scholarly journals Global and regional left ventricular circumferential strain during incremental cycling and isometric knee extension exercise

2018 ◽  
Vol 35 (8) ◽  
pp. 1149-1156
Author(s):  
Alexander Beaumont ◽  
Nicholas Sculthorpe ◽  
John Hough ◽  
Viswanath Unnithan ◽  
Joanna Richards
Keyword(s):  
Circumferential Strain ◽  
Knee Extension ◽  
Left Ventricular ◽  
Isometric Knee Extension ◽  
Knee Extension Exercise

Neuromuscular recovery from severe- and extreme-intensity exercise in men and women

2022 ◽  
Author(s):  
Andrew M Alexander ◽  
Shane M Hammer ◽  
Kaylin D Didier ◽  
Lillie M Huckaby ◽  
Thomas J. Barstow
Keyword(s):  
Knee Extension ◽  
Voluntary Contraction ◽  
Voluntary Activation ◽  
Partial Recovery ◽  
Men And Women ◽  
Task Failure ◽  
Isometric Knee Extension ◽  
Severe Intensity ◽  
Time Courses ◽  
Knee Extension Exercise

Maximal voluntary contraction force (MVC), potentiated twitch force (Qpot), and voluntary activation (%VA) recover to baseline within 90s following extreme-intensity exercise. However, methodological limitations masked important recovery kinetics. We hypothesized reductions in MVC, Qpot, and %VA at task failure following extreme-intensity exercise would be less than following severe-intensity exercise, and Qpot and MVC following extreme-intensity exercise would show significant recovery within 120s but remain depressed following severe-intensity exercise. Twelve subjects (6 men) completed two severe-intensity (40, 50%MVC) and two extreme-intensity (70, 80%MVC) isometric knee-extension exercise bouts to task failure (Tlim). Neuromuscular function was measured at baseline, Tlim, and through 150s of recovery. Each intensity significantly reduced MVC and Qpot compared to baseline. MVC was greater at T¬lim (p<0.01) and at 150s of recovery (p=0.004) following exercise at 80%MVC compared to severe-intensity exercise. Partial recovery of MVC and Qpot were detected within 150s following Tlim for each exercise intensity; Qpot recovered to baseline values within 150s of recovery following exercise at 80%MVC. No differences in %VA were detected pre- to post-exercise or across recovery for any intensity. Although further analysis showed sex-specific differences in MVC and Qpot, future studies should closely examine sex-dependent responses to extreme-intensity exercise. It is clear, however, that these data reinforce that mechanisms limiting exercise tolerance during extreme-intensity exercise recover quickly. NOVELTY: •Severe- and extreme-intensity exercise cause independent responses in fatigue accumulation and the subsequent recovery time courses. •Recovery of MVC and Qpot occurs much faster following extreme-intensity exercise in both men and women.

scholarly journals Effects of acute isometric knee extension exercise at 40% MVC on muscle mechanical properties and Ca2+ pump function

2008 ◽  
Vol 22 (S1) ◽  
Author(s):  
Riley David Stewart ◽  
Ryan A Sayer ◽  
Andrew Hopf ◽  
Chris Vigna ◽  
Eric Bombardier ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Knee Extension ◽  
Pump Function ◽  
Isometric Knee Extension ◽  
Knee Extension Exercise

scholarly journals Oxygen Utilization During The Contraction-relaxation Of Isometric Knee Extension Exercise

2019 ◽  
Vol 51 (Supplement) ◽  
pp. 302
Author(s):  
Camryn N. Webster ◽  
Shane M. Hammer ◽  
Andrew M. Alexander ◽  
Kaylin D. Didier ◽  
Lillie M. Huckaby ◽  
...  
Keyword(s):  
Knee Extension ◽  
Oxygen Utilization ◽  
Isometric Knee Extension ◽  
Knee Extension Exercise

scholarly journals Relationship between Muscle Oxygenation Kinetics and Tolerance to Fatigue on Short-term Isometric Knee Extension Exercise

2013 ◽  
Vol 53 (July) ◽  
pp. 93-98
Author(s):  
Kaori Mitsuoka ◽  
Ryotaro Kime ◽  
Takuya Osada ◽  
Norio Murase ◽  
Toshihito Katsumura
Keyword(s):  
Knee Extension ◽  
Muscle Oxygenation ◽  
Short Term ◽  
Isometric Knee Extension ◽  
Knee Extension Exercise

Circumferential deformation in diagnosis and risk assessment of patients with left ventricular non-compaction

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
S Anwer ◽  
P.S Heiniger ◽  
S Rogler ◽  
D Cassani ◽  
L Rebellius ◽  
...  
Keyword(s):  
Longitudinal Strain ◽  
Circumferential Strain ◽  
Strong Association ◽  
Global Longitudinal Strain ◽  
Diagnostic Algorithm ◽  
Left Ventricular ◽  
Deformation Analysis ◽  
Funding Source ◽  
Apical Rotation ◽  
Increased Risk

Abstract Introduction Echocardiography-based deformation analysis is used for studying left ventricular (LV) mechanics and have an emerging role in the diagnosis of cardiomyopathies. Left ventricular non-compaction (LVNC) is a rare cardiomyopathy characterised by a two-layered LV myocardium with prominent trabeculae separated by deep recesses perfused from the LV cavity. Left ventricular hypertrabeculation (LVHT) may be difficult to differentiate from LVNC. In this study, we aim to develop a diagnostic algorithm based on the circumferential deformation (CD) of LVNC, LVHT and controls; and find their associations with LVNC outcomes. Methods We compared 45 LVNC patients, 45 LVHT individuals, and 45 matched healthy controls. LVNC was diagnosed according to current echocardiographic criteria. LVHT was defined as presence of three or more trabeculae in the LV apex visualised in both parasternal short axis and apical views. Controls had a normal echocardiographic examination and no evidence of cardiovascular disease. Strain analysis was performed using TomTec Image-Arena (version 4.6). Results Receiver observer characteristics curve (ROC) analyses revealed that GCS &lt;22.3% differentiated LVNC from control or LVHT. In individuals with global circumferential strain (GCS) below 22.3%, an apical peak circumferential strain (PCS) cut-off value of 18.4% differentiated LVNC [&lt;18.4%] and LVHT [≥18.4%] (fig. 1). An independent echocardiographer (Table 1) performed blind validation of diagnosis on 32 subjects from each group. Combined endpoint of cardiovascular events in LVNC (CVE) is described in figure 2. Multi-variate regression analyses have shown that GCS was associated with 11-fold increased risk of CVE independent of LVEF and NC:C ratio, while global longitudinal strain (GLS) displayed only 2-fold increased risk. Regional basal and apical peak circumferential or longitudinal strain, left ventricular twist, basal-apical rotation ratio have shown significant associations (Fig. 3). Conclusions A diagnostic algorithm with GCS and aPCS (threshold value 18.4%) differentiates LVNC from LVHT and control with very high sensitivity and specificity independent of additional echocardiographic or clinical information. Circumferential strain derived parameters exhibit a very strong association with outcomes independent of LVEF and NC:C ratio. Absence of CVE in LVHT provides further evidence on the distinct nature of LVNC and LVHT. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): 2018 research grant from the Swiss Heart Foundation

Effects of a prior high-intensity knee-extension exercise on muscle recruitment and energy cost: a combined local and global investigation in humans

2009 ◽  
Vol 94 (6) ◽  
pp. 704-719 ◽  
Author(s):  
Gwenael Layec ◽  
Aurélien Bringard ◽  
Yann Le Fur ◽  
Christophe Vilmen ◽  
Jean-Paul Micallef ◽  
...  
Keyword(s):  
Energy Cost ◽  
High Intensity ◽  
Knee Extension ◽  
Muscle Recruitment ◽  
Knee Extension Exercise

Prior heavy knee extension exercise does not affect $$\dot{V}\hbox{O}_{2}$$ kinetics during subsequent heavy cycling exercise

2007 ◽  
Vol 102 (4) ◽  
pp. 481-491 ◽  
Author(s):  
John R. Thistlethwaite ◽  
Benjamin C. Thompson ◽  
Joaquin U. Gonzales ◽  
Barry W. Scheuermann
Keyword(s):  
Knee Extension ◽  
Cycling Exercise ◽  
Knee Extension Exercise

scholarly journals Cardiovascular magnetic resonance-determined left ventricular myocardium impairment is associated with C-reactive protein and ST2 in patients with paroxysmal atrial fibrillation

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Lei Zhao ◽  
Songnan Li ◽  
Chen Zhang ◽  
Jie Tian ◽  
Aijia Lu ◽  
...  
Keyword(s):  
Cardiovascular Disease ◽  
Healthy Subjects ◽  
T1 Mapping ◽  
Circumferential Strain ◽  
Myocardial Strain ◽  
Left Ventricular ◽  
Healthy Controls ◽  
C Reactive Protein ◽  
Reactive Protein ◽  
Native T1

Abstract Background Myocardial strain assessed with cardiovascular magnetic resonance (CMR) feature tracking can detect early left ventricular (LV) myocardial deformation quantitatively in patients with a variety of cardiovascular diseases, but this method has not yet been applied to quantify myocardial strain in patients with atrial fibrillation (AF) and no coexistent cardiovascular disease, i.e., the early stage of AF. This study sought to compare LV myocardial strain and T1 mapping indices in AF patients and healthy subjects, and to investigate the associations of a portfolio of inflammation, cardiac remodeling and fibrosis biomarkers with LV myocardial strain and T1 mapping indices in AF patients with no coexistent cardiovascular disease. Methods The study consisted of 80 patients with paroxysmal AF patients and no coexistent cardiovascular disease and 20 age- and sex-matched healthy controls. Left atrial volume (LAV), LV myocardial strain and native T1 were assessed with CMR, and compared between the AF patients and healthy subjects. Biomarkers of C-reactive protein (CRP), transforming growth factor beta-1 (TGF-β1), collagen III N-terminal propeptide (PIIINP), and soluble suppression of tumorigenicity 2 (sST2) were obtained with blood tests, and compared between the AF patients and healthy controls. Associations of these biomarkers with those CMR-measured parameters were analyzed for the AF patients. Results For the CMR-measured parameters, the AF patients showed significantly larger LAV and LV end-systolic volume, and higher native T1 than the healthy controls (max P = 0.027). The absolute values of the LV peak systolic circumferential strain and its rate as well as the LV diastolic circumferential strain rate were all significantly reduced in the AF patients (all P < 0.001). For the biomarkers, the AF patients showed significantly larger CRP (an inflammation biomarker) and sST2 (a myocardium stiffness biomarker) than the controls (max P = 0.007). In the AF patients, the five CMR-measured parameters of LAV, three LV strain indices and native T1 were all significantly associated with these two biomarkers of CRP and sST2 (max P = 0.020). Conclusions In patients with paroxysmal AF and no coexistent cardiovascular disease, LAV enlargement and LV myocardium abnormalities were detected by CMR, and these abnormalities were associated with biomarkers that reflect inflammation and myocardial stiffness.

scholarly journals EARLY STRENGTH TESTING AFTER ACL RECONSTRUCTION IMPACTS ISOKINETIC STRENGTH PERFORMANCE AT TIME OF RETURN TO SPORT

2021 ◽  
Vol 9 (7_suppl3) ◽  
pp. 2325967121S0011
Author(s):  
Adam Weaver ◽  
Dylan Roman ◽  
Maua Mosha ◽  
Nicholas Giampetruzzi
Keyword(s):  
Test Performance ◽  
Knee Extension ◽  
Strength Test ◽  
Strength Testing ◽  
Isokinetic Strength ◽  
Rehabilitation Process ◽  
Strength Performance ◽  
Knee Extension Strength ◽  
Isometric Knee Extension ◽  
Strength Tests

Background: The standard of care in ACL reconstruction (ACLR) typically involves standardized strength testing at 6 months or later to assess a patient’s readiness to return to play (RTP) using isokinetic and isometric testing, and functional strength testing. Recent literature suggests that isokinetic knee extension strength should demonstrate 89% limb symmetry index (LSI) or greater prior to returning to sport. However, there is little known on the effects of strength testing early in the rehabilitation process and the relationship to strength test performance at time of RTP. Purpose: The purpose of this study was to examine how early post-operative strength test performance impacts isokinetic strength outcomes at RTP testing in adolescents. Methods: The retrospective cohort study included patients undergoing primary ACLR between 12 and 18 years of age, early post-operative strength measures, and isokinetic dynamometer strength at RTP from July 2017 and April 2019. Data was dichotomized into desired outcomes at 3 months: >70% isometric knee extension LSI, > 20 repetitions on anterior stepdown test (AST), > 90% LSI Y Balance. At RTP testing, isokinetic knee extension strength data was categorized into >89% LSI at 3 speeds (300, 180, 60°/sec). Chi square testing and odds ratio statistics were used to examine association and its magnitude. Results: 63 patients met inclusion criteria (38 females; 15.37±1.66 years old). >70% LSI isometric knee extension strength at 3 months showed a significant association (Table 2) and demonstrated the strongest odds of having >89% LSI on isokinetic strength tests at all 3 speeds at RTP with 180°/sec being the highest (OR=14.5; 95% CI=4.25,49.43; p= <0.001). Performance on AST showed a significant association (χ2 (1, n=63) = 17.00, p <0.001), and highest odds at 180°/sec (OR=4.61; 95% CI = 1.59, 13.39, p=<0.001) and 60°/sec (OR= 3.07; 95% CI = 1.10, 8.63, p= 0.04). Combination of performance on isometric strength tests and AST showed a significant association to isokinetic strength at all three speeds, but less predictive then isometrics in isolation. (Table 2). There was no significant relationship between YBR LSI at 3 months and isokinetic strength at 6 months. Conclusion: Standardized strength testing early in rehabilitation can help identify patients that will successfully complete RTP testing. Our results suggest that isometric knee extension strength and timed anterior stepdown test provide meaningful clinical information early in the rehabilitation process. This data also suggests that the use of YBAL for predicting isokinetic strength performance is limited. [Table: see text][Table: see text]

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