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Stilwell G, Symons D, Gooch S, Dunn J. Comparison of multidirectional upper limb strength for non-disabled individuals and individuals with C4-C7 spinal cord injury in a seated position. Ergonomics 2024:1-11. [PMID: 38456824 DOI: 10.1080/00140139.2024.2325536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 02/24/2024] [Indexed: 03/09/2024]
Abstract
This study investigates the multidirectional upper limb strength of individuals with a C4-C7 spinal cord injury (SCI) and non-disabled individuals in a seated position by measuring multidirectional force at the hand. Current literature lacks quantitative strength data to evaluate strength requirements for people who have reduced upper limb function due to a cervical SCI. Seated multidirectional force measurements were recorded for eleven non-disabled and ten males with a C4-C7 SCI. Collected data was displayed using detailed force polar plots. The resulting plots revealed a clear difference in polar plot shape for non-disabled participants and participants with a C4-C7 SCI. Namely that SCI participants had more elliptical polar plots due to reductions in circumferential strength compared to non-disabled participants. However, the polar plots for higher SCIs tended to have an increasingly more circular shape. The results provide insight into the differences in strength between people with cervical SCI and no disability.
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Affiliation(s)
- George Stilwell
- Department of Mechanical Engineering, University of Canterbury, Christchurch, New Zealand
| | - Digby Symons
- Department of Mechanical Engineering, University of Canterbury, Christchurch, New Zealand
| | - Shayne Gooch
- Department of Mechanical Engineering, University of Canterbury, Christchurch, New Zealand
| | - Jennifer Dunn
- Department of Orthopaedic Surgery and Musculoskeletal Medicine, University of Otago, Dunedin, New Zealand
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Lee TL, Ko DK, Kang N. Advanced Force Coordination of Lower Extremities During Visuomotor Control Task in Soccer Players. Res Q Exerc Sport 2023:1-7. [PMID: 38100608 DOI: 10.1080/02701367.2023.2283034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 11/04/2023] [Indexed: 12/17/2023]
Abstract
Purpose: This study is aimed to determine specific bilateral lower extremity motor performances and coordination patterns in soccer players with healthy controls using the bilateral force control paradigm. We hypothesized that soccer players would show more advanced bilateral force control performances than untrained controls. Methods: Participants were 13 university soccer players and 13 healthy controls. Each group performed bilateral ankle dorsiflexion force control tasks across two vision conditions (i.e., vision and no-vision) and two targeted force levels (i.e., 10% and 40% maximum voluntary contraction). We calculated force accuracy, variability, and symmetry to assess force control performances. To estimate bilateral force coordination, we calculated Pearson's correlation coefficients between feet-within a single trial and considered uncontrolled manifold variables across multiple trials. In the no-vision condition, we performed secondary analyses for initial force control patters after removal of visual feedback. Results: There were no significant group differences in bilateral force accuracy and variability but, compared to the control group, soccer players showed higher force symmetry between left and right ankle dorsiflexion forces. For force coordination between feet, soccer players revealed more negative values of the correlation coefficient and greater good variability from the uncontrolled manifold analysis than those for the control group. The secondary analysis revealed no significant group differences in the time until force drift and amount of force adjustments. Conclusions: Soccer players have more compensatory and flexible interlimb force coordination strategies between feet.
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Lynch AE, Davies RW, Allardyce JM, Carson BP. The Effect of Unilateral Versus Bilateral Strength Training on Isometric-Squat Peak Force and Interlimb Asymmetry in Young, Recreationally Strength-Trained Men. Int J Sports Physiol Perform 2023; 18:195-203. [PMID: 36634311 DOI: 10.1123/ijspp.2022-0299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 10/09/2022] [Accepted: 10/19/2022] [Indexed: 01/14/2023]
Abstract
PURPOSE To compare the effects of bilateral strength training (BLST) versus unilateral strength training (ULST) on changes in peak force (PF) and interlimb asymmetry (ILA) in the isometric squat at a 120° knee angle (ISq120). METHOD A total of 31 young, recreationally strength-trained men performed either BLST (n = 18) or ULST (n = 13), twice per week for 6 weeks. The total number of repetitions, duty cycle, and effort were standardized between training groups (ie, differing only in the exercises performed). Changes in PF and ILA were assessed pretraining and posttraining. RESULTS Comparable increases in PF were observed in the BLST group (mean [SD] change; 17.4% [20.5%], P = .001, standardized mean difference [SMD] = 0.45) and the ULST group (11.4% [19.1%], P = .042, SMD = 0.25). No significant changes in symmetry index (SI) scores were observed following BLST (mean [SD] change; 0 [5.7], P = .526, SMD = -0.12) or ULST (+3 [6.0], P = .702, SMD = 0.4). Individual analyses of subjects with marked ILA (ie, baseline SI score > baseline coefficient of variation) revealed a trend toward BLST being more effective at attenuating SI scores in the ISq120. CONCLUSIONS Overall, both BLST and ULST are effective for increasing ISq120 PF. However, it appears that BLST may be more effective at reducing SI scores in those with marked ILA.
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Cook MD, Dunne A, Bosworth M, Willems MET. Effect of New Zealand Blackcurrant Extract on Force Steadiness of the Quadriceps Femoris Muscle during Sustained Submaximal Isometric Contraction. J Funct Morphol Kinesiol 2022; 7. [PMID: 35736015 DOI: 10.3390/jfmk7020044] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 05/15/2022] [Accepted: 05/27/2022] [Indexed: 11/25/2022] Open
Abstract
Intake of anthocyanin-rich New Zealand blackcurrant (NZBC) can alter physiological responses that enhance exercise performance. In two studies, we examined the effects of NZBC extract on force steadiness during a sustained submaximal isometric contraction of the quadriceps femoris muscle. With repeated measures designs, male participants in study one (n = 13) and study two (n = 19) performed a 120 s submaximal (30%) isometric contraction of the quadriceps femoris muscle following a 7-day intake of NZBC extract and placebo (study one) and following 0 (control), 1-, 4- and 7-day intake of NZBC extract (study two). Participants for both studies were different. In study one, NZBC extract enhanced isometric force steadiness during the 120 s contraction (placebo: 6.58 ± 2.24%, NZBC extract: 6.05 ± 2.24%, p = 0.003), with differences in the third (60-89 s) and fourth quartile (90-120 s) of the contraction. In study two, isometric force steadiness was not changed following 1 and 4 days but was enhanced following 7-day intake of NZBC extract in comparison to control. In study two, the enhanced isometric force steadiness following 7-day intake did occur in the second (30-59 s), third (60-89 s) and fourth (90-120 s) quartiles. Daily supplementation of anthocyanin-rich NZBC extract can enhance force steadiness of the quadriceps femoris muscle during a sustained submaximal isometric contraction. Our observations may have implications for human tasks that require postural stability.
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Yuan CC, Kazmierczak K, Liang J, Ma W, Irving TC, Szczesna-Cordary D. Molecular basis of force-pCa relation in MYL2 cardiomyopathy mice: Role of the super-relaxed state of myosin. Proc Natl Acad Sci U S A 2022; 119:e2110328119. [PMID: 35177471 DOI: 10.1073/pnas.2110328119] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2022] [Indexed: 01/22/2023] Open
Abstract
Many forms of cardiomyopathy manifest with changes in sarcomeric structure, function, and energetics. We used small-angle X-ray diffraction and myosin super-relaxed (SRX) state approaches to investigate the mechanisms underlying the clinical phenotypes associated with HCM-related D166V (aspartate-to-valine) and DCM-linked D94A (aspartate-to-alanine) mutations in the cardiac myosin RLC (MYL2 gene). Modulation of myosin function through dysregulation of the SRX state was closely coupled with structural rearrangements and the Ca2+ dependence of force development in HCM–D166V mice. The DCM–D94A model favored the SRX state without altering structure/force–pCa relationships. Understanding the regulation of SRX ↔ DRX equilibrium in the normal heart and how it is changed in heart disease may advance future therapeutics of patients suffering from the mutated MYL2 gene. In this study, we investigated the role of the super-relaxed (SRX) state of myosin in the structure–function relationship of sarcomeres in the hearts of mouse models of cardiomyopathy-bearing mutations in the human ventricular regulatory light chain (RLC, MYL2 gene). Skinned papillary muscles from hypertrophic (HCM–D166V) and dilated (DCM–D94A) cardiomyopathy models were subjected to small-angle X-ray diffraction simultaneously with isometric force measurements to obtain the interfilament lattice spacing and equatorial intensity ratios (I11/I10) together with the force-pCa relationship over a full range of [Ca2+] and at a sarcomere length of 2.1 μm. In parallel, we studied the effect of mutations on the ATP-dependent myosin energetic states. Compared with wild-type (WT) and DCM–D94A mice, HCM–D166V significantly increased the Ca2+ sensitivity of force and left shifted the I11/I10-pCa relationship, indicating an apparent movement of HCM–D166V cross-bridges closer to actin-containing thin filaments, thereby allowing for their premature Ca2+ activation. The HCM–D166V model also disrupted the SRX state and promoted an SRX-to-DRX (super-relaxed to disordered relaxed) transition that correlated with an HCM-linked phenotype of hypercontractility. While this dysregulation of SRX ↔ DRX equilibrium was consistent with repositioning of myosin motors closer to the thin filaments and with increased force-pCa dependence for HCM–D166V, the DCM–D94A model favored the energy-conserving SRX state, but the structure/function–pCa data were similar to WT. Our results suggest that the mutation-induced redistribution of myosin energetic states is one of the key mechanisms contributing to the development of complex clinical phenotypes associated with human HCM–D166V and DCM–D94A mutations.
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James LP, Comfort P. The reliability of novel, temporal-based dynamic strength index metrics. Sports Biomech 2022:1-12. [PMID: 35119349 DOI: 10.1080/14763141.2022.2032298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 01/17/2022] [Indexed: 10/19/2022]
Abstract
The purpose of this study was: i) to determine the reliability of alternate forms of the dynamic strength index (DSI) calculated over time-specific intervals that represent decisive actions in sport and ii) to assess the association between the original form of the DSI (DSItrad) and its variants. Twenty-three resistance-trained males (BM = 80.4 ± 10.18 kg; age = 26.3 ± 10.2 y; 1-RM squat kg/kg/BM = 1.61 ± 0.37) performed trials of the countermovement jump (CMJ) and isometric squat. Several variations of the DSI were calculated by dividing the mean force in the CMJ by the mean force in the isometric squat calculated over the following epochs: 100 ms (DSI100), 150 ms (DSI150) and CMJ propulsive phase duration (DSIprop). In the fourth method, mean force across the CMJ propulsive phase duration was divided by mean force in the isometric squat between initiation and peak force (DSIpeak). All alternate DSI measures achieved acceptable absolute reliability (CV < 10%), however they did not achieve at least a moderate relative reliability. DSIprop (R2 = 0.41), DSI100 (R2 = 0.03) and DSI150 (R2 = 0.14) demonstrated limited commonality with DSItrad. The alternate forms of DSI can cautiously be considered in strength assessment systems.
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Affiliation(s)
- Lachlan P James
- Department of Dietetics, Nutrition and Sport, School of Allied Health, Human Services and Sport, La Trobe University, Melbourne, Australia
| | - Paul Comfort
- Directorate of Psychology and Sport, University of Salford, Salford, UK
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, Australia
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Markandran K, Yu H, Song W, Lam DTUH, Madathummal MC, Ferenczi MA. Functional and Molecular Characterisation of Heart Failure Progression in Mice and the Role of Myosin Regulatory Light Chains in the Recovery of Cardiac Muscle Function. Int J Mol Sci 2021; 23:ijms23010088. [PMID: 35008512 PMCID: PMC8745055 DOI: 10.3390/ijms23010088] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 12/07/2021] [Accepted: 12/14/2021] [Indexed: 02/07/2023] Open
Abstract
Heart failure (HF) as a result of myocardial infarction (MI) is a major cause of fatality worldwide. However, the cause of cardiac dysfunction succeeding MI has not been elucidated at a sarcomeric level. Thus, studying the alterations within the sarcomere is necessary to gain insights on the fundamental mechansims leading to HF and potentially uncover appropriate therapeutic targets. Since existing research portrays regulatory light chains (RLC) to be mediators of cardiac muscle contraction in both human and animal models, its role was further explored In this study, a detailed characterisation of the physiological changes (i.e., isometric force, calcium sensitivity and sarcomeric protein phosphorylation) was assessed in an MI mouse model, between 2D (2 days) and 28D post-MI, and the changes were related to the phosphorylation status of RLCs. MI mouse models were created via complete ligation of left anterior descending (LAD) coronary artery. Left ventricular (LV) papillary muscles were isolated and permeabilised for isometric force and Ca2+ sensitivity measurement, while the LV myocardium was used to assay sarcomeric proteins’ (RLC, troponin I (TnI) and myosin binding protein-C (MyBP-C)) phosphorylation levels and enzyme (myosin light chain kinase (MLCK), zipper interacting protein kinase (ZIPK) and myosin phosphatase target subunit 2 (MYPT2)) expression levels. Finally, the potential for improving the contractility of diseased cardiac papillary fibres via the enhancement of RLC phosphorylation levels was investigated by employing RLC exchange methods, in vitro. RLC phosphorylation and isometric force potentiation were enhanced in the compensatory phase and decreased in the decompensatory phase of HF failure progression, respectively. There was no significant time-lag between the changes in RLC phosphorylation and isometric force during HF progression, suggesting that changes in RLC phosphorylation immediately affect force generation. Additionally, the in vitro increase in RLC phosphorylation levels in 14D post-MI muscle segments (decompensatory stage) enhanced its force of isometric contraction, substantiating its potential in HF treatment. Longitudinal observation unveils potential mechanisms involving MyBP-C and key enzymes regulating RLC phosphorylation, such as MLCK and MYPT2 (subunit of MLCP), during HF progression. This study primarily demonstrates that RLC phosphorylation is a key sarcomeric protein modification modulating cardiac function. This substantiates the possibility of using RLCs and their associated enzymes to treat HF.
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Affiliation(s)
- Kasturi Markandran
- Lee Kong Chian School of Medicine, Nanyang Technological University, Experimental Medicine Building, 59 Nanyang Drive, Singapore 636921, Singapore; (K.M.); (H.Y.); (W.S.); (D.T.U.H.L.); (M.C.M.)
| | - Haiyang Yu
- Lee Kong Chian School of Medicine, Nanyang Technological University, Experimental Medicine Building, 59 Nanyang Drive, Singapore 636921, Singapore; (K.M.); (H.Y.); (W.S.); (D.T.U.H.L.); (M.C.M.)
| | - Weihua Song
- Lee Kong Chian School of Medicine, Nanyang Technological University, Experimental Medicine Building, 59 Nanyang Drive, Singapore 636921, Singapore; (K.M.); (H.Y.); (W.S.); (D.T.U.H.L.); (M.C.M.)
| | - Do Thuy Uyen Ha Lam
- Lee Kong Chian School of Medicine, Nanyang Technological University, Experimental Medicine Building, 59 Nanyang Drive, Singapore 636921, Singapore; (K.M.); (H.Y.); (W.S.); (D.T.U.H.L.); (M.C.M.)
- Laboratory of Precision Disease Therapeutics, Genome Institute of Singapore, 60 Biopolis Street, Singapore 138672, Singapore
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, 10 Medical Drive, Singapore 117597, Singapore
| | - Mufeeda Changaramvally Madathummal
- Lee Kong Chian School of Medicine, Nanyang Technological University, Experimental Medicine Building, 59 Nanyang Drive, Singapore 636921, Singapore; (K.M.); (H.Y.); (W.S.); (D.T.U.H.L.); (M.C.M.)
- A*STAR Microscopy Platform—Electron Microscopy, 61 Biopolis Drive, Proteos, Singapore 138673, Singapore
| | - Michael A. Ferenczi
- Lee Kong Chian School of Medicine, Nanyang Technological University, Experimental Medicine Building, 59 Nanyang Drive, Singapore 636921, Singapore; (K.M.); (H.Y.); (W.S.); (D.T.U.H.L.); (M.C.M.)
- Brunel Medical School, Brunel University London, Kingston Lane, Uxbridge UB8 3PH, UK
- Correspondence:
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Stover KK, Sleboda DA, Brainerd EL, Roberts TJ. Gastrocnemius Muscle Structural and Functional Changes Associated with Domestication in the Turkey. Animals (Basel) 2021; 11:1850. [PMID: 34206329 PMCID: PMC8300382 DOI: 10.3390/ani11071850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/14/2021] [Accepted: 06/16/2021] [Indexed: 11/30/2022] Open
Abstract
Selection for increased muscle mass in domestic turkeys has resulted in muscles twice the size of those found in wild turkeys. This study characterizes muscle structural changes as well as functional differences in muscle performance associated with selection for increased muscle mass. We compared peak isometric force production, whole muscle and individual fiber cross-sectional area (CSA), connective tissue collagen concentration and structure of the lateral gastrocnemius (LG) muscle in wild and adult domestic turkeys. We also explored changes with age between juvenile and adult domestic turkeys. We found that the domestic turkey's LG muscle can produce the same force per cross-sectional area as a wild turkey; however, due to scaling, domestic adults produce less force per unit body mass. Domestic turkey muscle fibers were slightly smaller in CSA (3802 ± 2223 μm2) than those of the wild turkey (4014 ± 1831 μm2, p = 0.013), indicating that the absolutely larger domestic turkey muscles are a result of an increased number of smaller fibers. Collagen concentration in domestic turkey muscle (4.19 ± 1.58 μg hydroxyproline/mg muscle) was significantly lower than in the wild turkeys (6.23 ± 0.63 μg/mg, p = 0.0275), with visible differences in endomysium texture, observed via scanning electron microscopy. Selection for increased muscle mass has altered the structure of the LG muscle; however, scaling likely contributes more to hind limb functional differences observed in the domestic turkey.
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Affiliation(s)
- Kristin K. Stover
- The Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA; (D.A.S.); (E.L.B.); (T.J.R.)
- Department of Biomedical Science, West Virginia School of Osteopathic Medicine, Lewisburg, WV 24901, USA
| | - David A. Sleboda
- The Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA; (D.A.S.); (E.L.B.); (T.J.R.)
| | - Elizabeth L. Brainerd
- The Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA; (D.A.S.); (E.L.B.); (T.J.R.)
| | - Thomas J. Roberts
- The Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA; (D.A.S.); (E.L.B.); (T.J.R.)
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Lafe CW, Newell KM. Task and Informational Constraints on Search Strategies: Testing the Idea of Convergence to Tolerant Regions. J Mot Behav 2021; 55:603-618. [PMID: 34130615 DOI: 10.1080/00222895.2021.1913088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 03/09/2021] [Accepted: 03/31/2021] [Indexed: 10/21/2022]
Abstract
The experiment reported was designed to investigate the interaction of information and force variability on the evolving search strategy, specifically testing the hypothesis of convergence to tolerant regions. Participants were required to produce proportional bimanual isometric force output over three days of practice, with no prespecified force target and where performance was more tolerant to force variability at higher forces. The duration of intermittent visual feedback was manipulated to test the effects of information and force variability on the search process and the resulting sensitivity to tolerant regions of the task space. The findings showed that just under half of the participants exploited more tolerant regions and that this was predicted by the initial force conditions. Different characterizations of the individual search patterns were also predicted by inherent force-dependent variability and initial force conditions. Visual intermittency feedback did not affect the time-dependent properties of the search process but did influence the within-trial variability. Our findings suggest that the attraction to tolerant regions needs to be considered within the interactions of the different categories of constraints on the search process.
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Affiliation(s)
- Charley W Lafe
- Department of Kinesiology, University of Georgia, Athens, GA, USA
| | - Karl M Newell
- Department of Kinesiology, University of Georgia, Athens, GA, USA
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Bartolomei S, Nigro F, Malagoli Lanzoni I, Mangia AL, Cortesi M, Ciacci S, Fantozzi S. Acute Effects of a High Volume vs. High Intensity Bench Press Protocol on Electromechanical Delay and Muscle Morphology in Recreationally Trained Women. Int J Environ Res Public Health 2021; 18:4874. [PMID: 34063665 DOI: 10.3390/ijerph18094874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 04/27/2021] [Accepted: 05/02/2021] [Indexed: 11/17/2022]
Abstract
The purpose of the present investigation was to compare the acute responses on muscle architecture, electromechanical delay (EMD) and performance following a high volume (HV: 5 sets of 10 reps at 70% of 1 repetition maximum (1RM)) and a high intensity (HI: 5 sets of 3 reps at 90% of 1RM) bench press protocol in women. Eleven recreationally trained women (age = 23.3 ± 1.8 y; body weight = 59.7 ± 6.0 kg; height = 164.0 ± 6.3 cm) performed each protocol in a counterbalanced randomized order. Muscle thickness of pectoral (PEC MT) and triceps muscles (TR MT) were collected prior to and 15 min post each trial. In addition, EMD of pectoral (PEC EMD) and triceps (TR EMD) muscles were calculated during isometric bench press maximum force tests performed at the same timepoints (IBPF). Significantly greater increases in PEC MT (p < 0.001) and TR MT (p < 0.001) were detected following HV compared to HI. PEC EMD showed a significantly greater increase following HV compared to HI (p = 0.039). Results of the present study indicate that the HV bench press protocol results in greater acute morphological and neuromuscular changes compared to a HI protocol in women. Evaluations of muscle morphology and electromechanical delay appear more sensitive to fatigue than maximum isometric force assessments.
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van den Tillaar R, Kristiansen EL, Larsen S. Is the Occurrence of the Sticking Region in Maximum Smith Machine Squats the Result of Diminishing Potentiation and Co-Contraction of the Prime Movers among Recreationally Resistance Trained Males? Int J Environ Res Public Health 2021; 18:ijerph18031366. [PMID: 33540938 PMCID: PMC7908405 DOI: 10.3390/ijerph18031366] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 01/27/2021] [Accepted: 01/29/2021] [Indexed: 11/23/2022]
Abstract
This study compared the kinetics, barbell, and joint kinematics and muscle activation patterns between a one-repetition maximum (1-RM) Smith machine squat and isometric squats performed at 10 different heights from the lowest barbell height. The aim was to investigate if force output is lowest in the sticking region, indicating that this is a poor biomechanical region. Twelve resistance trained males (age: 22 ± 5 years, mass: 83.5 ± 39 kg, height: 1.81 ± 0.20 m) were tested. A repeated two-way analysis of variance showed that Force output decreased in the sticking region for the 1-RM trial, while for the isometric trials, force output was lowest between 0–15 cm from the lowest barbell height, data that support the sticking region is a poor biomechanical region. Almost all muscles showed higher activity at 1-RM compared with isometric attempts (p < 0.05). The quadriceps activity decreased, and the gluteus maximus and shank muscle activity increased with increasing height (p ≤ 0.024). Moreover, the vastus muscles decreased only for the 1-RM trial while remaining stable at the same positions in the isometric trials (p = 0.04), indicating that potentiation occurs. Our findings suggest that a co-contraction between the hip and knee extensors, together with potentiation from the vastus muscles during ascent, creates a poor biomechanical region for force output, and thereby the sticking region among recreationally resistance trained males during 1-RM Smith machine squats.
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12
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Cross MR, Rivière JR, Coulmy N, Morin JB, Samozino P. Lower limb force-production capacities in alpine skiing disciplines. Scand J Med Sci Sports 2020; 31:848-860. [PMID: 33259106 DOI: 10.1111/sms.13897] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 11/20/2020] [Accepted: 11/27/2020] [Indexed: 11/29/2022]
Abstract
Specific force capacities might be a limiting factor for alpine skiing performance, yet there is little consensus on the capabilities in question, and whether they differ between disciplines. We aimed to test discipline (speed and technical) and performance (event-specific world standing) effects on lower limb force-production qualities. National-level skiers (N = 31) performed loaded squat jumps and isometric mid-thigh pulls to detect dynamic force output at extremely low and high velocities and maximum isometric force and rate of force development, respectively. Discipline differences were assessed via a general linear model including performance and allowing for interaction effects, with performance associations further characterized via distinct Pearson's correlations. Jump height did not differentiate disciplines, with absolute power slightly higher in speed athletes (F(1,27) = 4.42, P = .045, ω2 = 0.10), and neither variables were related to performance. Speed athletes possessed greater dynamic force at low velocities (F0 ; F(1,27) = 13.8, P < .001, ω2 = 0.17), and greater relative and absolute maximum isometric force (F(1,25) = 11.19-20.70, ω2 = 0.16-0.22, P < .003). Overall, higher ranked athletes possessed more force-dominant profiles (F(1,27) = 16.28, ω2 = 0.34; r = 0.60 to 0.67, P < .001) and increased rate of force development characteristics (average and maximum, r = -0.50 to -0.82, P < .048). Very robust associations existed between maximum isometric force and speed performance (r = -0.88, P < .001), but only a trend for higher absolute isometric force in technical athletes (r = -0.49, P = .052). Alpine skiers display a preponderance for dynamic force output at low velocities, and isometric force for speed athletes, which highlights the interest in specific assessment and conditioning practices for ski athletes.
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Affiliation(s)
- Matthew R Cross
- Laboratoire Interuniversitaire de Biologie de la Motricité, Université Savoie Mont Blanc, Le Bourget du Lac, France.,Département Scientifique et Sportif, Fédération Française de Ski, Annecy, France.,Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand
| | - Jean Romain Rivière
- Laboratoire Interuniversitaire de Biologie de la Motricité, Université Savoie Mont Blanc, Le Bourget du Lac, France
| | - Nicolas Coulmy
- Département Scientifique et Sportif, Fédération Française de Ski, Annecy, France
| | - Jean-Benoit Morin
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Auckland, New Zealand.,Inter-university Laboratory of Human Movement Biology, Université Jean Monnet, Saint-Étienne, France
| | - Pierre Samozino
- Laboratoire Interuniversitaire de Biologie de la Motricité, Université Savoie Mont Blanc, Le Bourget du Lac, France
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Barlow S, Custead R, Lee J, Hozan M, Greenwood J. Wireless Sensing of Lower Lip and Thumb-Index Finger 'Ramp-and-Hold' Isometric Force Dynamics in a Small Cohort of Unilateral MCA Stroke: Discussion of Preliminary Findings. Sensors (Basel) 2020; 20:s20041221. [PMID: 32102239 PMCID: PMC7070866 DOI: 10.3390/s20041221] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/18/2020] [Accepted: 02/20/2020] [Indexed: 01/22/2023]
Abstract
Automated wireless sensing of force dynamics during a visuomotor control task was used to rapidly assess residual motor function during finger pinch (right and left hand) and lower lip compression in a cohort of seven adult males with chronic, unilateral middle cerebral artery (MCA) stroke with infarct confirmed by anatomic magnetic resonance imaging (MRI). A matched cohort of 25 neurotypical adult males served as controls. Dependent variables were extracted from digitized records of ‘ramp-and-hold’ isometric contractions to target levels (0.25, 0.5, 1, and 2 Newtons) presented in a randomized block design; and included force reaction time, peak force, and dF/dtmax associated with force recruitment, and end-point accuracy and variability metrics during the contraction hold-phase (mean, SD, criterion percentage ‘on-target’). Maximum voluntary contraction force (MVCF) was also assessed to establish the force operating range. Results based on linear mixed modeling (LMM, adjusted for age and handedness) revealed significant patterns of dissolution in fine force regulation among MCA stroke participants, especially for the contralesional thumb-index finger followed by the ipsilesional digits, and the lower lip. For example, the contralesional thumb-index finger manifest increased reaction time, and greater overshoot in peak force during recruitment compared to controls. Impaired force regulation among MCA stroke participants during the contraction hold-phase was associated with significant increases in force SD, and dramatic reduction in the ability to regulate force output within prescribed target force window (±5% of target). Impaired force regulation during contraction hold-phase was greatest in the contralesional hand muscle group, followed by significant dissolution in ipsilateral digits, with smaller effects found for lower lip. These changes in fine force dynamics were accompanied by large reductions in the MVCF with the LMM marginal means for contralesional and ipsilesional pinch forces at just 34.77% (15.93 N vs. 45.82 N) and 66.45% (27.23 N vs. 40.98 N) of control performance, respectively. Biomechanical measures of fine force and MVCF performance in adult stroke survivors provide valuable information on the profile of residual motor function which can help inform clinical treatment strategies and quantitatively monitor the efficacy of rehabilitation or neuroprotection strategies.
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Affiliation(s)
- Steven Barlow
- Department of Special Education and Communication Disorders, University of Nebraska, 141 Barkley Memorial Center, Lincoln, NE 68583-0738, USA; (R.C.); (M.H.); (J.G.)
- Department of Biological Systems Engineering, University of Nebraska, 230 L.W. Chase Hall, Lincoln, NE 68583-0726, USA
- Center for Brain-Biology-Behavior, University of Nebraska, C89 East Stadium, Lincoln, NE 68588-0156, USA
- Correspondence: ; Tel.: +1-402-472-6395; Fax: +1-402-472-7697
| | - Rebecca Custead
- Department of Special Education and Communication Disorders, University of Nebraska, 141 Barkley Memorial Center, Lincoln, NE 68583-0738, USA; (R.C.); (M.H.); (J.G.)
| | - Jaehoon Lee
- Department of Educational Psychology & Leadership, Texas Tech University, PO Box 41071, Lubbock, TX 79409, USA;
| | - Mohsen Hozan
- Department of Special Education and Communication Disorders, University of Nebraska, 141 Barkley Memorial Center, Lincoln, NE 68583-0738, USA; (R.C.); (M.H.); (J.G.)
- Department of Biological Systems Engineering, University of Nebraska, 230 L.W. Chase Hall, Lincoln, NE 68583-0726, USA
- Center for Brain-Biology-Behavior, University of Nebraska, C89 East Stadium, Lincoln, NE 68588-0156, USA
| | - Jacob Greenwood
- Department of Special Education and Communication Disorders, University of Nebraska, 141 Barkley Memorial Center, Lincoln, NE 68583-0738, USA; (R.C.); (M.H.); (J.G.)
- Department of Biological Systems Engineering, University of Nebraska, 230 L.W. Chase Hall, Lincoln, NE 68583-0726, USA
- Center for Brain-Biology-Behavior, University of Nebraska, C89 East Stadium, Lincoln, NE 68588-0156, USA
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14
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Lee EJ, Kolb J, Hwee DT, Malik FI, Granzier HL. Functional Characterization of the Intact Diaphragm in a Nebulin-Based Nemaline Myopathy (NM) Model-Effects of the Fast Skeletal Muscle Troponin Activator tirasemtiv. Int J Mol Sci 2019; 20:ijms20205008. [PMID: 31658633 PMCID: PMC6829460 DOI: 10.3390/ijms20205008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 10/05/2019] [Accepted: 10/06/2019] [Indexed: 02/08/2023] Open
Abstract
Respiratory failure due to diaphragm dysfunction is considered a main cause of death in nemaline myopathy (NM) and we studied both isometric force and isotonic shortening of diaphragm muscle in a mouse model of nebulin-based NM (Neb cKO). A large contractile deficit was found in nebulin-deficient intact muscle that is frequency dependent, with the largest deficits at low–intermediate stimulation frequencies (e.g., a deficit of 72% at a stimulation frequency of 20 Hz). The effect of the fast skeletal muscle troponin activator (FSTA) tirasemtiv on force was examined. Tirasemtiv had a negligible effect at maximal stimulation frequencies, but greatly reduced the force deficit of the diaphragm at sub-maximal stimulation levels with an effect that was largest in Neb cKO diaphragm. As a result, the force deficit of Neb cKO diaphragm fell (from 72% to 29% at 20 Hz). Similar effects were found in in vivo experiments on the nerve-stimulated gastrocnemius muscle complex. Load-clamp experiments on diaphragm muscle showed that tirasemtiv increased the shortening velocity, and reduced the deficit in mechanical power by 33%. Thus, tirasemtiv significantly improves muscle function in a mouse model of nebulin-based nemaline myopathy.
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Affiliation(s)
- Eun-Jeong Lee
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, USA.
| | - Justin Kolb
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, USA.
| | - Darren T Hwee
- Research and Early Development, Cytokinetics, Inc., South San Francisco, CA 94080, USA.
| | - Fady I Malik
- Research and Early Development, Cytokinetics, Inc., South San Francisco, CA 94080, USA.
| | - Henk L Granzier
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, USA.
- Medical Research Building, RM 325, 1656 E Mabel St, Tucson, AZ 85721, USA.
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15
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Santos CC, Rama LM, Marinho DA, Barbosa TM, Costa MJ. Kinetic Analysis of Water Fitness Exercises: Contributions for Strength Development. Int J Environ Res Public Health 2019; 16:E3784. [PMID: 31597379 PMCID: PMC6801693 DOI: 10.3390/ijerph16193784] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 10/02/2019] [Accepted: 10/04/2019] [Indexed: 11/16/2022]
Abstract
The evaluation of propulsive forces in water allows the selection of the most appropriate strategies to develop strength during water fitness sessions. The aim of this study was threefold: (i) to analyze the rate of force production; (ii) to analyze the rate of force variation; and (iii) to compare limbs' symmetry in two water fitness exercises. Twenty-two young health subjects (age: 21.23 ± 1.51 years old, body mass: 67.04 ± 9.31 kg, and height: 166.36 ± 8.01 cm) performed incremental protocols of horizontal adduction (HA) and rocking horse (RHadd), from 105 until 150 b·min-1. Data acquisition required an isokinetic dynamometer and a differential pressure system that allowed the assessment of (a) isometric peak force of dominant upper limb (IsometricFD); (b) propulsive peak force of dominant upper limb (PropulsiveFD); and (c) propulsive peak force of nondominant upper limb (PropulsiveFND). Significant differences were found in the rate of force production (RateFD) between the majority cadences in both exercises. The RateFD reached ~68% of the force in dry-land conditions, and lower cadences promoted a higher rate of force variation (ΔForce). Most actions were asymmetric, except for the HA at 135 b·min-1. In conclusion, the musical cadence of 135 b·min-1 seems to elicit a desired rate of force production with a symmetric motion in both exercises.
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Affiliation(s)
- Catarina C Santos
- Faculty of Sports Science and Physical Education, University of Coimbra, Coimbra 3040-256, Portugal.
| | - Luís M Rama
- Faculty of Sports Science and Physical Education, University of Coimbra, Coimbra 3040-256, Portugal.
| | - Daniel A Marinho
- Department of Sport Sciences, University of Beira Interior, Covilhã 6201-001, Portugal.
- Research Center in Sport, Health and Human Development, CIDESD, Vila Real 5001-801, Portugal.
| | - Tiago M Barbosa
- Research Center in Sport, Health and Human Development, CIDESD, Vila Real 5001-801, Portugal.
- Department of Physical Education & Sports Sciences, Nanyang Technological University, Singapore 637616, Singapore.
- Department of Sports Sciences, Polytechnic Institute of Bragança, Bragança 5300-252, Portugal.
| | - Mário J Costa
- Research Center in Sport, Health and Human Development, CIDESD, Vila Real 5001-801, Portugal.
- Department of Sports Sciences, Polytechnic Institute of Guarda, Guarda 6300-559, Portugal.
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16
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Prkić A, Viveen J, The B, van Bergen CJ, Koenraadt KL, Eygendaal D. Comparison of isometric triceps brachii force measurement in different elbow positions. J Orthop Surg (Hong Kong) 2019; 26:2309499018783907. [PMID: 29954252 DOI: 10.1177/2309499018783907] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
PURPOSE Objective and reliable force measurement is necessary to monitor the rehabilitation after triceps brachii pathology, injuries, and posterior approach-based surgery. It is unclear at which amount of extension the triceps is best tested and if comparison to the uninjured sided is reliable. This study aims to identify the most reliable elbow position at which elbow extension force is measured using a dynamometer. Furthermore, it aims to compare the extension strength of the dominant arm with that of the nondominant arm. METHODS Isometric elbow extension force of the dominant and nondominant arms of healthy subjects was measured. The measurements were taken in three sequences per arm in 0, 30, 60, 90, and 120 degrees of flexion. A subgroup repeated the measurements to analyze test-retest reliability using intraclass correlation. RESULTS We included a total of 176 volunteers. The repeated measures analysis of variance for within-subject effect showed the lowest variation coefficient at 30 degrees of flexion. Extension forces showed a mean difference of 3.2-6.9 N in advantage of the dominant arm, resulting in ratios from 1.05 to 1.09. Learning curve analysis showed that during the first session in dominant and nondominant arms, less forces were exerted. CONCLUSION The most reliable isometric triceps brachii muscle strength measurement was at 30 degrees of flexion of the elbow. Considering the learning curve, a first tryout session for both arms is indicated. Then, a second measurement suffices as no further learning curve is observed.
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Affiliation(s)
- Ante Prkić
- 1 Department of Orthopedic Surgery, Amphia Hospital, Breda, The Netherlands
| | - Jetske Viveen
- 1 Department of Orthopedic Surgery, Amphia Hospital, Breda, The Netherlands
| | - Bertram The
- 1 Department of Orthopedic Surgery, Amphia Hospital, Breda, The Netherlands
| | | | - Koen Lm Koenraadt
- 1 Department of Orthopedic Surgery, Amphia Hospital, Breda, The Netherlands
| | - Denise Eygendaal
- 1 Department of Orthopedic Surgery, Amphia Hospital, Breda, The Netherlands.,2 Department of Orthopedic Surgery, University of Amsterdam, Amsterdam, The Netherlands
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17
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Song J, Baer LA, Threlkeld MRS, Geng C, Wade CE, Wolf SE. Insulin and exercise improved muscle function in rats with severe burns and hindlimb unloading. Physiol Rep 2019; 7:e14158. [PMID: 31353827 PMCID: PMC6661272 DOI: 10.14814/phy2.14158] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 06/11/2019] [Indexed: 12/03/2022] Open
Abstract
Prior work established that exercise alleviates muscle function loss in a clinically relevant rodent model mimicking the clinical sequelae of severely burned patients. On the basis of these data, we posit that pharmacologic treatment with insulin combined with exercise further mitigates loss of muscle function following severe burn with immobilization. Twenty-four Sprague-Dawley rats were assessed and trained to complete a climbing exercise. All rats followed a standardized protocol to mimic severe burn patients (40% total body surface area scald burn); all rats were immediately placed into a hindlimb unloading apparatus to simulate bedrest. The rats were then randomly assigned to four treatment groups: saline vehicle injection without exercise (VEH/NEX), insulin (5 U/kg) injection without exercise (INS/NEX), saline vehicle with daily exercise (VEH/EX), and insulin with daily exercise (INS/EX). The animals were assessed for 14 days following injury. The groups were compared for multiple variables. Isometric tetanic (Po) and twitch (Pt) forces were significantly elevated in the plantaris and soleus muscles of the INS/EX rats (P < 0.05). Genomic analysis revealed mechanistic causes with specific candidate changes. Molecular analysis of INS/EX rats revealed Akt phosphorylated by PDPK1 was increased with this treatment, and it further activated downstream signals mTOR, eEF2, and GSK3-β (P < 0.05). Furthermore, muscle RING-finger protein-1 (MuRF-1), an E3 ubiquitin ligase, was reduced in the INS/EX group (P < 0.05). Insulin and resistance exercise have a positive combined effect on the muscle function recovery in this clinically relevant rodent model of severe burn. Both treatments altered signaling pathways of increasing protein synthesis and decreasing protein degradation.
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Affiliation(s)
- Juquan Song
- Department of SurgeryUniversity of Texas Medical Branch and Shriners Hospitals for ChildrenGalvestonTexas
| | - Lisa A. Baer
- Department of SurgeryUniversity of Texas Health Science Center at HoustonHoustonTexas
| | | | - Calvin Geng
- Department of SurgeryUniversity of Texas Southwestern Medical CenterDallasTexas
| | - Charles E. Wade
- Department of SurgeryUniversity of Texas Health Science Center at HoustonHoustonTexas
| | - Steven E. Wolf
- Department of SurgeryUniversity of Texas Medical Branch and Shriners Hospitals for ChildrenGalvestonTexas
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18
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Passipieri JA, Dienes J, Frank J, Glazier J, Portell A, Venkatesh KP, Bliley JM, Grybowski D, Schilling BK, Marra KG, Christ GJ. Adipose Stem Cells Enhance Nerve Regeneration and Muscle Function in a Peroneal Nerve Ablation Model. Tissue Eng Part A 2019; 27:297-310. [PMID: 30760135 DOI: 10.1089/ten.tea.2018.0244] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Severe peripheral nerve injuries have devastating consequences on the quality of life in affected patients, and they represent a significant unmet medical need. Destruction of nerve fibers results in denervation of targeted muscles, which, subsequently, undergo progressive atrophy and loss of function. Timely restoration of neural innervation to muscle fibers is crucial to the preservation of muscle homeostasis and function. The goal of this study was to evaluate the impact of addition of adipose stem cells (ASCs) to polycaprolactone (PCL) nerve conduit guides on peripheral nerve repair and functional muscle recovery in the setting of a critical size nerve defect. To this end, peripheral nerve injury was created by surgically ablating 6 mm of the common peroneal nerve in a rat model. A PCL nerve guide, filled with ASCs and/or poloxamer hydrogel, was sutured to the nerve ends. Negative and positive controls included nerve ablation only (no repair), and reversed polarity autograft nerve implant, respectively. Tibialis anterior (TA) muscle function was assessed at 4, 8, and 12 weeks postinjury, and nerve and muscle tissue was retrieved at the 12-week terminal time point. Inclusion of ASCs in the PCL nerve guide elicited statistically significant time-dependent increases in functional recovery (contraction) after denervation; ∼25% higher than observed in acellular (poloxamer-filled) implants and indistinguishable from autograft implants, respectively, at 12 weeks postinjury (p < 0.05, n = 7-8 in each group). Analysis of single muscle fiber cross-sectional area (CSA) revealed that ASC-based treatment of nerve injury provided a better recapitulation of the overall distribution of muscle fiber CSAs observed in the contralateral TA muscle of uninjured limbs. In addition, the presence of ASCs was associated with improved features of re-innervation distal to the defect, with respect to neurofilament and S100 (Schwann cell marker) expression. In conclusion, these initial studies indicate significant benefits of inclusion of ASCs to the rate and magnitude of both peripheral nerve regeneration and functional recovery of muscle contraction, to levels equivalent to autograft implantation. These findings have important implications to improved nerve repair, and they provide input for future work directed to restoration of nerve and muscle function after polytraumatic injury. Impact Statement This works explores the application of adipose stem cells (ASCs) for peripheral nerve regeneration in a rat model. Herein, we demonstrate that the addition of ASCs in poloxamer-filled PCL nerve guide conduits impacts nerve regeneration and recovery of muscle function, to levels equivalent to autograft implantation, which is considered to be the current gold standard treatment. This study builds on the importance of a timely restoration of innervation to muscle fibers for preservation of muscle homeostasis, and it will provide input for future work aiming at restoring nerve and muscle function after polytraumatic injury.
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Affiliation(s)
- Juliana A Passipieri
- Biomedical Engineering Department, University of Virginia, Charlottesville, Virginia
| | - Jack Dienes
- Biomedical Engineering Department, University of Virginia, Charlottesville, Virginia
| | - Joseph Frank
- Biomedical Engineering Department, University of Virginia, Charlottesville, Virginia
| | - Joshua Glazier
- Biomedical Engineering Department, University of Virginia, Charlottesville, Virginia
| | - Andrew Portell
- Biomedical Engineering Department, University of Virginia, Charlottesville, Virginia
| | - Kaushik P Venkatesh
- Department of Bioengineering and University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Jacqueline M Bliley
- Department of Plastic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Damian Grybowski
- Department of Plastic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Benjamin K Schilling
- Department of Bioengineering and University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Kacey G Marra
- Department of Bioengineering and University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Plastic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania.,McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - George J Christ
- Biomedical Engineering Department, University of Virginia, Charlottesville, Virginia.,Orthopaedics Department, University of Virginia, Charlottesville, Virginia
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Küüsmaa-Schildt M, Liukkonen J, Vuong MK, Nyman K, Häkkinen K, Häkkinen A. Effects of morning vs. evening combined strength and endurance training on physical performance, sleep and well-being. Chronobiol Int 2019; 36:811-825. [PMID: 30950283 DOI: 10.1080/07420528.2019.1592184] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The aim of the present study was to examine how combined strength and endurance training in the morning and evening influences the adaptations in strength and endurance performance, perception of time management, psychological well-being and sleep. The combined training period lasted for 24 weeks and the participants were divided into the morning training (MG, n = 18), evening training (EG, n = 24) and control groups (CG, n = 10). Isometric leg press force (iLP), maximal oxygen consumption (VO2max), sleep behavior, fatigue, time management, motivation, self-esteem and health-related quality of life (HRQoL) were assessed. Morning to evening difference in iLP was observed in both MG and EG at Pre and Post, with higher force values in the evening, but not for VO2max. iLP force increased significantly in EG in the morning (p < 0.001) and evening (p = 0.010). VO2max increased in MG and EG both in the morning (both p < 0.001) and in the evening (MG: p < 0.001; EG: p = 0.003). Participants of the present study slept 7-8 h per night and the self-reported sleep duration, get-up time and the average time to go to bed were similar between the groups and did not change from Pre to Post. From HRQoL dimensions, the score for bodily pain decreased in MG (p = 0.029) and significant between-group differences were observed for Pre-Post changes in MG and EG (p = 0.001) as well as between MG and CG (p < 0.001). In vitality, a significant between-group difference was observed for Pre to Post changes in MG and EG (p = 0.014). Perception of time management decreased in EG (p = 0.042) but stayed unchanged for MG and CG. For the intrinsic motivation to participate, significant between-group differences were observed for MG and EG (p = 0.033) and between MG and CG (p = 0.032) for Pre to Post changes. Self-esteem improved in MG (p = 0.029) and EG (p = 0.024). The present combined strength and endurance training program performed in the morning and in the evening led to similar improvements in strength and endurance performance. Training in the morning or in the evening did not disrupt the already good sleep behavior and it was able to further increase the self-esteem. Although training in the morning hours may leave more time for free time activities or social life (i.e. family and friends) compared to the evening training, it might be more challenging to stay motivated to participate in prolonged training programs in the morning hours.
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Affiliation(s)
- M Küüsmaa-Schildt
- a Neuromuscular Research Center, Biology of Physical Activity, Faculty of Sport and Health Sciences , University of Jyväskylä , Jyväskylä , Finland
| | - J Liukkonen
- b Behavioral Sciences, Faculty of Sport and Health Sciences , University of Jyväskylä , Jyväskylä , Finland d
| | - M K Vuong
- a Neuromuscular Research Center, Biology of Physical Activity, Faculty of Sport and Health Sciences , University of Jyväskylä , Jyväskylä , Finland
| | - K Nyman
- c Department of Cardiology , Central Hospital of Central Finland , Jyväskylä , Finland
| | - K Häkkinen
- a Neuromuscular Research Center, Biology of Physical Activity, Faculty of Sport and Health Sciences , University of Jyväskylä , Jyväskylä , Finland
| | - A Häkkinen
- c Department of Cardiology , Central Hospital of Central Finland , Jyväskylä , Finland.,d Health Sciences, Faculty of Sport and Health Sciences , University of Jyväskylä , Jyväs , Finland
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20
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Park S, Spirduso W, Eakin T, Abraham L. Force and Directional Force Modulation Effects on Accuracy and Variability in Low-Level Pinch Force Tracking. J Mot Behav 2017; 50:210-218. [PMID: 28846066 DOI: 10.1080/00222895.2017.1327412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The authors investigated how varying the required low-level forces and the direction of force change affect accuracy and variability of force production in a cyclic isometric pinch force tracking task. Eighteen healthy right-handed adult volunteers performed the tracking task over 3 different force ranges. Root mean square error and coefficient of variation were higher at lower force levels and during minimum reversals compared with maximum reversals. Overall, the thumb showed greater root mean square error and coefficient of variation scores than did the index finger during maximum reversals, but not during minimum reversals. The observed impaired performance during minimum reversals might originate from history-dependent mechanisms of force production and highly coupled 2-digit performance.
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Affiliation(s)
- Sangsoo Park
- a Department of Kinesiology , University of Massachusetts Amherst
| | - Waneen Spirduso
- b Department of Kinesiology and Health Education , The University of Texas at Austin
| | - Tim Eakin
- b Department of Kinesiology and Health Education , The University of Texas at Austin
| | - Lawrence Abraham
- b Department of Kinesiology and Health Education , The University of Texas at Austin
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21
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Venugopal G, Deepak P, Ghosh DM, Ramakrishnan S. Generation of synthetic surface electromyography signals under fatigue conditions for varying force inputs using feedback control algorithm. Proc Inst Mech Eng H 2017; 231:1025-1033. [PMID: 28830284 DOI: 10.1177/0954411917727307] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Surface electromyography is a non-invasive technique used for recording the electrical activity of neuromuscular systems. These signals are random, complex and multi-component. There are several techniques to extract information about the force exerted by muscles during any activity. This work attempts to generate surface electromyography signals for various magnitudes of force under isometric non-fatigue and fatigue conditions using a feedback model. The model is based on existing current distribution, volume conductor relations, the feedback control algorithm for rate coding and generation of firing pattern. The result shows that synthetic surface electromyography signals are highly complex in both non-fatigue and fatigue conditions. Furthermore, surface electromyography signals have higher amplitude and lower frequency under fatigue condition. This model can be used to study the influence of various signal parameters under fatigue and non-fatigue conditions.
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Affiliation(s)
- G Venugopal
- 1 Non-Invasive Imaging and Diagnostics Laboratory, Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai, India.,2 Department of Instrumentation and Control Engineering, N. S. S. College of Engineering, Palakkad, Kerala, India
| | - P Deepak
- 2 Department of Instrumentation and Control Engineering, N. S. S. College of Engineering, Palakkad, Kerala, India
| | - Diptasree M Ghosh
- 1 Non-Invasive Imaging and Diagnostics Laboratory, Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai, India
| | - S Ramakrishnan
- 1 Non-Invasive Imaging and Diagnostics Laboratory, Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai, India
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22
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Bazett-Jones DM, Tylinksi T, Krstic J, Stromquist A, Sparks J. PEAK HIP MUSCLE TORQUE MEASUREMENTS ARE INFLUENCED BY SAGITTAL PLANE HIP POSITION. Int J Sports Phys Ther 2017; 12:535-542. [PMID: 28900559 PMCID: PMC5534143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023] Open
Abstract
BACKGROUND An optimal position for strength testing of the hip musculature has not been identified. However, sagittal plane hip position during testing has been shown to influence hip external rotation strength. HYPOTHESIS/PURPOSE The purpose of this study was to compare hip extension, external rotation, and abduction isometric torque at positions with differing degrees of hip flexion using a handheld dynamometer. STUDY DESIGN A cross-sectional laboratory study. METHODS Twenty-nine healthy and physically active females participated in this study. Peak isometric contractions were measured with a handheld dynamometer secured with a non-elastic strap and then converted to torque using segment lengths. Hip external rotation and extension were tested at 0°, 30°, and 90° of hip flexion. Hip abduction was tested at 0° and 30° of hip flexion and 5° of extension. Testing was randomized and counterbalanced. Repeated measures ANOVAs with Sidak's test for multiple comparisons were used for statistical analysis. Significance was set at p<0.05. RESULTS Significant main effects were found for hip extension (p<0.001) and external rotation (p<0.027), but not for abduction (p=0.085). Pairwise comparisons showed significant differences between all three testing positions for hip extension torque (0°v30° : p<0.001, 0°v90° : p<0.001, 30°v90°: p=0.002). Extension torque was highest in 90° of flexion (1.43 ± 0.50 Nm/kg*m) and lowest in 0° of flexion (0.83 ± 0.30 Nm/kg*m). Comparisons of hip external rotation torque tested at 0°v90° (p=0.096) and 30°v90° (p=0.080) were not significantly different but did have medium effect sizes. External rotation torque was highest in 90° of flexion (0.29 ± 0.13 Nm/kg*m). CONCLUSIONS Direct comparisons of torque values of hip extension and external rotation tested at different sagittal plane positions should be cautioned due to differences. Hip extension and external rotation should be measured in consistent sagittal plane positions across examiners and testing sessions. Test position will be dependent upon the goals of strength testing. LEVEL OF EVIDENCE 2b.
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Affiliation(s)
| | - Tyler Tylinksi
- Department of Physical Therapy, Carroll University, Waukesha, WI, USA
| | - Jelena Krstic
- Department of Physical Therapy, Carroll University, Waukesha, WI, USA
| | | | - Jay Sparks
- Department of Physical Therapy, Carroll University, Waukesha, WI, USA
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23
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Sohn MH, Ting LH. Suboptimal Muscle Synergy Activation Patterns Generalize their Motor Function across Postures. Front Comput Neurosci 2016; 10:7. [PMID: 26869914 PMCID: PMC4740401 DOI: 10.3389/fncom.2016.00007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 01/13/2016] [Indexed: 01/01/2023] Open
Abstract
We used a musculoskeletal model to investigate the possible biomechanical and neural bases of using consistent muscle synergy patterns to produce functional motor outputs across different biomechanical conditions, which we define as generalizability. Experimental studies in cats demonstrate that the same muscle synergies are used during reactive postural responses at widely varying configurations, producing similarly-oriented endpoint force vectors with respect to the limb axis. However, whether generalizability across postures arises due to similar biomechanical properties or to neural selection of a particular muscle activation pattern has not been explicitly tested. Here, we used a detailed cat hindlimb model to explore the set of feasible muscle activation patterns that produce experimental synergy force vectors at a target posture, and tested their generalizability by applying them to different test postures. We used three methods to select candidate muscle activation patterns: (1) randomly-selected feasible muscle activation patterns, (2) optimal muscle activation patterns minimizing muscle effort at a given posture, and (3) generalizable muscle activation patterns that explicitly minimized deviations from experimentally-identified synergy force vectors across all postures. Generalizability was measured by the deviation between the simulated force direction of the candidate muscle activation pattern and the experimental synergy force vectors at the test postures. Force angle deviations were the greatest for the randomly selected feasible muscle activation patterns (e.g., >100°), intermediate for effort-wise optimal muscle activation patterns (e.g., ~20°), and smallest for generalizable muscle activation patterns (e.g., <5°). Generalizable muscle activation patterns were suboptimal in terms of effort, often exceeding 50% of the maximum possible effort (cf. ~5% in minimum-effort muscle activation patterns). The feasible muscle activation ranges of individual muscles associated with producing a specific synergy force vector was reduced by ~45% when generalizability requirements were imposed. Muscles recruited in the generalizable muscle activation patterns had less sensitive torque-producing characteristics to changes in postures. We conclude that generalization of function across postures does not arise from limb biomechanics or a single optimality criterion. Muscle synergies may reflect acquired motor solutions globally tuned for generalizability across biomechanical contexts, facilitating rapid motor adaptation.
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Affiliation(s)
- M Hongchul Sohn
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of TechnologyAtlanta, GA, USA; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory UniversityAtlanta, GA, USA
| | - Lena H Ting
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of TechnologyAtlanta, GA, USA; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory UniversityAtlanta, GA, USA
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24
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Abstract
Analysis of the contractile properties of chemically skinned, or permeabilized, skeletal muscle fibers offers a powerful means by which to assess muscle function at the level of the single muscle cell. Single muscle fiber studies are useful in both basic science and clinical studies. For basic studies, single muscle fiber contractility measurements allow investigation of fundamental mechanisms of force production, and analysis of muscle function in the context of genetic manipulations. Clinically, single muscle fiber studies provide useful insight into the impact of injury and disease on muscle function, and may be used to guide the understanding of muscular pathologies. In this video article we outline the steps required to prepare and isolate an individual skeletal muscle fiber segment, attach it to force-measuring apparatus, activate it to produce maximum isometric force, and estimate its cross-sectional area for the purpose of normalizing the force produced.
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Affiliation(s)
- Stuart M Roche
- Department of Orthopaedic Surgery, University of Michigan Medical School
| | - Jonathan P Gumucio
- Department of Orthopaedic Surgery, University of Michigan Medical School; Department of Molecular & Integrative Physiology, University of Michigan Medical School
| | - Susan V Brooks
- Department of Molecular & Integrative Physiology, University of Michigan Medical School; Department of Biomedical Engineering, University of Michigan Medical School
| | - Christopher L Mendias
- Department of Orthopaedic Surgery, University of Michigan Medical School; Department of Molecular & Integrative Physiology, University of Michigan Medical School
| | - Dennis R Claflin
- Department of Biomedical Engineering, University of Michigan Medical School; Department of Surgery, Section of Plastic Surgery, University of Michigan Medical School;
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25
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Haupenthal DPDS, de Noronha M, Haupenthal A, Ruschel C, Nunes GS. Skin Cooling and Force Replication at the Ankle in Healthy Individuals: A Crossover Randomized Controlled Trial. J Athl Train 2015; 50:621-8. [PMID: 25761136 DOI: 10.4085/1062-6050-49.6.07] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
CONTEXT Proprioception of the ankle is determined by the ability to perceive the sense of position of the ankle structures, as well as the speed and direction of movement. Few researchers have investigated proprioception by force-replication ability and particularly after skin cooling. OBJECTIVE To analyze the ability of the ankle-dorsiflexor muscles to replicate isometric force after a period of skin cooling. DESIGN Randomized controlled clinical trial. SETTING Laboratory. PATIENTS OR OTHER PARTICIPANTS Twenty healthy individuals (10 men, 10 women; age = 26.8 ± 5.2 years, height = 171 ± 7 cm, mass = 66.8 ± 10.5 kg). INTERVENTION(S) Skin cooling was carried out using 2 ice applications: (1) after maximal voluntary isometric contraction (MVIC) performance and before data collection for the first target force, maintained for 20 minutes; and (2) before data collection for the second target force, maintained for 10 minutes. We measured skin temperature before and after ice applications to ensure skin cooling. MAIN OUTCOME MEASURE(S) A load cell was placed under an inclined board for data collection, and 10 attempts of force replication were carried out for 2 values of MVIC (20%, 50%) in each condition (ice, no ice). We assessed force sense with absolute and root mean square errors (the difference between the force developed by the dorsiflexors and the target force measured with the raw data and after root mean square analysis, respectively) and variable error (the variance around the mean absolute error score). A repeated-measures multivariate analysis of variance was used for statistical analysis. RESULTS The absolute error was greater for the ice than for the no-ice condition (F1,19 = 9.05, P = .007) and for the target force at 50% of MVIC than at 20% of MVIC (F1,19 = 26.01, P < .001). CONCLUSIONS The error was greater in the ice condition and at 50% of MVIC. Skin cooling reduced the proprioceptive ability of the ankle-dorsiflexor muscles to replicate isometric force.
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Affiliation(s)
| | - Marcos de Noronha
- Center of Health and Sports Sciences, University of the State of Santa Catarina, Brazil;,Rural Health School, La Trobe University, Victoria, Australia
| | - Alessandro Haupenthal
- Center of Health and Sports Sciences, University of the State of Santa Catarina, Brazil
| | - Caroline Ruschel
- Center of Health and Sports Sciences, University of the State of Santa Catarina, Brazil
| | - Guilherme S Nunes
- Center of Health and Sports Sciences, University of the State of Santa Catarina, Brazil
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26
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Cantagallo A, Di Russo F, Favilla M, Zoccolotti P. Targeted isometric force impulses in patients with traumatic brain injury reveal delayed motor programming and change of strategy. J Neurotrauma 2015; 32:563-70. [PMID: 25273979 DOI: 10.1089/neu.2014.3571] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The capability of quickly (as soon as possible) producing fast uncorrected and accurate isometric force impulses was examined to assess the motor efficiency of patients with moderate to severe traumatic brain injury (TBI) and good motor recovery at a clinical evaluation. Twenty male right-handed patients with moderate to severe TBI and 24 age-matched healthy male right-handed controls participated in the study. The experimental task required subjects to aim brief and uncorrected isometric force impulses to targets visually presented along with subjects' force displays. Both TBI patients and controls were able to produce force impulses whose mean peak amplitudes varied proportionally to the target load with no detectable group difference. Patients with TBI, however, were slower than controls in initiating their responses (reaction times [RTs] were longer by 125 msec) and were also slower during the execution of their motor responses, reaching the peak forces requested 23 msec later than controls (time to peak force: 35% delay). Further, their mean dF/dt (35 kg/sec) was slower than that of controls (53 kg/sec), again indicating a 34% impairment with respect to controls. Overall, patients with TBI showed accurate but delayed and slower isometric force impulses. Thus, an evaluation taking into account also response time features is more effective in picking up motor impairments than the standard clinical scales focusing on accuracy of movement only.
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Martin D, Cooper S, Sale C, Compton G, Elliott-Sale K. Reliability of force per unit cross-sectional area measurements of the first dorsal interosseus muscle. J Sports Sci 2014; 33:1159-65. [PMID: 25514211 DOI: 10.1080/02640414.2014.986504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The purpose of this study was to determine the reliability of maximum voluntary isometric force (MVIF), cross-sectional area (CSA) and force per unit CSA measures, of the first dorsal interosseus (FDI) muscle, using a custom-built dynamometer and ultrasonography. Twenty-seven participants completed MVIF and CSA measurements on two separate occasions under the same conditions. Reliability was determined using paired samples t-tests, systematic bias ratio and ratio limits of agreement (RLoA), intra-class correlation (ICC) and coefficient of variation (CV). MVIF of the FDI muscle (mean ± s; 31.8 ± 7.6 N and 31.6 ± 7.3 N) was not different between trials (P = 0.63); RLoA between trials were 1.00 ×/÷ 1.09, ICC = 0.990 and CV = 3.22%. CSA of the FDI muscle (22.6 ± 6.9 and 22.9 ± 6.9 mm²) was also not different between trials (P = 0.31); RLoA between trials were 0.98 ×/÷ 1.19, ICC = 0.979 and CV = 6.61%. Force per unit CSA was not different between trials (1.49 ± 0.43 and 1.46 ± 0.44 N·mm²; P = 0.18), RLoA were 1.02 ×/÷ 1.17, ICC = 0.985 and CV = 5.76%. The techniques used to determine MVIF and CSA of the FDI muscle were reliable and can be combined to calculate force per unit CSA.
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Affiliation(s)
- Daniel Martin
- a Department of Sport Science , Nottingham Trent University , Clifton , UK
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Chawla A, Spinner RJ, Torres Lizardi M, Yaszemski MJ, Windebank AJ, Wang H. Non-invasive isometric force measurement of plantar flexors in rats. Muscle Nerve 2014; 50:812-21. [PMID: 24639363 DOI: 10.1002/mus.24219] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 02/11/2014] [Accepted: 02/19/2014] [Indexed: 11/10/2022]
Abstract
INTRODUCTION Isometric muscle force measurement is a sensitive marker for motor function recovery in rat nerve repair models. Current methods of eliciting maximal isometric force with nerve stimulation cannot provide longitudinal data. METHODS We developed a novel method for measuring isometric muscle force with a device designed to allow minimally invasive nerve stimulation and measurement of plantar flexion force. This indirectly elicited muscle force was compared with muscle force elicited by direct muscle stimulation in 3 surgical models. RESULTS The force measured after sciatic nerve transection and repair followed a parabolic trend. There was a postinjury decrease in force that continued until postoperative day 42, after which the force increased with time, indicating muscle reinnervation. CONCLUSIONS This approach can track longitudinal changes in force in the most common animal model for studies of clinically relevant problems in the peripheral nerve field.
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Affiliation(s)
- Aditya Chawla
- Department of Neurologic Surgery, Mayo Clinic, 200 First Street SW, Rochester, Minnesota, 55905
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29
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Abstract
Muscle synergies have been proposed as a way for the central nervous system (CNS) to simplify the generation of motor commands and they have been shown to explain a large fraction of the variation in the muscle patterns across a variety of conditions. However, whether human subjects are able to control forces and movements effectively with a small set of synergies has not been tested directly. Here we show that muscle synergies can be used to generate target forces in multiple directions with the same accuracy achieved using individual muscles. We recorded electromyographic (EMG) activity from 13 arm muscles and isometric hand forces during a force reaching task in a virtual environment. From these data we estimated the force associated to each muscle by linear regression and we identified muscle synergies by non-negative matrix factorization. We compared trajectories of a virtual mass displaced by the force estimated using the entire set of recorded EMGs to trajectories obtained using 4–5 muscle synergies. While trajectories were similar, when feedback was provided according to force estimated from recorded EMGs (EMG-control) on average trajectories generated with the synergies were less accurate. However, when feedback was provided according to recorded force (force-control) we did not find significant differences in initial angle error and endpoint error. We then tested whether synergies could be used as effectively as individual muscles to control cursor movement in the force reaching task by providing feedback according to force estimated from the projection of the recorded EMGs into synergy space (synergy-control). Human subjects were able to perform the task immediately after switching from force-control to EMG-control and synergy-control and we found no differences between initial movement direction errors and endpoint errors in all control modes. These results indicate that muscle synergies provide an effective strategy for motor coordination.
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Affiliation(s)
- Denise J Berger
- Laboratory of Neuromotor Physiology, Santa Lucia Foundation Rome, Italy
| | - Andrea d'Avella
- Laboratory of Neuromotor Physiology, Santa Lucia Foundation Rome, Italy
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30
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Abstract
The authors examined how force generation repeatability changes as the result of incremental maximal test to volitional exhaustion by well-trained (VO2/kg [mL · kg(-1) · min(-1)] 62.55 ± 5.27) individuals. 13 young biathletes (18.9 ± 1.7 years) performed isometric maximum voluntary contraction (IMVC) and submaximal targeted (98N) pushes against the force transducers by arms: elbow extension (EE), elbow flexion (EF) and legs: knee extensions (KE) in pre- and posttest conditions after incremental exhaustive test performed on treadmill. IMVC did not differ significantly between pre and posttest conditions for upper and statistically decrease in lower extremities measurements (p <.01). The mean force of 10 submaximal targeted force productions (F(mean); N) is similar for pre- and posttest measurements. Standard deviation of F(mean) (Fsd; N) and coefficient variation (CV;%) decrease statistically in elbows flexion p <.02 but not extension. The reduction of force repetition accuracy in left knee extension was noticed (p <.01). The fatigue induced by incremental running test decreases a magnitude of force production variability in specifically trained muscle groups in biathletes.
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Affiliation(s)
- Agnieszka D Jastrzębska
- a University School of Physical Education , Department of Physiology and Biochemistry , Wrocław , Poland
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31
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Hampton S, Armstrong G, Ayyar MS, Li S. Quantification of perceived exertion during isometric force production with the Borg scale in healthy individuals and patients with chronic stroke. Top Stroke Rehabil 2014; 21:33-9. [PMID: 24521838 DOI: 10.1310/tsr2101-33] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND The Borg Rating of Perceived Exertion (RPE) scale is widely used for many patient populations, but the ability of patients to accurately report their RPE without visual feedback has not been studied. OBJECTIVE The objective was to determine whether the Borg scale could be used as a measure of perceived isometric exertion in healthy subjects and patients with stroke. METHODS In experiment 1, young healthy subjects (n = 15) were instructed to perform spontaneous pushes (ie, self-selected effort) without visual feedback and to produce and hold self-determined isometric finger flexion at 5 Borg levels without visual feedback. In experiment 2, subjects with chronic stroke (n = 10) were instructed to produce self-determined isometric elbow flexion at 4 perceptual levels on the impaired and nonimpaired sides. RESULTS In experiment 1, young healthy subjects, asked to self-select without visual feedback (spontaneous push), tended to exert at a "somewhat hard" level, about 12% of maximal voluntary contraction (MVC). Self-selection of forces ranged from 2% of MVC (ie, very light) to 39% of MVC (ie, very hard). In experiment 2, subjects with stroke were able to distinguish different levels of perceived exertion among light (19% MVC), somewhat hard (33% MVC), and hard (63% MVC) levels; this ability was not different for the impaired and nonimpaired limbs. CONCLUSION Both healthy subjects and subjects with stroke are able to differentiate distinct levels of perceived exertion during isometric force when prompted with the Borg scale. Efforts at lower percentages of MVC are perceived by subjects with stroke as greater-than-normal Borg RPE levels.
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Affiliation(s)
- Stephen Hampton
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, Texas Neurorehabilitation Research Laboratory, TIRR Memorial Hermann Hospital, Houston, Texas
| | - Gina Armstrong
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, Texas Neurorehabilitation Research Laboratory, TIRR Memorial Hermann Hospital, Houston, Texas
| | - Monika Shah Ayyar
- Rehabilitation Unit, Houston Methodist Hospital, Houston, Texas Clinical Rehabilitation Medicine, Weill Cornell Medical College, Houston Methodist Hospital, Houston, Texas
| | - Sheng Li
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, Texas Neurorehabilitation Research Laboratory, TIRR Memorial Hermann Hospital, Houston, Texas
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32
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Borzelli D, Berger DJ, Pai DK, d'Avella A. Effort minimization and synergistic muscle recruitment for three-dimensional force generation. Front Comput Neurosci 2013; 7:186. [PMID: 24391581 PMCID: PMC3868911 DOI: 10.3389/fncom.2013.00186] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 12/05/2013] [Indexed: 12/21/2022] Open
Abstract
To generate a force at the hand in a given spatial direction and with a given magnitude the central nervous system (CNS) has to coordinate the recruitment of many muscles. Because of the redundancy in the musculoskeletal system, the CNS can choose one of infinitely many possible muscle activation patterns which generate the same force. What strategies and constraints underlie such selection is an open issue. The CNS might optimize a performance criterion, such as accuracy or effort. Moreover, the CNS might simplify the solution by constraining it to be a combination of a few muscle synergies, coordinated recruitment of groups of muscles. We tested whether the CNS generates forces by minimum effort recruitment of either individual muscles or muscle synergies. We compared the activation of arm muscles observed during the generation of isometric forces at the hand across multiple three-dimensional force targets with the activation predicted by either minimizing the sum of squared muscle activations or the sum of squared synergy activations. Muscle synergies were identified from the recorded muscle pattern using non-negative matrix factorization. To perform both optimizations we assumed a linear relationship between rectified and filtered electromyographic (EMG) signal which we estimated using multiple linear regressions. We found that the minimum effort recruitment of synergies predicted the observed muscle patterns better than the minimum effort recruitment of individual muscles. However, both predictions had errors much larger than the reconstruction error obtained by the synergies, suggesting that the CNS generates three-dimensional forces by sub-optimal recruitment of muscle synergies.
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Affiliation(s)
- Daniele Borzelli
- Laboratory of Neuromotor Physiology, Santa Lucia Foundation Rome, Italy
| | - Denise J Berger
- Laboratory of Neuromotor Physiology, Santa Lucia Foundation Rome, Italy
| | - Dinesh K Pai
- Department of Computer Science, University of British Columbia Vancouver, BC, Canada
| | - Andrea d'Avella
- Laboratory of Neuromotor Physiology, Santa Lucia Foundation Rome, Italy
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33
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Abstract
During visuomotor adaptation a novel mapping between visual targets and motor commands is gradually acquired. How muscle activation patterns are affected by this process is an open question. We tested whether the structure of muscle synergies is preserved during adaptation to a visuomotor rotation. Eight subjects applied targeted isometric forces on a handle instrumented with a force transducer while electromyographic (EMG) activity was recorded from 13 shoulder and elbow muscles. The recorded forces were mapped into horizontal displacements of a virtual sphere with simulated mass, elasticity, and damping. The task consisted of moving the sphere to a target at one of eight equally spaced directions. Subjects performed three baseline blocks of 32 trials, followed by six blocks with a 45° CW rotation applied to the planar force, and finally three wash-out blocks without the perturbation. The sphere position at 100 ms after movement onset revealed significant directional error at the beginning of the rotation, a gradual learning in subsequent blocks, and aftereffects at the beginning of the wash-out. The change in initial force direction was closely related to the change in directional tuning of the initial EMG activity of most muscles. Throughout the experiment muscle synergies extracted using a non-negative matrix factorization algorithm from the muscle patterns recorded during the baseline blocks could reconstruct the muscle patterns of all other blocks with an accuracy significantly higher than chance indicating structural robustness. In addition, the synergies extracted from individual blocks remained similar to the baseline synergies throughout the experiment. Thus synergy structure is robust during visuomotor adaptation suggesting that changes in muscle patterns are obtained by rotating the directional tuning of the synergy recruitment.
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Affiliation(s)
- Reinhard Gentner
- Laboratory of Neuromotor Physiology, Santa Lucia Foundation Rome, Italy
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Rosene J, Matthews T, Ryan C, Belmore K, Bergsten A, Blaisdell J, Gaylord J, Love R, Marrone M, Ward K, Wilson E. Short and longer-term effects of creatine supplementation on exercise induced muscle damage. J Sports Sci Med 2009; 8:89-96. [PMID: 24150561 PMCID: PMC3737793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Accepted: 01/12/2008] [Indexed: 06/02/2023]
Abstract
The purpose of this investigation was to determine if creatine supplementation assisted with reducing the amount of exercise induced muscle damage and if creatine supplementation aided in recovery from exercise induced muscle damage. Two groups of subjects (group 1 = creatine; group 2 = placebo) participated in an eccentric exercise protocol following 7 and 30 days of creatine or placebo supplementation (20 g.d(-1) for 7 d followed by 6g.d(-1) for 23 d = 30 d). Prior to the supplementation period, measurements were obtained for maximal dynamic strength, maximal isometric force, knee range of motion, muscle soreness, and serum levels of creatine kinase (CK) and lactate dehydrogenase (LDH). Following 7 days of creatine supplementation, on day 8, subjects began consuming 6 g.d(-1) of creatine for 23 days. Additionally on days 8 and 31, subjects performed an eccentric exercise protocol using the knee extensors to induce muscle damage. Indirect markers of muscle damage, including maximal isometric force, knee range of motion, muscle soreness, and serum levels of CK and LDH, were collected at 12, 24, and 48 hours following each exercise bout. The results indicated that acute bouts of creatine have no effect on indirect markers of muscle damage for the acute (7 days) bout. However, maximal isometric force was greater for the creatine group versus placebo for the chronic (30 days) bout. This suggests that the ergogenic effect of creatine following 30 days of supplementation may have a positive impact on exercise induced muscle damage. Key pointsEccentric muscle actions highly associated with exercise induced muscle damage.Creatine supplementation has ergogenic effect to increase protein synthesis.Creatine supplementation does not attenuate exercise induced muscle damage with short term supplementation (7 days).Increased maximal isometric force seen with creatine supplementation after 30 days following exercise induced muscle damage.Ergogenic effect of creatine supplementation may contribute to reduced exercise induced muscle damage.
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Affiliation(s)
- John Rosene
- Health and Human Performance Department, Plymouth State University, Plymouth, NH, USA
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35
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Mah CD, Mussa-Ivaldi FA. Generalization of object manipulation skills learned without limb motion. J Neurosci 2003; 23:4821-5. [PMID: 12832503 PMCID: PMC6741162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023] Open
Abstract
Recent work suggests that human subjects may learn mappings between object motion and exerted torque during manipulation of freely pivoting or unstable objects. In the present work, we studied an object manipulation task involving no arm movement to determine how subjects internally represent the force-motion relationship of an object during a skilled manipulation task. Human subjects learned to balance a simulated inverted pendulum. The simulation was controlled by pressing on a fixed force sensor, and applied forces resulted in motion of the simulated pendulum on a computer screen according to its equation of motion. Each subject initially learned the task in one arm posture and was tested 1 d later in a new arm posture. In one test condition, the effects of arm torque were matched to the original task, and in the other test condition, the simulation was unchanged. The pattern of skill transfer to different arm postures suggested that subjects had learned joint torque responses rather than a general model of the object interface forces. A second experiment showed that the advantage of training with matched arm torques was object specific, because torque-matched training on a tracking task involving similar forces was not a substitute for training in the balancing task.
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Affiliation(s)
- Christopher D Mah
- Department of Physical Medicine and Rehabilitation, Northwestern University Medical School, Chicago, Illinois 60611, USA.
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