Effects of application resistive and flex resistance to breath in training sportsmen

The research on studying influence of a rate of muscular training in conditions of additional aerodynamic and flex resistance to breath on a level of physical working capacity, aerobic productivity and a functional condition of system of breath is carried out. It is shown, that regular muscular training on a background of use of the dosed out breath with increased aerodynamic and flex resistance to respiratory streams and respiratory movements, first of all, provides essential growth of functionalities of the respiratory muscles expressed in authentic increase of power and speed-power parameters, shortening of time of impellent reaction of respiratory muscles. Improvement of a functional condition of respiratory system, and, in particular, respiratory muscles, causes significant growth of physical working capacity and physical readiness of young sportsmen.     

Does the respiratory system limit the aerobic working capacity of humans?

The question concerning respiratory function reserves among the factors determining the maximal power of muscular work is considered. Even in strenuous physical exercise, pulmonary ventilation does not exceed a rather constant level for every individual. Studies conducted using the programmed isocapnic hyperpnea method developed by the authors demonstrated that this level precisely reflects the functional respiratory reserve that is one of the factors limiting maximal work performance intensity. Under normal conditions, the functional respiratory reserve is 20 to 40% less than the so-called maximal breathing capacity (MBC) determined in a test, which requires voluntarily forcing respiratory efforts and exorbitant energy expenditure for the respiratory muscles performance. Therefore, the MBC should be regarded only as a parameter of ventilatory forced capacity used in extreme situations such as competitive athletic loading or in more resistive breathing when decreased respiratory system reserves become a leading factor rigidly limiting aerobic working capacity. A scheme is given that illustrates the ambiguous role of the respiratory system in this aspect.     

Physiological effects of low-intensity strength training without relaxation

The effects of low-intensity strength training without relaxation (LISTR) on the force-velocity properties of hip and knee extensor muscles, the power endurance of the knee extensor muscles, and the aerobic performance of the body were studied. The difference between the LISTR and classical strength training (CST) is that the working muscle groups do not relax at the extreme points of the range of motion. The study was performed in two groups each comprising nine young physically active men who trained three times a week for eight weeks. The study showed that LISTR increased the maximum voluntary force to about the same extent as CST, but this was achieved with lower training loads. Moreover, LISTR did not lead to a decrease in the local muscular work capacity, which is usually observed during CST.     

Resistive loading and mechanisms regulating respiration

In experiments on anesthetized cats, switch on of additional inelastic respiration resistance (resistive load) produced, apart from slowing of the respiratory flows, an increase in the activity of motoneurons and inspiratory intrathoracic pressure. Bilateral vagotomy resulted in disappearance of resistive load-induced elevation of the phrenic nerve activity, but did not abolish the growth of the inspiratory effort. Analysis of the evidence obtained indicates that activation of phrenic motoneurons associated with increased respiration resistance is underlain by prolongation of the inspiratory phase that is consequent on relaxation of the inspiratory inhibition. It is suggested that, in addition to the mechanism depicted, the compensatory reaction to the resistive load involves, apart from diaphragm participation, other inspiratory muscles as well as enhanced contractions of respiratory muscles provided by the properties of muscular fiber.     

Efficacy of two intervention approaches on functional walking capacity and balance in children with Duchene muscular dystrophy

Objectives:Children with Duchene muscular dystrophy have weak muscles, which may impair postural adjustments. These postural adjustments are required for gait and dynamic balance during the daily living activities. The aim was to compare between the effect of bicycle ergometer versus treadmill on functional walking capacity and balance in children with Duchenne muscular dystrophy.Methods:Thirty boys aged from 6 to 10 years old diagnosed as Duchene muscular dystrophy participated in this study. Children were assigned randomly into two groups (A&B). Children in group (A) underwent a designed program of physical therapy plus aerobic exercise training in form of bicycle ergometer while, group (B) received the same program as group (A) and aerobic exercise training by treadmill for one hour, at three times a week for three successive months. Functional walking capacity and balance were assessed before and after treatment by using the 6-minute walk test and Biodex balance system equipment respectively.Results:The post treatment results revealed significant difference in all measured variables (P<0.05) as compared with its pre-treatment results. Post-treatment values indicated that there was a significant difference in all measured variables in favor of group B.Conclusions:treadmill training as an aerobic exercise can improve walking capacity and balance more effectively than bicycle ergometer in children with Duchenne muscular dystrophy.     

Energy-supply of the muscular activity at boys of 13-14 years in dependence from rates of puberty

In work on the basis of use functional and ergometric working capacity indicators specificity of power supply of muscular activity of healthy boys of 13-14 years (n = 162) with various at puberty stages (PSs). It is established, that the boys, being on II-IV PSs, considerably differ on indicators of power, capacity and efficiency of energy systems. Three groups of the bioenergy systems indicators differing on an orientation of their changes at teenagers depending on rates of puberty stages. The first group includes the physiological variables which most considerable levels are observed at children with high rates of development. All of them concern to anaerobic alactic and anaerobic glycolytic to components of physical working capacity. The second group unites the physiological variables which highest values are marked at teenagers with average rate of development, and the least--at children with the accelerated rate of maturing. These indicators reflect, mainly, set of aerobic possibilities of an organism. The third group includes the indicators which highest levels are marked at teenagers with low rate of development, and the least--at boys with the accelerated rate of maturing. They reflect the maximum aerobic power and endurance to power work. It is revealed, that teenagers of 13-14 years with average rates of development are characterised in comparison with children with the accelerated maturing, higher indicators of power and capacity of aerobic system of energy-supply, and in comparison to teenagers to the slowed down development--lower maximum aerobic power against higher capacity and profitability of functioning of aerobic system. Adolescents with average rates of maturing surpass also schoolboys with the accelerated and slowed down development concerning capacity of work in mixed anaerobic-aerobic a mode. In turn boys of 13-14 years with the accelerated development differ from schoolboys with the average and slowed down rates of maturing, high anaerobic productivity of an organism, rather low aerobic possibilities and increase of a tone of parasympathetic department of autonomic nervous system (AHC). The given circumstance is necessary for considering at realisation of the differentiated approach to rationing of loadings in the course of physical education and sports training of adolescents of 13-14 years.     

Development of the Energetics of Muscular Exercise with Age: Summary of a 30-Year Study: I. Structural and Functional Rearrangements

The series of articles summarizes a 30-year study on the development of skeletal muscles, bioenergetics of muscular exercise, and physical working capacity with age in elementary and secondary school students. Communication I deals with the growth of human skeletal muscles and age-related changes in their fiber composition and the main parameters of aerobic working capacity. The key periods of growth were determined and a substantial rearrangement of skeletal muscle composition and associated age-related changes in aerobic and anaerobic working capacity were found in 7- to 17-year-old boys.__________Translated from Fiziologiya Cheloveka, Vol. 31, No. 4, 2005, pp. 37–42.Original Russian Text Copyright © 2005 by Kornienko, Son’kin, Tambovtseva.     

Energy supply of muscular activity of five- to six-year-old children and complex assessment of physical working capacity

A complex study of the physical working capacity of five- to six-year-old children (n = 106) was performed. It was found that the physical working capacity of preschool children at this age is determined by the following five major factors: (I) aerobic capacity, (II) anaerobic glycolytic working capacity, (III) absolute aerobic power, (IV) relative aerobic power, and (V) anaerobic alactic working capacity. Sex-related differences in some parameters reflecting the physical working capacity and fitness, characterizing the anaerobic alactic and anaerobic glycolytic productivity of the body were revealed. These differences are apparently related to an advanced development of anaerobic energy-supply mechanisms of girls compared to age-matched boys. The procedure of a complex assessment of the physical working capacity of five- to six-year-old children has been developed, which includes informative parameters characterizing the power and capacity of energy systems selected on the basis of results of factor analysis and expert assessment. A rapid procedure for a complex assessment of working capacity based on calculating the time during which a physical load (2 W/kg) can be sustained is proposed. The study showed that shifts in the intensity of physical activity within the optimal range resulted in multifold changes in its duration. Importantly, the duration of physical activity’s performance at an intensity of 175–180 bpm in children with a high working capacity is comparable to the maximum work duration at a heart rate of 140–145 bmp in preschool children with a low physical condition. Differences between children with high and low physical working capacity were found to increase with an increase in the physical load aerobicity. The physical working capacity of five- to six-year-old children can be differentiated best of all on the basis of aerobic capacity parameters. The enormous range of changes in the aerobic capacity parameters makes them especially valuable for characterizing the level of somatic health of preschool children. The results of this study were used to construct a nomogram for the determination of the allowable training load depending on its intensity and physical working capacity.     

Strategies of adaptation of small arteries in diaphragm and gastrocnemius muscle to aerobic exercise training

Aerobic exercise training is associated with adaptive changes in skeletal muscles and their vascular bed; such changes in individual muscles may vary depending on their characteristics and recruitment. This study was aimed at comparing the effects of eight-week treadmill training on the locomotor and respiratory muscles in rats. The training course increased the aerobic performance in rats, which was evidenced by an increase in maximum O₂ consumption and a decrease in the blood lactate concentration in ramp test. The succinate dehydrogenase activity was increased in the red portion of the gastrocnemius muscle, but not in the diaphragm of trained rats. Arterial segments were isolated from feed arteries and studied by wire myography. The relaxation in response to acetylcholine in gastrocnemius arteries in trained animals was higher as compared with controls (due to higher NO production), while contractile responses to noradrenaline (in the presence of propranolol) were not changed. On the contrary, the endothelial function of diaphragm arteries was not affected by training, but contractile responses to activation of α-adrenoceptors were markedly increased. Thus, aerobic training may increase the blood supply rate to both locomotor and respiratory muscles, but the underlying regulatory mechanisms are different. The results obtained allow us to reveal the physiological mechanisms that determine the physical performance of the body under conditions of compromised functioning of the respiratory system.     

Breathing,voice, and movement therapy: Applications to breathing disorders

Elsa Gindler (1885–1961) developed a holistic approach to the human body and psyche via the movement of breath. Gindler experimented with movements to strengthen the deeper layers of the muscular system and improve the circulation of oxygen, movements that reduced tensions that had been preventing the breathing muscles from functioning properly. Subsequently, she founded a school for breathing and body awareness. The biggest breathing muscle in the human body is the diaphragm, the lowering of which can only take place when the jaw and the throat are relaxed, the belly is free, and the psoas (major and minor) and hip joints allow free leg-movement and flexibility in the lower back. When these conditions do not obtain, the body compensates by lifting the shoulders, pulling up the chest bone, and contracting the sphincter muscles in the throat, movements which weaken the muscles which assist the breathing process. Thus, the compensatory muscles are overburdened and the fine organization of the body is disturbed; the natural capacity to use the breath as a healing force is lost. The goal of breath therapy is to recognize and reestablish this capacity. Training sessions are devoted to relaxation; to exercises to rebuild muscle tone, strengthen weakened muscles, release contracted areas, and the use of the voice to stimulate the respiratory system. Sessions typically consist of (a) relaxation, (b) activation (experimenting with new, freer ways of moving), and (c) integration (application to everyday life). The therapist analyzes incidents of stress in the client's life where breathing is likely to be disturbed. This is especially important for asthmatics who can learn how to deal with an attack by relaxing rather than contracting. This work is especially beneficial for problems in (a) the skeletal structure, (b) respiration, (c) vital organs, and (d) general symptoms.     

The impact of a supervised strength and aerobic training program on muscular strength and aerobic capacity in individuals with type 2 diabetes

An intervention in the clinical management of individuals with type 2 diabetes is strength and aerobic training. Limited research has been conducted that investigates the effect of a supervised strength and aerobic training program on muscular strength and aerobic capacity in people with type 2 diabetes. The purpose of this 1-group repeated-measures-designed study was to investigate the impact of a supervised strength and aerobic training program on muscular strength and aerobic capacity in subjects with type 2 diabetes. Thirteen subjects with type 2 diabetes completed the training program. Subjects met the American Diabetes Association diagnostic criteria for type 2 diabetes. For each subject, muscular strength (estimated 1 repetition maximum) and aerobic capacity (estimated maximal oxygen uptake) were measured before and after a supervised strength and aerobic training program as well as during a 6-week follow-up. Repeated-measures analysis of variance was used to compare muscular strength and aerobic capacity between pretesting, posttesting, and follow-up testing periods. Significant improvements in muscular strength (p < 0.01) and aerobic capacity (p < 0.01) were found during posttesting and follow-up testing, as compared to pretesting measures. Yet a significant loss in muscular strength (p < 0.01) and no significant change in aerobic capacity (p > 0.05) were found during follow-up testing, as compared to posttesting measures. This study indicates that a supervised strength and aerobic training program can significantly improve muscular strength and aerobic capacity in people with type 2 diabetes. Yet improvements in muscular strength due to training will not be maintained if individuals with type 2 diabetes do not adhere to a continuous training program. In addition, aerobic capacity can be improved with training, but aerobic capacity will not continue to improve if people with type 2 diabetes are not compliant with a continuous training program.     

Airway resistance and respiratory muscle function in snorers during NREM sleep

The effect of non-rapid-eye-movement (NREM) sleep on total pulmonary resistance (RL) and respiratory muscle function was determined in four snorers and four nonsnorers. RL at peak flow increased progressively from wakefulness through the stages of NREM sleep in all snorers (3.7 +/- 0.4 vs. 13.0 +/- 4.0 cmH2O X 0.1(-1) X s) and nonsnorers (4.8 +/- 0.4 vs. 7.5 +/- 1.1 cmH2O X 1(-1) X s). Snorers developed inspiratory flow limitation and progressive increase in RL within a breath. The increased RL placed an increased resistive load on the inspiratory muscles, increasing the pressure-time product for the diaphragm between wakefulness and NREM sleep. Tidal volume and minute ventilation decreased in all subjects. The three snorers who showed the greatest increase in within-breath RL demonstrated an increase in the contribution of the lateral rib cage to tidal volume, a contraction of the abdominal muscles during a substantial part of expiration, and an abrupt relaxation of abdominal muscles at the onset of inspiration. We concluded that the magnitude of increase in RL leads to dynamic compression of the upper airway during inspiration, marked distortion of the rib cage, recruitment of the intercostal muscles, and an increased contribution of expiratory muscles to inspiration. This increased RL acts as an internal resistive load that probably contributes to hypoventilation and CO2 retention in NREM sleep.     

Morphological and Functional Changes in Overweight Persons under Combined Normobaric Hypoxia and Physical Training

Functional and morphological changes were studied in overweight persons in tests with various combinations of normobaric hypoxia and physical training. It was shown that normobaric hypoxia combined with training can be used for increasing physical working capacity and aerobic capacity in overweight persons. A combination of physical training and breathing hypoxic gas mixtures was demonstrated to be the most effective method of correcting and increasing the physiological functional potential in overweight persons.     

Exercise-induced respiratory muscle fatigue: implications for performance.

It is commonly held that the respiratory system has ample capacity relative to the demand for maximal O(2) and CO(2) transport in healthy humans exercising near sea level. However, this situation may not apply during heavy-intensity, sustained exercise where exercise may encroach on the capacity of the respiratory system. Nerve stimulation techniques have provided objective evidence that the diaphragm and abdominal muscles are susceptible to fatigue with heavy, sustained exercise. The fatigue appears to be due to elevated levels of respiratory muscle work combined with an increased competition for blood flow with limb locomotor muscles. When respiratory muscles are prefatigued using voluntary respiratory maneuvers, time to exhaustion during subsequent exercise is decreased. Partially unloading the respiratory muscles during heavy exercise using low-density gas mixtures or mechanical ventilation can prevent exercise-induced diaphragm fatigue and increase exercise time to exhaustion. Collectively, these findings suggest that respiratory muscle fatigue may be involved in limiting exercise tolerance or that other factors, including alterations in the sensation of dyspnea or mechanical load, may be important. The major consequence of respiratory muscle fatigue is an increased sympathetic vasoconstrictor outflow to working skeletal muscle through a respiratory muscle metaboreflex, thereby reducing limb blood flow and increasing the severity of exercise-induced locomotor muscle fatigue. An increase in limb locomotor muscle fatigue may play a pivotal role in determining exercise tolerance through a direct effect on muscle force output and a feedback effect on effort perception, causing reduced motor output to the working limb muscles.     

Resistance training enhances the stability of sensorimotor coordination

Strategies for the control of human movement are constrained by the neuroanatomical characteristics of the motor system. In particular, there is evidence that the capacity of muscles for producing force has a strong influence on the stability of coordination in certain movement tasks. In the present experiment, our aim was to determine whether physiological adaptations that cause relatively long-lasting changes in the ability of muscles to produce force can influence the stability of coordination in a systematic manner. We assessed the effects of resistance training on the performance of a difficult coordination task that required participants to synchronize or syncopate movements of their index finger with an auditory metronome. Our results revealed that training that increased isometric finger strength also enhanced the stability of movement coordination. These changes were accompanied by alterations in muscle recruitment patterns. In particular, the trained muscles were recruited in a more consistent fashion following the programme of resistance training. These results indicate that resistance training produces functional adaptations of the neuroanatomical constraints that underlie the control of voluntary movement.     

Hindlimb muscular contraction reflexly decreases total pulmonary resistance in dogs

We have previously shown that contraction of the gracilis muscles of anesthetized dogs reflexly relaxes tracheal smooth muscle. We have also found that electrical stimulation of these afferents decreases total pulmonary resistance (TPR), a calculation that provides a functional index of airway caliber. Despite these findings, we have yet to show that muscular contraction reflexly decreases TPR. Therefore, in 11 alpha-chloralose-anesthetized dogs, we contracted the hindlimb muscles by electrically stimulating the L6-L7 ventral roots while measuring TPR breath by breath. We found that static contraction decreased TPR from 12.6 +/- 1.1 to 10.4 +/- 0.9 cmH2O X l-1 X s (P less than 0.05). This decrease was reflex in origin because it was prevented by section of the spinal roots innervating the working hindlimb. Repetitive twitch contractions (5 Hz) also reflexly decreased TPR, but the effect was smaller than that evoked by static contraction. The reflex decreases in TPR evoked by contraction were unaffected by propranolol but were abolished by atropine. We conclude that muscular contraction dilates the airways by a reflex mechanism whose efferent arm consists of a withdrawal of cholinergic input to airway smooth muscle.     

The functional state of children from 9 to 10 years of age under the conditions of intense informational load and physical working capacity

Three-way ANOVA has shown that the functional state (FS) of children from 9 to 10 years of age (n = 91) under intense informational load is significantly influenced by the aerobic and anaerobic components of physical working capacity and their interaction. It has been found that 4 to 21% of the total variation of the studied FS indices are related to the bioenergetic resources of the body. It has been shown that the high levels of development of the aerobic and anaerobic glycolytic capacities are associated with the optimal changes in the FS under the conditions of intense informational load. At the same time, the interaction of the aerobic and anaerobic glycolytic components of physical working capacity exerts the most significant influence on the productivity and “psychophysiological cost” of intellectual activity. The high anaerobic glycolytic and anaerobic alactate capacities proved to have opposite functional effects. The former contribute to a decrease in excessive autonomic reactivity under the conditions of intense work and diminution of trait anxiety; the latter, on the contrary, determine hypermobilization of the system of autonomic support of activity. The results suggest that a combined use of rational proportions of physical loads of the aerobic, anaerobic glycolytic, and anaerobic alactate types will provide efficient control of children’s FS under the conditions of intense intellectual activity.     

Human Inspiratory Muscle Fatigue during Strenuous Resistive Loads under Normoxic and Hypoxic Conditions

A study involving nine healthy males was conducted to determine the developmental rate of inspiratory muscle fatigue during resistive loads under normoxic and hypoxic conditions. The subjects aged 19 to 38 years performed a bicycle exercise test of increasing power during an exhaustive inspiratory–expiratory resistive load of 40 cm water column/l s^–1 inhaling air or oxygen. The volumetric and temporal respiratory parameters, the partial CO₂ pressure in the alveolar gas, the total force of inspiratory muscle contractions, the electrical activity of parasternal muscles (EMG), and the initial inspiratory activity were recorded. The degree of inspiratory muscle fatigue was assessed by the tension–time index P _m/P _{m max} T _I/T _T as well as by the ratio of the mean amplitudes of the EMG-signal spectrum in the high-frequency (H) range to the mean spectrum amplitudes in the low-frequency (L) range (H/L). It was established that human working capacity during increasing muscular loads against the background of highly resistive breathing was not a function of the oxygen content in the inhalation mixtures within 21 to 100%; i.e., the maximal power of the work done did not significantly differ. It was shown that pulmonary ventilation, the force generated by inspiratory muscles, the breathing effort values, the initial inspiratory activity value, and the tension–time index increased in parallel with the intensity of the exercise when both air and oxygen were inhaled. The P _m/P _{m max} T _I/T _T values in the last minutes of the muscular load significantly exceeded the fatigue zone range, attaining 0.25 to 0.45 in different subjects. By the moment of refusal to continue the work, the H/L ratio had decreased by an average of 36% when air and oxygen were inhaled. The limitation of the physical working capacity of a healthy individual during an exhaustive resistive load is considered to be linked to inspiratory muscle fatigue developing at an equal rate under both normoxic and hyperoxic conditions. An impairment of the arterial blood supply to inspiratory muscles due to occlusion of the intramuscular vessels during intense muscular contractions and a considerable shortening of the time of the relaxation of the respiratory muscles in the expiratory phase is supposed to occur in forced respiration with an additional gas flow obstruction. The fact of the alternation of the electrical activity between the parasternal and other inspiratory muscles within individual inspiratory phases combined with resistive and physical loads is established, which may serve as one of the signs of inspiratory muscle fatigue.     

Physical working capacity and energy supply of muscle function during postnatal human ontogeny

On the basis of the results of our studies and literature data, an analysis of the physiological mechanisms responsible for the multifold increase in the physical working capacity during human development has been performed. Physiological and biochemical studies have shown that the aerobic energy system already has a high capacity during the second period of childhood, and the further increase in working capacity is mainly provided by the development of anaerobic mechanisms of energy supply. The maturation of mechanisms of energy production is related to considerable changes in the activity of tissue enzymes and radical rearrangement of the composition of muscular fibers. Puberty considerably influences the development of anaerobic muscle energetics in boys due to stimulation of the growth of type II fibers by testosterone. It has been shown that widespread tests for assessment of physical working capacity mainly reflect changes in the power of energy systems and only in rare cases may be used to characterize changes in their capacity. However, the capacity parameters, which depend to a greater extent on the quality of regulation at the cellular, tissue, and body levels, show multifold growth during ontogeny, which corresponds to the actual increase in the working capacity in the period from childhood to youth. A classification of tests of physical working capacity is proposed. The use and development of this classification may facilitate the development of new tests and an increased efficiency of testing involved in solving various applied and fundamental problems.     

The Phenomenon of Refusal in Muscular Activity. The Role of the Respiratory System

Among the factors leading to the refusal to continue muscular work, afferent impulsation carrying information about the efforts developed by the working muscles and about the respiratory function tension is noteworthy. Based on this information, the integral self-rating of the intensity of the physical load and its endurance is formed in the sensory CNS sphere, with one of the signals to stop the work being the feeling of shortness of breath. Under the cyclic working conditions, the so-called critical power load, which is high enough but does not lead to a refusal so far, enabling one to perform the maximum amount of useful work, appears to be the most effective. A question is posed as to the possibility of using an active choice of preferable load intensity by an individual in order to develop a method for determining the optimal work power according to the functional state of the body.