Ankle and Midfoot Power During Walking and Stair Ascent in Healthy Adults

2018 ◽  
Vol 34 (4) ◽  
pp. 262-269 ◽  
Author(s):  
Frank E. DiLiberto ◽  
Deborah A. Nawoczenski ◽  
Jeff Houck
Keyword(s):  
Power Generation ◽  
Repeated Measures ◽  
Peak Power ◽  
Healthy Adults ◽  
Total Power ◽  
Foot Motion ◽  
Reaction Forces ◽  
Foot Function ◽  
Main Effects ◽  
External Loads

Ankle power dominates forward propulsion of gait, but midfoot power generation is also important for successful push-off. However, it is unclear if midfoot power generation increases or stays the same in response to propulsive activities that induce larger external loads and require greater ankle power. The purpose of this study was to examine ankle and midfoot power in healthy adults during progressively more demanding functional tasks. Multisegment foot motion (tibia, calcaneus, and forefoot) and ground reaction forces were recorded as participants (N = 12) walked, ascended a standard step, and ascended a high step. Ankle and midfoot positive peak power and positive total power, and the proportion of midfoot to ankle positive total power were calculated. One-way repeated-measures analyses of variance were conducted to evaluate differences across tasks. Main effects were found for ankle and midfoot peak and total powers (all Ps < .01), but not for the proportion of midfoot-to-ankle total power (P = .33). Ankle and midfoot power significantly increased across each task. Midfoot power increased in proportion to ankle power and in congruence to the external load of a task. Study findings may serve to inform multisegment foot modeling applications and internal mechanistic theories of normal and pathological foot function.

Ankle and Midfoot Power During Single-Limb Heel Rise in Healthy Adults

2020 ◽  
Vol 36 (1) ◽  
pp. 52-55
Author(s):  
Frank E. DiLiberto ◽  
Deborah A. Nawoczenski
Keyword(s):  
Peak Power ◽  
Force Plate ◽  
Healthy Adults ◽  
Muscle Performance ◽  
Ground Reaction Forces ◽  
Inverse Dynamic ◽  
Heel Height ◽  
Foot Motion ◽  
Reaction Forces ◽  
Ankle Function

Although the midfoot is recognized to have an important role in the successful performance of a single-limb heel rise, healthy heel rise performance remains primarily characterized by ankle function. The purpose of this study was to examine the contribution of midfoot region power to single-limb heel rise in healthy adults. Participants (N = 12) performed 20 single-limb heel rises. An electromagnetic motion capture system and a force plate were used to record 3-segment foot motion and ground reaction forces. Inverse dynamic calculations were performed to obtain ankle and midfoot region powers. These data were evaluated with descriptive statistics. A correlation was performed to evaluate the contribution of midfoot region power to heel height, as heel height is a clinical measure of heel-rise performance. The midfoot contributed power during single-limb heel rise (peak positive power: 0.5 [0.2] W·kg−1). Furthermore, midfoot peak power accounted for 36% of the variance in heel height (P = .04). As energy generating internal mechanisms, such as muscle activity, are attributed to power generation, midfoot tissue loading and muscle performance should be considered during clinical and modeling applications of the heel-rise task.

scholarly journals Midfoot power during walking and stair ascent in healthy adults

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0021
Author(s):  
Frank DiLiberto ◽  
Jeff Houck ◽  
Deborah Nawoczenski
Keyword(s):  
Repeated Measures ◽  
Reaction Force ◽  
Healthy Adults ◽  
Joint Torque ◽  
Total Power ◽  
Pairwise Comparisons ◽  
Inverse Dynamic ◽  
Stair Ascent ◽  
Intrinsic Foot Muscles ◽  
Main Effects

Category: Midfoot/Forefoot Introduction/Purpose: Intrinsic foot muscles have the capacity to attenuate and reverse arch deformation under loaded conditions. This function is proposed to be an important component in generating the midfoot power and stability requisite for gastroc-soleus muscle action at the ankle during forward propulsion. Synergistic activation of intrinsic foot muscles is proposed to function as a ‘foot core’ during weightbearing activity that is analogous to the function of the smaller muscles at the spine. If this theory were sound, midfoot power would be expected to increase, potentially in proportion to ankle power, as the muscular demand of a task increases. The purpose of this study was to explore the nature and behavior of midfoot and ankle power during walking and stair ascent in healthy adults. Methods: Twelve healthy adults [Mean (SD): Age 31.3 (4.9) years; BMI 25.2 (3.4) Kg/m2; 50% female] walked, ascended a standard step, and ascended a high step. An electromagnetic sensor motion capture system and force plate were used to record multi-segment foot motion and ground reaction force data. Subject-specific three segment foot models (tibia, rearfoot, forefoot) were derived. Inverse dynamic calculations were performed to obtain ankle and midfoot positive total power. Positive total power, calculated as the sum of positive power (joint torque x segmental velocity) after heel off, reflects the entire amount of ankle or midfoot push-off power generated for a given task. The proportion of midfoot to ankle positive total power was also calculated. Multiple one-way repeated measures ANOVAs were conducted to evaluate differences in power variables across tasks. Bonferroni adjusted pairwise comparisons were made to assess differences in main effects. Effect sizes between conditions were also examined (Cohen’s d). Results: Significant main effects were found for both ankle and midfoot positive total power [ankle F = 29.8 (p < 0.01); midfoot F = 63.1 (p < 0.01)]. Pairwise comparisons revealed that total power significantly increased across each activity at both the ankle (d range: 0.09 - 2.3) and midfoot (d range: 1.4 - 2.9) [all p < 0.05]. Interestingly, a main effect was not observed in the proportion of midfoot to ankle total power across activity [F = 1.2 (p = 0.33)] (Figure 1). Conclusion: The findings of this study provide preliminary support for the idea of a midfoot ‘foot core’ system. While increased ankle and midfoot power is required as the muscular demand of activity increases from walking to standard step and high step ascent, the proportion of midfoot to ankle total power remains the same. Study findings may assist practitioner understanding in addressing regional foot muscle imbalances and advancing patients to higher-level functional activities.

scholarly journals Effects of Protein Source and Quantity on Appetite Control, Satiety and Subsequent Food Intake in Healthy Adults

2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 409-409
Author(s):  
Charlotte Griffith ◽  
Kamille Piacquadio ◽  
Morgan Braden ◽  
Heather Leidy
Keyword(s):  
Food Intake ◽  
Energy Intake ◽  
Food Consumption ◽  
Repeated Measures ◽  
Healthy Adults ◽  
Protein Source ◽  
Pea Protein ◽  
Desire To Eat ◽  
Main Effects ◽  
Eating Initiation

Abstract Objectives To examine whether consumption of breakfast preloads varying in protein source and quantity affect measures of appetite, satiety and subsequent energy intake in healthy adults. Methods Thirty-seven healthy adults (Age: 26 ± 4; BMI: 23 ± 2) participated in this randomized crossover design study. On 3 consecutive days, participants consumed 325 kcal preload breakfast yogurts, varying in protein quality (Whey vs. Pea) and quantity (20, 30, 40 g) vs. an isocaloric carbohydrate preload (Control). On day 4, participants completed a 5-hr in clinic testing day. At baseline time -15 min, questionnaires assessing hunger, fullness, desire to eat, prospective food consumption, and eating initiation, were completed. At time 0 min, the respective preload was provided, and palatability assessed. At time 15 min, after consumption, similar questionnaires were completed every 30 min during the 4-h postprandial period followed by an ad libitum pizza lunch. There was a 3–7 day washout period between testing days. To assess main effects of protein source, paired sample t-tests of incremental area under the curve (iAUC) were computed for 20g Pea vs. 20g Whey preloads on 4-h hunger, fullness, desire to eat, prospective food consumption, eating initiation and lunch energy intake. To assess main effects of protein quantity, repeated measures ANOVA was computed between control and pea protein preloads of 20g, 30g, and 40g on 4-h hunger, fullness, desire to eat, and prospective food consumption niAUC, eating initiation, and lunch energy intake. P &lt; 0.05 was considered statistically significant. Statistical analyses were performed using The R Foundation (R; version 4.0.3). Results No main effects of protein source or quantities were detected for 4-h postprandial hunger, fullness, desire to eat, and prospective food consumption niAUC. On average, participants requested to eat again 2-h after breakfast (134 ± 12 min) and consumed on average 830 ± 10 kcals at lunch with no differences between protein sources or quantities. Conclusions In the context of an acute feeding study, no differences in postprandial appetite, satiety, and subsequent food intake were detected when comparing protein preloads varying in source and quantity. These data suggest that 20 g pea protein is sufficient to elicit satiety effects and can be used as a plant-based alternative for whey protein. Funding Sources Roquette.

scholarly journals Ground Reaction Force Comparison Between Barefoot and Shod Single Leg Landing at Varied Heights

2021 ◽  
Vol 9 (4) ◽  
pp. 29
Author(s):  
Jocelyn E. Arnett ◽  
Cameron D. Addie ◽  
Ludmila M. Cosio-Lima ◽  
Lee E. Brown
Keyword(s):  
Ground Reaction Force ◽  
Repeated Measures ◽  
Reaction Force ◽  
Force Plate ◽  
Collegiate Athletes ◽  
Ground Reaction Forces ◽  
Repeated Measures Anova ◽  
Main Effect ◽  
Reaction Forces ◽  
Main Effects

Background: Landing is a common movement that occurs in many sports. Barefoot research has gained popularity in examining how shoes alter natural movements. However, it is unknown how a single leg landing under barefoot conditions, as well as landing height, affects ground reaction forces (GRF). Objective: The purpose of this research was to examine the differences in GRF during a single leg landing under barefoot and shod conditions from various heights. Methods: Sixteen female Division II collegiate athletes, 8 basketball (age: 19.88 ± 0.64 yrs; height: 1.77 ± 0.09 m; mass: 75.76 ± 12.97 kg) and 8 volleyball (age: 20.00 ± 1.07 yrs; height: 1.74 ± 0.08 m; mass: 72.41 ± 5.41 kg), performed single leg landings from 12, 18, 24, and 30 inches barefoot and shod. An AMTI AccuGait force plate was used to record GRF. A 2 (condition) x 4 (box height) x 2 (sport) repeated measures ANOVA was performed to determine any GRF differences. Results: There were no significant three way or two-way interactions (p > 0.05). There was also no main effect for sport (p > 0.05). There were main effects for footwear and box height (p = 0.000) where shod (2295.121 ± 66.025 N) had greater impact than barefoot (2090.233 ± 62.684 N). Conclusions: Single leg barefoot landings resulted in less vertical GRF than shod landings. This could be due to increased flexion at the joints which aids in force absorption.

scholarly journals The Effect of Different Turn Speeds on Whole-Body Coordination in Younger and Older Healthy Adults

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2827
Author(s):  
Fuengfa Khobkhun ◽  
Mark Hollands ◽  
Jim Richards
Keyword(s):  
Older Adults ◽  
Repeated Measures ◽  
Mixed Model ◽  
Healthy Adults ◽  
Whole Body ◽  
Onset Latency ◽  
Step Frequency ◽  
Step Size ◽  
Younger Adults ◽  
Mixed Model Analysis

Difficulty in turning is prevalent in older adults and results in postural instability and risk of falling. Despite this, the mechanisms of turning problems have yet to be fully determined, and it is unclear if different speeds directly result in altered posture and turning characteristics. The aim of this study was to identify the effects of turning speeds on whole-body coordination and to explore if these can be used to help inform fall prevention programs in older adults. Forty-two participants (21 healthy older adults and 21 younger adults) completed standing turns on level ground. Inertial Measurement Units (XSENS) were used to measure turning kinematics and stepping characteristics. Participants were randomly tasked to turn 180° at one of three speeds; fast, moderate, or slow to the left and right. Two factors mixed model analysis of variance (MM ANOVA) with post hoc pairwise comparisons were performed to assess the two groups and three turning speeds. Significant interaction effects (p < 0.05) were seen in; reorientation onset latency of head, pelvis, and feet, peak segmental angular separation, and stepping characteristics (step frequency and step size), which all changed with increasing turn speed. Repeated measures ANOVA revealed the main effects of speeds within the older adults group on those variables as well as the younger adults group. Our results suggest that turning speeds result in altered whole-body coordination and stepping behavior in older adults, which use the same temporospatial sequence as younger adults. However, some characteristics differ significantly, e.g., onset latency of segments, peak head velocity, step frequency, and step size. Therefore, the assessment of turning speeds elucidates the exact temporospatial differences between older and younger healthy adults and may help to determine some of the issues that the older population face during turning, and ultimately the altered whole-body coordination, which lead to falls.

Gigawatt peak power generation in a relativistic klystron amplifier driven by 1 kW seed-power

2013 ◽  
Vol 20 (11) ◽  
pp. 113102 ◽  
Author(s):  
Y. Wu ◽  
H. Q. Xie ◽  
Z. H. Li ◽  
Y. J. Zhang ◽  
Q. S. Ma
Keyword(s):  
Power Generation ◽  
Peak Power ◽  
Relativistic Klystron

Abstract P134: Preliminary Data: Dietary Nitrate Supplementation Does Not Extend Dry Static Apnea Or Wingate Performance

Circulation ◽  
2021 ◽  
Vol 143 (Suppl_1) ◽  
Author(s):  
Colin Carriker ◽  
Phillip Armentrout ◽  
Sarah Levine ◽  
James Smoliga
Keyword(s):  
Power Output ◽  
Preliminary Data ◽  
Repeated Measures ◽  
Peak Power ◽  
Hold Time ◽  
Wingate Test ◽  
Peak Power Output ◽  
Breath Hold ◽  
Dietary Nitrate ◽  
Nitrate Supplementation

Introduction: Previous studies have examined dietary nitrate supplementation and its effects on dry static apnea, and peak power. Dietary nitrate supplementation has been found to increase maximal apnea and peak power output. The purpose of this study was to determine the effects of beetroot juice on dry static apnea and Wingate performance. Hypothesis: Dietary nitrate will improve maximal breath hold time and peak power output. Dietary nitrate will improve tolerance to CO2, thereby improving maximal breath hold time and anaerobic capacity. Methods: In a randomized, double-blind, counterbalanced study, five healthy males (20.4±0.89 years) visited the lab on 3 separate occasions each separated by one week. Visit 1 served as a Wingate and breath hold familiarization visit. Prior to visits 2 and 3 participants were instructed to drink a beverage either a placebo (negligible nitrate content, PL) or dietary nitrate rich beverage (12.4 mmol nitrate, NIT) during the 4 days leading up to their next visit. Visits 2 and 3 consisted of two submaximal breath holds (80% of maximal determined during visit 1), with 2 minutes of rest between and three minutes of rest preceding the final breath hold for maximal duration. Finally, participants completed a standardized 10-minute warmup on the cycle ergometer before completing a 30-second maximal effort Wingate test. Results: A linear mixed effects model was used to determine whether treatment (NIT vs. PL) was associated with differences in VCO2 or PetCO2. Time (0, 10, 20, 30 min post-breath hold) and Treatment both served as repeated measures. Models were developed using multiple repeated measures covariance matrix structures, and the model with the lowest AIC was chosen as the final model. The interaction between time and treatment was included in the original models, and was removed if it was not statistically significant. Time was a statistically significant factor for VCO2 and PetCO2 (p < 0.001). Treatment, and the Time x Treatment interaction was not significant for either variable. No differences between NIT and PL were observed during the Wingate test for either time to peak power (5.02±2.45 and 6.2±2.43 sec, respectively) or maximal power (9.73±1.01 and 9.72±1.03 watts/kg, respectively) and fatigue index (49.42±14.98 and 47.30±6.99 watts/sec, respectively). Conclusion: Preliminary data indicates that in a general population four days of dietary nitrate supplementation may not improve breath hold time, tolerance to carbon dioxide in the lungs, or Wingate performance.

Low-Carbon Clean Technology for Waste Energy Recovery in Power Plants Based on Green Environmental Protection

2021 ◽  
Author(s):  
Yong Tian ◽  
Wen-Jing Liu ◽  
Qi-jie Jiang ◽  
Xin-Ying Xu
Keyword(s):  
Power Generation ◽  
Power Plants ◽  
Biomass Energy ◽  
Energy Utilization ◽  
Pollutant Emissions ◽  
Total Power ◽  
Economic Losses ◽  
Biomass Waste ◽  
Emission Analysis ◽  
Total Power Consumption

With the development of biomass power generation technology, biomass waste has a more excellent recycling value. The article establishes a biomass waste inventory model based on the material flow analysis method and predicts raw material waste’s energy utilization potential. The results show that the amount of biomass waste generated from 2016 to 2020 is on the rise. In 2020, biomass waste’s energy utilization can reach 107,802,300 tons, equivalent to 1,955.28PJ of energy. Through biomass energy analysis and emission analysis, the results show that the biomass waste can generate 182.02 billion kW⋅h in 2020, which can replace 35.9% of the region’s total power consumption, which is compared with the traditional power generation method under the same power generation capacity. Power generation can reduce SO2 emissions by 250,400 tons, NOx emissions by 399,300 tons, and PM10 emissions by 49,700 tons. Reduce direct economic losses by 712 million yuan. Therefore, Chinese promotion of the recycling of biomass waste and the acceleration of the biomass energy industry’s development is of great significance for reducing pollutant emissions and alleviating energy pressure.

scholarly journals Forefoot Striking Is More Effective in Reducing Loadrates than Increasing Cadence in Runners

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0005
Author(s):  
Erin Futrell ◽  
Irene Davis
Keyword(s):  
Repeated Measures ◽  
Auditory Signal ◽  
Gait Retraining ◽  
Loading Rates ◽  
Impact Forces ◽  
Running Injuries ◽  
Main Effects ◽  
Wireless Accelerometer ◽  
One Way Anova ◽  
Vertical Impact

Category: Sports Introduction/Purpose: Vertical impact forces are highly influenced by the way the foot contacts the ground. These impact forces are associated with high loading rates which have been related to running injuries. As a result, clinicians have begun to use gait retraining interventions to reduce loadrates and prevent future impact-related injuries. Two types of gait retraining techniques have been promoted to reduce excessive running impacts. The first involves increasing cadence (CAD), or number of steps per minute, by 5-10%, thereby reducing stride length. The second type of gait retraining involves landing on the ball of the foot at ground contact, or using a forefoot strike (FFS). Both of these gait-retraining styles have been reported to reduce impacts, but they have not been compared with each other. Methods: 33 healthy runners (9M, 24F), running 5-15 mpw, with a rearfoot strike pattern with cadence < 170 steps/min were recruited. Subjects were randomly allocated to either FFS or CAD retraining. All subjects underwent an 8-session gait retraining program (over 2-3 wks) with auditory feedback on a treadmill. The CAD group ran to a digital metronome to increase cadence by 7.5%. The FFS group wore a wireless accelerometer that provided an auditory signal on footstrike pattern. A gait analysis was conducted at baseline, 1 wk, 1 month, and 6 months. Variables included vertical average and instantaneous load rates (VALR, VILR). A 2 x 4 repeated measures ANOVA was used to compare differences within and between the CAD and FFS groups at baseline, 1 week, 1 month and 6 months post retraining. For variables with significant interactions, simple main effects of group, as well as time were further explored using one-way ANOVA Results: There were significant interaction effects of time*group for VALR (p= 0.001), VILR (p=0.001) and foot angle (p< 0.001), but not cadence. For the simple main effects for the CAD group, VALR reduced by 14%, 7% and 16% at 1 week, 1 month, and 6 months post gait retraining respectively, compared with baseline (Figure 1). However, these reductions were not significant. For the FFS group, VALR was significantly reduced by 50%, 51% and 51% at 1 week, 1 month, and 6 months post gait retraining respectively. Interestingly, both the CAD and FFS groups increased cadence by similar amounts. Conclusion: Transitioning to a FFS pattern is significantly more effective than increasing CAD when reducing vertical loadrate (both VALR and VILR) is the goal. These changes persisted out to 6 months post gait retraining, suggesting permanence of the new pattern.

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