Isometric Exercise

Alzheimer's disease (AD) is the most common form of dementia diagnosed amongst the elderly. Mild cognitive impairment (MCI) is a condition often indicative of the earliest symptomatology of AD with 10%–15% of MCI patients reportedly progressing to a diagnosis of AD. Individuals with a history of vascular risk factors (VRF's) are considered high risk candidates for developing cognitive impairment in later life. Evidence suggests that vascular injury resulting from untreated VRF's promotes progression from MCI to AD and exacerbates the severity of dementia in AD, and neuroimaging studies have found that the neurodegenerative processes associated with AD are heavily driven by VRF's that promote cerebral hypoperfusion. Subsequently, common links between vascular disorders such as hypertension and neurodegenerative disorders such as AD include compromised vasculature, cerebral hypoperfusion and chronic low grade inflammation (a hallmark of both hypertension and AD). Exercise has been demonstrated to be an effective intervention for blood pressure management, chronic low grade inflammation and improvements in cognition. Data from recent analyses suggests that isometric exercise training (IET) may improve vascular integrity and elicit blood pressure reductions in hypertensives greater than those seen with dynamic aerobic and resistance exercise. IET may also play an effective role in the management of VRF's at the MCI stage of AD and may prove to be a significant strategy in the prevention, attenuation or delay of progression to AD. A plausible hypothesis is that the reactive hyperemia stimulated by IET initiates a cascade of vascular, neurotrophic and neuro-endocrine events that lead to improvements in cognitive function.

The purpose of the present study was to examine the effect of different conditioning activities (CAs) on short-term increase in sprint performance. In twelve male sprinters (21.1±2.6 years, 100 m performance: 11.5±0.6 s) their body composition, half squat maximum strength, 100 m sprinting and countermovement jump performances were evaluated. The performance of a 50 m sprint (splits at 10 m, 30 m and 50 m) was evaluated before and 5, 10 and 15 min after four postactivation performance enhancement CAs on different occasions: [1] 3 sets x 4 s maximum isometric half squat (IHF), [2] 3 sets x 3 consecutive countermovement jumps (cCMJs), [3] 3 repetitions x 30 m overspeed sprinting (OVSP) and [4] dynamic submaximal half squat (2 sets x 2 reps x 90% of 1-RM half squat; HSQ). Significant improvements of sprinting performance were found 10 and 15 min following the cCMJs, OVSP and HSQ's interventions, in all distances (p<.05;-2.14±1.21% and-3.56±2.47%), without any significant difference between these interventions and time points (p>.05). Significant inter-individual differences were found in the magnitude of sprint performance improvements as well as in the optimal time window (p<.05), with the stronger sprinters responding better after HSQs, while the more powerful sprinters after cCMJs and OVSPs. In conclusion, it seems that cCMJs, OVSP and HSQ can acutely increase sprinting performance after 10 min, but CA's induced increases in sprinting performance are highly related to the strength and power characteristics of each sprinter.

This study examined the effects of jaw clenching, and a self-adapted, jaw repositioning mouthpiece on force production during maximum countermovement vertical jump and maximum isometric mid-thigh clean pull assessments in an attempt to determine any ergogenic effects attributable to clenching, jaw repositioning mouthpiece use, or the combination of both. Thirty-six male subjects performed vertical jump and isometric clean pull assessments from a force platform under various mouthpiece and clench conditions. A 3x2 (mouthpiece x clench) repeated measures ANOVA was conducted to analyze each of the following force production variables for both assessments: peak force, normalized peak force, and rate of force development. Additionally, jump height was analyzed for the vertical jump. Results revealed improvements in peak force (F1,35 = 15.84, p &lt; 0.001, ηp= 0.31), normalized peak force (F1,35 = 16.28, p &lt; 0.001, ηp= 0.32), and rate of force development (F1,35 = 12.89, p = 0.001, ηp=...

Background: In patients with chronic tension-type headache (CTTH) changes in pressure pain in the cervical region are associated with peripheral or central sensitization. It is hypothesized that an increase of isometric strength of neck flexors would lead to a decrease of pressure pain in CTTH, as an expression of reduced peripheral or central sensitization Objective: In this study we aimed to analyze the correlation between change in isometric strength of the neck flexors and change in pressure pain scores (PPS) in patients with CTTH. Study Design: Comparative analysis of data from previous study. Setting: Primary healthcare center. Methods: Data from 145 patients with CTTH who underwent a manual therapy program including isometric strength training of the neck flexors were analyzed at 8 and 26 weeks posttreatment. PPS were measured as a total of pain scores on a numeric rating scale (score 0 to 10) on application of a pressure stimulus of 3kg/cm at 8 cervical- and suboccipital mus...

Background: Adjunctive isometric exercise in the form of sustained submaximal handgrip (HG) is considered to increase the sensitivity of dobutamine stress echo (DSE) for detection of functionally significant coronary artery disease.Hypothesis: The study was undertaken to quantify invasive-ly the impact of HG in humans on hemodynamics and myocardial oxygen consumption (MVO2) during DSE.Methods: An invasive hemodynamic evaluation was performed during DSE and with addition of adjunctive HG in 11 subjects. Coronary sinus (CS) blood flow, right-sided and systemic pressures, oxygen saturations, and transthoracic two-dimensional echocardiography were obtained at each 3-min stage and after adding HG at peak DSE. Myocardial oxygen consumption was calculated by the Fick method and circumferential end-systolic wall stress (ESWS) by Mirsk's formula.Results: At peak DSE, heart rate, left ventricular ejection fraction, CS flow, and MVO2 increased, whereas pulmonary capillary wedge pressure (PCWP) and circumferential end-systolic wall stress (ESWS) decreased from baseline. Compared with peak DSE, the addition of isometric HG at peak DSE caused an increase in PCWP (7 ± 3 vs. 8.4 ± 3 mmHg, p < 0.05), ESWS (112 ± 25 × 103 vs. 125 ± 32 × 103 dyne·s·cm2, p = 0.02), and CS flow (260 ± 92 vs. 301 ± 105 ml/min, p < 0.05). There was a minimal increase in left ventricular volumes, heart rate, and systolic blood pressure. The MVO2 increased from 29 ± 8 ml/min at peak DSE to 31 ± 9 ml/min with adjunctive HG (p = 0.03).Conclusion: Handgrip adjunctive to peak DSE results in a modest increase in MVO2, primarily by an increase in end-systolic wall stress.

This paper deals with isometric muscle force response of the human lower limb when the leg is subjected to various external forces applied on the knee and ankle joints. The major components of the research apparatus are a subject restraint system, a force application device which employs three sonic emitters, and an upper leg cuff with four sonic emitters. The sonic emitters are used to determine the direction and the location of the force application on the lower limb and the orientation of the upper leg with respect to the torso. The numerical results are presented from experiments conducted on three male and three female subjects to determine their isometric muscle resistance against external forces trying to dislodge their lower limbs from several initial configurations. Quantitative results on the isometric muscle force capability of the subjects, when their lower limbs are dislodged from the initial stowed position, are also presented. It is concluded that, although there are ...

Isometric knee extension force and average integrated EMG of the vastus lateralis muscle were obtained from 27 healthy subjects using a maximum effort, ramp and hold protocol. In each of the 125 total trials mat were included in the analysis, a 2-s plateau region was extracted and divided into two adjacent 1000-ms bins. Variability and reliability of bin-to-bin measurements of force and EMG were then evaluated across 14 different integration intervals ranging from 10 to 1000 ms. Statistical analyses of bin-to-bin variability measures demonstrated that integration intervals of 250 ms and longer significantly reduced variability and improved reliability of average integrated EMG values during maximum effort isometric exertions. Bin-to-bin EMG reliability increased from .728 at 10 ms to .991 at 1000 ms. Force parameters appeared less sensitive to changes in length of the integration interval. It was suggested that longer intervals might also improve the validity of the EMG-force relati...

Decellularized whole muscle constructs represent an ideal scaffold for muscle tissue engineering means as they retain the network and proteins of the extracellular matrix of skeletal muscle tissue. The presence of a vascular pedicle enables a more efficient perfusion-based decellularization protocol and allows for subsequent recellularization and transplantation of the muscle construct in vivo. The goal of this study was to create a baseline for transplantation of decellularized whole muscle constructs by establishing an animal model for investigating a complete native muscle isolated on its pedicle in terms of vascularization and functionality. The left medial gastrocnemius muscles of 5 male Lewis rats were prepared and raised from their beds for in situ muscle stimulation. The stimulation protocol included twitches, tetanic stimulation, fatigue testing, and stretching of the muscles. Peak force, maximum rate of contraction and relaxation, time to maximum contraction and relaxation...

Background: Exercise is believed to be a non-pharmacological approach to treat hypertension. The present study was conducted to investigate the impact of high-intensity interval training (HIIT) and isometric handgrip (IHG) exercise on hemodynamic responses of High blood pressure women. Methods: In this experimental study 45 sedentary women (age, 45±5 years) from the Al-Zahra Heart Hospital, Shiraz-Iran (2019) with pre to stage 1 hypertension, without any chronic disease, who volunteered to participate in the research. The subjects were randomly divided into three groups of 15 members: Acute HIIT, Acute IHG exercise, and control. Blood pressure (systolic, diastolic, and mean), rate pressure product and heart rate were measured employing Aneroid Sphygmomanometer Polar HR recorder at the pre-workout time, 0 (immediately after exercise), 5, 10, 15, 30, 45, 60 minutes during the recovery period. The data were analyzed using repeated-measures ANOVA and Bonferroni post hoc test. Results: O...

Introduction
Monitoring the effects of physical exercise is an integral part of the training process and the measurement of the runner's pulse rate at intervals between run cycles is one of them. A characteristic feature of a well-trained runner is their ability to recover quickly after physical effort. The work of the VMO is an important part of the muscle synergy responsible for correct running. Proper functioning of the VMO muscle prevents the overload process in the knee region due to an intense workout (patellofemoral pain syndrome), it also induces a smaller amount of trauma in this area
Aim
To compare the heart rate after interval effort exercise and the endurance of the VMO in runners training frequently and occasionally
Material and method
The study comprised 40 runners aged 20-28 years. The study subjects were divided into two equal groups, i.e. 20 runners in each group: amateur runners, and professional runners. An endurance test, which consisted of 6 running cycles, was carried out. Throughout the duration of the test each runner's pulse rate values were recorded. The average value of reduction in the heart rate (restitution), calculated from the end of each running cycle to the end of the break following the cycle, was compared. Next, the bioelectric activity of the VMO in the isometric contraction (half squat position) in the right and left lower extremity were measured.
Results
The mean value of restitution pulse between the running cycles was 56 bpm for the professional runners and 35.2 bpm for the amateurs. Comparing the amplitude of sEMG during isometric exercise in the amateur runners revealed a significant increase in the average amplitude of the sEMG signal (IF-1.30). The mean amplitude of the sEMG signal in professional runners increased (IF-1.14), but it was statistically significantly lower than in the amateurs. The results were considered to be statistically significant since the value of test probability was below the assumed significance level (p < 001)
Conclusions
Professional runners have a better ability to recover after physical effort than amateur runners. The endurance of the VMO muscles in professional runners is significantly higher in comparison to amateurs.

Inactivity negatively influences general health, and sedentary behaviour is known to impact the musculoskeletal system. The aim of the study was to assess the impact of time spent in active and sedentary behaviour on foot muscle strength. In this observational study, we compared the acute effects of one day of prolonged sitting and one day of low-to-moderate level of activity on ankle torque in one group of eight healthy participants. Peak ankle torque was measured using a portable custom-made electronic dynamometer. Three consecutive maximal voluntary isometric contractions for bilateral plantar flexor and dorsiflexor muscles were captured at different moments in time. The average peak torque significant statistically decreased at 6 h (p = 0.019) in both static and active behaviours, with a higher average peak torque in the active behaviour (p &lt; 0.001). Age, gender, body mass index and average steps did not have any significant influence on the average value of maximal voluntary...

There is a lack of data about the contractile behavior of the right atrial myocardium in chronic pulmonary heart disease. We thoroughly characterized the contractility and Ca transient of isolated right atrial strips of healthy rats (CONT) and rats with the experimental model of monocrotaline-induced pulmonary hypertension (MCT) in steady state at different preloads (isometric force-length), during slow force response to stretch (SFR), and during post-rest potentiation after a period of absence of electrical stimulation (PRP). The preload-dependent changes in the isometric twitch and Ca transient did not differ between CONT and MCT rats while the kinetics of the twitch and Ca transient were noticeably slowed down in the MCT rats. The magnitude of SFR was significantly elevated in the MCT right atrial strips and this was accompanied by the significantly higher elevation of the Ca transient relative amplitude at the end of SFR. The slow changes in the contractility and Ca transient in...

The separate effects of 18 weeks of intensive strength and endurance training on isometric knee extension (KE) and flexion (KF) strength and walking speed were studied in 76- to 78- year-old women. Maximal voluntary isometric force for both KE and KF was measured in a sitting position on a custom-made dynamometer chair at a knee angle of 60 degrees from full extension. Maximal walking speed was measured over a distance of 10 m. The endurance-trained women increased KE torque and KE torque/body mass after the first 9 weeks of training when compared with the controls. when comparing the baseline, 9 week and 18 week measurements within the groups separately, both the endurance- and strength-training groups increased KE torque, KE torque/body mass and walking speed. Individual changes in KE torque/body mass before and after 18 weeks of training averaged 19.1% in the strength group, 30.9% in the endurance group and 2.0% in the controls. This study indicates that in elderly women the effects of physical training on muscle strength and walking speed occur after endurance as well as strength training. The considerable interindividual variation in change of muscle performance is also worth noticing.

Background: Neck pain is associated with scapular dyskinesis and impaired axio-scapular and shoulder muscle activity and function. However, there is little research on force steadiness, specifically during shoulder motion in patients with neck pain with scapular dyskinesis. Its relationship with characteristics of neck pain is also unknown. Objectives: to investigate force steadiness at 20% and 50% of MVC of shoulder abduction (30 degrees) in persons with neck pain with scapular dyskinesis compared to asymptomatic controls and to determine its relationships with characteristics of neck pain. Materials and methods: Fifty-two women and men (26 neck pain with scapular dyskinesis and 26 asymptomatic controls) were recruited to the study. Force steadiness of 30 degrees of shoulder abduction was measured at 20% and 50% of maximal voluntary contraction (MVC) and coefficient of variation (CV) of force values were calculated. Characteristics of neck pain included neck pain intensity, duratio...

The purpose of the present study was to examine the effect of different conditioning activities (CAs) on short-term increase in sprint performance. In twelve male sprinters (21.1±2.6 years, 100 m performance: 11.5±0.6 s) their body composition, half squat maximum strength, 100 m sprinting and countermovement jump performances were evaluated. The performance of a 50 m sprint (splits at 10 m, 30 m and 50 m) was evaluated before and 5, 10 and 15 min after four postactivation performance enhancement CAs on different occasions: [1] 3 sets x 4 s maximum isometric half squat (IHF), [2] 3 sets x 3 consecutive countermovement jumps (cCMJs), [3] 3 repetitions x 30 m overspeed sprinting (OVSP) and [4] dynamic submaximal half squat (2 sets x 2 reps x 90% of 1-RM half squat; HSQ). Significant improvements of sprinting performance were found 10 and 15 min following the cCMJs, OVSP and HSQ&#39;s interventions, in all distances (p&lt;.05;-2.14±1.21% and-3.56±2.47%), without any significant differen...

There exists no examination of what is the minimum anti-hypertensive threshold intensity for isometric exercise training. Twenty two normotensive participants were randomly assigned to training intensities at either 5 % or 10 % of their maximal contraction. Twenty participants completed the study. Clinical meaningful, but not statistically significant, reductions in systolic blood pressure were observed in both 5 % and 10 % groups –4.04 mm Hg (95 % CI –8.67 to +0.59, p=0.08) and –5.62 mm Hg (95 % CI –11.5 to +0.29, p=0.06) respectively after 6 weeks training. No diastolic blood pressure reductions were observed in either 5 % –0.97 mm Hg (95 % CI –2.56 to +0.62, p=0.20) or 10 % MVC +1.8 mm Hg (95 % CI –1.29 to +4.89, p=0.22) groups respectively after training. In those unable to complete isometric exercise at the traditional 30 % intensity, our results suggest there is no difference between 5 and 10 % groups and based on the principle of regression to the mean, this could mean both i...

There is considerable disagreement in the literature on the clinical usefulness of exercise testing as a tool for prediction of future hypertension. Much of the discrepancy between various reports is attributable to the difficulties of blood pressure (BP) measurement during exercise. Therefore, we investigated whether accurate intraarterial BP measurement will increase the predictive power of exercise testing. The BP responses to dynamic and isometric exercise were evaluated in 97 healthy, unmedicated men, of whom 34 were normotensive (NT), 29 borderline (BHT), and 34 mildly hypertensive (HT) using three criteria: 1) achieved BP during the test, 2) the change of the BP from baseline to exercise, and 3) the group was divided into high responders (HIGH, n = 19, systolic BP &gt; or = 220 and diastolic BP &gt; or = 105 mm Hg) and normal responders (n = 60). Five years later the BP was reassessed by casual measurements and noninvasive ambulatory 24-h monitoring (NAMB) in 79 (81%; 27 NT, ...

The purpose of this study was to see if motor imagery and maximal isometric action would increase grip strength in elderly men. Thirty elderly men were randomly assigned to either a control group, motor imagery group or isometric action group. The study was conducted over a three-week period using a pretest, posttest and control group design. The motor imagery group was instructed to cognitively practice isometric contractions of their non-preferred hand. During these sessions, the isometric action group actively practiced isometric contractions of their non-preferred hand. The control group did neither motor imagery nor isometric action. Maximal isometric action was measured by dynamometer before and after the protocol period. The data were analyzed using a one-way analysis of variance, Tukey's Post Hoc test and paired t-test. The results showed that the motor imagery group and isometric action group significantly increased their grip strength compared to the control group (p<0.05). Moreover, it was significantly different in the pretest and posttest of the motor imagery group and isometric action group (p<0.05). Exercise increased grip strength. It is optimistic to use mental imagery in the absence of physical exercise conditions to increase or preserve muscular strength especially for the elderly experiencing retrograde trends in nervo-muscular system due to senility.

Fitness which may be defined as the successful adaptation to the stressors of one's life style is a desirable human condition and is based on a scientific and systematic training programme and those who are enamored of practice without science, are like a pilot who goes to the ship without rudder. As pointed out earlier and out of the latest scientific progress in the field of physical education and sports, it is a fact that strength is the most indispensable factor of physical prowess and the best way to develop strength is through an organized programme of weight training and all the empirical evidence available shows conclusively that through the judicious use of weight training, we effectively improve strength, muscular endurance and power, all of which are vital to the athlete. Based on the analysis and findings of the study, the hypothesis formulated earlier that there would be no difference in the effect of isometric and isotonic exercises on the performance of selected field events, is rejected in the case of putting the shot and running broad jump. With regard to the performance in putting the shot, both isotonic exercises and isometric exercises produced equal training effect in this event. All the two methods of strength training namely isometric, isotonic proved to be superior as compared to the control group in improving performance in running broad jump and putting the shot. Introduction In athletics, some amount of resistance has to be overcome and the greater the resistance, stronger should be the sportsman. A high level of speed, endurance, technique, and other coordinated abilities are impossible if the sportsman lacks the requisite amount of strength, which is regarded as the ability of the sportsman to overcome resistance or to act against it. The strength can be dynamic or static. The static (isometric) and dynamic (isotonic) strength are two principal types of strength which we come across in athletics. A more accurate measure of strength can be obtained by using dynamometers or tensiometers – instrument which measure force. The maximum strength which is the highest possible resistance, a sportsman can overcome through voluntary contractions of the muscles, the explosive strength which is the ability of the sportsman to overcome resistance with high speed, and the strength endurance which is the ability to act against resistance under conditions of fatigue can be developed through different weight training exercises. The maximum strength, strength endurance can be dynamic or static and the explosive strength can be dynamic. There is no short cut to strength development as there is non for the development of skill, agility or endurance in an athlete. No amount of fancy gimmicks or equipment or adoption of alleged time saving fads will substitute for a long term programme of hard work that is required to develop the quality of strength, needed by an athlete for optimum performance in his specialty. Greater progress in track and field performance during the past few years has been the result of harder work by the athlete, not by resorting to short cuts and less work. Since isotonic and isometric exercises are backbone of building the strength which is the pre – requisite for better result, it is mostly indispensable to have the better knowledge about the two types of strength builders. It further tempts the researcher to know as to which type is better than the other since so far the differentiation is not available. The two type of exercises must be taken up after warm up, for no one has yet disapproved that a warm, stretched muscle gives a greater response to a stimulus than a cold, unscratched one. At the same time to guard against stiffness, the cooling down at the end of each weight training session is necessary.