Decreased blood oxidative stress after repeated muscle-damaging exercise

PURPOSE: To examine the effect of repeated muscle-damaging exercise on the time-course changes in several indices of muscle damage, and to compare them with changes in blood oxidative stress indices. METHODS: Twelve females underwent an isokinetic exercise session consisting of 75 lengthening knee flexions, which was repeated after 3 wk. Isometric torque, range of movement (ROM), delayed-onset muscle soreness (DOMS), creatine kinase (CK), reduced glutathione (GSH), oxidized glutathione (GSSG), thiobarbituric acid-reactive substances (TBARS), protein carbonyls, catalase, uric acid, bilirubin, and total antioxidant capacity (TAC) in blood were measured before, immediately after, and 1, 2, 3, 4, and 7 d after lengthening contractions. RESULTS: All muscle damage indices (torque, ROM, DOMS, and CK) changed significantly after exercise. The concentration of all oxidative stress indices changed significantly in a way indicating increased oxidative stress in the blood (GSH and GSH/GSSG decreased, whereas GSSG, TBARS, protein carbonyls, catalase, uric acid, bilirubin, and TAC increased), peaking in all but bilirubin at 3 d and returning to baseline values by 7 d after exercise. The repeated bout of lengthening contractions induced significantly less changes in indices of muscle damage and blood oxidative stress than the first bout. In general, from the increasing or decreasing area under the curve calculated for each oxidative stress index, the second bout produced 1.8- to 6.1-fold less changes in oxidative stress than after the first bout. CONCLUSION: A repeated bout of lengthening contractions attenuated muscle damage and blood oxidative stress compared with the first bout.     

Obesity exacerbates oxidative stress levels after acute exercise

INTRODUCTION/PURPOSE: This study compared oxidative stress levels and antioxidant capacity in nonobese and obese participants after acute resistance (RX) and aerobic exercise (AX). METHODS: Blood samples were collected from 28 nonobese (mean = 20.8% body fat) and obese (mean = 35.0% body fat) participants pre- and immediately post-RX and AX. Lipid hydroperoxides (PEROX), malondialdehyde (TBARS) and total antioxidant status (TAS) were measured. Oxygen consumption (VO2) and minute ventilation (VE) values were determined during each exercise session. RESULTS: In both groups, PEROX and TBARS were elevated post-RX and AX, with the greater elevations occurring in the obese group in each case (P < 0.05). In the obese, TBARS increased by 42% and 41% post-RX and AX, respectively, compared with 7.1% and 26.9% in the nonobese group. PEROX increased by 100% and 70% post-RX and AX, respectively, in the obese, and by 85% and 62% in the nonobese. TAS was 17% higher (P < 0.05) post-RX in the nonobese compared with the obese, whereas TAS values were not different post-AX. Peak and average VE, and relative VO2). rates were higher in the obese post-AX compared with the nonobese (P < 0.05) Correlations existed between the exercise-induced change in PEROX and body fat, vitamin C and A intake, peak oxygen consumption, and exercise ventilation rates in the obese group (r = 0.784-0.776, P < 0.05). In both groups, the exercise-induced changes in PEROX were associated with vitamin C intake, exercise ventilation rates, VO2peak, and plasma triglycerides (r = 0.669-0.558, P < 0.05). CONCLUSION: Lipid peroxidation is elevated in both RX and AX, and it is exacerbated in the obese. The mechanisms underlying this response in each exercise may be different but could involve plasma triglycerides, oxygen consumption, and antioxidant intake.     

Sports massage after eccentric exercise

BACKGROUND: The use of sports massage is very common in the athletic community. However, only a few studies have shown any therapeutic effect of massage. HYPOTHESIS: Sports massage can improve the recovery after eccentric exercise. STUDY DESIGN: Prospective randomized clinical trial. METHODS: Sixteen subjects performed 300 maximal eccentric contractions of the quadriceps muscle bilaterally. Massage was given to 1 leg, whereas the other leg served as a control. Subjects were treated once daily for 3 days. Maximal strength was tested on a Kin-Com dynamometer, and functional tests were based on 1-leg long jumps. Pain was evaluated using a visual analog scale. RESULTS: There was a marked loss of strength and function of the quadriceps directly after exercise and on the third day after exercise. The massage treatment did not affect the level or duration of pain or the loss of strength or function following exercise. CONCLUSION: Sports massage could not improve the recovery after eccentric exercise.     

Effect of eccentric exercise on muscle oxidative metabolism in humans

PURPOSE: The purpose of this study was to evaluate the effects of eccentric exercise on muscle oxidative function. METHODS: Thirteen subjects performed high-intensity eccentric cycling for 30 min. Muscle oxidative function in vastus lateralis was evaluated by measurements of respiration in permeabilized muscle fibers (skinned fibers) and from the kinetics of oxyhemoglobin (oxyHb) saturation measured with near infrared spectroscopy (NIRS). RESULTS: After eccentric cycling, all subjects reported extensive delayed onset muscle soreness (DOMS), but plasma markers of muscle damage (creatine kinase and beta-glucuronidase activity) were not significantly altered. The half time of oxyHb desaturation after circulatory occlusion (128 +/- 11 s, mean +/- SE) and oxyHb resaturation after restoration of blood flow (13.8 +/- 0.7 s) were not significantly changed after eccentric cycling (N = 7). Respiration in skinned muscle fibers measured in the absence of ADP and in the presence of a submaximal (0.1 mM) or maximal ADP concentration (1 mM) was not significantly changed after eccentric cycling (N = 6). The sensitivity of respiration to ADP was not significantly changed after eccentric cycling. CONCLUSIONS: Muscle oxidative function (maximal respiration and respiratory control by ADP) was not compromised after high-intensity eccentric cycle exercise. Furthermore, NIRS indicates that after eccentric cycling muscle oxygen utilization and local oxygen transport at rest are unchanged. It is concluded that eccentric cycling, although causing DOMS, does not negatively affect skeletal muscle oxidative function.     

The effects of acute exercise on neutrophils and plasma oxidative stress

PURPOSE: To investigate the influence of intensity versus total energy expenditure on neutrophilia and blood oxidative stress to acute exercise. METHODS: Nine males (18-30 yr) completed one maximal (Max) and three submaximal exercise sessions: 1) 45 min at 10% above (LT+) lactate threshold (LT), 2) 45 min at 10% below (LT-) LT, and 3) 10% below LT until caloric expenditure equaled the 10%+ trial (LT-kcal). Blood was sampled before (PRE), immediately (POST), 1 h, and 2 h after exercise to measure neutrophils, myeloperoxidase, superoxide (O(2)-), neutrophil activation (O(2)-/neutrophils), ascorbic acid, uric acid, malondialdehyde, and lipid hydroperoxides. RESULTS: Intensity-dependent neutrophilia occurred POST exercise with significant increases (P 相似文献   

Acute effects of stretching on muscle stiffness after a bout of exhaustive eccentric exercise

With the aim to analyze the influence of stretching on muscle stiffness after eccentric exercise, 30 young men (18 - 32 years old), were divided into three groups: STR, undergoing a stretching program (SP) of the dominant quadriceps muscle, ECC, undergoing exhaustive eccentric exercise, and ECC/STR, undergoing eccentric exercise, followed by SP. Muscle stiffness (MS) was assessed immediately before the respective programs, and 1 and 24 hours after, measuring the following parameters during Wartenberg pendulum test: angle and angular velocity of first knee flexion (FKF) and following oscillating extension, time of oscillating movements and final resting knee angle (FRKA). Despite the slight (2%) but significant increase of FRKA, all further parameters did not change over time in STR. MS in ECC was documented by the reduced range of motion (ROM) and the slower angular velocity. Reduction in FRKA (10%) was still present after 24 hours, while other variables tended to recover eventually. Similar reduction in FKF was observed for ECC/STR, but with significantly less impairment in the range of pendulum movement one hour after the exercise and in tendency still remained less impaired 24 hours after. The results suggest that SP conducted after exhaustive eccentric exercise alleviated reductions in ROM induced by exercise.     

Myofibers express IL-6 after eccentric exercise

BACKGROUND: Interleukin (IL)-6 is locally produced in skeletal muscles and shows a remarkable increase in plasma after eccentric exercises. OBJECTIVE: To elucidate the cell types in the muscles responsible for IL-6 production after eccentric exercises. STUDY DESIGN: Controlled laboratory study. METHODS: An eccentric contraction model was made using electrical stimulation. The authors investigated the muscle damage and regeneration processes after eccentric exercises histologically, and the cell types expressing IL-6 and its subcellular compartimentalization with time immunohistochemically after eccentric exercises. RESULTS: Swollen myofibers were detected from 8 hours to 3 days after exercises. Disrupted myofibers were detected from 24 hours to 7 days, with a peak of 3 days. IL-6 was detected only in the cytoplasm of myofibers until 12 hours; thereafter, it was found in the inflammatory cells and proliferating satellite cells as well. The swollen myofibers were negatively stained for IL-6. The positive ratios of IL-6 in myofibers immediately increased after exercises, peaked in 12 hours, and then decreased. CONCLUSIONS: After eccentric exercises, IL-6 expression increased in myofibers preceding the disruption of myofibers. IL-6 might be closely related to muscle damage caused by strenuous exercises.     

Repeated bout effect after maximal eccentric exercise

We hypothesized that a bout of high or low volume eccentric exercise would protect against muscle damage following a subsequent high volume bout and that adaptation would be attributable to neural changes, independent of the initial exercise volume. Sixteen males performed either 45 (ECC45) or 10 (ECC10) maximal eccentric contractions using the elbow flexors, followed by an ECC45 bout 2 weeks later. Damage markers were measured for the following 96 h; EMG and work done during the first 10 eccentric contractions were also recorded. CK, soreness, and decrements in MVC and range of motion (ROM) were greater in bout 1 than bout 2 (p < 0.01). Soreness, MVC and ROM were greater after the initial ECC45 bout compared to the initial ECC10 bout and the repeated bouts of ECC45 exercise in both groups (p < 0.01). Median frequency decreased from bout 1 to bout 2 (p < 0.001), no differences between groups were observed. An ECC45 bout of maximal eccentric exercise causes more initial damage than an ECC10 bout of maximal eccentric exercise, although both confer protection from subsequent ECC45 bouts of maximal eccentric contractions, which are attributable, at least in part, to a shift in the frequency content of EMG.     

Ibuprofen use during extreme exercise: effects on oxidative stress and PGE2

PURPOSE: Oxidative stress was examined with use (N = 29) or nonuse (N = 25) of ibuprofen in ultramarathoners after the Western States Endurance Run. METHODS: Oxidative stress was assessed by measuring plasma and urinary F2-isoprostanes, plasma nitrite, and plasma urate. A urinary prostaglandin E2 metabolite (PGE-M) was used as an end point to assess ibuprofen use. Ibuprofen users consumed 600 and 1200 mg of ibuprofen the day before and on race day, respectively, and nonusers avoided all antiinflammatory medications. Blood and urine were collected in the morning before the race and immediately after the race. RESULTS: Use compared with nonuse of ibuprofen significantly increased plasma (P 相似文献   

Cyclic compressive loading facilitates recovery after eccentric exercise

PURPOSE: To assess the biologic basis of massage therapies, we developed an experimental approach to mimic Swedish massage and evaluate this approach on recovery from eccentric exercise-induced muscle damage using a well-controlled animal model. METHODS: Tibialis anterior muscles of six New Zealand White rabbits were subjected to one bout of damaging, eccentric contractions. One muscle was immediately subjected to cyclic compressive loads, and the contralateral served as the exercised control. RESULTS: We found that commencing 30 min of cyclic compressive loading to the muscle, immediately after a bout of eccentric exercise, facilitated recovery of function and attenuated leukocyte infiltration. In addition, fiber necrosis and wet weight of the tissue were also reduced by compressive loading. CONCLUSION: We conclude that subjecting muscle to compressive loads immediately after exercise leads to an enhanced recovery of muscle function and attenuation of the damaging effects of inflammation in the rabbit model. Although these observations suggest that skeletal muscle responds to cyclic compressive forces similar to those generated by clinical approaches, such as therapeutic massage, further research is needed to assess the translational efficacy of these findings.     

Muscle function at the wrist after eccentric exercise

PURPOSE: The purpose of this experiment was to investigate the effects of eccentric exercise by the wrist extensor muscles on the function and motor control of synergist wrist extensor muscles and the antagonist wrist flexor muscles. METHODS: Ten subjects were tested repeatedly over a period of 11 d, once before and four times after a bout of strenuous eccentric exercise with the wrist extensor muscles. Tests performed as indicators of muscle injury were wrist extension MVC, ROM, and soreness. Tests performed as measures of function and motor control were maximum joint velocity, ability to sustain a constant torque, and the ability to track a changing torque. RESULTS: Indicators of muscle injury: subjects exhibited a decline in wrist extension MVC and ROM, which peaked on day 1, and reported that muscle soreness was greatest on day 2. All measures returned to baseline values by day 10. Measures of function and motor control: subjects exhibited a greater difficulty sustaining a submaximal contraction and tracking torque after eccentric exercise. Greater torque variances in these tests were most evident at high torque levels. Subjects exhibited the greatest difficulty 24 h after eccentric exercise and had recovered by day 10. There was no change in maximal wrist extension velocity. CONCLUSIONS: Strenuous eccentric exercise by wrist extensors had an effect on function and motor control of the wrist extensor muscles. The effect was most evident during contractions in which high torque was required. The response of all of the wrist extensors after the exercise bout was similar, suggesting that they operated in a synergistic manner. The antagonists wrist flexors showed increased coactivation after eccentric exercise.     

Shift of peak torque angle after eccentric exercise

This study aims to investigate the changes in the mechanical properties of quadriceps muscle following a sub-maximal concentric-eccentric stepping exercise protocol. Twenty-four untrained healthy subjects aged 21.9 +/- 0.55 years were asked to perform a 10-minute stepping exercise where the dominant leg worked eccentrically and the non-dominant leg worked concentrically at a rate of 15 cycles/min. The quadriceps isokinetic peak torque and the corresponding peak torque angle at angular velocity of 60 degrees /sec, and muscle soreness were determined at baseline, immediately after, day 1 and day 2 after the exercise protocol. Repeated measures of ANOVA showed no change in the peak torque after the eccentric exercise and concentric exercise (p > 0.05). There was a significant shift in the peak torque angle to longer muscle lengths in the eccentrically-exercised leg immediately (65.6 +/- 2.21 degrees ) and on the following two days after exercise (day 1: 68.3 +/- 2.71 degrees ; day 2: 67.4 +/- 2.51 degrees ) when compared with baseline (61.4 +/- 1.55 degrees , p < 0.05). These features were not observed in the concentrically-exercised leg. Eccentric exercise produced a higher level of soreness than concentric exercise at day 1 and 2 after the protocol. Submaximal eccentric exercise could bring about changes in the muscle properties resulting in a shift in the angle-torque relationship to longer muscle length without significant force deficit.     

The effects of muscle damage following eccentric exercise on gait biomechanics

To examine the effects of knee extensors muscle damage on walking and running biomechanics in healthy males. Muscle damage was caused by 60 (6x10) maximal eccentric knee flexions of both legs, selected in a random order, at an angular velocity of 1.05rad/s in 10 volunteers (mean age 20+/-1.0 years). Muscle damage indicators (creatine kinase (CK), lactate dehydrogenase (LDH), delayed onset muscle soreness (DOMS), eccentric and isometric (110 degrees knee flexion) peak torque), pelvic three dimensional (3D) orientation, as well as hip, knee and ankle-joint flexion/extension angles during gait (walking at 1.2m/s and running at 2.8m/s) were assessed pre- and 48h post-eccentric exercise. All muscle damage indicators revealed significant changes post- compared to pre-exercise data (P<0.05) confirming that muscle damage did occur. Kinematic analysis revealed that muscle damage significantly decreased the knee-joint angle range of movement at the stance and swing phases during walking (P<0.05) and running (P<0.05), respectively. These changes were accompanied by corresponding increases of pelvic rotation (P<0.05) and decrease of pelvic tilt (P<0.05). The present data demonstrate that damage of knee extensors result in changes of treadmill walking and running kinematics at both knee joint and pelvis. The fact that these alterations occur at different gait phases could be attributed to the speed of movement and to a self-protection mechanism to prevent further damage.     

Ibuprofen and acetaminophen: effect on muscle inflammation after eccentric exercise

PURPOSE: We examined the influence of ibuprofen and acetaminophen on muscle neutrophil and macrophage concentrations after novel eccentric contractions. METHODS: Twenty-four males (25 +/- 3 yr) were divided into three groups that received the maximal over-the-counter dose of either ibuprofen (1200 mg x d-1), acetaminophen (4000 mg x d-1), or a placebo after eccentric contractions of the knee extensors. Biopsies from the vastus lateralis were taken before and 24 h after exercise. Inflammatory cells were quantified in muscle cross-sections using immunohistochemistry. RESULTS: Macrophage concentrations were elevated by 1.5- to 2.5-fold (P < 0.05) at 24 h postexercise relative to preexercise concentrations, whereas neutrophil concentrations were not significantly elevated. Muscle inflammatory cell concentrations were unaffected by treatment with ibuprofen or acetaminophen when compared with placebo. CONCLUSIONS: Maximal over-the-counter doses of ibuprofen or acetaminophen, when administered therapeutically, do not affect muscle concentrations of neutrophils or macrophages 24 h after a novel bout of eccentric contractions.     

Effects of kinesio taping on anaerobic power recovery after eccentric exercise

The aim of the study was to evaluate the effectiveness of kinesio taping (KT) in anaerobic power recovery after eccentric exercise. The study was carried out on 10 healthy men. The participants performed two 60-min downhill runs with a constant intensity. Peak anaerobic power (PP) and mean power (MP) were measured before and five times after eccentric exercise. Anaerobic power was evaluated with the Maximal Cycling Sprint Test. After the downhill run, passive recovery (PR) and KT (lymphatic application) were applied in random order. A significant decrease in PP and MP was observed at least for 24 h after PR, compared to baseline. After the KT application 24 h after eccentric exercises, anaerobic power was already similar to the baseline measurement. The application of KT significantly improved anaerobic power recovery time after eccentric exercise compared to the period of passive rest immediately prior to testing.