Littérature scientifique sur le sujet « Isotonic training »

Isometric and isotonic exercises are important modes of resistance training for enhancement of athletic performance. However, less is known about their effects on fitness and health in recreationally physically active individuals. This study evaluates the effect of isometric and isotonic training protocols on health-related fitness components in young university students. A group of one hundred males (18–24 years) underwent a 12-week isotonic and isometric training program (two days per week, 45 min per session). They were randomized into two groups, group A (n = 50) and group B (n = 50). While group A underwent the isotonic resistance training, the group B completed isometric resistance training. Prior to and after training programs, body mass index (BMI) was measured and the bench press 1RM test, sit-ups test, sit and reach test, and 12 min run/walk test were performed. Results showed significant improvements in BMI, bench press 1RM test, sit-ups test, sit and reach test, and 12 min run/walk test after both isotonic and isometric training protocols. The isotonic training group increased in BMI by 2.70%, bench press 1RM by 34.45%, number of sit-ups by 24.13%, sit and reach distance by 29.12%, and 12 min run/walk distance by 19.82%. Isometric training group increased in BMI by 1.96%, bench press 1RM by 14.23%, number of sit-ups by 7.80%, sit and reach distance by 6.92%, and 12 min run/walk distance by 6.99%. A comparison of these training protocols revealed that the isotonic group improved significantly more than the isometric group in the bench press 1RM (20.22%), number of sit-ups (16.33%), and sit and reach distance (22.2%) but not in the 12 min run/walk distance (12.83%) and BMI (0.74%). These findings indicate that both isotonic and isometric resistance training protocols improve health-related fitness components in young adults; however isotonic training is more efficient than isometric training in increasing their muscle strength, muscular endurance, and flexibility.

AbstractIn the past, different training scenarios have been developed and implemented on robotic research platforms, but no systematic analysis and comparison have been done so far. This paper deals with the comparison of an isokinematic (motion with constant velocity) and an isotonic (motion against constant weight) training algorithm. Both algorithms are designed for a robotic research platform consisting of a 3D force plate and a high payload industrial robot, which allows leg extension training with arbitrary six-dimensional motion trajectories. In the isokinematic as well as the isotonic training algorithm, individual paths are defined i n C artesian s pace by sufficient s upport p oses. I n t he i sotonic t raining s cenario, the trajectory is adapted to the measured force as the robot should only move along the trajectory as long as the force applied by the user exceeds a minimum threshold. In the isotonic training scenario however, the robot’s acceleration is a function of the force applied by the user. To validate these findings, a simulative experiment with a simple linear trajectory is performed. For this purpose, the same force path is applied in both training scenarios. The results illustrate that the algorithms differ in the force dependent trajectory adaption.

Background: Rebuilding the strength of the quadriceps as soon as possible after total knee replacement (TKR) is important so as to restore gait stability. To date, there are no standard postoperative strength training programs during the early recovery stage after TKR. Purpose: To compare the therapeutic effects between isokinetic and isotonic strengthening in patients after TKR. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: From April 2018 to August 2020, 37 patients met the inclusion criteria and were randomly assigned to perform either 4-week isokinetic or isotonic strength training programs. Other components of the rehabilitation program were kept the same between the 2 groups. All cases were evaluated by the Timed Up and Go (TUG) test, peak torque of knee extension and flexion (60 and 120 deg/s), 36-item Short Form Health Survey (SF-36), and Western Ontario and McMaster Universities Arthritis Index (WOMAC). Results: After undergoing a 4-week strength training regimen, significant improvements in the TUG test were noted in both groups; however, the time improvement in the isotonic group did not reach the minimal detectable change. All peak torque measurements improved in the isokinetic group but not in the isotonic group for knee flexion at 60 deg/s. The pain subdomain, physical domain, mental domain, total SF-36 score, and WOMAC index all improved significantly in both groups after training. Both training groups improved significantly in peak torque of knee strength, TUG test, and functional scores, but the differences between isokinetic and isotonic training were not statistically significant. Conclusion: The study findings showed that a 4-week strengthening exercise program in the early postoperative stage, involving either isokinetic or isotonic training, resulted in significant improvements in patients undergoing TKR. Registration: NCT02938416 ( ClinicalTrials.gov identifier).

Context: Resistance exercise training commonly is performed against a constant external load (isotonic) or at a constant velocity (isokinetic). Researchers comparing the effectiveness of isotonic and isokinetic resistance-training protocols need to equalize the mechanical stimulus (work and velocity) applied. Objective: To examine whether the standardization protocol could be adjusted and applied to an eccentric training program. Design: Controlled laboratory study. Setting: Controlled research laboratory. Patients or Other Participants: Twenty-one sport science male students (age = 20.6 ± 1.5 years, height = 178.0 ± 4.0 cm, mass = 74.5 ± 9.1 kg). Intervention(s): Participants performed 9 weeks of isotonic (n = 11) or isokinetic (n = 10) eccentric training of knee extensors that was designed so they would perform the same amount of angular work at the same mean angular velocity. Main Outcome Measure(s): Angular work and angular velocity. Results: The isotonic and isokinetic groups performed the same total amount of work (−185.2 ± 6.5 kJ and −184.4 ± 8.6 kJ, respectively) at the same angular velocity (21 ± 1°/s and 22°/s, respectively) with the same number of repetitions (8.0 and 8.0, respectively). Bland-Altman analysis showed that work (bias = 2.4%) and angular velocity (bias = 0.2%) were equalized over 9 weeks between the modes of training. Conclusions: The procedure developed allows angular work and velocity to be standardized over 9 weeks of isotonic and isokinetic eccentric training of the knee extensors. This method could be useful in future studies in which researchers compare neuromuscular adaptations induced by each type of training mode with respect to rehabilitating patients after musculoskeletal injury.

The purpose was to test the hypothesis that twice daily, short-term, variable intensity isotonic and intermittent high-intensity isokinetic leg exercise would maintain peak O2 uptake (VO2) and muscular strength and endurance, respectively, at or near ambulatory control levels during 30 days of -6 degrees head-down bed rest (BR) deconditioning. Nineteen men (aged 32-42 yr) were divided into no exercise control (peak VO2 once/wk, n = 5), isokinetic (Lido ergometer, n = 7), and isotonic (Quinton ergometer, n = 7) groups. Exercise training was conducted in the supine position for two 30-min periods/day for 5 days/wk. Isotonic training was at 60-90% of peak VO2, and isokinetic training (knee flexion-extension) was at 100 degrees/s. Mean (+/- SE) changes (P less than 0.05) in peak VO2 (ml.m-1.kg-1) from ambulatory control to BR day 28 were 44 +/- 4 to 36 +/- 3, -18.2% (3.27-2.60 l/m) for no exercise, 39 +/- 4 to 40 +/- 3, +2.6% (3.13-3.14 l/min) for isotonic, and 44 +/- 3 to 40 +/- 2, -9.1% (3.24-2.90 l/min) for isokinetic. There were no significant changes in any groups in leg peak torque (right knee flexion or extension), leg mean total work, arm total peak torque, or arm mean total work. Mean energy costs for the isotonic and isokinetic exercise training were 446 kcal/h (18.8 +/- 1.6 ml.min-1.kg-1) and 214 kcal/h (8.9 +/- 0.5 ml.m-1.kg-1), respectively. Thus near-peak, variable intensity, isotonic leg exercise maintains peak VO2 during 30 days of BR, while this peak, intermittent, isokinetic leg exercise protocol does not.

Batting is known to be one of the most complex motions in sports. Successful hitting may be influenced by many factors, one of which is response time (RT). Response time is known to be altered by various training techniques such as isokinetic and isometric weight training. Eighteen, right-handed female college softball players were measured for RT with three methods, experimental in design, using an Automatic Performance Analyzer.In addition, hitting performance was determined through film analysis of bat velocity while swinging at a ball delivered from a pitching machine. A Locam camera was used for the cinematography techniques.From this initial testing, three equivalent groups were formed. One group served as a control, while the other two groups performed two contrasting seven week isotonic training programs: 1) a rapid dynamic (RD) group performed many, quick light weight activities; while, 2) the slow exercises. The rapid dynamic group had their exercises triggered by an auditory stimulus. Following the seven week training program, RT and batting performance were again determined. Pre- and post-training response times were analyzed using an analysis of variance and covariance with p=0.05.The results of the RT post-test analysis indicated that response times were not significantly decreased for any of the tests. Film analysis was inadequate to make any conclusive judgments on bat velocity.The following conclusion is warranted from the results: isotonic weight training did not significantly decrease response time for either the slow dynamic or rapid dynamic group.

Thesis (M.S.)--Central Connecticut State University, 1997.
Thesis advisor: Dr. Robert Trichka. " ... in partial fulfillment of the requirements for the degree of Master of Science in Physical Education." Includes bibliographical references (leaves 162-169).

碩士
國立臺灣師範大學
體育學系
93
Traditional muscle strength measurement is using the isotonic weight training equipments to test the one repetition maximum (1RM). However, the outcome of this method is not precise and the test processes are complicated. Thus, the purposes of current research were to establish a quantitative isotonic muscle training system, investigate the relationship between maximal voluntary isometric contraction (MVIC) and one repetition maximum (1RM) of quadriceps femoris, investigate the relationship between %MVIC and repetitions when using MVIC as reference, and determine the correlation between measured mechanical work and prescribed training volume. The subjects of this study included 14 healthy male university students (mean age=20.21) who were instructed to perform leg extension on an isotonic weight training machine. One strain gauge, a displacement sensor and a counter switch were used to collect force, displacement and repetitions data. The selected parameters were tested by the paired t-test, liner regression and Pearson product-moment correlation. P-value<0.05 was considered statistically significant. According to the results, we concluded that: (1)There was no significant correlation between MVIC and 1RM of quadriceps femoris but the P value was close to .05 (P=.07). Further more, the difference between between MVIC and 1RM of quadriceps Femoris was not significant, either. It indicated that MVIC could be used to measure the strength of quadriceps femoris. (2)When using MVIC as reference, the %MVIC and repetitions produced a regression equation as Y=36.30-40.19X (P=.00) with Y presenting the repetition and X as load. The result showed that when using MVIC as reference, the repetitions of %MVIC can be predicted. In addition, the predicted repetitions can be used to design a weight training prescription. (3)At high levels of training load (90-70%MVIC), the correlation between measured mechanical work and prescribed training volume were significant (P=.00). However, the significant correlations were not discovered in low MVIC levels (40-60%) Therefore, we concluded that the prescribed training volume can not present the real mechanical work produced by the contracting muscles when performing weight training at low level of training load and suggested that the mechanical work should be measured.

碩士
國立臺灣師範大學
體育學系在職進修碩士班
94
The study aims to use quantitative measurement to evaluate the effect of different ways of isotonic strength training on the volleyball players’ lower limbs strength, maximal contraction velocity, jump height and energetic power’s performances. In addition, the correlation among the four kinds of performances will also be discussed. The data was collected from 30 male subjects. They were college volleyball players, who belonged to two school teams in the 2000 academic year and the 2004 academic year respectively. After different Ways of isotonic training, these subjects were examined and measured with four kinds of performances: lower limbs strength, maximal contraction velocity, jump height and energetic power. Two statistical tests, t-test and Pearson Correlation were used to analyze the data. The results of the study show that there is a positive correlation between two kinds of performances: maximal contraction velocity and jump height; the r value is 0.884. However, there is no positive correlation among the other kinds of performances. Besides, there are two significant differences (the p value < 0.05) between the two teams of subjects in the performances of maximal contraction velocity and jump height. The mean differences are 0.25m/sec and 0.18m/sec respectively. While, there are no significant differences between the two teams of subjects in the performances of lower limbs strength and energetic power. Another important finding in the study is that plyometric training has positive effect on enhancing contraction velocity and continuous smashing training can improve the height of jumping. Furthermore, the study also suggests making good use of action plyometric training to train the volleyball players.

碩士
長庚大學
物理治療學系
103
Background : Fatigue is a common symptom affecting patients with idiopathic Parkinson’s disease(PD). Fatigue could be divided in central or peripheral fatigue, but the weighting of central v.s. peripheral fatigue and the contribution of fatigue to the related walking disability have not been established for individuals with PD. Electrical stimulation ( ES ) assisted strength training had been reported to be beneficial to fatigue in neurological patients. Whether the training can allievate different types of fatigue in patients with PD is not clear. Purpose : The purpose of this study was (1) to identify the effects of ES assisted strength training on central, peripheral and subjective fatigue, (2) to establish the correlation of fatigue severity and gait function Method: Fifteen individuals with PD were divided as training (n=8) and control (n=7) groups. Subjects in the training group received eight weeks of ES assisted quadriceps muscle strength training. Subjects in the control group keep their daily life. Before and after training, subjects received maximum voluntary contraction (MVC) test, activation level test using interpolated twitch technique, and twitch force test induced the electrical simulation to represent the general, central, and peripheral components of strength. The MVC, activation level, and twitch force were tested again after 15 minutes of isotonic knee extensor fatigue exercise to calculate general fatigue index, central fatigue index, and peripheral fatigue index. Result: There was no different in muscle property and muscle fatigue between health control and patients with PD. The healthy control had better performance of fastest and self-paced walking speed than patients with PD . The ES assisted strengthening training improved the central and peripheral fatigue and subjective fatigue in training group. No significant changes were found in individual gait parameters. The improvement of step length during fast walking can be explained partially by the improvement of peripheral fatigue index of quadriceps. Conclusion: The ES assisted training had advantage on central and peripheral fatigue. Pure strength training could not improve gait function in individuals with PD. Future development of functional strength training that also focuses on gait control is suggested.

The main metabolic pathway involved during an exercise of duration greater than 1 minute is the oxidative metabolism. The functional evaluation of oxidative metabolism is based on the analysis of two main functional indexes: O2max and O2 kinetics. These indexes are determined by a finite ability to deliver oxygen to the working muscles (central factor) and a limited ability of the muscles to extract oxygen (peripheral factor). The relative contribution of central and peripheral factors to the overall limitation of oxidative metabolism, yet remains controversial. Near Infrared Spectroscopy (NIRS) was recently added to the classical methods of muscle oxidative metabolism functional evaluation. NIRS is a non-invasive technology that continuously monitors changes (relative or absolute) in oxygenated and deoxygenated haemoglobin (HHb). NIRS HHb signal directly depends on the ratio between the muscular O2 utilization rate and the capillary O2 delivery in the region explored by the probe, providing a non-invasive estimate of the changes in O2 extraction occurring inside the muscles. The general aim of the thesis is to elucidate the relative contribution of central and peripheral factors in limiting oxidative metabolism by the application of non invasive techniques. We have proposed to modulate oxidative metabolism with different manipulations: 1) High fat diet; 2) Heavy intensity warm up and 3) two kinds of training: Aerobic and Isotonic. In the study #1 we used a high fat diet (HFdiet) to manipulate the peripheral factor in healthy young moderate trained males. Animal and human studies suggest that fat adaptation induces structural and functional muscle adaptations that may benefit oxidative metabolism. We tested the hypothesis that a long term HFdiet enhances oxidative metabolism by augmenting the muscle’s capacity to extract oxygen. 22 young healthy moderately trained males (28±5 yrs, 53±6 ml*Kg-1*min-1) were randomly assigned to: Hdiet (HFD, 55% of calories from fat, 30% carbohydrate and 15% proteins) or control diet (C, 30, 55 and 15%) for 10 days. Before and after the diet the subjects performed an incremental cycling test to exhaustion and 3 step transitions at moderate intensity. Respiratory variables and heart rate (HR) were measured bbb. The maximal and submaximal response to exercise were evaluated ( O2, respiratory exchange ratio, R) and the kinetics of pulmonary O2 were fitted by a double exponential model. HF diet was associated with a shift in substrate selection towards a higher contribution of fat to the production of energy in the moderate intensity domain of exercise (reduced R). Furthermore, HFD increased the speed of adaptation of pulmonary O2 kinetics by the reduction of the time constant of the primary component. Our findings support the hypothesis that, in healthy young males, a 10-day high fat diet may increase the speed of adaptation of oxidative metabolism at the onset of a moderate intensity exercise by increasing the relative contribution of fats oxidation to ATP production. In the study #2 we applied heavy intensity warm-up (HWu) to manipulate O2 delivery in sedentary healthy older adults. HWu increases VO2 kinetics during successive moderate intensity transitions. We tested the hypothesis that such improvement is due to a better matching of O2 delivery to utilization within the working muscles. We tested the hypothesis that HWu improvement is due to a better matching of O2 delivery to utilization within the working muscles, rather than to an increase in O2 bulk delivery. In 21 healthy older adults (65.7 5 yrs) we measured contemporarily and non-invasively indexes of the overall speed of adaptation of the oxidative metabolism ( i.e. pulmonary O2 kinetic), of the bulk O2 delivery (i.e. ) and of the rate of muscle deoxygenation (i.e. HHb) during moderate intensity step transitions, either with (Wu) or without (nWu) prior Hwu. The local matching of O2 delivery to utilization was evaluated by the HHb/ O2 ratio index. The innovative findings of this study are: i) HWu does not modify the speed of adaptation of bulk O2 delivery (i.e. ) and TPR; ii) HWu reduces the “overshoot” of the HHb/ O2 ratio, suggesting a better matching of O2 delivery to O2 utilization. Our data are compatible with the hypothesis that, in older adults, HWu, may beneficially affect oxidative metabolism thanks to acute improvement of the local matching of O2 delivery to O2 utilization. The evidences of Study # 2 motivated us to apply a manipulation that modifies O2 delivery in an adaptive way. Thus in the study #3 we applied aerobic training (AT) to manipulate O2 delivery in sedentary healthy older adults. We tested the hypothesis that older adults may benefit from 12 weeks of AT mainly thanks to an adaptive enhancement of O2 delivery to the working muscles. 14 healthy elderly (66 ± 6 yrs) were tested before and after a 12-week training consisting of an AT or a control (remained sedentary). Subjects performed: the same test protocol described in study # 2. Cardio-respiratory variables were measured bbb and muscle oxygen extraction (HHb) was measured, at the vastus lateralis, by quantitative NIRS. We calculated the time delay and the time constant of both the primary component of the pulmonary O2 and of HHb. The main findings of this study wereAT: i) increased O2max and pulmonary O2 kinetics, preceded (Wu) or not (nWu) by HWu; ii) did not modify the speed of adaptation of muscle oxygen extraction (HHb kinetics); iii) abolished the HWu effect in pulmonary O2 kinetics; iv) attenuated HWu effect in muscle oxygen extraction kinetics; v) abolished the peak of the HHb/ O2 ratio. Our data are compatible with the hypothesis that, in older adults, AT may beneficially affect oxidative metabolism thanks to an adaptive improvement in the matching of O2 delivery to the local O2 utilization. The attenuation yet not an abolishment of the HWu effect in HHb kinetics suggested us an underlying limitation in muscle O2 extraction, unaffected by AT. Isotonic Training is known to increase strength and muscle mass in older adults. We tested the hypothesis that older adults may benefits from 12 weeks of isotonic + aerobic training (IT) thanks to an adaptive enhancement in O2 delivery and O2 utilization. 14 healthy elderly (66 ± 6 yrs) were tested before and after a 12-week training consisting of an isotonic training added to aerobic training (IT) or a control condition (remained sedentary). Subjects performed the test protocol described in study #2 and were measured the variables and analyzed data as described for study # 4 The main finding of this study was that IT produced at the lungs an attenuation of HWu effect (i.e.TD remained shorter). These results suggested that older adults can be beneficially affected by IT, however it is not enough to produce the necessary variations in muscle O2 delivery to completely avoid HWu effect. Furthermore at muscle level the variations IT supressed the HWu effect. Thus in agreement with our hypothesis isotonic training added to aerobic training was enough to eliminate completely the effect of priming exercise. Regarding nWu exercise, the effect of IT was a reduction in the HHb/ O2 ratio peak, suggestive of a better matching in O2 delivery to the O2 utilization following training. Our data are compatible with the hypothesis that in older adults oxidative metabolism may be beneficially affected by IT thanks to an adaptive improvement of the local O2 delivery and a further adaptations in the working muscle to O2 utilization. In summary, eucaloric high fat diet, priming and training (aerobic and isotonic) beneficially affect the speed of adaptation of oxidative matabolism at the onset of an exercise of moderate intensity. The observed benefits are related to a variable combination of adaptations in O2 delivery and utilization that have been non-invasively evaluated in our studies.
The main metabolic pathway involved during an exercise of duration greater than 1 minute is the oxidative metabolism. The functional evaluation of oxidative metabolism is based on the analysis of two main functional indexes: O2max and O2 kinetics. These indexes are determined by a finite ability to deliver oxygen to the working muscles (central factor) and a limited ability of the muscles to extract oxygen (peripheral factor). The relative contribution of central and peripheral factors to the overall limitation of oxidative metabolism, yet remains controversial. Near Infrared Spectroscopy (NIRS) was recently added to the classical methods of muscle oxidative metabolism functional evaluation. NIRS is a non-invasive technology that continuously monitors changes (relative or absolute) in oxygenated and deoxygenated haemoglobin (HHb). NIRS HHb signal directly depends on the ratio between the muscular O2 utilization rate and the capillary O2 delivery in the region explored by the probe, providing a non-invasive estimate of the changes in O2 extraction occurring inside the muscles. The general aim of the thesis is to elucidate the relative contribution of central and peripheral factors in limiting oxidative metabolism by the application of non invasive techniques. We have proposed to modulate oxidative metabolism with different manipulations: 1) High fat diet; 2) Heavy intensity warm up and 3) two kinds of training: Aerobic and Isotonic. In the study #1 we used a high fat diet (HFdiet) to manipulate the peripheral factor in healthy young moderate trained males. Animal and human studies suggest that fat adaptation induces structural and functional muscle adaptations that may benefit oxidative metabolism. We tested the hypothesis that a long term HFdiet enhances oxidative metabolism by augmenting the muscle’s capacity to extract oxygen. 22 young healthy moderately trained males (28±5 yrs, 53±6 ml*Kg-1*min-1) were randomly assigned to: Hdiet (HFD, 55% of calories from fat, 30% carbohydrate and 15% proteins) or control diet (C, 30, 55 and 15%) for 10 days. Before and after the diet the subjects performed an incremental cycling test to exhaustion and 3 step transitions at moderate intensity. Respiratory variables and heart rate (HR) were measured bbb. The maximal and submaximal response to exercise were evaluated ( O2, respiratory exchange ratio, R) and the kinetics of pulmonary O2 were fitted by a double exponential model. HF diet was associated with a shift in substrate selection towards a higher contribution of fat to the production of energy in the moderate intensity domain of exercise (reduced R). Furthermore, HFD increased the speed of adaptation of pulmonary O2 kinetics by the reduction of the time constant of the primary component. Our findings support the hypothesis that, in healthy young males, a 10-day high fat diet may increase the speed of adaptation of oxidative metabolism at the onset of a moderate intensity exercise by increasing the relative contribution of fats oxidation to ATP production. In the study #2 we applied heavy intensity warm-up (HWu) to manipulate O2 delivery in sedentary healthy older adults. HWu increases VO2 kinetics during successive moderate intensity transitions. We tested the hypothesis that such improvement is due to a better matching of O2 delivery to utilization within the working muscles. We tested the hypothesis that HWu improvement is due to a better matching of O2 delivery to utilization within the working muscles, rather than to an increase in O2 bulk delivery. In 21 healthy older adults (65.7 5 yrs) we measured contemporarily and non-invasively indexes of the overall speed of adaptation of the oxidative metabolism ( i.e. pulmonary O2 kinetic), of the bulk O2 delivery (i.e. ) and of the rate of muscle deoxygenation (i.e. HHb) during moderate intensity step transitions, either with (Wu) or without (nWu) prior Hwu. The local matching of O2 delivery to utilization was evaluated by the HHb/ O2 ratio index. The innovative findings of this study are: i) HWu does not modify the speed of adaptation of bulk O2 delivery (i.e. ) and TPR; ii) HWu reduces the “overshoot” of the HHb/ O2 ratio, suggesting a better matching of O2 delivery to O2 utilization. Our data are compatible with the hypothesis that, in older adults, HWu, may beneficially affect oxidative metabolism thanks to acute improvement of the local matching of O2 delivery to O2 utilization. The evidences of Study # 2 motivated us to apply a manipulation that modifies O2 delivery in an adaptive way. Thus in the study #3 we applied aerobic training (AT) to manipulate O2 delivery in sedentary healthy older adults. We tested the hypothesis that older adults may benefit from 12 weeks of AT mainly thanks to an adaptive enhancement of O2 delivery to the working muscles. 14 healthy elderly (66 ± 6 yrs) were tested before and after a 12-week training consisting of an AT or a control (remained sedentary). Subjects performed: the same test protocol described in study # 2. Cardio-respiratory variables were measured bbb and muscle oxygen extraction (HHb) was measured, at the vastus lateralis, by quantitative NIRS. We calculated the time delay and the time constant of both the primary component of the pulmonary O2 and of HHb. The main findings of this study wereAT: i) increased O2max and pulmonary O2 kinetics, preceded (Wu) or not (nWu) by HWu; ii) did not modify the speed of adaptation of muscle oxygen extraction (HHb kinetics); iii) abolished the HWu effect in pulmonary O2 kinetics; iv) attenuated HWu effect in muscle oxygen extraction kinetics; v) abolished the peak of the HHb/ O2 ratio. Our data are compatible with the hypothesis that, in older adults, AT may beneficially affect oxidative metabolism thanks to an adaptive improvement in the matching of O2 delivery to the local O2 utilization. The attenuation yet not an abolishment of the HWu effect in HHb kinetics suggested us an underlying limitation in muscle O2 extraction, unaffected by AT. Isotonic Training is known to increase strength and muscle mass in older adults. We tested the hypothesis that older adults may benefits from 12 weeks of isotonic + aerobic training (IT) thanks to an adaptive enhancement in O2 delivery and O2 utilization. 14 healthy elderly (66 ± 6 yrs) were tested before and after a 12-week training consisting of an isotonic training added to aerobic training (IT) or a control condition (remained sedentary). Subjects performed the test protocol described in study #2 and were measured the variables and analyzed data as described for study # 4 The main finding of this study was that IT produced at the lungs an attenuation of HWu effect (i.e.TD remained shorter). These results suggested that older adults can be beneficially affected by IT, however it is not enough to produce the necessary variations in muscle O2 delivery to completely avoid HWu effect. Furthermore at muscle level the variations IT supressed the HWu effect. Thus in agreement with our hypothesis isotonic training added to aerobic training was enough to eliminate completely the effect of priming exercise. Regarding nWu exercise, the effect of IT was a reduction in the HHb/ O2 ratio peak, suggestive of a better matching in O2 delivery to the O2 utilization following training. Our data are compatible with the hypothesis that in older adults oxidative metabolism may be beneficially affected by IT thanks to an adaptive improvement of the local O2 delivery and a further adaptations in the working muscle to O2 utilization. In summary, eucaloric high fat diet, priming and training (aerobic and isotonic) beneficially affect the speed of adaptation of oxidative matabolism at the onset of an exercise of moderate intensity. The observed benefits are related to a variable combination of adaptations in O2 delivery and utilization that have been non-invasively evaluated in our studies.

In order to improve the simplicity and accuracy of detecting muscle strength, a recognition method based on deep learning is proposed. CNN algorithm and RNN algorithm are used to complete the classification of B-ultrasound images and videos with different muscle strength. The convolutional neural network CNN algorithm is used to extract the features of B-ultrasound video, and then the cyclic neural network RNN is used to complete the time sequence analysis. The experiment uses the data set in this paper for training and testing. The results show that the accuracy of the proposed model for four categories of muscle strength video based on 0%, 20%, 40% and 60% of individual maximum strength (MVC) is about 93.45%. The resnet50 RNN algorithm proposed in this paper can effectively classify B-ultrasound videos with different muscle strength. This muscle strength detection model has strong universality for different individuals. The method of processing B-ultrasound image video can provide theoretical guidance for medical rehabilitation treatment, prosthetic limb control, professional sports training, public health and other fields, and promote the development of these fields, which is worthy of our in-depth study.

Multivariate probability calibration is the problem of predicting class membership probabilities from classification scores of multiple classifiers. To achieve better performance, the calibrating function is often required to be coordinate-wise non-decreasing; that is, for every classifier, the higher the score, the higher the probability of the class labeling being positive. To this end, we propose a multivariate regression method based on shape-restricted Bernstein polynomials. This method is universally flexible: it can approximate any continuous calibrating function with any specified error, as the polynomial degree increases to infinite. Moreover, it is universally consistent: the estimated calibrating function converges to any continuous calibrating function, as the training size increases to infinity. Our empirical study shows that the proposed method achieves better calibrating performance than benchmark methods.