ABSTRACTKawczyński, A, Samani, A, Fernández-de-las-Peñas, C, Chmura, J, and Madeleine, P. Sensory mapping of the upper trapezius muscle in relation to consecutive sessions of eccentric exercise. J ...Strength Cond Res 26(6)1577–1583, 2012—The aim of this study was to evaluate the changes in pressure pain sensitivity maps in untrained subjects over 2 subsequent sessions of eccentric exercise (ECC) expected to result in (a) delayed onset muscle soreness (DOMS) and (b) adaptation/recovery, respectively. Eleven healthy male subjects participated in this study. Pressure pain threshold (PPT), rate of perceived exertion (RPE), pain intensity, soreness area drawing, maximal voluntary contraction (MVC), and shoulder range of motion were assessed in session 1 before, immediately after, and 24 hours after ECC. The ECC protocol that was used to induce DOMS consisted of 50 eccentric contractions of the right shoulder that were divided into 5 bouts, including 10 contractions at MVC level separated by a 2-minute resting period. Session 2 was identical to session 1 and performed exactly 1 week later. There was only a significant increase in the RPE assessed before the exercise and 24 hours after the exercise in session 1 (p = 0.001). The average PPT only decreased significantly from before the exercise (660.2 ± 76.2 kPa) to 24 hours after the exercise (435.6 ± 59.3 kPa) in session 1 (p = 0.016). The present study confirmed a heterogeneous distribution of mechanical sensitivity before and after sessions of ECC. The first session of ECC underlined increased mechanical sensitivity because of DOMS, whereas the second session reflected an adaptation process. Our results support the potential role of ECC bouts in training regimens.
1 Department of Genetics and Molecular Biology, the Zinman College of Physical Education and Sport Sciences at the Wingate Institute, Netanya; and 2 Department of Cardiology, Lady Davis Carmel ...Medical Center, Haifa, Israel
Submitted 12 August 2007
; accepted in final form 19 September 2007
Unaccustomed exercise may cause muscle breakdown with marked increase in serum creatine kinase (CK) activity. The skeletal muscle renin-angiotensin system (RAS) plays an important role in exercise metabolism and tissue injury. A functional insertion ( I )/deletion ( D ) polymorphism in the angiotensin I-converting enzyme ( ACE ) gene (rs4646994) has been associated with ACE activity. We hypothesized that ACE ID genotype may contribute to the wide variability in individuals' CK response to a given exercise. Young individuals performed maximal eccentric contractions of the elbow flexor muscles. Pre- and postexercise CK activity was determined. ACE genotype was significantly associated with postexercise CK increase and peak CK activity. Individuals harboring one or more of the I allele had a greater increase and higher peak CK values than individuals with the DD genotype. This response was dose-dependent (mean ± SE U/L: II , 8,882 ± 2,362; ID , 4,454 ± 1,105; DD , 2,937 ± 753, ANOVA, P = 0.02; P = 0.009 for linear trend). Multivariate stepwise regression analysis, which included age, sex, body mass index, and genotype subtypes, revealed that ACE genotype was the most powerful independent determinant of peak CK activity (adjusted odds ratio 1.3, 95% confidence interval 1.03–1.64, P = 0.02). In conclusion, we indicate a positive association of the ACE ID genotype with CK response to strenuous exercise. We suggest that the II genotype imposes increased risk for developing muscle damage, whereas the DD genotype may have protective effects. These findings support the role of local RAS in the regulation of exertional muscle injury.
genetics; ACE ; insertion/deletion; renin-angiotensin system; eccentric exercise
Address for reprint requests and other correspondence: R. Amir, Director, Dept. of Genetics and Molecular Biology, Zinman College of Physical Education and Sport Sciences at the Wingate Institute, Netanya 42902, Israel (e-mail: ruthieam{at}012.net.il )
Alpha-actinin-3 (ACTN3) is an integral part of the Z line of the sarcomere. The ACTN3 R577X (rs1815739) polymorphism determines the presence or absence of functional ACTN3, which may influence the ...extent of exercise-induced muscle damage. This study aimed to compare the impact of, and recovery from, muscle-damaging eccentric exercise on subjects with or without functional ACTN3. Seventeen young men (20–33 years old), homozygous for the R (n = 9) or X (n = 8) alleles, performed two bouts of stretch–shortening exercise (50 drop jumps) two weeks apart. Muscle soreness, plasma creatine kinase (CK) activity, jump height, maximal voluntary isometric torque (MVC), peak concentric isokinetic torque (IT), and electrically stimulated knee extension torques at 20 and 100 Hz were measured at baseline and at a number of time points up to 14 days after each bout. There were no significant baseline differences between the groups. However, significant time point × genotype interactions were observed for MVC (p = 0.021) and IT (p = 0.011) for the immediate effect of eccentric exercise in bout 1. The RR group showed greater voluntary force decrements (RR vs. XX: MVC, –33.3% vs. –24.5%; IT, –35.9% vs. –23.2%) and slower recovery. A repeated-bout effect was clearly observed, but there were no differences by genotype group. The ACTN3 genotype modulates the response of muscle function to plyometric jumping exercise, although the differences are modest. The ACTN3 genotype does not influence the clearly observed repeated-bout effect; however, XX homozygotes recover baseline voluntary torque values faster and thus may be able to undertake more frequent training sesssions.
Celotno besedilo
Dostopno za:
DOBA, FSPLJ, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The present study was aimed to investigate in elderly humans changes in NF-κB activation and in the expression of the inflammation-related genes inducible nitric oxide synthase (iNOS), ...cyclooxygenase-2 (COX-2) and interleukin-6 (IL-6) induced in peripheral blood mononuclear cells (PBMC) by acute eccentric exercise and by submaximal eccentric training. Eleven subjects, aged 66–75 years, carried out 2 bouts of eccentric exercise separated by 8 weeks of training. Following the first bout, NF-κB activation, and protein level of p50/p65 subunits, phospho-IκBα and phospho-IKKα increased, while IκBα protein level was significantly reduced. This was accompanied by a significant increase in iNOS, COX-2 and IL-6 mRNA protein level and protein content. Changes were significantly attenuated following the second exercise bout. In conclusion, acute eccentric exercise increases NF-κB activation and the expression of several inflammation-related genes in PBMC from elderly individuals. Regular eccentric training might be an effective method of preventing undesirable inflammatory responses induced by eccentric exercise.
Muscle damage is a common response to unaccustomed eccentric exercise; however, the effects of skeletal muscle damage on local vascular function and blood flow are poorly understood. This study ...examined serial local vascular responses to flow-mediated (endothelial-dependent) and nitroglycerin-mediated (endothelial-independent) dilation in the brachial artery after strenuous eccentric exercise and serially assessed resting blood flow. Ten healthy males performed 50 maximal eccentric unilateral arm contractions to induce muscle damage to the biceps brachii. Changes in maximal isometric strength and vascular responses were assessed 1, 24, 48, and 96 h after exercise. Mean blood velocities and arterial diameters, measured with Doppler ultrasound, were used to calculate blood flow and shear stress (expressed as area under the curve). Eccentric exercise resulted in impaired maximal isometric strength for up to 96 h (p < 0.001). Reductions in flow-mediated dilation (before exercise, 9.4% ± 2.6%; 1 h after exercise, 5.1% ± 2.2%) and nitroglycerin responses (before exercise, 26.3% ± 6.5%; 1 h after exercise, 20.7% ± 4.7%) were observed in the 1 h after exercise and remained lower for 96 h (p < 0.05). The shear stress response was attenuated immediately after exercise and remained impaired for 48 h (p < 0.05). Resting blood pressure and muscle blood flow remained similar throughout the study. Results suggest that muscle damage from eccentric exercise leads to impaired local endothelial and vascular smooth muscle function. Lower shear stress after exercise might contribute to the observed reduction in flow-mediated dilation responses, but the mechanism responsible for the attenuated endothelial-independent vasodilation remains unclear.
Celotno besedilo
Dostopno za:
DOBA, FSPLJ, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Twenty males ran either on a level treadmill (nonmuscle-damaging condition) or on a downhill treadmill (muscle-damaging condition). Blood and urine samples were collected before and after exercise ...(immediately after, 1h, 4h, 24h, 48h, and 96h). The following assays were performed: F2-isoprostanes in urine, protein carbonyls in plasma, glutathione, superoxide dismutase, glutathione peroxidase, and catalase in erythrocytes. The main finding was that monophasic redox responses were detected after nonmuscle-damaging exercise compared to the biphasic responses detected after muscle-damaging exercise. Based on these findings, muscle-damaging exercise may be a more appropriate experimental model to induce physiological oxidative stress.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Recovery following muscle-damaging downhill running is associated with increased muscle inflammatory cytokines. Various inflammatory challenges can also increase cytokines in the brain, which have ...been linked to sickness behaviors, including fatigue, but little is known about the brain cytokine response to stressful exercise. We used a downhill running model to determine the relationship between brain IL-1β and recovery of running performance. Male C57BL/6 mice were assigned to: downhill (DH), uphill (UH), or non-running control (Con) groups and run on a treadmill at 22
m/min and −14% or 14% grade, for 150
min. Following the run, a subset of DH and UH was placed into activity wheel cages where voluntary running activity was measured for 7 days. A second subset was run to fatigue on a motorized treadmill at 36
m/min, 8% grade at 24, 48, and 96
h post-up/downhill run. A third subset of DH, UH, and Con mice had brains dissected and assayed for IL-1β at 24 and 48
h. DH resulted in delayed recovery of both voluntary wheel-running and treadmill running to fatigue as compared to UH (
p
<
.05). DH was also associated with increased IL-1β concentrations in cortex (at 24 and 48
h) and cerebellum (24
h) as compared to UH and Con. UH was not different than Con in any brain region. Eccentric-biased downhill running results in an increase in plasma CK and delayed recovery in running performance, as compared to the more metabolically demanding uphill running, and this was associated with increased concentrations of IL-1β in regions of the brain responsible for movement, coordination, motivation, perception of effort, and pain.
Eccentric cycling may present an interesting alternative to traditional exercise rehabilitation for patients with advanced COPD, because of the low ventilatory cost associated with lengthening muscle ...actions. However, due to muscle damage and soreness typically associated with eccentric exercise, there has been reluctance in using this modality in clinical populations. This study assessed the feasibility of applying an eccentric cycling protocol, based on progressive muscle overload, in six severe COPD patients with the aim of minimizing side effects and maximizing compliance. Over 5 weeks, eccentric cycling power was progressively increased in all patients from a minimal 10-Watt workload to a target intensity of 60% peak oxygen consumption (attained in a concentric modality). By 5 weeks, patients were able to cycle on average at a 7-fold higher power output relative to baseline, with heart rate being maintained at ∼85% of peak. All patients complied with the protocol and presented tolerable dyspnea and leg fatigue throughout the study; muscle soreness was minimal and did not compromise increases in power; creatine kinase remained within normal range or was slightly elevated; and most patients showed a breathing reserve > 15 L.min−1. At the target intensity, ventilation and breathing frequency during eccentric cycling were similar to concentric cycling while power was approximately five times higher (p = 0.02). This study showed that an eccentric cycling protocol based on progressive increases in workload is feasible in severe COPD, with no side effects and high compliance, thus warranting further study into its efficacy as a training intervention.
BACKGROUND: Reduced strength and flexibility are commonly hypothesised risk factors for the development of hamstring injury, and both are improved with eccentric training in non-injured populations. ...However, there is a lack of studies investigating the effect of eccentric training on strength and flexibility among previously injured athletes. This study examined the effects of a modified eccentric hamstring strength program on strength and flexibility in previously injured athletes. METHODS: Ten participants (8 Male, 2 Female) ranging from 1836 years of age were recruited from the local community to participate in the study. All participants demonstrated a previous history of hamstring injury but had since returned to their chosen sport of Gaelic football, hurling, soccer or rugby. A single group repeated measures intervention study was carried out. Two strength parameters; peak torque (PT) and angle of peak torque (AngPT), as well as two flexibility parameters; stretch tolerance (ST) and extensibility were assessed before and after a six week eccentric hamstring strength program. Muscle soreness was recorded using a likert scale. Paired samples t-tests and Wilcoxon signed-ranks tests compared strength and flexibility before and after the eccentric program. RESULTS: There was a significant increase in eccentric hamstring PT (p 0.001) and eccentric hamstring AngPT (p = 0.001) following the intervention. The results also indicated a significant increase in ST (p 0.001), but not extensibility (p = 0.892), following the eccentric intervention. Mean(SD) muscle soreness with the exercise programme was minimal (1.85 0.84) with 100% compliance during the eccentric programme. CONCLUSIONS: Significant changes in PT, AngPT and ST were observed after the eccentric training programme, consistent with previous research among uninjured populations. Extensibility was unchanged after the intervention. Eccentric training programmes similar to that performed in the current study have been associated with reduced injury rates when progressed gradually throughout a season. This study adds support to the hypothesis that eccentric training can improve both strength and flexibility parameters. However further well designed randomised control trials (RCTs) and field-based studies, which include injury outcomes, are needed.
Purpose: L-glutamine is the most abundant amino acid found in human muscle and plays an important role in protein synthesis and can reduce the levels of inflammation biomarkers and creatine kinase ...(CK) after training sessions. Delayed onset muscle soreness (DOMS) develops after intense exercise and is associated with an inflammatory response. The purpose of this study was to investigate the effect of glutamine supplementation on surface electromyography activity of the vastus medialis muscle (VMM) and rectus femoris muscle (RFM) and levels of creatine kinase after an eccentric contraction. Methods: Seventeen healthy men (age: 22.35 ± 2.27yr; body mass: 69.91 ± 9.78kg; height: 177.08 ± 4.32cm) were randomly assigned to experimental (n=9) and control groups (n=8) in a double-blind manner. In both groups, subjects were given L-glutamine supplementation (0.1g.kg.sup.-1) or placebo three times a week for 4 weeks. Median frequency (MDF) and mean power frequency (MPF) for VMM and RFM muscles and also CK measurements were performed before, 24h and 48 h after a resistance training session. The resistance training included 6 sets of eccentric leg extensions to exhaustion with 75% of 1RM. Results: There was no significant difference between groups for MDF or MPF in VMM and RFM. The difference of CK level between the groups was also not significant. Conclusion: The results of this study indicate that glutamine supplementation has no positive effect on muscle injury markers after a resistance training session. Key Words: Mean Power Frequency; Median Frequency; Creatine Kinase; Eccentric Exercise
PDF
