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Orientation-specific responses to sustained uniaxial stretching in focal adhesion growth and turnover. Proc Natl Acad Sci U S A 2013; 110:E2352-61. [PMID: 23754369 DOI: 10.1073/pnas.1221637110] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Cells are mechanosensitive to extracellular matrix (ECM) deformation, which can be caused by muscle contraction or changes in hydrostatic pressure. Focal adhesions (FAs) mediate the linkage between the cell and the ECM and initiate mechanically stimulated signaling events. We developed a stretching apparatus in which cells grown on fibronectin-coated elastic substrates can be stretched and imaged live to study how FAs dynamically respond to ECM deformation. Human bone osteosarcoma epithelial cell line U2OS was transfected with GFP-paxillin as an FA marker and subjected to sustained uniaxial stretching. Two responses at different timescales were observed: rapid FA growth within seconds after stretching, and delayed FA disassembly and loss of cell polarity that occurred over tens of minutes. Rapid FA growth occurred in all cells; however, delayed responses to stretch occurred in an orientation-specific manner, specifically in cells with their long axes perpendicular to the stretching direction, but not in cells with their long axes parallel to stretch. Pharmacological treatments demonstrated that FA kinase (FAK) promotes but Src inhibits rapid FA growth, whereas FAK, Src, and calpain 2 all contribute to delayed FA disassembly and loss of polarity in cells perpendicular to stretching. Immunostaining for phospho-FAK after stretching revealed that FAK activation was maximal at 5 s after stretching, specifically in FAs oriented perpendicular to stretch. We hypothesize that orientation-specific activation of strain/stress-sensitive proteins in FAs upstream to FAK and Src promote orientation-specific responses in FA growth and disassembly that mediate polarity rearrangement in response to sustained stretch.
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102
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Muscle fatigue and metabolic responses following three different antagonist pre-load resistance exercises. J Electromyogr Kinesiol 2013; 23:1090-6. [PMID: 23742915 DOI: 10.1016/j.jelekin.2013.04.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Revised: 01/29/2013] [Accepted: 04/22/2013] [Indexed: 11/21/2022] Open
Abstract
PURPOSE Preload of antagonist muscles can be achieved by reciprocal actions (RAs) or by opposing muscle actions. However, evidence concerning neuromuscular and fatigue responses are scarce. OBJECTIVE To compare the effects of different knee flexor (KF) preload methods on knee extension (KE) vastus medialis muscle fatigue, based on EMG-spectral index (FI), load range (LR), total work (TW), blood lactate (LAC) and biceps femoris co-activation (BFc) during resistance exercise. METHODS Twenty-four healthy men (23.5±3.6yrs) performed three antagonist pre-load isokinetic exercises (4 sets, 10 repetitions, 60°s(-1), 1min rest between sets): RA (KF contraction immediately followed by KE); Superset (SS; one KF set immediately followed by one KE set); Multiple Set (MS; four KF sets followed by four KE sets). RESULTS Total work was significantly greater in RA. There was no significant decrease in LR between sets in RA. The BFc did not differ between protocols (p=0.063). However, RA presented greater biceps femoriscoactivation. The FI was greater during SS compared to RA and MS (p<0.05). The SS had greater LAC when compared to MS and RA (p=0.005 and p=0.007, respectively). CONCLUSION It is suggested that the RA protocol is more neuromuscular and metabolic efficient during the performance of knee extension resistance exercise.
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103
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Neyroud D, Rüttimann J, Mannion AF, Millet GY, Maffiuletti NA, Kayser B, Place N. Comparison of neuromuscular adjustments associated with sustained isometric contractions of four different muscle groups. J Appl Physiol (1985) 2013; 114:1426-34. [DOI: 10.1152/japplphysiol.01539.2012] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The extent and characteristics of muscle fatigue of different muscle groups when subjected to a similar fatiguing task may differ. Thirteen healthy young men performed sustained contractions at 50% maximal voluntary contraction (MVC) force until task failure, with four different muscle groups, over two sessions. Per session, one upper limb and one lower limb muscle group were tested (knee extensors and thumb adductor, or plantar and elbow flexors). Changes in voluntary activation level and contractile properties were derived from doublet responses evoked during and after MVCs before and after exercise. Time to task failure differed ( P < 0.05) between muscle groups (220 ± 64 s for plantar flexors, 114 ± 27 s for thumb adductor, 77 ± 25 s for knee extensors, and 72 ± 14 s for elbow flexors). MVC force loss immediately after voluntary task failure was similar (−30 ± 11% for plantar flexors, −37 ± 13% for thumb adductor, −34 ± 15% for knee extensors, and −40 ± 12% for elbow flexors, P > 0.05). Voluntary activation was decreased for plantar flexors only (from 95 ± 5% to 82 ± 9%, P < 0.05). Potentiated evoked doublet amplitude was more depressed for upper limb muscles (−59.3 ± 14.7% for elbow flexors and −60.1 ± 24.1% for thumb adductor, P < 0.05) than for knee extensors (−28 ± 15%, P < 0.05); no reduction was found in plantar flexors (−7 ± 12%, P > 0.05). In conclusion, despite different times to task failure when sustaining an isometric contraction at 50% MVC force for as long as possible, diverse muscle groups present similar loss of MVC force after task failure. Thus the extent of muscle fatigue is not affected by time to task failure, whereas this latter determines the etiology of fatigue.
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Affiliation(s)
- Daria Neyroud
- Institute of Movement Sciences and Sports Medicine, University of Geneva, Geneva, Switzerland
| | - Jennifer Rüttimann
- Institute of Movement Sciences and Sports Medicine, University of Geneva, Geneva, Switzerland
| | | | | | | | - Bengt Kayser
- Institute of Movement Sciences and Sports Medicine, University of Geneva, Geneva, Switzerland
| | - Nicolas Place
- Institute of Movement Sciences and Sports Medicine, University of Geneva, Geneva, Switzerland
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Effects of Ramadan on the Diurnal Variations of Repeated-Sprint Performance. Int J Sports Physiol Perform 2013; 8:254-62. [DOI: 10.1123/ijspp.8.3.254] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Purpose:This study examined the effects of Ramadan on cycling repeated-sprint ability (RSA) and corresponding diurnal variations.Methods:Twelve active men performed an RSA test (5 × 6-s maximal sprints interspersed with 24 s passive recovery) during morning and afternoon sessions 1 wk before Ramadan (BR), during the second (R2) and the fourth (R4) weeks of Ramadan, and 2 wk after Ramadan (AR). Maximal voluntary contraction was assessed before (MVCpre), immediately after (MVCpost), and 5 min after the RSA test (MVCpost5). Moreover, hematocrit, hemoglobin, and plasma sodium and potassium (K+) concentrations were measured at rest and after the RSA test and MVCpost.Results:Overall, peak power (Ppeak) during the RSA test decreased throughout the 5 sprints. Ppeak measured in the first sprint and MVCpre were lower during Ramadan than BR in the afternoon (P < .05) and higher in the afternoon than the morning BR and AR (P < .05). However, this diurnal rhythmicity was not found for the last 4 sprints’ Ppeak, MVCpost, and MVCpost5 in all testing periods. Furthermore, the last 4 sprints’ Ppeak, MVCpost, MVCpost5, and morning MVCpre were not affected by Ramadan. [K+] measured at rest and after the RSA test and MVCpost were higher during Ramadan than BR in the afternoon (P < .05) and higher in the afternoon than the morning during Ramadan (P < .05).Conclusions:Fatigability is higher in the afternoon during Ramadan, and, therefore, training and competition should be scheduled at the time of day when physical performance is less affected.
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105
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Girard O, Bishop DJ, Racinais S. Neuromuscular adjustments of the quadriceps muscle after repeated cycling sprints. PLoS One 2013; 8:e61793. [PMID: 23650503 PMCID: PMC3641084 DOI: 10.1371/journal.pone.0061793] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Accepted: 03/13/2013] [Indexed: 11/19/2022] Open
Abstract
PURPOSE This study investigated the supraspinal processes of fatigue of the quadriceps muscle in response to repeated cycling sprints. METHODS Twelve active individuals performed 10 × 6-s "all-out" sprints on a cycle ergometer (recovery = 30 s), followed 6 min later by 5 × 6-s sprints (recovery = 30 s). Transcranial magnetic and electrical femoral nerve stimulations during brief (5-s) and sustained (30-s) isometric contractions of the knee extensors were performed before and 3 min post-exercise. RESULTS Maximal strength of the knee extensors decreased during brief and sustained contractions (~11% and 9%, respectively; P<0.001). Peripheral and cortical voluntary activation, motor evoked potential amplitude and silent period duration responses measured during briefs contractions were unaltered (P>0.05). While cortical voluntary activation declined (P<0.01) during the sustained maximal contraction in both test sessions, larger reductions occurred (P<0.05) after exercise. Lastly, resting twitch amplitude in response to both femoral nerve and cortical stimulations was largely (> 40%) reduced (P<0.001) following exercise. CONCLUSION The capacity of the motor cortex to optimally drive the knee extensors following a repeated-sprint test was shown in sustained, but not brief, maximal isometric contractions. Additionally, peripheral factors were largely involved in the exercise-induced impairment in neuromuscular function, while corticospinal excitability was well-preserved.
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Affiliation(s)
- Olivier Girard
- Aspetar, Qatar Orthopaedic and Sports Medicine Hospital, Doha, Qatar.
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106
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Neuromuscular fatigue induced by whole-body vibration exercise. Eur J Appl Physiol 2013; 113:1625-34. [PMID: 23344670 DOI: 10.1007/s00421-013-2590-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Accepted: 01/10/2013] [Indexed: 10/27/2022]
Abstract
The aim of this study was to examine the magnitude and the origin of neuromuscular fatigue induced by half-squat static whole-body vibration (WBV) exercise, and to compare it to a non-WBV condition. Nine healthy volunteers completed two fatiguing protocols (WBV and non-WBV, randomly presented) consisting of five 1-min bouts of static half-squat exercise with a load corresponding to 50 % of their individual body mass. Neuromuscular fatigue of knee and ankle muscles was investigated before and immediately after each fatiguing protocol. The main outcomes were maximal voluntary contraction (MVC) torque, voluntary activation, and doublet peak torque. Knee extensor MVC torque decreased significantly (P < 0.01) and to the same extent after WBV (-23 %) and non-WBV (-25 %), while knee flexor, plantar flexor, and dorsiflexor MVC torque was not affected by the treatments. Voluntary activation of knee extensor and plantar flexor muscles was unaffected by the two fatiguing protocols. Doublet peak torque decreased significantly and to a similar extent following WBV and non-WBV exercise, for both knee extensors (-25 %; P < 0.01) and plantar flexors (-7 %; P < 0.05). WBV exercise with additional load did not accentuate fatigue and did not change its causative factors compared to non-WBV half-squat resistive exercise in recreationally active subjects.
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107
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Wada M, Kuratani M, Kanzaki K. Calcium kinetics of sarcoplasmic reticulum and muscle fatigue. JOURNAL OF PHYSICAL FITNESS AND SPORTS MEDICINE 2013. [DOI: 10.7600/jpfsm.2.169] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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108
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Froyd C, Millet GY, Noakes TD. The development of peripheral fatigue and short-term recovery during self-paced high-intensity exercise. J Physiol 2012; 591:1339-46. [PMID: 23230235 DOI: 10.1113/jphysiol.2012.245316] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The time course of muscular fatigue that develops during and after an intense bout of self-paced dynamic exercise was characterized by using different forms of electrical stimulation (ES) of the exercising muscles. Ten active subjects performed a time trial (TT) involving repetitive concentric extension/flexion of the right knee using a Biodex dynamometer. Neuromuscular function (NMF), including ES and a 5 s maximal isometric voluntary contraction (MVC), was assessed before the start of the TT and immediately (<5 s) after each 20% of the TT had been completed, as well as 1, 2, 4 and 8 min after TT termination. The TT time was 347 ± 98 s. MVCs were 52% of baseline values at TT termination. Torque responses from ES were reduced to 33-68% of baseline using different methods of stimulation, suggesting that the extent to which peripheral fatigue is documented during exercise depends upon NMF assessment methodology. The major changes in muscle function occurred within the first 40% of exercise. Significant recovery in skeletal muscle function occurs within the first 1-2 min after exercise, showing that previous studies may have underestimated the extent to which peripheral fatigue develops during exercise.
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Affiliation(s)
- Christian Froyd
- UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Sports Science Instituteof South Africa, Boundary Road, Newlands, 7925, South Africa.
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109
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Neyroud D, Maffiuletti NA, Kayser B, Place N. Mechanisms of fatigue and task failure induced by sustained submaximal contractions. Med Sci Sports Exerc 2012; 44:1243-51. [PMID: 22215181 DOI: 10.1249/mss.0b013e318245cc4d] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE The present study was designed to investigate whether central neural mechanisms limit the duration of a sustained low-force isometric contraction and the maximal force-generating capacity of the knee extensors. METHODS Fourteen healthy males (28 ± 7 yr) were asked to sustain, until voluntary exhaustion, an isometric contraction with their right knee extensor muscles at a target force equal to 20% of their maximal voluntary contraction (MVC) force. At task failure, the muscle was immediately electrically stimulated for 1 min aiming the same target force (20% MVC force). Subsequently, subjects were asked to resume the voluntary contraction for as long as possible. Knee extensor neuromuscular function was assessed before and after the entire protocol for comparison. RESULTS When electrically stimulated at the point of task failure, all subjects developed the 20% MVC force target, indicating that lack of force-generating capacity from peripheral impairment had not limited the duration of the first task. We observed a reduction in MVC force after the entire protocol (-57% ± 12%), which correlated with a decrease in potentiated peak doublet force (-48% ± 17%, P < 0.001). The level of voluntary activation, as quantified with the interpolated twitch technique, was slightly depressed after the entire protocol (from 93% ± 7% to 87% ± 10%, P < 0.01). CONCLUSIONS It follows that task failure from a sustained isometric contraction is mainly affected by central/motivational factors, whereas MVC force loss is largely explained by the extent of contractile failure of the muscle.
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Affiliation(s)
- Daria Neyroud
- Institute of Movement Sciences and Sports Medicine, University of Geneva, Geneva, Switzerland
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110
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Alghannam AF. Metabolic limitations of performance and fatigue in football. Asian J Sports Med 2012; 3:65-73. [PMID: 22942991 PMCID: PMC3426724 DOI: 10.5812/asjsm.34699] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2011] [Accepted: 12/29/2011] [Indexed: 12/21/2022] Open
Abstract
Football participation requires considerable utilization of both aerobic and anaerobic energy systems to match the high energetic demands of the sport. The consequent stresses imposed on the physiological and metabolic systems carries players to the threshold of exhaustion during match-play, from which they are required to recover in preparation for the subsequent game. A high number of players experience fatigue during the high-intensity bouts and a consequent decline in their performance towards the end of the game is a likely outcome during match-play. The current review aims to establish the current understanding that relates to metabolic limitations of performance and the associated mechanisms for the onset of fatigue that may be instrumental in further development of evidence-based nutritional and training interventions in this event.
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Affiliation(s)
- Abdullah F. Alghannam
- Corresponding Author:Address: Human Physiology Research Group, Department for Health, University of Bath, BA2 7AY, UK. E-mail:
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111
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Effects of extreme-duration heavy load carriage on neuromuscular function and locomotion: a military-based study. PLoS One 2012; 7:e43586. [PMID: 22927995 PMCID: PMC3425486 DOI: 10.1371/journal.pone.0043586] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 07/23/2012] [Indexed: 11/29/2022] Open
Abstract
Trekking and military missions generally consist of carrying heavy loads for extreme durations. These factors have been separately shown to be sources of neuromuscular (NM) fatigue and locomotor alterations. However, the question of their combined effects remains unresolved, and addressing this issue required a representative context.
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112
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Ge HY, Arendt-Nielsen L, Madeleine P. Accelerated muscle fatigability of latent myofascial trigger points in humans. PAIN MEDICINE 2012; 13:957-64. [PMID: 22694218 DOI: 10.1111/j.1526-4637.2012.01416.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVE Muscle fatigue is prevalent in acute and chronic musculoskeletal pain conditions in which myofascial trigger points (MTPs) are involved. The aim of this study was to investigate the association of latent MTPs with muscle fatigue. DESIGN Intramuscular electromyographic (EMG) recordings were obtained from latent MTPs and non-MTPs together with surface EMG recordings from the upper trapezius muscles during sustained isometric muscle contractions in 12 healthy subjects. OUTCOME MEASURES Normalized root mean square (RMS) EMG amplitude and mean power frequency (MNF) were analyzed. The rate of perceived exertion and pain intensity from MTP side and non-MTP side were recorded. RESULTS Pain intensity on the MTP side was significantly higher than the non-MTP side (P < 0.05). Intramuscular EMG from latent MTPs showed an early onset of decrease in MNF and a significant decrease at the end of fatiguing contraction as compared with non-MTPs (P < 0.05). Surface EMG from muscle fibers close to latent MTPs presented with an early onset of the increase in RMS amplitude and the increase was significantly higher than that from non-MTPs at the end of sustained isometric contraction (P < 0.05). CONCLUSIONS A latent MTP is associated with an accelerated development of muscle fatigue and simultaneously overloading active motor units close to an MTP. Elimination of latent MTPs and inactivation of active MTPs may effectively reduce accelerated muscle fatigue and prevent overload spreading within a muscle.
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Affiliation(s)
- Hong-You Ge
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark.
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113
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Knorr S, Rice CL, Garland SJ. Perspective on neuromuscular factors in poststroke fatigue. Disabil Rehabil 2012; 34:2291-9. [DOI: 10.3109/09638288.2012.683233] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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114
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Strejcová B, Konopková R. The effect of active recovery, cold water immersion and passive recovery on subsequent knee extension and flexion strength. ACTA GYMNICA 2012. [DOI: 10.5507/ag.2012.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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115
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Sánchez-Medina L, González-Badillo JJ. Velocity loss as an indicator of neuromuscular fatigue during resistance training. Med Sci Sports Exerc 2012; 43:1725-34. [PMID: 21311352 DOI: 10.1249/mss.0b013e318213f880] [Citation(s) in RCA: 415] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE This study aimed to analyze the acute mechanical and metabolic response to resistance exercise protocols (REP) differing in the number of repetitions (R) performed in each set (S) with respect to the maximum predicted number (P). METHODS Over 21 exercise sessions separated by 48-72 h, 18 strength-trained males (10 in bench press (BP) and 8 in squat (SQ)) performed 1) a progressive test for one-repetition maximum (1RM) and load-velocity profile determination, 2) tests of maximal number of repetitions to failure (12RM, 10RM, 8RM, 6RM, and 4RM), and 3) 15 REP (S × R[P]: 3 × 6[12], 3 × 8[12], 3 × 10[12], 3 × 12[12], 3 × 6[10], 3 × 8[10], 3 × 10[10], 3 × 4[8], 3 × 6[8], 3 × 8[8], 3 × 3[6], 3 × 4[6], 3 × 6[6], 3 × 2[4], 3 × 4[4]), with 5-min interset rests. Kinematic data were registered by a linear velocity transducer. Blood lactate and ammonia were measured before and after exercise. RESULTS Mean repetition velocity loss after three sets, loss of velocity pre-post exercise against the 1-m·s load, and countermovement jump height loss (SQ group) were significant for all REP and were highly correlated to each other (r = 0.91-0.97). Velocity loss was significantly greater for BP compared with SQ and strongly correlated to peak postexercise lactate (r = 0.93-0.97) for both SQ and BP. Unlike lactate, ammonia showed a curvilinear response to loss of velocity, only increasing above resting levels when R was at least two repetitions higher than 50% of P. CONCLUSIONS Velocity loss and metabolic stress clearly differs when manipulating the number of repetitions actually performed in each training set. The high correlations found between mechanical (velocity and countermovement jump height losses) and metabolic (lactate, ammonia) measures of fatigue support the validity of using velocity loss to objectively quantify neuromuscular fatigue during resistance training.
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116
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Enoka RM. Muscle fatigue – from motor units to clinical symptoms. J Biomech 2012; 45:427-33. [DOI: 10.1016/j.jbiomech.2011.11.047] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 11/16/2011] [Indexed: 11/26/2022]
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117
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Plattner K, Baumeister J, Lamberts RP, Lambert MI. Dissociation in changes in EMG activation during maximal isometric and submaximal low force dynamic contractions after exercise-induced muscle damage. J Electromyogr Kinesiol 2011; 21:542-50. [DOI: 10.1016/j.jelekin.2011.01.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 12/17/2010] [Accepted: 01/27/2011] [Indexed: 11/25/2022] Open
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Boyas S, Guével A. Neuromuscular fatigue in healthy muscle: underlying factors and adaptation mechanisms. Ann Phys Rehabil Med 2011; 54:88-108. [PMID: 21376692 DOI: 10.1016/j.rehab.2011.01.001] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2010] [Revised: 01/15/2011] [Accepted: 01/18/2011] [Indexed: 01/04/2023]
Abstract
OBJECTIVES This review aims to define the concept of neuromuscular fatigue and to present the current knowledge of the central and peripheral factors at the origin of this phenomenon. This review also addresses the literature that focuses on the mechanisms responsible for the adaption to neuromuscular fatigue. METHOD One hundred and eighty-two articles indexed in PubMed (1954-2010) have been considered. RESULTS Neuromuscular fatigue has central and peripheral origins. Central fatigue, preponderant during long-duration, low-intensity exercises, may involve a drop in the central command (motor, cortex, motoneurons) elicited by the activity of cerebral neurotransmitters and muscular afferent fibers. Peripheral fatigue, associated with an impairment of the mechanisms from excitation to muscle contraction, may be induced by a perturbation of the calcium ion movements, an accumulation of phosphate, and/or a decrease of the adenosine triphosphate stores. To compensate for the consequent drop in force production, the organism develops several adaptation mechanisms notably implicating motor units. CONCLUSION Fatigue onset is associated with an alteration of the mechanisms involved in force production. Then, the interaction between central and peripheral mechanisms leads to a series of events that ultimately contribute to the observed decrease in force production.
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Affiliation(s)
- S Boyas
- EA 4334, UFR STAPS de Nantes, laboratoire « Motricité, Interactions, Performance », université de Nantes, 25 bis, boulevard Guy-Mollet, 44322 Nantes cedex 3, France.
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What limits exercise during high-intensity aerobic exercise? Eur J Appl Physiol 2010; 110:661-2; author reply 663-4. [DOI: 10.1007/s00421-010-1538-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2010] [Indexed: 11/24/2022]
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