Journal articles: 'Concentric exercise'

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Lepley, Lindsey K., Steven M. Davi, Emily R. Hunt, Julie P. Burland, McKenzie S. White, Grace Y. McCormick, and Timothy A. Butterfield. "Morphology and Anabolic Response of Skeletal Muscles Subjected to Eccentrically or Concentrically Biased Exercise." Journal of Athletic Training 55, no. 4 (April 1, 2020): 336–42. http://dx.doi.org/10.4085/1062-6050-174-19.

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Context Long-term eccentric exercise is known to promote muscle growth better than concentric exercise, but its acute effect on muscle is not well understood because of misinterpreted modeling and in situ and in vitro stretch protocols. Knowing if the initial bout of eccentric exercise promotes muscle growth and limits damage is critical to understanding the effect of this mode of exercise. Objective To directly evaluate the immediate effects of eccentric and concentric exercises on untrained muscle when fiber strains were physiological and exercise doses were comparable. Design Controlled laboratory study. Setting Laboratory. Patients or Other Participants A total of 40 skeletally mature male Long-Evans rats (age = 16 weeks, mass = 452.1 ± 35.2 g) were randomly assigned to an eccentric exercise (downhill walking, n = 16), concentric exercise (uphill walking, n = 16), or control (no exercise, n = 8) group. Intervention(s) Rats were exposed to a single 15-minute bout of eccentric or concentric exercise on a motorized treadmill and then were euthanized at 6 or 24 hours postexercise. We harvested the vastus lateralis muscle bilaterally. Main Outcome Measure(s) The percentage increase or decrease in protein abundance in exercised animals relative to that in unexercised control animals was evaluated as elevated phosphorylated p70S6k relative to total p70S6k. Fiber damage was quantified using immunoglobulin G permeability staining. One-way analysis of variance and post hoc Tukey tests were performed. Results Rats exposed to eccentric exercise and euthanized at 24 hours had higher percentage response protein synthesis rates than rats exposed to eccentric exercise and euthanized at 6 hours (P = .02) or to concentric exercise and euthanized at 6 (P = .03) or 24 (P = .03) hours. We assessed 9446 fibers for damage and found only 1 fiber was infiltrated (in the concentric exercise group euthanized at 6 hours). Furthermore, no between-groups differences in immunoglobulin G fluorescent intensity were detected (P = .94). Conclusions Incorporating eccentric exercise is a simple, universally available therapeutic intervention for promoting muscle recovery. A single 15-minute dose of eccentric exercise to a novice muscle can better exert an anabolic effect than a comparable dose of concentric exercise, with very limited evidence of fiber damage.

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Friden, J., P. N. Sfakianos, and A. R. Hargens. "Muscle soreness and intramuscular fluid pressure: comparison between eccentric and concentric load." Journal of Applied Physiology 61, no. 6 (December 1, 1986): 2175–79. http://dx.doi.org/10.1152/jappl.1986.61.6.2175.

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This study investigates the dynamic and resting intramuscular pressures associated with eccentric and concentric exercise of muscles in a low-compliance compartment. The left and righ leg anterior compartments of eight healthy males (ages 22–32 yr) were exercised by either concentric or eccentric contractions of the same load (400 submaximal contractions at constant rate, 20/min for 20 min at a load corresponding to 15% of individual maximal dorsiflexion torque). Tissue fluid pressures were measured with the slit-catheter technique before, during, and after the exercise. Average peak intramuscular pressure generated during eccentric exercise (236 mmHg) was significantly greater than during concentric exercise (157 mmHg, P less than 0.001). Peak isometric contraction pressure in the eccentrically exercised compartment was significantly higher both within 20 min postexercise and on the second postexercise day (P less than 0.001). Resting pressure 2 days postexercise was significantly higher on the eccentrically exercised side (10.5 mmHg) compared with the concentrically exercised (4.4 mmHg, P less than 0.05). The ability to sustain tension during postexercise isometric contractions was impaired on the “eccentric” side. Soreness was exclusively experienced in the eccentrically exercised muscles. We conclude that eccentric exercise causes significant intramuscular pressure elevation in the anterior compartment, not seen following concentric exercise, and that this may be one of the factors associated with development of delayed muscle soreness in a tight compartment.

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Chaudhry, Saira, Dylan Morrissey, Roger C. Woledge, Dan L. Bader, and Hazel R. C. Screen. "Eccentric and Concentric Exercise of the Triceps Surae: An in Vivo Study of Dynamic Muscle and Tendon Biomechanical Parameters." Journal of Applied Biomechanics 31, no. 2 (April 2015): 69–78. http://dx.doi.org/10.1123/jab.2013-0284.

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Triceps surae eccentric exercise is more effective than concentric exercise for treating Achilles tendinopathy, however the mechanisms underpinning these effects are unclear. This study compared the biomechanical characteristics of eccentric and concentric exercises to identify differences in the tendon load response. Eleven healthy volunteers performed eccentric and concentric exercises on a force plate, with ultrasonography, motion tracking, and EMG applied to measure Achilles tendon force, lower limb movement, and leg muscle activation. Tendon length was ultrasonographically tracked and quantified using a novel algorithm. The Fourier transform of the ground reaction force was also calculated to investigate for tremor, or perturbations. Tendon stiffness and extension did not vary between exercise types (P= .43). However, tendon perturbations were significantly higher during eccentric than concentric exercises (25%–40% higher,P= .02). Furthermore, perturbations during eccentric exercises were found to be negatively correlated with the tendon stiffness (R2= .59). The particular efficacy of eccentric exercise does not appear to result from variation in tendon stiffness or extension within a given session. However, varied perturbation magnitude may have a role in mediating the observed clinical effects. This property is subject-specific, with the source and clinical timecourse of such perturbations requiring further research.

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Kujawa-Holbrook, Sheryl A. "Concentric Circles Dialogue Exercise." Teaching Theology & Religion 16, no. 4 (October 2013): 389. http://dx.doi.org/10.1111/teth.12141.

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Perentis, Panagiotis A., Evgenia D. Cherouveim, Vassiliki J. Malliou, Nikos V. Margaritelis, Panagiotis N. Chatzinikolaou, Panayiotis Koulouvaris, Charilaos Tsolakis, Michalis G. Nikolaidis, Nickos D. Geladas, and Vassilis Paschalis. "The Effects of High-Intensity Interval Exercise on Skeletal Muscle and Cerebral Oxygenation during Cycling and Isokinetic Concentric and Eccentric Exercise." Journal of Functional Morphology and Kinesiology 6, no. 3 (July 16, 2021): 62. http://dx.doi.org/10.3390/jfmk6030062.

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The aim of the present study was to study the effects of cycling and pure concentric and pure eccentric high-intensity interval exercise (HIIE) on skeletal muscle (i.e., vastus lateralis) and cerebral oxygenation. Twelve healthy males (n = 12, age 26 ± 1 yr, body mass 78 ± 2 kg, height 176 ± 2 cm, body fat 17 ± 1% of body mass) performed, in a random order, cycling exercise and isokinetic concentric and eccentric exercise. The isokinetic exercises were performed on each randomly selected leg. The muscle and the cerebral oxygenation were assessed by measuring oxyhemoglobin, deoxyhemoglobin, total hemoglobin, and tissue saturation index. During the cycling exercise, participants performed seven sets of seven seconds maximal intensity using a load equal to 7.5% of their body mass while, during isokinetic concentric and eccentric exercise, they were performed seven sets of five maximal muscle contractions. In all conditions, a 15 s rest was adopted between sets. The cycling HIIE caused greater fatigue (i.e., greater decline in fatigue index) compared to pure concentric and pure eccentric isokinetic exercise. Muscle oxygenation was significantly reduced during HIIE in the three exercise modes, with no difference between them. Cerebral oxygenation was affected only marginally during cycling exercise, while no difference was observed between conditions. It is concluded that a greater volume of either concentric or eccentric isokinetic maximal intensity exercise is needed to cause exhaustion which, in turn, may cause greater alterations in skeletal muscle and cerebral oxygenation.

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Sipavičienė, Saulė, Albertas Skurvydas, Irina Ramanauskienė, Žibuoklė Senikienė, and Audronė Dumčienė. "Cooling makes recovery of muscle faster after eccentric-concentric than concentric exercise." Medicina 44, no. 3 (March 17, 2008): 225. http://dx.doi.org/10.3390/medicina44030029.

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The aim of the study was to establish the influence of muscle cooling on muscle recovery after concentric and eccentric-concentric exercise. Healthy untrained males (n=40) took part in this study. During the first experiment, subjects performed concentric and during the second – eccentric-concentric exercise. During both experiments, the subjects were divided into the groups. In the first group, the muscles of the lower limbs were cooled down after the physical load, while the muscles of the subjects of the second group were not cooled. The rectal, skin, and muscle temperature was repeatedly measured immediately after physical load and after cooling of the muscle. Before exercise and after 2 min and 4, 8, 24, 48, 72 hours after performing exercise, quadriceps muscle strength, generated by electrical stimulation at frequencies of 20 Hz and 50 Hz, and maximal voluntary contraction force were registered. Serum creatine kinase levels were measured before and 24 hours after exercise. In addition, the subjects subjectively rated their muscle pain on a 10-point scale 24, 48, 72 hours after exercise. The results show that cooling applied to muscles after concentric and eccentricconcentric exercise affected the indicators of muscle damage – the activity of creatine kinase was decreased and muscle strength recovered faster. The cooling effect is greater when it is applied after eccentric-concentric exercise.

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Thomas, Tom R., Ben R. Londeree, and Deborah A. Lawson. "Prolonged Recovery From Eccentric Versus Concentric Exercise." Canadian Journal of Applied Physiology 19, no. 4 (December 1, 1994): 441–50. http://dx.doi.org/10.1139/h94-036.

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In order to determine whether exercise mode affects recovery energy expenditure, 7 active men (average age 25 yrs) performed a control rest and three submaximal exercise bouts in counterbalanced order in separate weeks. The bouts, designed to involve three levels of eccentric muscular activity, included 60% [Formula: see text] jog (60 J), 60% downhill (−5%) jog (60 DH), 60% cycling (60 C), and a control session. Following a 24-hr period of regulated activity and diet, subjects exercised for 60 min. [Formula: see text] and RER were assessed during 48 hrs of regulated recovery. Total energy use was elevated following 60 C and 60 DH versus control, and fat energy use was elevated following 60 J, 60 DH, and 60 C versus control. For combined trials, the total energy use was higher at 1, 2, and 9 hrs postexercise. These results do not support the hypothesis that eccentric muscular activity affects the magnitude of recovery energy expenditure. Key words: energy expenditure, fat energy expenditure, excess postexercise oxygen consumption, exercise mode

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Doyle, J. A., W. M. Sherman, and R. L. Strauss. "Effects of eccentric and concentric exercise on muscle glycogen replenishment." Journal of Applied Physiology 74, no. 4 (April 1, 1993): 1848–55. http://dx.doi.org/10.1152/jappl.1993.74.4.1848.

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Eccentric contractions appear to reduce muscle glycogen replenishment during the 1- to 10-day period after exercise. The main purpose of this study was to determine whether consuming a large amount of carbohydrate (1.6 g.kg-1.h-1) during the 4 h after glycogen-reducing exercise would produce different patterns of glycogen replenishment in human muscle that had undergone either eccentric or concentric contractions approximately 2 or 48 h earlier. Subjects cycled for 75 min and undertook interval exercise to deplete glycogen on days 1 and 3. After cycling exercise on day 1 only, subjects performed 10 sets of 10 repetitions of either concentric or eccentric contractions in opposite legs. During the 4 h after exercise, subjects consumed 0.4 g carbohydrate/kg body wt every 15 min. Biopsies were obtained immediately before the feedings and 4 h later, and blood was sampled every 15 min. For days 1 and 3 combined, total integrated areas for the glucose and insulin response curves averaged 1,683 mumol.ml-1.240 min-1 and 21,450 microU.ml-1.240 min-1, respectively. For days 1 and 3 combined, muscle glycogen replenishment after concentric exercise averaged 10 mmol.kg-1.h-1. On day 1 glycogen replenishment was similar for subjects performing either concentric or eccentric contractions. On day 3, however, glycogen replenishment was 25% lower (P < 0.05) in muscle that had undertaken eccentric contractions 48 h earlier than in concentrically exercised muscle. In conclusion, glycogen replenishment can be stimulated to a high rate when a large amount of carbohydrate is consumed after glycogen-depleting concentric exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

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Ahmadi, Sirous, Peter J. Sinclair, and Glen M. Davis. "Muscle oxygenation following concentric exercise." Isokinetics and Exercise Science 15, no. 4 (November 19, 2007): 309–19. http://dx.doi.org/10.3233/ies-2007-0288.

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Chamari, Karim, Guillaume Laffaye, Luca Paolo Ardigò, and Johnny Padulo. "RETRACTED: Concentric and Eccentric Exercise." Journal of Pain 14, no. 11 (November 2013): 1531–32. http://dx.doi.org/10.1016/j.jpain.2013.07.001.

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Ritter, Ophélie, Laurie Isacco, Mark Rakobowchuk, Nicolas Tordi, Davy Laroche, Malika Bouhaddi, Bruno Degano, and Laurent Mourot. "Cardiorespiratory and Autonomic Nervous System Responses to Prolonged Eccentric Cycling." International Journal of Sports Medicine 40, no. 07 (May 20, 2019): 453–61. http://dx.doi.org/10.1055/a-0783-2581.

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AbstractOffering large muscle benefits despite low metabolic demand, continuous eccentric exercise appears to be an interesting alternative to concentric exercise. Nevertheless, further knowledge is needed about prolonged eccentric exercise. This work sought to investigate the cardiovascular responses to prolonged constant-load eccentric compared to concentric cycling. Ten healthy males performed two 45-min exercise sessions of either concentric or eccentric cycling separated by a month and matched for heart rate during the first 5 min of exercise. Cardiorespiratory, autonomic nervous system and vascular responses were assessed at rest, and during exercise and recovery. During cycling, oxygen uptake, cardiac output and systolic blood pressure were similar but heart rate and diastolic blood pressure were greater whereas stroke volume was lower during eccentric than concentric cycling (118±21 vs. 104±10 bpm; 77±9 vs. 65±8 mmHg; 122±12 vs. 135±13 mL). Baroreflex and noradrenaline concentration were altered during eccentric cycling, and after eccentric exercise, vascular tone was greater than after concentric cycling. We observed increased cardiovascular strain and altered baroreflex activity during eccentric compared with concentric exercise, suggesting eccentric cycling triggers greater sympathetic activity.

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Banzet, Sébastien, Mounir Chennaoui, Olivier Girard, Sébastien Racinais, Catherine Drogou, Hakim Chalabi, and Nathalie Koulmann. "Changes in circulating microRNAs levels with exercise modality." Journal of Applied Physiology 115, no. 9 (November 1, 2013): 1237–44. http://dx.doi.org/10.1152/japplphysiol.00075.2013.

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Here, we studied muscle-specific and muscle-related miRNAs in plasma of exercising humans. Our aim was to determine whether they are affected by eccentric and/or concentric exercise modes and could be biomarkers of muscle injuries or possible signaling molecules. On two separate days, nine healthy subjects randomly performed two 30-min walking exercises, one downhill (high eccentric component) and one uphill (high concentric component). Perceived exertion and heart rate were higher during the uphill exercise, while subjective pain and ankle plantar flexor strength losses within the first 48-h were higher following the downhill exercise. Both exercises increased serum creatine kinase and myoglobin with no significant differences between conditions. Plasma levels of circulating miRNAs assessed before, immediately after, and at 2-, 6-, 24-, 48-, and 72-h recovery showed that 1) hsa-mir-1, 133a, 133b, and 208b were not affected by concentric exercise but significantly increased during early recovery of eccentric exercise (2 to 6 h); 2) hsa-mir-181b and 214 significantly and transiently increased immediately after the uphill, but not downhill, exercise. The muscle-specific hsa-mir-206 was not reliably quantified and cardiac-specific hsa-mir-208a remained undetectable. In conclusion, changes in circulating miRNAs were dependent on the exercise mode. Circulating muscle-specific miRNAs primarily responded to a downhill exercise (high eccentric component) and could potentially be alternative biomarkers of muscle damage. Two muscle-related miRNAs primarily responded to an uphill exercise (high exercise intensity), suggesting they could be markers or mediators of physiological adaptations.

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Buitrago, Sebastian, Nicolas Wirtz, Ulrich Flenker, and Heinz Kleinöder. "Physiological and metabolic responses as function of the mechanical load in resistance exercise." Applied Physiology, Nutrition, and Metabolism 39, no. 3 (March 2014): 345–50. http://dx.doi.org/10.1139/apnm-2013-0214.

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The present study aimed to investigate the relationship between the mechanical load during resistance exercise and the elicited physiological responses. Ten resistance-trained healthy male subjects performed 1 set of resistance exercise each at 55%, 70%, and 85% of 1 repetition maximum for as many repetitions as possible and in 4 training modes: 4-1-4-1 (4 s concentric, 1 s isometric, 4 s eccentric, and 1 s isometric successive actions), 2-1-2-1, 1-1-1-1, and explosive (maximum velocity concentric). Mean concentric power and total concentric work were determined. Oxygen uptake (V̇O2) was measured during exercise and for 30 min post exercise. Total volume of consumed oxygen (O2 consumed) and excess post-exercise oxygen consumption (EPOC) were calculated. Maximum blood lactate concentration (LAmax) was also determined. V̇O2 exhibited a linear dependency on mean concentric power. Mean concentric power did not have a detectable effect on EPOC and LAmax. An augmentation of total concentric work resulted in significant linear increase of O2 consumed and EPOC. Total concentric work caused a significant increase in LAmax. In general, a higher mechanical load induced a larger physiological response. An increase in mean concentric power elicited higher aerobic energy turnover rates. However, a higher extent of total concentric work augments total energy cost covered by oxidative and (or) glycolytic pathways.

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Matos-Santos, Lenifran, Paulo Farinatti, Juliana P. Borges, Renato Massaferri, and Walace Monteiro. "Cardiovascular Responses to Resistance Exercise Performed with Large and Small Muscle Mass." International Journal of Sports Medicine 38, no. 12 (September 19, 2017): 883–89. http://dx.doi.org/10.1055/s-0043-116671.

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AbstractPrior research about the effects of the amount of exercised muscle mass upon cardiovascular responses (CVR) has neglected a potential bias related to total exercise and concentric/eccentric duration. Autonomic responses and perceived exertion (RPE) were compared in resistance exercises performed with larger and smaller muscle mass and matched for total exercise and concentric/eccentric duration. Twelve men performed 4 sets of 12 repetitions of unilateral (UNI) and bilateral (BIL) knee extensions at 70% of 12RM. Increases in CVR were always greater at the last set of BIL over UNI, as were SBP (35% vs. 23%), DBP (36% vs. 23%), HR (40% vs. 26%), RRP (90% vs 53%) and CO (55% vs 39%). No difference between protocols was found for autonomic modulation before and after exercise, but BIL induced significantly greater changes than UNI from baseline for R-R intervals (−13% vs. −7%), SDNN (−38% vs. −17%) and rMSSD (−41% vs. −21%). The rate of perceived exertion in the last set was higher in BIL than UNI (7.6±0.5 vs. 6.6±1.4 OMNI-RES; P<0.05) and did not correlate with any CVR. Thus, CVR were greater in resistance exercise performed with larger than smaller muscle mass. This information is relevant for patients with high cardiovascular risk.

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Pedersen, Helene, Atle Hole Saeterbakken, Markus Vagle, Marius Steiro Fimland, and Vidar Andersen. "Electromyographic Comparison of Flywheel Inertial Leg Curl and Nordic Hamstring Exercise Among Soccer Players." International Journal of Sports Physiology and Performance 16, no. 1 (January 1, 2021): 97–102. http://dx.doi.org/10.1123/ijspp.2019-0921.

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Purpose: The Nordic hamstring exercise (NHE) has been shown to considerably reduce hamstring injuries among soccer players. However, as the load in the NHE is the person’s own bodyweight, it is a very heavy exercise and difficult to individualize. The flywheel inertial leg curl (FLC) could be an alternative since the eccentric overload is based on the amount of work produced in the concentric movement. Therefore, the primary aim of this study was to compare the activation in the hamstrings at long muscle lengths in the NHE and the FLC in amateur soccer players. Methods: Fifteen male amateur soccer players performed 5 repetitions in each exercise in a randomized and counterbalanced order. The concentric and eccentric movements were divided into lower and upper phases. Surface EMG was measured distally, proximally, and in the middle, at both muscles. Results: In the lower phase in the eccentric movement, there were no significant differences between the 2 exercises (P = .101–.826). In the lower concentric movement, the FLC led to higher activation in all parts of both the biceps femoris (31%–52%, P < .001) and the semitendinosus (20%–35%, P = .001–.023). Conclusion: Both exercises activated the hamstrings similarly at long muscle lengths during eccentric contractions (Nordic hamstring, nonsignificantly higher). However, when performing concentric contractions, the FLC induced higher activations. Therefore, the FLC could be a useful alternative to the NHE and particularly suitable for weaker athletes before progressing to NHE.

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Tsatalas, Themistoklis, George Bellis, Evangeli Karampina, Charalampos Krommidas, Fotios Tsilfoglou, Athanasios Patas, Christos Fotos, Christos Kokkotis, Athanasios Z. Jamurtas, and Giannis Giakas. "Development and Usability of a Prototype Upper Extremities Lever-Driven Exercise System." BioMed 3, no. 1 (December 27, 2022): 32–49. http://dx.doi.org/10.3390/biomed3010003.

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The purpose of this paper is to present the design, construction, and technical aspects of a prototype upper extremities lever-driven exercise system, called FIT-WHEEL (Functional and Intelligent Training system for WHEELchair users), as well as the preliminary experimental measurements conducted to test the device’s usability in healthy individuals. FIT-WHEEL was developed to provide a training modality that combines the known benefits of eccentric exercise and lever-propelled wheelchairs. Eleven healthy male participants performed, seven days apart, a moderate intensity concentric and eccentric exercise protocol on FIT-WHEEL consisting of 30 trials of both upper extremities at 30% of peak concentric and peak eccentric force, respectively. At the end of each exercise bout, participants completed a number of valid and reliable instruments examining attitudes, intention and enjoyment during concentric or eccentric exercise on the FIT-WHEEL system as well as the usability of the two exercise protocols on the novel lever-driven exercise system. Statistical analyses revealed high scores in all the examined parameters (attitudes, intention, enjoyment, and usability) in both eccentric and concentric exercise protocols, without any significant differences emerging between them. Moreover, total mechanical work during eccentric exercise was 18.3% higher compared to concentric exercise performed on the FIT-WHEEL training system (p = 0.001). The preliminary experimental results discussed serve as an initial step to implement lever-driven eccentric exercise in wheelchair dependent populations in the future and evaluate the potential long-term benefits and limitations.

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Muyor, José M., Pedro A. López-Miñarro, and Fernando Alacid. "Comparison of Electromyographic Activity during Barbell Pullover and Straight Arm Pulldown Exercises." Applied Sciences 12, no. 21 (November 3, 2022): 11138. http://dx.doi.org/10.3390/app122111138.

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Pullover and straight arm pulldown exercises are commonly used in resistance exercise programs to improve sports performance or in physical activity health programs. This study aimed to evaluate the individual electromyographic (EMG) activity of the pectoralis major (clavicular, sternal, and costal portions), latissimus dorsi, anterior deltoid, triceps brachii, and rectus abdominis muscles in a barbell pullover exercise at a 100% biacromial width and a straight arm pulldown exercise at a 100% and 150% biacromial width and to compare the EMG activity in these selected muscles and exercises. Twenty healthy and physically active adults performed a set of eight repetitions of each exercise against 30% of their body mass. The barbell pullover exercise presented a higher EMG activity (p ≤ 0.01) than the straight arm pulldown exercise in both biacromial widths in all evaluated muscles except for the latissimus dorsi and the triceps brachii. These muscles showed the highest EMG activity in the straight arm pulldown exercise at both biacromial widths. In all of the exercises and muscles evaluated, the concentric phase showed a greater EMG activity than the eccentric phase. In conclusion, the barbell pullover exercise can highlight muscle activity in the pectoralis major (mainly in the sternal and lower portions), triceps brachii, and rectus abdominis muscles. However, the straight arm pulldown exercise at 100% and 150% biacromial widths could be a better exercise to stimulate the latissimus dorsi and triceps brachii muscles. Moreover, all exercises showed significantly greater EMG activity (p < 0.001) in the concentric phase than in the eccentric phase for all the evaluated muscles.

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Yu, Il-young, Dong-kyu Lee, Myoung-Joo Kang, and Jae-seop Oh. "Effects of 3 Infraspinatus Muscle Strengthening Exercises on Isokinetic Peak Torque and Muscle Activity." Journal of Sport Rehabilitation 28, no. 3 (March 1, 2019): 229–35. http://dx.doi.org/10.1123/jsr.2017-0110.

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Context: The infraspinatus muscle plays a particularly important role in producing primary external rotation (ER) torque and dynamic stability of the shoulder joint. Previous studies have reported that prone external rotation with horizontal abduction (PER), side-lying wiper exercise (SWE), and standing external rotation (STER) were effective exercises for strengthening the infraspinatus. However, we do not have enough knowledge about changes in muscle strength and dynamic muscle activity in each exercise under dynamic conditions. Objective: To compare the ER muscle strength, muscle activity among exercise methods and between muscle contraction types during 3 different exercises. Design: Repeated measures design in which ER muscle strength and muscle activities data were collected from subjects under 3 exercise conditions. Setting: Outpatient clinic. Participants: A total of 15 healthy men with no shoulder, neck, or upper-extremity pain were participated. Intervention: The subjects performed 3 different exercises randomly in concentric and eccentric using a Biodex dynamometer at an angular velocity of 60°/s. Main Outcome Measures: The ER peak torque (PT) data was collected and surface electromyography was used to measure the activity of the infraspinatus and posterior deltoid muscles and infraspinatus to posterior deltoid muscle activity ratio. Results: There was significant main effect for muscle contraction type in ER PT (P < .05). The concentric PT was greater during PER (P < .05) and SWE (P < .05) compared with eccentric. The main effect for exercise was found in ER PT and muscle activity (P < .05). The ER PT and infraspinatus muscle activity were the largest increased during PER whereas the lowest during STER in both concentric and eccentric (P < .05). Conclusion: The results of this study suggest that PER is an exercise for strengthening the infraspinatus muscle effectively.

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Priego-Quesada, Jose I., Carlos De la Fuente, Marcos R. Kunzler, Pedro Perez-Soriano, David Hervás-Marín, and Felipe P. Carpes. "Relationship between Skin Temperature, Electrical Manifestations of Muscle Fatigue, and Exercise-Induced Delayed Onset Muscle Soreness for Dynamic Contractions: A Preliminary Study." International Journal of Environmental Research and Public Health 17, no. 18 (September 18, 2020): 6817. http://dx.doi.org/10.3390/ijerph17186817.

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Delayed onset muscle soreness (DOMS) indicates the presence of muscle damage and impairs force production and control. Monitorization of DOMS is useful to improving recovery intervention plans. The magnitude of DOMS may relate to muscle fatigue, which can be monitored by surface electromyography (EMG). Additionally, growing interest has been expressed in determining whether the skin temperature over a muscle group during exercise to fatigue could be a non-invasive marker for DOMS. Here we determine whether skin temperature and manifestations of muscle fatigue during exercise are correlated and can predict DOMS after concentric–eccentric bicep curl exercises. We tested 10 young adults who performed concentric–eccentric bicep curl exercises to induce muscle damage in the biceps brachialis to investigate the relationship between skin temperature and fatigue during exercise and DOMS after exercise. Muscle activation and skin temperature were recorded during exercise. DOMS was evaluated 24 h after exercise. Data analysis was performed using Bayesian regression models with regularizing priors. We found significant muscle fatigue and an increase in skin temperature during exercise. DOMS was observed 24 h after exercise. The regression models showed no correlation of changes in skin temperature and muscle fatigue during exercise with DOMS 24 h after exercise. In conclusion, our preliminary results do not support a relationship between skin temperature measured during exercise and either muscle fatigue during exercise or the ability to predict DOMS 24 h after exercise.

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Taliari, Jean Donizete Silveira, Rogério Rodrigo Ramos, Alessandra de Lourdes Ballaris, Matheus Alexandre da Silva Taliari, and Egberto Munin. "Blood glucose kinetics during concentric and eccentric muscle contractions." Bioscience Journal 38 (September 23, 2022): e38078. http://dx.doi.org/10.14393/bj-v38n0a2022-60463.

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Studies comparing the two classes of stimuli (concentric and eccentric) have shown differences in the improvement of cardiovascular, metabolic, and muscle strength gain. This is an experimental, quantitative, and prospective study that aimed to verify the effect of eccentric exercise on glycolytic consumption and kinetics. The blood glucose kinetics of 17 male subjects was evaluated during a treadmill exercise with a 10% declined floor and velocity that required a 60% metabolic activity of VO2max, for 30 minutes. Seventy-two hours later, the same subjects exercised on the treadmill with a 10% inclined floor and 60% VO2max, for 30 minutes. To quantify glucose, blood samples were collected before the exercise, every three minutes along the 30 minutes of physical activity, and five and 10 minutes after finishing the exercise. For the downward slope, there was a homogeneous group behavior for blood glucose dynamics during the exercise, which was characterized by a monotonic decrease of glucose levels until reaching a minimum value at experimental times between 20 and 30 min, followed by a progressive recovery toward initial values. For the acclivity condition, blood glucose dynamics did not follow such a homogeneous behavior. A set of different types of dynamics could be identified. Experimental data showed that the type of dynamics could be predicted, to some extent, by the basal blood glucose level of subjects. The type of floor slope (upward or downward) directly affected glycolytic consumption and kinetics for the individuals analyzed.

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Eliasson, Jörgen, Thibault Elfegoun, Johnny Nilsson, Rickard Köhnke, Björn Ekblom, and Eva Blomstrand. "Maximal lengthening contractions increase p70 S6 kinase phosphorylation in human skeletal muscle in the absence of nutritional supply." American Journal of Physiology-Endocrinology and Metabolism 291, no. 6 (December 2006): E1197—E1205. http://dx.doi.org/10.1152/ajpendo.00141.2006.

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The aim of this study was to compare the training stimuli of eccentric (lengthening) and concentric (shortening) contractions regarding the effect on signaling enzymes involved in protein synthesis. Ten male subjects performed 4 × 6 maximal eccentric contractions on one leg followed by 4 × 6 maximal concentric contractions on the other. Six additional subjects performed the same protocol, but with maximal concentric and submaximal eccentric exercise of equal force to that of the maximal concentric contractions. Muscle biopsy samples were taken from the vastus lateralis before, immediately after, and 1 and 2 h after exercise in both legs. The average peak force produced during the maximal eccentric exercise was 31% higher than during the maximal concentric exercise, 2,490 (±100) vs. 1,894 (±108) N ( P < 0.05). The maximal eccentric contractions led to two- to eightfold increases in the phosphorylation of p70 S6 kinase (p70S6k) and the ribosomal protein S6 that persisted for 2 h into recovery but no significant changes in phosphorylation of Akt or mammalian target of rapamycin (mTOR). Maximal concentric and submaximal eccentric contractions did not induce any significant changes in Akt, mTOR, p70S6k, or S6 phosphorylation up to 2 h after the exercise. The results indicate that one session of maximal eccentric contractions activates p70S6k in human muscle via an Akt-independent pathway and suggest that maximal eccentric contractions are more effective than maximal concentric contractions in stimulating protein synthesis in the absence of a nutritional intake, an effect that may be mediated through a combination of greater tension and stretching of the muscle.

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Hamlin, Michael J., and Brian M. Quigley. "Quadriceps concentric and eccentric exercise 1: Changes in contractile and electrical activity following eccentric and concentric exercise." Journal of Science and Medicine in Sport 4, no. 1 (March 2001): 88–103. http://dx.doi.org/10.1016/s1440-2440(01)80011-6.

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Hortobagyi, T., J. P. Hill, J. A. Houmard, D. D. Fraser, N. J. Lambert, and R. G. Israel. "Adaptive responses to muscle lengthening and shortening in humans." Journal of Applied Physiology 80, no. 3 (March 1, 1996): 765–72. http://dx.doi.org/10.1152/jappl.1996.80.3.765.

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We tested the hypothesis that exercise training with maximal eccentric (lengthening) muscle actions results in greater gains in muscle strength and size than training with concentric (shortening) actions. Changes in muscle strength, muscle fiber size, and surface electromyographic (EMG) activity of the quadriceps muscle were compared after 36 sessions of isokinetic concentric (n = 8) or eccentric (n = 7) exercise training over 12 wk with use of a one-leg model. Eccentric training increased eccentric strength 3.5 times more (pre/post 46%, P < 0.05) than concentric training increased concentric strength (pre/post 13%). Eccentric training increased concentric strength and concentric training increased eccentric strength by about the same magnitude (5 and 10%, respectively, P = 0.05). Eccentric training increased EMG activity seven times more during eccentric testing (pre/post 86%, P < 0.05) than concentric training increased EMG activity during concentric testing (pre/post 12%). Eccentric training increased the EMG activity measured during concentric tests and concentric training increased the EMG activity measured during eccentric tests by about the same magnitude (8 and 11%, respectively, P = 0.05). Type I muscle fiber percentages did not change significantly, but type IIa fibers increased and type IIb fibers decreased significantly (P < 0.05) in both training groups. Type I fiber areas did not change significantly (P = 0.05), but type II fiber area increased approximately 10 times more (P < 0.05) in the eccentric than in the concentric group. It is concluded that adaptations to training with maximal eccentric contractions are specific to eccentric muscle actions that are associated with greater neural adaptation and muscle hypertrophy than concentric exercise.

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Isacco, Laurie, Ophélie Ritter, Nicolas Tordi, Davy Laroche, Bruno Degano, Malika Bouhaddi, Mark Rakobowchuk, and Laurent Mourot. "Similar substrate oxidation rates in concentric and eccentric cycling matched for aerobic power output." Applied Physiology, Nutrition, and Metabolism 41, no. 11 (November 2016): 1204–7. http://dx.doi.org/10.1139/apnm-2016-0107.

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This study investigated substrate oxidation in concentric and eccentric cycling matched for aerobic power output in the postprandial state. Energy expenditure, respiratory exchange ratio, and fat and carbohydrate oxidation rates were measured at rest and after 15, 30, and 45 min of eccentric and concentric cycling in 12 men. Absolute and relative aerobic power output and energy expenditure were similar during concentric and eccentric exercise. No effect of exercise modality was observed for substrate metabolism.

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Saxton, J., and A. Donnelly. "Light Concentric Exercise During Recovery from Exercise-Induced Muscle Damage." International Journal of Sports Medicine 16, no. 06 (August 1995): 347–51. http://dx.doi.org/10.1055/s-2007-973018.

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Fatima, Ishrat, Misbah Mustafa, Muhammad Irfan Fazal, Afeera Tariq, Nimra Nadeem, and Muhammad Nauman Jala. "Comparison of the Effectiveness of Isometric, Isotonic Eccentric And Isotonic Concentric Exercises in Pain Management." Pakistan Journal of Medical and Health Sciences 15, no. 11 (November 30, 2021): 2859–61. http://dx.doi.org/10.53350/pjmhs2115112859.

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Aim: To compare the effect of isometrics, isotonic concentric and isotonic eccentric strengthening techniques on patients diagnosed with subacromial impingement syndrome. Methods: The study design used is randomized clinical trial. 36 patients are allocated in 3 groups with 12 patients in each group with age limit from 30-50 years treated for 6 weeks on alternate days with isometrics, isotonic concentric and isotonic eccentric with baseline exercise plan respectively. Each patient received 18 sessions of exercise plan. Intervention plan is divided into 2 phases, with each phase of 3 weeks. Outcome measuring tools used are Numeric Pain Rating Scale(NPRS) to measure pain, Manual Muscle Testing (MMT) to measure muscle strength was assessed at Day 0, Week3, and Week 6. Result: Results are generated by using SPSS 21. Post treatment ONE WAY ANOVA showed no significant difference in reduction of pain assessed by NPRS in GROUP1 treated with isometric exercise plan and GROUP2 & GROUP3 treated with isotonic eccentric and isotonic concentric exercise plan respectively. Post treatment One way anova showed p value .117 which is greater than 0.05. Post treatment ONE WAY ANOVA showed significant difference for strength of all the rotator cuff muscles. Conclusion: Isometric exercise plan conclusively proved to be better as compared to isotonic eccentric and isotonic concentric program in strengthening of patients with subacromial impingement syndrome. Keywords: Subacromial Impingement Syndrome, Isometric, Isotonic Eccentric, Isotonic Concentric.

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Padulo, J., G. Laffaye, and K. Chamari. "Concentric and Eccentric: Muscle Contraction or Exercise?" Journal of Ultrasound in Medicine 32, no. 11 (October 23, 2013): 2047–48. http://dx.doi.org/10.7863/ultra.32.11.2047.

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Padulo, Johnny, Guillaume Laffaye, Luca Paolo Ardigò, and Karim Chamari. "Concentric and Eccentric: Muscle Contraction or Exercise?" Journal of Human Kinetics 37, no. 1 (June 1, 2013): 5–6. http://dx.doi.org/10.2478/hukin-2013-0019.

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Padulo, Johnny, Guillaume Laffaye, Karim Chamari, and Alberto Concu. "Concentric and Eccentric: Muscle Contraction or Exercise?" Sports Health: A Multidisciplinary Approach 5, no. 4 (June 18, 2013): 306. http://dx.doi.org/10.1177/1941738113491386.

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Plato, P., W. M. Sherman, J. Betts, and J. M. Lash. "ECCENTRIC & CONCENTRIC EXERCISE AND INSULIN ACTION." Medicine and Science in Sports and Exercise 21, Supplement (April 1989): S30. http://dx.doi.org/10.1249/00005768-198904001-00175.

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Chamari, Karim, Guillaume Laffaye, Luca Paolo Ardigò, and Johnny Padulo. "Retraction Notice to Concentric and Eccentric Exercise." Journal of Pain 15, no. 7 (July 2014): 780. http://dx.doi.org/10.1016/j.jpain.2014.05.005.

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Padulo, Johnny, Juliano dal Pupo, Guillaume Laffaye, and Karim Chamari. "Concentric and eccentric: Muscle contraction or exercise?" Enfermería Clínica 23, no. 4 (July 2013): 177–78. http://dx.doi.org/10.1016/j.enfcli.2013.05.001.

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Kirwan, J. P., R. C. Hickner, K. E. Yarasheski, W. M. Kohrt, B. V. Wiethop, and J. O. Holloszy. "Eccentric exercise induces transient insulin resistance in healthy individuals." Journal of Applied Physiology 72, no. 6 (June 1, 1992): 2197–202. http://dx.doi.org/10.1152/jappl.1992.72.6.2197.

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Euglycemic-hyperinsulinemic clamps were performed on six healthy untrained individuals to determine whether exercise that induces muscle damage also results in insulin resistance. Clamps were performed 48 h after bouts of predominantly 1) eccentric exercise [30 min, downhill running, -17% grade, 60 +/- 2% maximal O2 consumption (VO2max)], 2) concentric exercise (30 min, cycle ergometry, 60 +/- 2% VO2max), or 3) without prior exercise. During the clamps, euglycemia was maintained at 90 mg/dl while insulin was infused at 30 mU.m-2.min-1 for 120 min. Hepatic glucose output (HGO) was determined using [6,6–2H]glucose. Eccentric exercise caused marked muscle soreness and significantly elevated creatine kinase levels (273 +/- 73, 92 +/- 27, 87 +/- 25 IU/l for the eccentric, concentric, and control conditions, respectively) 48 h after exercise. Insulin-mediated glucose disposal rate was significantly impaired (P less than 0.05) during the clamp performed after eccentric exercise (3.47 +/- 0.51 mg.kg-1.min-1) compared with the clamps performed after concentric exercise (5.55 +/- 0.94 mg.kg-1.min-1) or control conditions (5.48 +/- 1.0 mg.kg-1.min-1). HGO was not significantly different among conditions (0.77 +/- 0.26, 0.65 +/- 0.27, and 0.66 +/- 0.64 mg.kg-1.min-1 for the eccentric, concentric, and control clamps, respectively). The insulin resistance observed after eccentric exercise could not be attributed to altered plasma cortisol, glucagon, or catecholamine concentrations. Likewise, no differences were observed in serum free fatty acids, glycerol, lactate, beta-hydroxybutyrate, or alanine. These results show that exercise that results in muscle damage, as reflected in muscle soreness and enzyme leakage, is followed by a period of insulin resistance.

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Rakobowchuk, Mark, Laurie Isacco, Ophélie Ritter, Alicia Represas, Malika Bouhaddi, Bruno Degano, Nicolas Tordi, and Laurent Mourot. "Muscle Oxygenation Responses to Low-intensity Steady Rate Concentric and Eccentric Cycling." International Journal of Sports Medicine 39, no. 03 (January 24, 2018): 173–80. http://dx.doi.org/10.1055/s-0043-121272.

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AbstractMuscle deoxygenation responses provide information about the training impulse of an exercise session enabling adaptation to be predicted. Our aim was to investigate muscle oxygenation profiles during prolonged low-intensity eccentric and concentric cycling. Twelve healthy men performed two 45-min exercise sessions of concentric (CON) and eccentric (ECC) cycling, matched for the same heart rate at the start of each session. Mechanical power output during ECC was ~2.5 times that of CON (210±40 W vs. 82±16 W). Oxygen uptake, blood lactate, cardiac output and systolic arterial pressure responses did not differ between exercises. Heart rate was similar at 5 min of each exercise bout but progressively increased during ECC and was higher at 15, 30 and 45 min of ECC compared to CON (+10 bpm), with a trend for a lower stroke volume. Diastolic and mean blood pressures were higher during ECC. No significant differences were observed in muscle oxygenation profiles. Muscle oxygenation responses during prolonged low-intensity exercise were not affected by the type of muscle action at the same metabolic demand and cardiac output.

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Michaut, A., M. Pousson, G. Millet, J. Belleville, and J. Van Hoecke. "Maximal Voluntary Eccentric, Isometric and Concentric Torque Recovery Following a Concentric Isokinetic Exercise." International Journal of Sports Medicine 24, no. 1 (2003): 51–56. http://dx.doi.org/10.1055/s-2003-37199.

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Yanagisawa, Osamu, and Atsuki Fukutani. "Muscle Recruitment Pattern of The Hamstring Muscles in Hip Extension and Knee Flexion Exercises." Journal of Human Kinetics 72, no. 1 (March 31, 2020): 51–59. http://dx.doi.org/10.2478/hukin-2019-0124.

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AbstractWe aimed to compare dynamic exercise performance between hip extension exercises with different knee angles and between knee flexion exercises with different hip angles, and to investigate the recruitment pattern of the hamstrings in each exercise. Seven men performed 4 isokinetic exercises (3 maximal concentric contractions at 30°/s (peak torque) and 30 maximal concentric contractions at 180°/s (total work)): hip extension with the knee fully extended (HEke) and with the knee flexed at 90° (HEkf) and knee flexion with the hip fully extended (KFhe) and with the hip flexed at 90° (KFhf). The recruitment pattern of the hamstrings was evaluated in each exercise using magnetic resonance imaging (T2 calculation). The HEke condition showed significantly greater peak torque than the HEkf condition (p < 0.05). The KFhf condition had significantly greater peak torque and total work values than the KFhe condition (p < 0.05). Although the biceps femoris long head, semitendinosus, and semimembranosus had significantly increased post-exercise T2 values in the HEke (p < 0.05), KFhe, and KFhf conditions (p < 0.01), the T2 increase values were significantly greater under the KFhf than the HEke condition (p < 0.05). The semitendinosus showed a significantly greater T2 increase value than other muscles under both KFhe and KFhf conditions (p < 0.05). Performance of hip extension and knee flexion exercises increases when the hamstring muscles are in a lengthened condition. The hamstring muscles (particularly the semitendinosus) are more involved in knee flexion than in hip extension.

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Berzosa, César, Fernando Sanz-López, Oliver Gonzalo-Skok, Carlos Valero-Campo, José Luis Arjol-Serrano, Eduardo Piedrafita, Guillermo Aladrén, and A. Vanessa Bataller-Cervero. "Effect of Three Half-Squat Protocols on the Tensiomyographic Twitch Response and Tissue Damage of the Rectus Femoris and the Biceps Femoris." Journal of Human Kinetics 75, no. 1 (October 31, 2020): 15–27. http://dx.doi.org/10.2478/hukin-2020-0034.

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Abstract The aim of this study was to analyse the acute effects of a concentric exercise and two different eccentric overload exercises (EOEs) on blood markers of muscle damage (i.e. creatine kinase [CK], lactate dehydrogenase [LDH], myoglobin [Myo], and malondialdehyde [MDA]) and muscle contractile properties. Ten healthy, young (27 ± 1.5 years, 179 ± 6 cm, 78.7 ± 10.8 kg), physically active men (3.5 ± 1.9 h·w-1) randomly performed three training sessions using the following protocols: a half-squat (HS) as a concentric exercise, and exercises using Versapulley (VP) or YoYo isoinertial technology (YIT) as EOEs (4 x 7 repetitions with a 2 min rest interval between sets). Blood samples and tensiomyography measurements were obtained after each training session. Repeated measures analysis of variance (ANOVA) followed by the Tukey test was used to detect differences between the four time points of each variable. The standardized difference or effect size (ES, 90% confidence limit) in the selected variables was calculated using the basal SD. After all exercises, a greater activity of CK, LDH, and concentration of Myo, and MDA were found compared to baseline values (p < 0.05). A substantially greater activity of CK, LDH, and Myo concentration, but not MDA, were found after EOEs when compared to the HS protocol. Substantially lower tensiomyography results in the rectus femoris (RF) were reported, irrespective of the exercise mode performed. Also, no substantial differences were obtained in the biceps femoris (BF) between EOEs and the HS protocol. Time of contraction (Tc) in the RF was possibly to very likely lower in the HS in comparison to EOEs. Additionally, muscular displacement (Dm) in the RF was substantially lower in the HS compared to EOEs. VP produced higher concentrations of damage markers than YIT and concentric exercise did. Furthermore, tensiomyography variables showed similar activation in both exercises, although higher specific fatigue (in the RF) was registered in the traditional HS.

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Garnacho-Castaño, Manuel Vicente, Juan Hernández-Lougedo, Pablo García-Fernández, and José Luis Maté-Muñoz. "Effect of Muscle Action on the Kinetic and Kinematic Behavior of the Barbell during Isoinertial Strength Assessment." Applied Sciences 11, no. 5 (March 6, 2021): 2354. http://dx.doi.org/10.3390/app11052354.

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An isoinertial strength assessment was performed to examine the kinetic and kinematic behavior of the barbell during several muscle actions. Velocity–time characteristics, force–time relationship, one repetition maximum (1RM), power output, and acceleration were compared in eccentric–concentric (EC) versus concentric only (C) sequences of the bench press (BP) and military press (MP). In two separate sessions, 28 and 29 resistance-trained athletes executed EC or C sequences in random order of the BP and MP, respectively, in an incremental load test up to their 1RM. Higher values were recorded in BP-EC than in BP-C, MP-EC, or MP-C (p < 0.01) for peak acceleration, peak rate of force development, peak rate of velocity development, and power output. Significant differences were detected between exercises in terms of the portion of the concentric phase (%) at which peak acceleration was detected, or acceleration up until peak velocity was observed (p < 0.05). No differences were observed between exercises in the portion of the concentric phase where acceleration up to the braking phase took place. The eccentric muscle action prior to concentric movement was a key factor to enhance the kinematic and kinetic performance in BP exercise. No such effects of the countermovement were produced in MP.

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Nosaka, Kazunori, and Priscilla M. Clarkson. "Influence of previous concentric exercise on eccentric exercise-induced muscle damage." Journal of Sports Sciences 15, no. 5 (January 1997): 477–83. http://dx.doi.org/10.1080/026404197367119.

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Andersen, Ole Emil, Ole Bækgaard Nielsen, and Kristian Overgaard. "Early effects of eccentric contractions on muscle glucose uptake." Journal of Applied Physiology 126, no. 2 (February 1, 2019): 376–85. http://dx.doi.org/10.1152/japplphysiol.00388.2018.

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Muscle-damaging eccentric exercise impairs muscle glucose uptake several hours to days after exercise. Little, however, is known about the acute effects of eccentric exercise on contraction- and insulin-induced glucose uptake. This study compares glucose uptake rates in the first hours following eccentric, concentric, and isometric contractions with and without insulin present. Isolated rat extensor digitorum longus muscles were exposed to either an eccentric, concentric, or isometric contraction protocol, and muscle contractions were induced by electric stimulation that was identical between contraction protocols. In eccentric and concentric modes, length changes of 0.6 or 1.2 mm were used during contractions. Both contraction- and insulin-induced glucose uptake were assessed immediately and 2 h after contractions. Glucose uptake increased significantly following all modes of contraction and was higher after eccentric contractions with a stretch of 1.2 mm compared with the remaining contraction groups when assessed immediately after contractions [eccentric (1.2 mm) > eccentric (0.6 mm), concentric (1.2 mm), concentric (0.6 mm), isometric > rest; P < 0.05]. After 2 h, contraction-induced glucose uptake was still higher than noncontracting levels, but with no difference between contraction modes. The presence of insulin increased glucose uptake markedly, but this response was blunted by, respectively, 39–51% and 29–36% ( P < 0.05) immediately and 2 h after eccentric contractions stretched 1.2 mm compared with concentric and isometric contractions. The contrasting early effects of eccentric contractions on contraction- and insulin-induced glucose uptake suggest that glucose uptake is impaired acutely following eccentric exercise because of reduced insulin responsiveness.NEW & NOTEWORTHY This study shows that, in isolated rat muscle, muscle-damaging eccentric contractions result in a transient increase in contraction-induced glucose uptake compared with isometric and concentric contractions induced by identical muscle activation protocols. Furthermore, our results demonstrate that, in contrast, the insulin-stimulated glucose uptake is impaired immediately following muscle-damaging eccentric contractions.

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Widrick, J. J., D. L. Costill, G. K. McConell, D. E. Anderson, D. R. Pearson, and J. J. Zachwieja. "Time course of glycogen accumulation after eccentric exercise." Journal of Applied Physiology 72, no. 5 (May 1, 1992): 1999–2004. http://dx.doi.org/10.1152/jappl.1992.72.5.1999.

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This study examined the time course of glycogen accumulation in skeletal muscle depleted by concentric work and subsequently subjected to eccentric exercise. Eight men exercised to exhaustion on a cycle ergometer [70% of maximal O2 consumption (VO2max)] and were placed on a carbohydrate-restricted diet. Approximately 12 h later they exercised one leg to subjective failure by repeated eccentric action of the knee extensors against a resistance equal to 120% of their one-repetition maximum concentric knee extension force (ECC leg). The contralateral leg was not exercised and served as a control (CON leg). During the 72-h recovery period, subjects consumed 7 g carbohydrate.kg body wt-1.day-1. Moderate soreness was experienced in the ECC leg 24–72 h after eccentric exercise. Muscle biopsies from the vastus lateralis of the ECC and CON legs revealed similar glycogen levels immediately after eccentric exercise (40.2 +/- 5.2 and 47.6 +/- 6.4 mmol/kg wet wt, respectively; P greater than 0.05). There was no difference in the glycogen content of ECC and CON legs after 6 h of recovery (77.7 +/- 7.9 and 85.1 +/- 4.9 mmol/kg wet wt, respectively; P greater than 0.05), but 18 h later, the ECC leg contained 15% less glycogen than the CON leg (90.2 +/- 8.2 vs. 105.8 +/- 8.9 mmol/kg wet wt; P less than 0.05). After 72 h of recovery, this difference had increased to 24% (115.8 +/- 8.0 vs. 153.0 +/- 12.2 mmol/kg wet wt; P less than 0.05). These data confirm that glycogen accumulation is impaired in eccentrically exercised muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

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Hubal, Monica J., Trevor C. Chen, Paul D. Thompson, and Priscilla M. Clarkson. "Inflammatory gene changes associated with the repeated-bout effect." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 294, no. 5 (May 2008): R1628—R1637. http://dx.doi.org/10.1152/ajpregu.00853.2007.

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This study proposed that attenuated expression of inflammatory factors is an underlying mechanism driving the repeated-bout effect (rapid adaptation to eccentric exercise). We investigated changes in mRNA levels and protein localization of inflammatory genes after two bouts of muscle-lengthening exercise. Seven male subjects performed two bouts of lower body exercise (separated by 4 wk) in which one leg performed 300 eccentric-concentric actions, and the contralateral leg performed 300 concentric actions only. Vastus lateralis biopsies were collected at 6 h, and strength was assessed at baseline and at 0, 3, and 5 days after exercise. mRNA levels were measured via semiquantitative RT-PCR for the following genes: CYR61, HSP40, HSP70, IL1R1, TCF8, ZFP36, CEBPD, and MCP1. Muscle functional adaptation was demonstrated via attenuated strength loss (16% less, P = 0.04) at 5 days after bout 2 compared with bout 1 in the eccentrically exercised leg. mRNA expression of three of the eight genes tested was significantly elevated in the eccentrically exercised leg from bout 1 to bout 2 (+3.9-fold for ZFP36, +2.3-fold for CEBPD, and +2.6-fold for MCP1), while all eight mRNA levels were unaffected by bout in the concentrically exercised leg. Immunohistochemistry further localized the protein of one of the elevated factors [monocyte chemoattractant protein-1 (MCP1)] within the tissue. MCP1 colocalized with resident macrophage and satellite cell populations, suggesting that alterations in cytokine signaling between these cell populations may play a role in muscle adaptation to exercise. Contrary to our hypothesis, several inflammatory genes were transcriptionally upregulated (rather than attenuated) after a repeated exercise bout, potentially indicating a role for these genes in the adaptation process.

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Chourasia, Amrish O., Mary E. Sesto, Youngkyoo Jung, Robert S. Howery, and Robert G. Radwin. "Comparison of Biomechanical and Anatomical Effects Following Eccentric and Concentric Exertions." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 49, no. 14 (September 2005): 1287–91. http://dx.doi.org/10.1177/154193120504901405.

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Work place exertions may include muscle shortening (concentric) or muscle lengthening (eccentric) contractions. This study investigates the upper limb mechanical properties and magnetic resonance images (MRI) of the involved muscles following submaximal eccentric and concentric exertions. Twelve participants were randomly assigned to perform at 30° per second eccentric or concentric forearm supination exertions at 50% isometric maximum voluntary contraction (MVC) for 30 minutes. Measurement of mechanical stiffness, isometric MVC, localized discomfort and MRI supinator: extensor signal intensity ratio was done before, immediately after, 1 hour after and 24 hours after the bout of exercise. A 53% average decrease in mechanical stiffness after 1 hour was observed for the eccentric group (p< 0.05) compared to a 1% average decrease for the concentric group (p> 0.05). Edema, indicative of swelling, was observed 24 hrs after exercise, with an average increase in the MRI supinator: extensor signal intensity ratio of 36% for the eccentric group and less than 10% for the concentric group (p<0.05).

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Krishnathasan, Dhivo, and Anthony A. Vandervoort. "Ankle Plantar Flexion Strength in Resistance and Endurance Trained Middle-Aged Adults." Canadian Journal of Applied Physiology 27, no. 5 (October 1, 2002): 479–90. http://dx.doi.org/10.1139/h02-026.

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Maximum concentric (CONC) and eccentric (ECC) strength of the ankle plantar flexor muscles were compared between middle-aged adults who regularly participated in resistance exercise training versus those who participated in weight-bearing endurance exercise. A total of 40 men and women with a mean age of 48.9 years (SD = 5.3) were tested for CONC and ECC plantar flexor (PF) strength, using an isokinetic device at 3 velocities: 30, 90 and 180°/s. Mean strength values for the groups of men and women involved in resistance exercise were consistently higher than those involved in the endurance training for the CONC tests, where values ranged from 35% to 46% (avg. 41%, p < .01), but less between-group difference was observed for the ECC loading condition: 4% to 30% (avg. 18%). Thus ECC/CONC ratios, which rose with increasing velocity, were consistently higher for the endurance group vs. resistance-trained. Finally, since concentric PF torque values were found to be quite low for the middle-aged women who did only endurance training, this movement may require preventive strengthening exercises. Key words: muscle, exercise, isokinetic, aging, human

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Endoh, Takashi, Norio Saga, Junichi Ushiba, Motoi Tsuchiya, and Tsugutake Yoneda. "Corticomuscular Coherence Immediately After Eccentric And Concentric Exercise." Medicine & Science in Sports & Exercise 41 (May 2009): 354. http://dx.doi.org/10.1249/01.mss.0000355626.18201.6a.

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Cadore, Eduardo Lusa, Miriam González-Izal, Rafael Grazioli, Igor Setuain, Ronei Silveira Pinto, and Mikel Izquierdo. "Effects of Concentric and Eccentric Strength Training on Fatigue Induced by Concentric and Eccentric Exercises." International Journal of Sports Physiology and Performance 14, no. 1 (January 1, 2019): 91–98. http://dx.doi.org/10.1123/ijspp.2018-0254.

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Purpose: To compare the concentric and eccentric training effects on fatigue induced by eccentric and concentric protocols. Methods: A total of 22 men and women (22 [3.6] y) were assigned to concentric (GCON, n = 11) or eccentric training (GECC, n = 11). The concentric (CON) and eccentric (ECC) protocols were composed of 4 sets of 20 knee-extension/flexion repetitions. Force losses were analyzed by comparing 10 repetitions’ mean torques during the protocols and by verifying the maximal voluntary contraction and rate of torque development before and after the protocols. Muscle damage was assessed using echo intensity of the vastus lateralis 48 h after the protocols. Training consisted of 6 wk of isokinetic exercise at 60°/s (concentric or eccentric) twice weekly. Results: Before training, both protocols resulted in dynamic and isometric force losses in GCON and GECC (P < .01), but the magnitude was greater after the CON protocol than after the ECC protocol (P < .001). After training, both GCON and GECC showed similar force decreases during the CON and ECC protocols (P < .01), and these changes were not different from the pretraining decreases. Regarding maximal voluntary contraction after training, GECC showed lower force decreases than GCON after ECC exercise (−13.7% vs −22.3%, respectively, P < .05), whereas GCON showed lower maximal voluntary contraction decreases after CON exercise compared with pretraining (−29.2%, P < .05). Losses in rate of torque development were similar after the protocols before and after the training regimens. No changes in echo intensity were observed after the protocols before and after training. Conclusion: Both interventions resulted in similar force decreases during fatigue protocols compared with those associated with pretraining.

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Hasni, Hasni, Hening Laswati Putra, and Nuniek Nugraheni. "Comparison of Acute Level of CK After Five Weeks Eccentric vs Concentric High Intensity Strength Exercise in Healthy Subject." Surabaya Physical Medicine and Rehabilitation Journal 1, no. 2 (December 24, 2019): 38. http://dx.doi.org/10.20473/spmrj.v1i2.16171.

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Background: Musculoskeletal injuries both in sport and recreational activities, at each age level, can lead to immobilization. Injury and immobilization can lead to muscle strength decrease and deconditioning. These conditions can be addressed by provision of strength training therapy especially for people with low exercise tolerance such as the elderly and patients with chronic disease. Existing studies stated eccentric exercise can increase muscle strength with less energy expenditure compared to concentric exercise. However eccentric exercise can lead to muscle damage indicated with an acute CK level increase, and eccentric exercise has not been carried out regularly for post muscle injuries and deconditioned patients. The American College of Sport Medicine (ACSM) stated strength increase and muscle hypertrophy require high intensity load strengthening exercise with a minimum load of 70% 1 Maximum Repetition. The recommended load was given to the subjects in this research. Our pleriminary study intervention was well tolerated by healthy subjects.Aim: Comparing acute CK level alteration in high intensity eccentric and concentric muscle strengthening exercise on untrained healthy subjects.Methods: Randomized pre test and post test group design. Subjects of the study (n = 16) were untrained healthy males. CK level was evaluated by laboratory test.Results: Our study showed decline of acute CK level in both groups with p value 0.65 and 0.76, respectively. No significant differences found on both groups.Conclusion: The increase of acute CK level after five weeks of eccentric strengthening exercise is not higher than that in concentric strengthening exercise.

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Hasni, Hasni, Hening Laswati Putra, and Nuniek Nugraheni. "Comparison of Acute Level of CK After Five Weeks Eccentric vs Concentric High Intensity Strength Exercise in Healthy Subject." Surabaya Physical Medicine and Rehabilitation Journal 1, no. 2 (December 24, 2019): 38. http://dx.doi.org/10.20473/spmrj.v1i2.2019.38-43.

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Abstract:

Background: Musculoskeletal injuries both in sport and recreational activities, at each age level, can lead to immobilization. Injury and immobilization can lead to muscle strength decrease and deconditioning. These conditions can be addressed by provision of strength training therapy especially for people with low exercise tolerance such as the elderly and patients with chronic disease. Existing studies stated eccentric exercise can increase muscle strength with less energy expenditure compared to concentric exercise. However eccentric exercise can lead to muscle damage indicated with an acute CK level increase, and eccentric exercise has not been carried out regularly for post muscle injuries and deconditioned patients. The American College of Sport Medicine (ACSM) stated strength increase and muscle hypertrophy require high intensity load strengthening exercise with a minimum load of 70% 1 Maximum Repetition. The recommended load was given to the subjects in this research. Our pleriminary study intervention was well tolerated by healthy subjects.Aim: Comparing acute CK level alteration in high intensity eccentric and concentric muscle strengthening exercise on untrained healthy subjects.Methods: Randomized pre test and post test group design. Subjects of the study (n = 16) were untrained healthy males. CK level was evaluated by laboratory test.Results: Our study showed decline of acute CK level in both groups with p value 0.65 and 0.76, respectively. No significant differences found on both groups.Conclusion: The increase of acute CK level after five weeks of eccentric strengthening exercise is not higher than that in concentric strengthening exercise.

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Gibala, Martin J., Stephen A. Interisano, Mark A. Tarnopolsky, Brian D. Roy, Jay R. MacDonald, Kevin E. Yarasheski, and J. Duncan MacDougall. "Myofibrillar disruption following acute concentric and eccentric resistance exercise in strength-trained men." Canadian Journal of Physiology and Pharmacology 78, no. 8 (August 1, 2000): 656–61. http://dx.doi.org/10.1139/y00-036.

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We have previously quantified the extent of myofibrillar disruption which occurs following an acute bout of resistance exercise in untrained men, however the response of well-trained subjects is not known. We therefore recruited six strength-trained men, who ceased training for 5 days and then performed 8 sets of 8 uni-lateral repetitions, using a load equivalent to 80% of their concentric (Con) 1-repetition maximum. One arm performed only Con actions by lifting the weight and the other arm performed only eccentric actions (Ecc) by lowering it. Needle biopsy samples were obtained from biceps brachii of each arm ~21 h following exercise, and at baseline (i.e., after 5 days without training), and subsequently analyzed using electron microscopy to quantify myofibrillar disruption. A greater (P [Formula: see text] 0.05) proportion of disrupted fibres was found in the Ecc arm (45 ± 11%) compared with baseline values (4 ± 2%), whereas fibre disruption in the Con arm (27 ± 4%) was not different (P > 0.05) from baseline values. The proportion of disrupted fibres and the magnitude of disruption (quantified by sarcomere counting) was considerably less severe than previously observed in untrained subjects after an identical exercise bout. Mixed muscle protein synthesis, assessed from ~21-29 h post-exercise, was not different between the Con- and Ecc-exercised arms. We conclude that the Ecc phase of resistance exercise is most disruptive to skeletal muscle and that training attenuates the severity of this effect. Moreover, it appears that fibre disruption induced by habitual weightlifting exercise is essentially repaired after 5 days of inactivity in trained men.Key words: muscle damage, muscle injury, protein synthesis, hypertrophy, leucine.

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Stavres, Jon, Stephen Fischer, and John McDaniel. "Post Exercise Hypotension and Blood Flow Characteristics Between Eccentric and Concentric Exercise." Medicine & Science in Sports & Exercise 49, no. 5S (May 2017): 811. http://dx.doi.org/10.1249/01.mss.0000519174.92440.ec.

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Journal articles on the topic 'Concentric exercise'

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