Joohyung Lee

Eccentric exercise effect on blood oxidative- stress markers and delayed onset of muscle soreness

PURPOSE This study examined the effects of a single bout of high-intensity eccentric exercise (EE) on blood protein carbonyls, glutathione status, and muscle damage indicators to ascertain whether blood markers of oxidative stress are elevated at the time delayed onset of muscle soreness (DOMS) occurs. METHODS Eight healthy men (26.5 +/- 1.5 yr) performed 60 eccentric contractions at approximately 135-150% dominant arm maximum isometric force (MIF) using their nondominant arm elbow flexors. DOMS, range of motion (ROM), MIF, and blood were obtained before, immediately after, and 24, 48, 72, and 96 h after the EE. Blood samples were analyzed for plasma creatine kinase (CK) activity, and protein carbonyls (PC), and erythrocyte glutathione status. RESULTS A significant decrease in MIF occurred at all times after the EE. ROM decreased from 24 to 96 h, and DOMS increased 24 to 72 h in the nondominant arm as indicated by a repeated measure ANOVA. Plasma CK activity peaked at 72 h (1620 +/- 500 IU x L(-1)) compared with baseline (154 +/- 27 IU x L(-1). Erythrocyte-reduced glutathione (GSH) concentration was not significantly affected by the EE but tended to decrease 23% by 24 h and continued at this level for 96 h. Oxidized glutathione (GSSG) and total glutathione were unchanged over time. A significant increase in plasma PC occurred at 24 and 48 h after eccentric exercise. CONCLUSIONS The results suggest that 60 EE at 135-150% MIF can result in DOMS, with decreased muscle function and increases in plasma PC at 24 and 48 h without alterations in blood glutathione status.

Plasma creatine kinase activity and glutathione after eccentric exercise.

PURPOSE This study examined whether plasma total glutathione levels could explain the intersubject variability in the creatine kinase (CK) response to eccentric exercise. We hypothesized that the increase in plasma CK activity after eccentric exercise would be lower for individuals with low plasma total glutathione (<2.5 micromol x L-1) compared with individuals with high total glutathione (>3.8 micromol x L-1), but other indicators of muscle damage would be the same between groups. METHODS Resting blood samples were obtained over 2 d from 60 subjects and analyzed for plasma total glutathione. Eight subjects who had total glutathione values below 2.5 micromol x L-1 (LG), and nine who had values above 3.8 micromol x L-1 (HG) performed 50 maximal eccentric actions of the elbow flexors. Maximal voluntary isometric contraction (MVC), relaxed arm angle (RANG), and blood samples for CK, myoglobin (Mb), and total glutathione were obtained pre, post (except blood samples), 24, 48, 72, 96, and 120 h after exercise. RESULTS There was a significant group-by-time interaction in analysis of MVC, RANG, total glutathione, CK, and Mb response to exercise. Although LG showed a smaller CK response to eccentric exercise compared with HG, LG also showed a smaller increase in plasma Mb, a faster recovery of MVC and RANG, and an increase in plasma total glutathione. CONCLUSION Subjects with low plasma total glutathione levels had a smaller plasma CK and Mb response and a faster recovery from eccentric exercise compared with subjects having high plasma total glutathione levels. We suggest that a blunted inflammatory response in subjects with low plasma glutathione may be one explanation for these findings.

Effect of exercise during the follicular and luteal phases on indices of oxidative stress in healthy women

PURPOSE Eleven healthy nonsmoking women (24+/-1.1 yr) exercised for 30 min at 75-80% VO2max during the follicular (F) and luteal (L) phases of their menstrual cycle to determine whether menstrual phase influenced indices of oxidative stress. METHODS Subjects completed the exercise in a randomized order. Subjects reported between 0800 and 0900 in a postabsorptive state, rested for 15-30 min, and had a venous blood sample obtained by Vacutainer before and after exercise. RESULTS Resting estradiol was 54.4+/-12.0 pg.mL(-1) for F phase and was significantly higher in L phase (147.2+/-25.5 pg.mL(-1)). Plasma malondialdehyde and thiobarbituric acid substances were no different before and after exercise independent of menstrual cycle phase. No differences in resting blood total glutathione (TGSH), oxidized glutathione (GSSG), and reduced glutathione (GSH) were evident comparing the F and L phases. After exercise, TGSH decreased (P = 0.03) but reached significance only in the F phase = 8.1 %(P = 0.04), L phase = 2.5% (P = 0. 15). Exercise increased GSSG 10.5% in F (P = 0.15) and 27.8% in L phases(P = 0.01). GSH decreased after exercise independent of menstrual phase (F = 17%, L = 16%, P = 0.01). CONCLUSION These data suggest that 30 min of moderate-intensity exercise in female subjects can result in mild oxidative stress as indicated by blood glutathione status and that menstrual cycle phase has minimal influences on these exercise responses.

Activity and immobilization after eccentric exercise : I. Recovery of muscle function

PURPOSE The purpose of the present study was to determine whether activity would affect the recovery of muscle function after high-force eccentric exercise of the elbow flexors. METHODS Twenty-six male volunteers were randomly assigned to one of three groups for a 4-d treatment period: immobilization (N = 9), control (N = 8), and light exercise (N = 9). Relaxed arm angle (RANG), flexed arm angle (FANG), maximal isometric force (MIF), and perceived muscle soreness (SOR) were obtained for 3 consecutive days pre-exercise (baseline), immediately post-exercise, and for 8 consecutive days after the 4-d treatment period (recovery). During the treatment period, the immobilization group had their arm placed in a cast and supported in a sling at 90 degrees. The control group had no restriction of their arm activity. The light exercise group performed a daily exercise regimen of 50 biceps curls with a 5-lb dumbbell. RESULTS All subjects showed a prolonged decrease in RANG, increase in FANG, loss in MIF, and increase in SOR in the days after eccentric exercise. During recovery, there was no significant interaction observed among groups over time in RANG (P > 0.05) or FANG (P > 0.05), but there was a significant interaction observed among groups over time in both MIF (P < 0.01) and SOR (P < 0.01). Recovery of MIF was facilitated by light exercise and immobilization, whereas recovery from SOR was facilitated by light exercise and delayed by immobilization. CONCLUSIONS The recovery of MIF in both the light exercise and immobilization groups suggests that more than one mechanism may be involved in the recovery of isometric force after eccentric exercise.

Activity and immobilization after eccentric exercise: II. Serum CK.

PURPOSE The purpose of the present study was to examine the effect of muscle activity level on serum creatine kinase (CK) activity after high-force eccentric exercise of the elbow flexors. METHODS Twenty-six male volunteers were randomly assigned to one of three groups for a 4-d treatment period after exercise: immobilization (N = 9), control (N = 8), and light exercise (N = 9). During the treatment period, the immobilization group had their arm casted and supported in a sling at 90 degrees. The control group had no restriction of their arm activity. The light exercise group performed a daily exercise regimen of 50 biceps curls with a 5-lb dumbbell. Serum CK activity was obtained by venipuncture for three consecutive days before eccentric exercise and during the 4-d treatment period. To quantify activity of the arm, CSA (Computer Science and Applications, Inc.) activity-monitoring devices were worn. RESULTS Serum CK measurements revealed that there was a significant group by time interaction in the analysis of variance (P < 0.05). Peak serum CK activity of the immobilized group (668 IU) was lower than either the control (4230 IU) or light exercise (2740 IU) group. During the treatment period, activity level among the three groups was significantly different from each other (P < 0.001): 529 counts x min(-1) for the immobilization group, 944 counts x min(-1) for the control group, and 1334 counts x min(-1) for the light exercise group. CONCLUSIONS These results suggest that immobilization of exercised damaged muscle during recovery significantly blunted serum CK activity, which may be due to attenuated removal of CK from the muscle and/or decrease lymphatic transport.