scholarly journals Effect of elastic energy on the mechanical work and power enhancement in counter movement exercise of ankle joint

2004 ◽  
Vol 40 (2) ◽  
pp. 82-89 ◽  
Author(s):  
Norihide SUGISAKI ◽  
Junichi OKADA ◽  
Hiroaki KANEHISA ◽  
Tetsuo FUKUNAGA
Keyword(s):  
Ankle Joint ◽  
Elastic Energy ◽  
Mechanical Work ◽  
Power Enhancement

The absorption of work by a muscle stretched during a single twitch or a short tetanus

1951 ◽  
Vol 139 (894) ◽  
pp. 86-104 ◽  
Keyword(s):  
Chemical Synthesis ◽  
Elastic Energy ◽  
Physical System ◽  
Active Phase ◽  
Mechanical Work ◽  
Significant Part ◽  
Chemical System ◽  
Relaxation Phase ◽  
Single Twitch ◽  
Work Done

When a stimulated muscle is stretched fairly quickly during the active phase of contraction, it resists strongly and mechanical work must be done in stretching it. What happens to this work? If the length to which the muscle is stretched is not too great no significant part of the work remains as mechanical (elastic) energy after the muscle has relaxed. The total heat produced up to the end of relaxation is greater than it would have been had no work been performed on the muscle, but the excess is too small to account for all the work done. It is concluded that the missing work, about half of the whole, is absorbed, presumably as chemical energy. If a stretch is applied entirely during the relaxation phase, when activity is over but tension is still present, the whole of the work performed reappears as heat. If the view is accepted that the missing work is absorbed in chemical synthesis, it appears that the physical system responsible for mechanical work is reversibly coupled, during the active state, with a chemical system providing the necessary energy; and that this coupling is broken when activity passes off. Other possible hypotheses, however, are discussed. The application to ordinary muscular movement is referred to.

Mechanical Work and Power Analysis in the Joints of the Lower Extremity of Adults With Down Syndrome During Plane Walking

2017 ◽  
Author(s):  
Amirtaha Taebi ◽  
Matteo Zago ◽  
Claudia Condoluci ◽  
Manuela Galli
Keyword(s):  
Down Syndrome ◽  
Lower Extremity ◽  
Ankle Joint ◽  
Movement Analysis ◽  
Normal Subjects ◽  
Mechanical Work ◽  
Mechanical Power ◽  
P Value ◽  
Significance Level ◽  
Motor Strategy

Individuals with Down syndrome (DS) use a different motor gait strategy than healthy people. This study aims at analyzing plane walking differences between two groups of normally developed (ND) subjects and subjects with DS in terms of the generated mechanical power and work in the joints of the lower limb. Thirty-nine adults including two groups of 21 subjects with DS (age: 21.6 ± 7 years (mean ± SD)) and 18 ND subjects (age: 25.1 ± 2.4 years) participated in this study. Gait data and ground reaction forces were acquired using a quantitative movement analysis system composed of an optoelectronic motion analyzer (Elite2002, BTS) with eight infrared cameras, and two force platforms mounted in the middle of walkway. Mechanical power and work exchanges were computed during the stance phase by dedicated software, and then compared between the two groups (significance level: p-value = 0.05). Results showed that the mechanical power at the ankle joint was significantly larger in ND subjects compared to subjects with DS (0.084 ± 0.015 vs 0.027 ± 0.010 W/kg). The mechanical work of the ankle joint and the knee joint was significantly lower in ND compared to DS (0.015 ± 0.013 vs 0.028 ± 0.008 kJ/kg.m, and 0.066 ± 0.031 vs 0.109 ± 0.023 kJ/kg.m, respectively). For both groups, the mechanical work done by knee was less than that performed at the ankle and hip level, which might indicate that the knee muscles mainly absorb the energy, rather than generate it. Our results suggest that the subjects with DS walk with a different motor strategy than normal subjects in terms of mechanical power and work in the joints of the lower extremity. Further investigations are warranted to study the relation between these parameters and gait strategy in subjects with DS, which can lead to better rehabilitative strategies.

THE EFFECTS OF INCREASING INSOLE STIFFNESS ON FOOT AND ANKLE MECHANICS IN WALKING GAIT

2021 ◽  
pp. 2150023
Author(s):  
Li Jin
Keyword(s):  
Ankle Joint ◽  
Stance Phase ◽  
Mechanical Energy ◽  
Energy Generation ◽  
Bending Stiffness ◽  
Mechanical Work ◽  
Compensatory Mechanism ◽  
Walking Gait ◽  
Normal Speed ◽  
Positive Work

The energetic pattern of the foot–ankle system is critical in human walking gait. While some of the mechanical energy was dissipated due to foot segment deformation in walking stance phase. Increasing footwear insole bending stiffness was reported to restrict foot segment bending behavior and this was reported to reduce foot segment energy dissipation. While little is known whether increasing footwear insole bending stiffness would alter foot–ankle system mechanical work generation and absorption patterns. Two healthy subjects (one female, one male; age [Formula: see text] years, height [Formula: see text][Formula: see text]cm, weight [Formula: see text][Formula: see text]kg) participated in this study and they were asked to walk at self-selected normal speed with the same footwear (Nike Free RN Flyknit, 2017) in two different insole stiffness conditions: (i) normal shoe insole (NSI); (ii) carbon fiber insole (CFI). Paired sample [Formula: see text]-test was conducted between NSI and CFI for all outcome measures. No statistically significant differences in the outcome variables were found between the two insole conditions. While foot segment positive work and mechanical work ratio were 45.54% and 68.43% higher in CFI than in NSI condition, respectively; foot negative work was 25.02% lower in CFI than in NSI condition. However, ankle joint positive work and work ratio were around more than 10% higher in NSI than in CFI condition, and ankle peak positive power in NSI was 23.93% higher than in CFI condition. Additionally, foot–ankle system overall positive work and mechanical work ratio were both similar between NSI and CFI conditions. The findings indicate increasing footwear insole bending stiffness may influence foot segment and ankle joint energetic patterns in walking stance phase. And the mechanical energy generation compensatory mechanism may exist between foot segment and ankle joint. Specifically, a decreased foot segment energy generation tended to result in a higher amount of ankle joint positive work and peak power generation. This will be beneficial for maintaining a relatively consistent foot–ankle system overall energy generation and work ratio in response to altered insole stiffness and foot segment work during gait.

Multiple Sclerosis Alters the Mechanical Work Performed on the Body’s Center of Mass During Gait

2013 ◽  
Vol 29 (4) ◽  
pp. 435-442 ◽  
Author(s):  
Shane R. Wurdeman ◽  
Jessie M. Huisinga ◽  
Mary Filipi ◽  
Nicholas Stergiou
Keyword(s):  
Multiple Sclerosis ◽  
Elastic Energy ◽  
Stance Phase ◽  
Center Of Mass ◽  
Mechanical Work ◽  
Healthy Controls ◽  
Double Support ◽  
Negative Work ◽  
Positive Work

Patients with multiple sclerosis (MS) have less-coordinated movements of the center of mass resulting in greater mechanical work. The purpose of this study was to quantify the work performed on the body’s center of mass by patients with MS. It was hypothesized that patients with MS would perform greater negative work during initial double support and less positive work in terminal double support. Results revealed that patients with MS perform less negative work in single support and early terminal double support and less positive work in the terminal double support period. However, summed over the entire stance phase, patients with MS and healthy controls performed similar amounts of positive and negative work on the body’s center of mass. The altered work throughout different periods in the stance phase may be indicative of a failure to capitalize on passive elastic energy mechanisms and increased reliance upon more active work generation to sustain gait.

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

2020 ◽  
Vol 120 (11) ◽  
pp. 2507-2515 ◽  
Author(s):  
L. Rasica ◽  
S. Porcelli ◽  
A. E. Minetti ◽  
G. Pavei
Keyword(s):  
Elastic Energy ◽  
Metabolic Cost ◽  
Mechanical Work ◽  
Predictive Equation ◽  
Metabolic Power ◽  
Lower Efficiency ◽  
Kinematic Data

Abstract Purpose On 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. Methods Eight 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. Results Backward 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. Conclusion Efficiency 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.

scholarly journals Scaling of elastic energy storage in mammalian limb tendons: do small mammals really lose out?

2005 ◽  
Vol 1 (1) ◽  
pp. 57-59 ◽  
Author(s):  
Sharon R Bullimore ◽  
Jeremy F Burn
Keyword(s):  
Energy Storage ◽  
Body Mass ◽  
Elastic Energy ◽  
Storage Capacity ◽  
Mechanical Work ◽  
Kangaroo Rats ◽  
Percentage Contribution ◽  
Scaling Relationships ◽  
Kangaroo Rat ◽  
Energy Storage Capacity

It is widely believed that elastic energy storage is more important in the locomotion of larger mammals. This is based on: (a) comparison of kangaroos with the smaller kangaroo rat; and (b) calculations that predict that the capacity for elastic energy storage relative to body mass increases with size. Here we argue that: (i) data from kangaroos and kangaroo rats cannot be generalized to other mammals; (ii) the elastic energy storage capacity relative to body mass is not indicative of the importance of elastic energy to an animal; and (iii) the contribution of elastic energy to the mechanical work of locomotion will not increase as rapidly with size as the mass-specific energy storage capacity, because larger mammals must do relatively more mechanical work per stride. We predict how the ratio of elastic energy storage to mechanical work will change with size in quadrupedal mammals by combining empirical scaling relationships from the literature. The results suggest that the percentage contribution of elastic energy to the mechanical work of locomotion decreases with size, so that elastic energy is more important in the locomotion of smaller mammals. This now needs to be tested experimentally.

Effects of Saddle Height, Pedaling Cadence, and Workload on Joint Kinetics and Kinematics During Cycling

2010 ◽  
Vol 19 (3) ◽  
pp. 301-314 ◽  
Author(s):  
Rodrigo R. Bini ◽  
Aline C. Tamborindeguy ◽  
Carlos B. Mota
Keyword(s):  
Knee Joint ◽  
Ankle Joint ◽  
Outcome Measures ◽  
Repeated Measures ◽  
Cruciate Ligament ◽  
Joint Kinematics ◽  
Mechanical Work ◽  
Joint Power ◽  
Joint Kinetics ◽  
Work Distribution

Context:It is not clear how noncyclists control joint power and kinematics in different mechanical setups (saddle height, workload, and pedaling cadence). Joint mechanical work contribution and kinematics analysis could improve our comprehension of the coordinative pattern of noncyclists and provide evidence for bicycle setup to prevent injury.Objective:To compare joint mechanical work distribution and kinematics at different saddle heights, workloads, and pedaling cadences.Design:Quantitative experimental research based on repeated measures.Setting:Research laboratory.patients:9 healthy male participants 22 to 36 years old without competitive cycling experience.Intervention:Cycling on an ergometer in the following setups: 3 saddle heights (reference, 100% of trochanteric height; high, + 3 cm; and low, − 3 cm), 2 pedaling cadences (40 and 70 rpm), and 3 workloads (0, 5, and 10 N of braking force).Main Outcome Measures:Joint kinematics, joint mechanical work, and mechanical work contribution of the joints.Results:There was an increased contribution of the ankle joint (P = .04) to the total mechanical work with increasing saddle height (from low to high) and pedaling cadence (from 40 to 70 rpm, P < .01). Knee work contribution increased when saddle height was changed from high to low (P < .01). Ankle-, knee-, and hip-joint kinematics were affected by saddle height changes (P < .01).Conclusions:At the high saddle position it could be inferred that the ankle joint compensated for the reduced knee-joint work contribution, which was probably effective for minimizing soft-tissue damage in the knee joint (eg, anterior cruciate ligament and patellofemoral cartilage). The increase in ankle work contribution and changes in joint kinematics associated with changes in pedaling cadence have been suggested to indicate poor pedaling-movement skill.

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