scholarly journals A Self-Powered Biosensor for Monitoring Maximal Lactate Steady State in Sport Training

Biosensors ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 75
Author(s):  
Yupeng Mao ◽  
Wen Yue ◽  
Tianming Zhao ◽  
MaiLun Shen ◽  
Bing Liu ◽  
...  
Keyword(s):  
Steady State ◽  
Vinylidene Fluoride ◽  
Coupling Effect ◽  
Lactate Concentration ◽  
Skin Surface ◽  
Human Motion ◽  
Training System ◽  
Maximal Lactate Steady State ◽  
Self Powered ◽  
Surface Coupling

A self-powered biosensor for monitoring the maximal lactate steady state (MLSS) during exercise has been developed for intelligently assisting training system. It has been presented to create poly (vinylidene fluoride) (PVDF)/Tetrapod-shaped ZnO (T-ZnO)/enzyme-modified nanocomposite film through an efficient and cost-effective fabrication process. This sensor can be readily attached to the skin surface of the tester. Due to the piezoelectric surface coupling effect, this biosensor can monitor/sense and analyze physical information in real-time under the non-invasive condition and work independently without any battery. By actively outputting piezoelectric signals, it can quickly and sensitively detect body movements (changes of joint angle, frequency relative humidity during exercise) and physiological information (changes of lactate concentration in sweat). A practical application has been demonstrated by an excellent professional speed skater (male). The purpose of this study is to increase the efficiency of MLSS evaluation, promote the development of piezoelectric surface coupling effect and motion monitoring application, develop an intelligently assisting training system, which has opened up a new direction for human motion monitoring.

scholarly journals Comparison of maximal lactate steady state with V2, V4, individual anaerobic threshold and lactate minimum speed in horses

2014 ◽  
Vol 66 (1) ◽  
pp. 39-46 ◽  
Author(s):  
O.A.B. Soares ◽  
G.C. Ferraz ◽  
C.B. Martins ◽  
D.P.M. Dias ◽  
J.C. Lacerda-Neto ◽  
...  
Keyword(s):  
Steady State ◽  
Anaerobic Threshold ◽  
Exercise Physiology ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Maximal Lactate Steady State ◽  
Exercise Load ◽  
Individual Anaerobic Threshold ◽  
Minimum Speed ◽  
Lactate Minimum

The anaerobic threshold is a physiologic event studied in various species. There are various methods for its assessment, recognized in the human and equine exercise physiology literature, several of these involving the relationship between blood lactate concentration (LAC) and exercise load, measured in a standardized exercise test. The aim of this study was to compare four of these methods: V2, V4, individual anaerobic threshold (IAT) and lactate minimum speed (LMS) with the method recognized as the gold standard for the assessment of anaerobic threshold, maximal lactate steady-state (MLSS). The five tests were carried out in thirteen trained Arabian horses, in which velocities and associated LAC could be measured. The mean velocities and the LAC associated with the anaerobic threshold for the five methods were respectively: V2 = 9.67±0.54; V4 = 10.98±0.47; V IAT = 9.81±0.72; V LMS = 7.50±0.57 and V MLSS = 6.14±0.45m.s-1 and LAC IAT = 2.17±0.93; LAC LMS = 1.17±0.62 and LAC MLSS = 0.84±0.21mmol.L-1. None of the velocities were statistically equivalent to V MLSS (P<0.05). V2, V4 and V LMS showed a good correlation with V MLSS , respectively: r = 0.74; r = 0.78 and r = 0.83, and V IAT did not significantly correlate with V MLSS. Concordance between the protocols was relatively poor, i.e., 3.28±1.00, 4.84±0.30 and 1.43±0.32m.s-1 in terms of bias and 95% agreement limits for V2, V4 and LMS methods when compared to MLSS. Only LAC LMS did not differ statistically from LAC MLSS. Various authors have reported the possibility of the assessment of anaerobic threshold using rapid protocols such as V4 and LMS for humans and horses. This study corroborates the use of these tests, but reveals that adjustments in the protocols are necessary to obtain a better concordance between the tests and the MLSS.

Maximal Lactate Steady State in Children

1996 ◽  
Vol 8 (4) ◽  
pp. 328-336 ◽  
Author(s):  
Ralph Beneke ◽  
Volker Schwarz ◽  
Renate Leithäuser ◽  
Matthias Hütler ◽  
Serge P. von Duvillard
Keyword(s):  
Steady State ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Peak Heart Rate ◽  
Maximal Lactate Steady State ◽  
Specific Test ◽  
Testing Procedures ◽  
Time Courses ◽  
Kinetics Of ◽  
Submaximal Workload

Maximal lactate steady state (MLSS) corresponds to the prolonged constant workload whereby the kinetics of blood lactate concentration clearly increases from steady state. Different results of MLSS in children may reflect specific test protocols or definitions. Three methods corresponding to lactate time courses during 20 min (MLSS I), 16 min (MLSS II), and 8 min (MLSS III) of constant submaximal workload were intraindividually compared in 10 boys. At MLSS I, lactate, V̇O2peak, heart rate, and workload were higher (p < .05) than at MLSS II and at MLSS III. The differences between MLSS I, MLSS II, and MLSS III reflect insufficient contribution to lactate kinetics by testing procedures, strongly depending on the lactate time courses during the initial 10 min of constant workload. Previously published divergent results of MLSS in children seem to reflect a methodological effect more than a metabolic change.

Predicting Maximal Lactate Steady State in Children and Adults

2009 ◽  
Vol 21 (4) ◽  
pp. 493-505 ◽  
Author(s):  
Ralph Beneke ◽  
Hermann Heck ◽  
Helge Hebestreit ◽  
Renate M Leithäuser
Keyword(s):  
Steady State ◽  
Blood Lactate ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Load Test ◽  
Maximal Lactate Steady State ◽  
Test Power ◽  
Load Tests

The value of blood lactate concentration (BLC) measured during incremental load tests in predicting maximal lactate-steady-state (MLSS) workload has rarely been investigated in children. In 17 children and 18 adults MLSS was 4.1 ± 0.9mmol 1.1. Workload at BLC of 3.0mmol 1.1 determined during an incremental load test explained about 80% of the variance (p < .001) and best predicted MLSS workload independent of age. This was despite the increase in power per time related to maximum incremental load test power being higher (p < .001) in children than in adults. The BLC response to given exercise intensities is faster in children without affecting MLSS.

scholarly journals A 1-day maximal lactate steady-state assessment protocol for trained cyclists

2018 ◽  
Vol 7 (1) ◽  
pp. 9-16
Author(s):  
Jose Ramon Lillo-Bevia ◽  
Ricardo Moran-Navarro ◽  
Alejandro Martinez-Cava ◽  
Victor Cerezuela ◽  
Jesus G. Pallares
Keyword(s):  
Steady State ◽  
Data Analysis ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Constant Load ◽  
Load Test ◽  
Validity And Reliability ◽  
Maximal Lactate Steady State ◽  
Exercise Tests ◽  
Assessment Protocol

The main aim of this study is to assess the validity of a new cycling protocol to estimate the Maximal Lactate Steady-State workload (MLSS) through a one-day incremental protocol (1day_MLSS). Eleven well-trained male cyclists performed 3 to 4 trials of 30-min constant load test (48-72h in between) to determine their respective MLSS workload. Then, on separate days, each cyclist carried out two identical graded exercise tests, comprised of four 10-minute long stages, with the initial load at 63% of their respective maximal aerobic power, 0.2 W·Kg-1 increments, and blood lactate concentration (BLC) determinations each 5 min. The results of the 1day_MLSS tests were analysed through three different constructs: i) BLC difference between 5th and 10th min of each stage (DIF_5to10), ii) BLC difference between the 10th min of two consecutive stages (DIF_10to10), and iii) difference in the mean BLC between the 5th and 10th min of two consecutive stages (DIF_mean). For all constructs, the physiological steady state was determined as the highest workload that could be maintained with a BLC rise lower than 1mmol·L-1.  No significant differences were detected between the MLSS workload (247 ± 22W) and any of the 1day_MLSS data analysis (250 ± 24W, 245 ± 23W and 243 ± 21W, respectively; p>0.05). When compared to the MLSS workload, strong ICCs and low bias values were found for these three constructs, especially for the DIF_10to10 workload (r=0.960; Bias=2.2 W). High within-subject reliability data were found for the DIF10_10 construct (ICC=0.846; CV=0.4%; Bias=2.2 ± 6.4W). The 1day_MLSS test and DIF_10to10 data analysis is a valid assessment to predict the MLSS workload in cycling, that considerably reduces the dedicated time, effort and human resources that requires the original test. The validity and reliability values reported in this project are higher than those achieved by other previous MLSS estimation tests.

scholarly journals Physiological Responses of Continuous and Intermittent Swimming at Critical Speed and Maximum Lactate Steady State in Children and Adolescent Swimmers

Sports ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 25 ◽  
Author(s):  
Ioannis Nikitakis ◽  
Giorgos Paradisis ◽  
Gregory Bogdanis ◽  
Argyris Toubekis
Keyword(s):  
Heart Rate ◽  
Steady State ◽  
Critical Speed ◽  
Physiological Responses ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Metabolic Responses ◽  
Maximal Lactate Steady State ◽  
Children And Adolescent ◽  
Maximum Lactate

Background: The purpose of this study was to compare physiological responses during continuous and intermittent swimming at intensity corresponding to critical speed (CS: slope of the distance vs. time relationship using 200 and 400-m tests) with maximal lactate steady state (MLSS) in children and adolescents. Methods: CS and the speed corresponding to MLSS (sMLSS) were calculated in ten male children (11.5 ± 0.4 years) and ten adolescents (15.8 ± 0.7 years). Blood lactate concentration (BL), oxygen uptake ( V · O2), and heart rate (HR) at sMLSS were compared to intermittent (10 × 200-m) and continuous swimming corresponding to CS. Results: CS was similar to sMLSS in children (1.092 ± 0.071 vs. 1.083 ± 0.065 m·s−1; p = 0.12) and adolescents (1.315 ± 0.068 vs. 1.297 ± 0.056 m·s−1; p = 0.12). However, not all swimmers were able to complete 30 min at CS and BL was higher at the end of continuous swimming at CS compared to sMLSS (children: CS: 4.0 ± 1.8, sMLSS: 3.4 ± 1.5; adolescents: CS: 4.5 ± 2.3, sMLSS: 3.1 ± 0.8 mmol·L−1; p < 0.05). V · O2 and HR in continuous swimming at CS were not different compared to sMLSS (p > 0.05). BL, V · O2 and HR in 10 × 200-m were similar to sMLSS and no different between groups. Conclusion: Intermittent swimming at CS presents physiological responses similar to sMLSS. Metabolic responses of continuous swimming at CS may not correspond to MLSS in some children and adolescent swimmers.

scholarly journals Self-Powered Smart Insole for Monitoring Human Gait Signals

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5336 ◽  
Author(s):  
Wei Wang ◽  
Junyi Cao ◽  
Jian Yu ◽  
Rong Liu ◽  
Chris R. Bowen ◽  
...  
Keyword(s):  
Vinylidene Fluoride ◽  
Rapid Development ◽  
Human Motion ◽  
Multiscale Entropy ◽  
Human Gait ◽  
Pvdf Film ◽  
Aluminum Electrode ◽  
Wearable Electronics ◽  
Motion Speed ◽  
Self Powered

With the rapid development of low-power consumption wireless sensors and wearable electronics, harvesting energy from human motion to enable self-powered sensing is becoming desirable. Herein, a pair of smart insoles integrated with piezoelectric poly(vinylidene fluoride) (PVDF) nanogenerators (NGs) are fabricated to simultaneously harvest energy from human motion and monitor human gait signals. Multi-target magnetron sputtering technology is applied to form the aluminum electrode layers on the surface of the PVDF film and the self-powered insoles are fabricated through advanced 3D seamless flat-bed knitting technology. Output responses of the NGs are measured at different motion speeds and a maximum value of 41 V is obtained, corresponding to an output power of 168.1 μW. By connecting one NG with an external circuit, the influence of external resistance, capacitor, and motion speed on the charging characteristics of the system is systematically investigated. To demonstrate the potential of the smart insoles for monitoring human gait signals, two subjects were asked to walk on a treadmill at different speeds or with a limp. The results show that one can clearly distinguish walking with a limp from regular slow, normal, and fast walking states by using multiscale entropy analysis of the stride intervals.

Room-temperature self-powered ethanol sensor based on the piezo-surface coupling effect of heterostructured α-Fe2O3/ZnO nanowires

2016 ◽  
Vol 166 ◽  
pp. 288-291 ◽  
Author(s):  
Dan Zhu ◽  
Yongming Fu ◽  
Weili Zang ◽  
Yayu Zhao ◽  
Lili Xing ◽  
...  
Keyword(s):  
Room Temperature ◽  
Coupling Effect ◽  
Zno Nanowires ◽  
Ethanol Sensor ◽  
Self Powered ◽  
Surface Coupling
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