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ABSTRACT Isometric exercise training (IET) effectively reduces resting blood pressure (BP). Traditionally, IET protocols use hand grip or leg extension exercise. IET using larger muscle mass may influence the rate and magnitude of BP reductions. This study aimed to examine the efficacy of a novel isometric wall squat protocol. Twenty participants c...
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The rating of perceived exertion (RPE) is a subjective load marker and may assist in individualizing training prescription, particularly by adjusting running intensity. Unfortunately, RPE has shortcomings (e.g., underreporting) and cannot be monitored continuously and automatically throughout a training sessions. In this pilot study, we aimed to pr...
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... Isometric activity is frequently encountered in activities of daily living along with aerobic exercise. Taken together with lower myocardial work and improved myocardial perfusion during diastole 51 IE is probably as safe as completing aerobic and/or traditional dynamic resistance training 52,50 . Others have reported that the incorporation of light IE training has been shown to elicit beneficial effects with very limited adverse events in those with cardiovascular disease 53 . ...
BACKGROUND: Hypertension affects 1:4 adults and increases the risk of CV disease. Management aims to reduce blood pressure to a level that minimizes risk; up to 50% of people don't achieve blood pressure targets often due to insufficient treatment or poor adherence. Exercise has a role to play in the management of hypertension. The impact of isometric exercise on hypertension in healthcare settings is poorly understood.
METHODS: Randomized controlled open-label multicentre feasibility study of isometric exercise compared to standard care in unmedicated hypertensives. Participants received an individualised isometric wall squat prescription and performed 4 x 2-minute bouts thrice weekly for 6-months. We assessed recruitment, deliverability, attrition, adherence, and variance in blood pressure change.
RESULTS: 41 participants (56 +/- 15 years), 59% women, were randomized. Isometric exercise was found to be easily deliverable to all participants. At 6-months 34% withdrew, of those who completed isometric exercise 87% of their sessions were at the correct intensity. Variance in blood pressure change was 14.4 mmHg. The study was not powered to show a difference in blood pressure between groups, however blood pressure reductions were seen in the intervention group at all study time points compared to baseline.
CONCLUSIONS: The results have allowed us to calculate a sample size (n=542) for a full randomised controlled trial. The results demonstrate good acceptability and adherence rates to the treatment protocol. Our results show a signal towards a consistent systolic blood pressure reduction in the isometric exercise group compared to baseline.
REGISTRATION:
NCT04936022
https://classic.clinicaltrials.gov/ct2/show/NCT04936022cond=isometric+exercise&draw=2&rank=7
Registry Identifier: ISRCTN:13472393
... However, it should be noted that such isometric modalities have been employed in various populations (e.g. people with hypertension) for both testing and training purposes, with high level of feasibility and safety (Baffour-Awuah et al., 2023;Wiles, Goldring, O'Driscoll, Taylor, & Coleman, 2018). Altogether, these arguments support the potential of this test for being used in a large variety of populations (e.g. ...
We aimed to develop a new field test to evaluate lower-limb muscle fatigability in young adults. In Experiment–A, we developed and determined the ability of an intermittent isometric wall-squat test to induce progressive level of muscle fatigability, as detected by the kinetics of changes in squat-jump height (SJH) and sit-to-stand time (STST) computed using two smartphone applications for feasibility purposes. In Experiment–B, participants performed the same test on two different days for reliability assessment. Kinetics of changes in our fatigability indicators were registered at isotime, exhaustion, and Post2min. The minimal detectable change (MDC95) and the absolute (CVTE) and relative (ICC3-1) reliability coefficients were assessed. In Experiment–A, we reported a progressive decrease in performance for SJH and STST throughout the task, reaching at exhaustion mean changes of –22±11% and +31±13%. Individual data-analysis showed decrease in performance for SJH and STST greater than the MDC95 in 85% and 95% of participants. In Experiment–B, Changes in our fatigability indicators demonstrated excellent inter-session reliability at isotime, exhaustion and Post2min for SJH (ICC3-1 > 0.97; CVTE < 7.5%) and STST (ICC3-1 > 0.92; CVTE < 3.3%). This test is feasible and reliable, making it very promising for evaluating muscle fatigability in applied and laboratory settings.
... A SH consistiu em quatro séries de 2 minutos, com 30% da CVM, para 2 minutos de intervalo, cuja posição era sentada e com os braços a 90° em relação ao antebraço; enquanto na sessão SA, os participantes foram orientados a apoiarem as costas na parede, com os pés na largura do quadril e a articulação do joelho flexionada no ângulo obtido mediante protocolo do teste incremental 18 Em conclusão, a massa muscular envolvida não teve efeito nas respostas pressóricas, e os exercícios isométricos não promoveram diminuição da pressão arterial de forma aguda em jovens saudáveis. Por outro lado, a sessão de menor massa muscular promoveu redução da frequência cardíaca e do duplo produto em jovens saudáveis. ...
Sabe-se que a maior massa muscular envolvida no exercício de força dinâmico promove maior redução da pressão arterial agudamente. Por outro lado, não são conhecidos os efeitos da massa muscular no exercício de força isométrico na pressão arterial. Para tanto, o objetivo do presente estudo foi comparar as respostas cardiovasculares agudas do exercício isométrico com diferentes massas musculares em jovens saudáveis. Nesse estudo randomizado controlado com delineamento cross-over, 12 homens jovens saudáveis realizaram, em ordem aleatória, quatro sessões experimentais: exercício isométrico com handgrip bilateral (SH), exercício isométrico de agachamento na parede (SA), sessão combinada de SH e SA (SCOMB) e sessão controle (SC). Todas as sessões de exercício isométrico tiveram 4 séries de 2 minutos. A pressão arterial, a frequência cardíaca e o duplo produto foram avaliados antes e 15, 30, 45 e 60 minutos após as sessões. Não houve redução da pressão arterial após o exercício de força isométrico (p>0,05 para todos). A frequência cardíaca foi reduzida após SH (70,3±8,3 vs. 66,1±8,0 bpm), enquanto na SA (70,9±13,6 vs. 74,1±12,8 bpm) e SCOMB (69,5±9,6 vs. 69,8 ± 10,1 bpm), houve aumento (p<0,05 para todos). O duplo produto foi menor após SH (8563±1689 vs.7869±1422 bpm*mmHg) que a SA (8589±1946 vs. 8965±1670bpm*mmHg), enquanto que na SCOMB, não mostrou diferenças significantes. Portanto, a massa muscular envolvida no exercício isométrico não afetou as respostas pressóricas, porém, a sessão de menor massa muscular promoveu a redução da frequência cardíaca e do duplo produto em jovens saudáveis.
... The IE intervention used is a wall squat (figure 1) protocol, which involves leaning against a wall and squatting at an individual specific (knee joint) angle prescribed to elicit the required exercise intensity based on HR. 22 To accurately prescribe an individual specific wall squat angle, participants must complete at least three-stages of a five-stage incremental IE test (IIET). 23 It was originally intended to subjectively preassess each patient's physical ability to meet this requirement during the Figure 1 Isometric wall squat exercise. ...
The COVID-19 pandemic has significantly impacted on the delivery of clinical trials in the UK, posing complicated organisational challenges and requiring adaptations, especially to exercise intervention studies based in the community. We aim to identify the challenges of public involvement, recruitment, consent, follow-up, intervention and the healthcare professional delivery aspects of a feasibility study of exercise in hypertensive primary care patients during the COVID-19 pandemic. While these challenges elicited many reactive changes which were specific to, and only relevant in the context of 'lockdown' requirements, some of the protocol developments that came about during this unprecedented period have great potential to inform more permanent practices for carrying out this type of research. To this end, we detail the necessary adaptations to many elements of the feasibility study and critically reflect on our approach to redesigning and amending this ongoing project in order to maintain its viability to date. Some of the more major protocol adaptations, such as moving the study to remote means wherever possible, had further unforeseen and undesirable outcomes (eg, additional appointments) with regards to extra resources required to deliver the study. However, other changes improved the efficiency of the study, such as the remote informed consent and the direct advertising with prescreening survey. The adaptations to the study have clear links to the UK Plan for the future of research delivery. It is intended that this specific documentation and critical evaluation will help those planning or delivering similar studies to do so in a more resource efficient and effective way. In conclusion, it is essential to reflect and respond with protocol changes in the current climate in order to deliver clinical research successfully, as in the case of this particular study.
... In addition, lower limb isometric exercises, involving larger muscle masses, have also been shown to be effective for chronic BP reduction [14][15][16]. However, the BP responses during these modalities of isometric exercise (IE) are unclear. ...
Background: This study aimed to identify the blood pressure (BP) responses during different types of isometric exercises (IE) in adults and to evaluate whether BP responses according to IE is influenced by the characteristics of participants and exercise protocols. Methods: The search was conducted in PubMed, Cochrane Central, SPORTDiscus, and LILACS databases in June 2020. Random effects models with a 95% confidence interval and p < 0.05 were used in the analyses. Results: Initially, 3201 articles were found and, finally, 102 studies were included in this systematic review, seven of which were included in the meta-analysis comparing handgrip to other IE. Two-knee extension and deadlift promoted greater increases in systolic (+9.8 mmHg; p = 0.017; I2 = 74.5% and +26.8 mmHg; p ≤ 0.001; I2 = 0%, respectively) and diastolic (+7.9 mmHg; p = 0.022; I2 = 68.6% and +12.4 mmHg; p ≤ 0.001; I2 = 36.3%, respectively) BP compared to handgrip. Men, middle-aged/elderly adults, hypertensive individuals, and protocols with higher intensities potentiate the BP responses to handgrip exercise (p ≤ 0.001). Conclusions: IE involving larger muscle groups elicit greater BP responses than those involving smaller muscle masses, especially in men, middle-aged/elderly adults and hypertensive individuals. Future studies should directly compare BP responses during various types of IE in different populations.
... Participants allocated to the training group performed 3 weekly wall squat IET sessions at 95% HR peak for 12 months in an unsupervised home-based setting. As previously described [14][15][16], each participant performed a maximal incremental wall squat test with beat-to-beat HR recording in order to determine HR peak corresponding to the prescribed knee angle. Following this test, participants were issued a 'Bend and Squat' device, which is a simple device developed in-house allowing for the alignment of a participant's feet and back placement into the correct position to elicit the appropriate HR response [9]. ...
Objective:
Isometric exercise training (IET) over 4-12 weeks is an effective antihypertensive intervention. However, blood pressure (BP) reductions are reversible if exercise is not maintained. No work to date has investigated the long-term effects of IET on resting BP.
Methods:
We randomized 24 unmedicated patients with high-normal BP to a 1-year wall squat IET intervention or nonintervention control group. Resting BP and various clinically important haemodynamic variables, including heart rate (HR), stroke volume (SV), cardiac output (CO) and total peripheral resistance (TPR) were measured pre and post the 1-year study period.
Results:
One year of IET produced statistically significant reductions in resting systolic (-8.5 ± 5 mmHg, P < 0.001) and diastolic (-7.3 ± 5.8 mmHg, P < 0.001) BP compared with the control group. There was also a significant reduction in resting HR (-4.2 ± 3.7 b/min, P = 0.009) and a significant increase in SV (11.2 ± 2.8 ml, P = 0.012), with no significant change in CO (0.12 ± 2.8 l/min, P = 0.7). TPR significantly decreased following IET (-246 ± 88 dyne·s/cm5, P = 0.011). Adherence to the IET sessions was 77% across all participants (3x IET sessions per week), with no participant withdrawals.
Conclusion:
This novel study supports IET as an effective long-term strategy for the management of resting BP, producing clinically important, chronic BP adaptations in patients at risk of hypertension. Importantly, this work also demonstrates impressive long-term adherence rates, further supporting the implementation of IET as a means of effective BP management in clinical populations.
... To maintain or improve muscular fitness, a combination of aerobic training and dynamic resistance training has been recommended to those with controlled HTN and no other overt cardiovascular or renal complications (36). In individuals with HTN, there is some hesitation in suggesting resistance exercise due to a blood pressure response potentially reaching upper limits (49,50). An exaggerated pressor response of isometric exercise presents a safety concern, especially in those with suboptimal BP control. ...
... 1271 which may facilitate increased blood flow to the myocardium, potentially increasing oxygen content, removal of carbon dioxide, and other by-products. Due to the lower myocardial work, it can be extrapolated that isometric exercise may be safer for those with HTN or others with impaired cardiovascular function (49,50). ...
... It is also important to mention that the HR response during IET in the study conducted by Wiles et al was considerably lower than the ACSM exercise test attainment of 85% predicted maximum HR (149 bpm vs 105 bpm) (48). Taken together with lower myocardial work and improved myocardial perfusion during diastole (23), isometric exercise may be as safe as completing aerobic and/or traditional resistance training (49,50). Others have reported that the incorporation of light IET has been shown to illicit beneficial effects with very limited adverse events in those with cardiovascular disease. ...
According to the American Heart Association 116.4 million, or 46% of US adults are estimated to have hypertension. Although, traditional moderate intensity aerobic exercise training is associated with reducing blood pressure by 5-8 mmHg, barriers to this modality of exercise training exist. Thus, the purpose of this review is to evaluate the mechanisms and incorporation of isometric exercise training (IET) as an adjunctive mode of exercise in a population with HTN. Based upon the articles reviewed from the years 2000-2020 which incorporated IET and provided clear protocols lasting 4 or more weeks, meaningful reductions in blood pressure occurred following IET (SBP, -9.7 ± 3.3 mmHg; DBP, -4.8 ± 2.6 mmHg) which support the need to increase adoption of this exercise form into practice to help treat hypertension. Specifically, an IET program of 12-20 minutes per day, 3 times per week, could improve blood pressure reduction in those with hypertension. IET has the potential to produce significant and clinically meaningful blood pressure reductions and could serve as an adjunctive exercise modality alongside the established exercise prescription for those with hypertension.
... The angle is then decreased every 2 min until the participant reaches the end of the 95° stage or can no longer maintain the knee joint angle within 5° of the target value (volitional Wiles . The HCP's were instructed to maintain a good dialogue (providing as much encouragement as was necessary) with the participant throughout, to ensure they stay calm and relax their breathing to avoid the Valsalva manoeuvre, to watch closely for any signs of physical distress and not to hesitate to stop the test immediately if they feel the participant's health is at risk [60]. Based upon each participant's test data, knee joint angle is plotted against the mean HR for the last 30 s of each incremental stage. ...
... The relationship between parameters is then used to calculate the specific knee joint angle required to elicit a target HR. The target HR selected for training is 95% HR peak , with HR peak defined as the mean HR of the final 30 s achieved during the incremental test [60]. Additionally, the individual target heart rate range (THRR) will be established using the 95% reference interval [61]. ...
... All IE training sessions thereafter will be completed in the home. Participants will use their Bend and Squat device to perform an IE training session composed of 4 bouts of 2-min wall squats with 2 min recovery in between each bout [60]. Participants will be instructed to perform three IE training sessions a week, ideally on alternate days to allow for adequate between session recovery. ...
Background
Hypertension (HTN) affects approximately 25% of the UK population and is a leading cause of mortality. Associated annual health care costs run into billions. National treatment guidance includes initial lifestyle advice, followed by anti-hypertensive medication if blood pressure (BP) remains high. However, adoption and adherence to recommended exercise guidelines, dietary advice and anti-hypertensive medication is poor. Four short bouts of isometric exercise (IE) performed 3 days per week (d/wk) at home elicits clinically significant reductions in BP in those with normal to high-normal BP. This study will determine the feasibility of delivering personalised IE to patients with stage 1 hypertension for whom lifestyle changes would be recommended before medication within NHS primary care.
Methods
This is a randomised controlled feasibility study. Participants were 18+ years, with stage 1 hypertension, not on anti-hypertensive medication and without significant medical contraindications. Trial arms will be standard lifestyle advice (control) or isometric wall squat exercise and standard lifestyle advice. Primary outcomes include the feasibility of healthcare professionals to deliver isometric exercise prescriptions in a primary care NHS setting and estimation of the variance of change in systolic BP. Secondary outcomes include accuracy of protocol delivery, execution of and adherence to protocol, recruitment rate, attrition, perception of intervention viability, cost, participant experience and accuracy of home BP. The study will last 18 months. Sample size of 100 participants (50 per arm) allows for 20% attrition and 6.5% incomplete data, based upon 74 (37 each arm) participants (two-sided 95% confidence interval, width of 1.33 and standard deviation of 4) completing 4 weeks. Ethical approval IRAS ID is 274676.
Discussion
Before the efficacy of this novel intervention to treat stage 1 hypertension can be investigated in any large randomised controlled trial, it is necessary to ascertain if it can be delivered and carried out in a NHS primary care setting. Findings could support IE viability as a prophylactic/alternative treatment option.
Trial registration
ISRCTN13472393 , registered 18 August 2020
... This study also demonstrated that there were significant increases in HR and BP with increases in time under tension (TUT) at a set workload. Subsequently, a laboratory-based maximal IWS test was developed, utilising the 10-degree workload resolution, to allow measurement of peak HR and for the relationship between HR and workload to be plotted (18). This information is then used to calculate a training knee joint angle that will elicit a 95% HR peak training stimulus. ...
... Rating of perceived exertion (RPE) is widely used as a measure of exercise intensity for many types of exercise testing and training (20), including during IWS training interventions (18). Additionally, RPE has been shown to be a valid measure of exercise intensity and physiological exertion during various forms of resistance exercise including dynamic squats (21), isometric handgrip training (22) and eccentric elbow flexor contractions (23). ...
... The wall squat was completed at one of five possible knee joint angles ranging from 135° to 95° in 10° increments, where approximately 180º represents a fully extended knee joint. These angles were chosen as they are currently used in the prescription of IWS exercise (18). The 125° and 105° angles were completed just once, while the 135°, 115° and 95° angles were completed twice. ...
Background and Aims: Isometric exercise (IE), including wall squat training, has been shown to be effective at reducing resting blood pressure (BP). Rating of perceived exertion (RPE) is also widely used as an accessible additional measure of IE intensity. Despite this, no RPE scales have been specifically designed for use with IE and it is not clear whether RPE is sensitive enough to distinguish between different lower limb IE workloads. Therefore, the aims of this study were to assess the validity and reliability of RPE as a measure of IE intensity (workload) and physiological exertion (Heart rate and BP), and to examine whether RPE is able to discern differences in wall squat workload (knee angle) at a resolution of 10-degrees, as was previous shown for heart rate (HR) and BP. Methods: Twenty-nine male participants completed 8 separate isometric wall squat testing sessions, separated by a minimum of 5-hours. Each session consisted of a single 2-minute isometric wall squat test, at one of five randomised workloads (knee joint angles). Three of the knee angles were repeated, a second time, to allow measurements of reliability. Throughout the exercise protocol, HR and BP were recorded continuously; values for each 30-second time-point were calculated as the mean of the proceeding 5-seconds, peak values for the 2-minute bout were taken as the mean results for the final 5-seconds of the bout. Additionally, mean results for the full 2-minute period were calculated. RPE was collected every 30 seconds. Concurrent validity was assessed by correlating RPE results with the criterion measures: Knee joint angle, HR and BP. Differences in RPE were assessed across consecutive workloads and time-points. Results: There were significant increases in RPE at each consecutive wall squat workload (p < 0.001) and between each consecutive 30-second time point (p < 0.001). Additionally, the RPE results produced a significant inverse relationship with knee angle (r =-0.79; p < 0.001) and significant positive relationships with HR (r = 0.53, p < 0.001) and BP (systolic: r = 0.77; diastolic: r = 0.62; mean arterial pressure: r = 0.70, p < 0.001). Conclusion: RPE provides a valid and reliable measure of isometric wall squat intensity, physiological exertion, and can discern between knee angles with a resolution of 10°. Relevance for patients: Patients and practitioners implementing isometric exercise training for arterial blood pressure reduction can use RPE to accurately monitor the intensity of the exercise and the physiological responses.
... This study also demonstrated that there were significant increases in HR and BP with increases in time under tension (TUT) at a set workload. Subsequently, a laboratory-based maximal IWS test was developed, utilizing the 10-degree workload resolution, to allow measurement of peak HR and for the relationship between HR and workload to be plotted [18]. This information is then used to calculate a training knee joint angle that will elicit a 95% HR peak training stimulus. ...
... Rating of perceived exertion (RPE) is widely used as a measure of exercise intensity for many types of exercise testing and training [20], including during IWS training interventions [18]. In addition, RPE has been shown to be a valid measure of exercise intensity and physiological exertion during various forms of resistance exercise including dynamic squats [21], isometric handgrip training [22], and eccentric elbow flexor contractions [23]. ...
... The wall squat was completed at one of five possible knee joint angles ranging from 135° to 95° in 10° increments, where approximately 180° represents a fully extended knee joint. These angles were chosen as they are currently used in the prescription of IWS exercise [18]. The 125° and 105° angles were completed just once, while the 135°, 115°, and 95° angles were completed twice. ...
Background and aims:
Isometric exercise (IE), including wall squat training, has been shown to be effective at reducing resting blood pressure (BP). Rating of perceived exertion (RPE) is also widely used as an accessible additional measure of IE intensity. Despite this, no RPE scales have been specifically designed for use with IE and it is not clear whether RPE is sensitive enough to distinguish between different lower limb IE workloads. Therefore, the aims of this study were to assess the validity and reliability of RPE as a measure of IE intensity (workload) and physiological exertion (Heart rate and BP), and to examine whether RPE is able to discern differences in wall squat workload (knee angle) at a resolution of 10-degrees, as was previous shown for heart rate (HR) and BP.
Methods:
Twenty-nine male participants completed eight separate isometric wall squat testing sessions, separated by a minimum of 5-h. Each session consisted of a single 2-min isometric wall squat test, at one of five randomized workloads (knee joint angles). Three of the knee angles were repeated, a second time, to allow measurements of reliability. Throughout the exercise protocol, HR and BP were recorded continuously; values for each 30-s time-point were calculated as the mean of the proceeding 5-s, and peak values for the 2-min bout were taken as the mean results for the final 5-s of the bout. In addition, mean results for the full 2-min period were calculated. RPE was collected every 30 s. Concurrent validity was assessed by correlating RPE results with the criterion measures: Knee joint angle, HR, and BP. Differences in RPE were assessed across consecutive workloads and time-points.
Results:
There were significant increases in RPE at each consecutive wall squat workload (P<0.001) and between each consecutive 30-s time point (P<0.001). In addition, the RPE results produced a significant inverse relationship with knee angle (r=-0.79; P<0.001) and significant positive relationships with HR (r=0.53, P<0.001) and BP (systolic: r=0.77; diastolic: r=0.62; and mean arterial pressure: r=0.70, P<0.001).
Conclusion:
RPE provides a valid and reliable measure of isometric wall squat intensity, physiological exertion and can discern between knee angles with a resolution of 10°.
Relevance for patients:
Patients and practitioners implementing isometric exercise training for arterial blood pressure reduction can use RPE to accurately monitor the intensity of the exercise and the physiological responses.
