dogs. Two groups of dogs that had undergone different training protocols (CP1, n=8 and CP2, n=11) underwent a 5-day deployment simulation that consisted of combined road clearing, orbit and point-to-point activities and lasted approximately 9 h per day. The CP1 dogs were fed according to the IDD Marine Corps Manual, while CP2 dogs were offered additional calories based on pilot study data of energy expenditure. The MEI was calculated based on feed intake rates and chemical composition of the diets. TEE was quantified using the doubly-labelled water technique in 2 of the CP1 dogs and 7 of the CP2 dogs. During the 5-day deployment simulation the MEI ranged from 189-310 kcal/bodyweight (BW)0.75 per day, with the CP2 dogs at the higher end because they were offered more feed. The TEE ranged between 375-507 kcal/BW0.75 per day, above the MEI, suggesting the dogs were in negative energy balance and metabolic reserves within the body were combusted for energy production. These findings reveal that energy requirements of deployed military working dogs are higher than previously published metabolic energy requirements of working dogs.

Adaptation of the preferred human bouncing pattern toward the metabolically optimal frequency

2012 ◽  
Vol 107 (8) ◽  
pp. 2244-2249 ◽  
Author(s):  
Kristen J. Merritt ◽  
Caroline E. Raburn ◽  
Jesse C. Dean
Keyword(s):  
Resonant Frequency ◽  
Metabolic Rate ◽  
Movement Pattern ◽  
The Body ◽  
Mechanical Work ◽  
Metabolic Energy ◽  
Motor Plan ◽  
Near Resonance ◽  
Sensory Acuity ◽  
Optimal Movement

Humans often appear to prefer movement patterns that minimize the metabolic energy expenditure of performing a task. However, it is not clear whether this preference is dependent on adaptation to feedback or results from a previously learned motor plan. We recently found that for a bouncing task with an identifiable neuromechanical resonant frequency, humans do not initially prefer to bounce at the resonant frequency despite its presumed metabolic benefits. The purpose of the present study was to determine whether humans adapt their preferred bouncing frequency over time to approach the metabolic optimum. Subjects ( n = 12) performed a series of 6-min reclined bouncing trials while we quantified bounce frequency, metabolic rate, and rate of positive mechanical work performed on the body. In one trial, subjects bounced at their preferred frequency. In five other trials, subjects bounced at frequencies prescribed by a metronome to match specific percentages of their resonant frequency (80–120%). Positive mechanical work rate was held constant across trials by having subjects match real-time visual feedback to a target. The metabolic rate was lowest during prescribed frequency trials near resonance, not during the preferred frequency trial when subjects were free to choose the bouncing frequency. While the initial preferred frequency was lower than the resonant frequency, the preferred frequency gradually approached resonance over the course of 6 min. These results provide evidence that humans do not choose their preferred movement pattern based on an unchanging learned motor plan, but instead adapt their preferred frequency in response to feedback. Our findings may have implications for clinical populations, as reduced sensory acuity could prevent identification of the metabolically optimal movement pattern.

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