Background: Inflammation and pain induced by delayed onset muscle soreness (DOMS) as a result of eccentric exercise (EE) or unaccustomed activity cause some difficulties in exercise for athletes. The purpose of this study was to survey the effect of ginger extract on biochemical and functional symptom of delayed onset muscle soreness. Methods: In a quasi-experimental study, 36 healthy female subjects, who were recruited by intra dormitory calls, randomly divided into 3 groups, including: ginger intake 1 hour before exercise (GIBE), ginger intake immediately after exercise (GIAE) and placebo group (PL). Subjects consumed capsules contain 60 mg of ginger extract (equivalent of 2 g dried ginger powder) or placebo before and after exercise. The exercise protocol consisted of a 20 minute step test using a 46cm step at a rate of 15 steps per minute. The blood samples were taken before, 1, 24 and 48 hour after exercise to assay creatine kinase (CK) and interleukin-6 (IL-6). Muscle pain scores, isometric strength and circumference of thigh muscle, and hip range of motion were recorded at mentioned times. The analysis of variance (ANOVA) with repeated measure was used to determine the differences between groups. Results: The results showed a significant reduction of pain in GIBE compared to GIAE after 24 and 48h of EE and GIAE compared to PL (p0.05). As it is shown in , there isn’t significant difference in isometric strength of thigh between and within groups after EE in none of the phases of measurement. The changes of CPK † Significant difference between GIBE and PL ḟḟ Significant difference between GIAE and PL * Significant difference in comparison with pre-test ! Significant difference in comparison with previous phase of measurement ! Significant difference in comparison with previous phase of measurement
The purpose of the current study was to examine the acute effect of oral consumption of 2-g dose of ginger extract on some biochemical and functional factors of delayed onset muscle soreness after one session step test as an eccentric exercise. Right and left thigh muscle circumference, ROM of right and left hip, isometric strength of thigh and CPK after step test did not differ between ginger and placebo conditions but the ratio of pain and IL-6 were significantly different between groups. Ginger exhibited hypoalgesic effect on quadriceps pain intensity in GIBE and GIAE compared with PL. The finding that ginger reduced muscle pain as a result of delayed onset muscle soreness caused by eccentric exercise is consisted with previous studies demonstrating that 2-g use of raw or heated ginger can reduce arm pain in human after eccentric elbow action (14). One study showed that administration of 1500 mg ginger powder daily for three days produce analgesia in students with primary dysmenorrheal (34). Ginger act as a pain relief in patients with osteoarthritis of the knee (35) and have more effect than ibuprofen (25). But ingesting 2-grams of ginger doesn’t have any effect on quadriceps muscle pain during and after moderate-intensity cycling exercise (15) and this may be because of the severity of the protocol was used. 6-Shogaol is one of the major biologically active compounds found in the rhizome of Zingiberofficinale/ ginger that have analgesic effects (26). To explain the effects of ginger on pain relief, it has been reported that ginger inhibits cyclooxygenase and lipooxygenase pathways in prostaglandin and leukotriene synthesis and the anti-inflammatory property of ginger has been attributed to inhibition of prostaglandin synthesis (26, 36). Inflammatory response ends up in autacoid leukotriene synthesis. PGE2 directly causes pain by sensitizing types III and IV pain receptors. In the current study, perception of pain in GIBE was less than GIAE and PL and this may be due to the inhibitory effect of ginger on prostaglandin’s release. It seems that consumption of ginger before exercise could cease the cascade of inflammatory factors and thereby caused a lesser pain report. Ginger also showed an inhibitory effect on IL-6 in GIBE compared with GIAE and PL; but within groupstherewas no difference. According to the results of some in vitro studies, rhizome of ginger and its main components, gingerols and shogaols, can inhibit synthesis ofpro-inflammatory cytokines including IL-1, TNF-α and IL-8 along with inhibiting prostaglandin and leukotriene synthesis enzymes (37). The systemic response to inflammation rapidly becomes anti-inflammatory as plasma levels of IL-6, IL-10, IL-1ra and soluble TNF-α receptors rise in direct proportion to the intensity and duration of exercise (38, 39). The release of the pro-inflammatory cytokines into the circulation is inhibited by IL-6, which stimulates the production of the anti-inflammatory cytokines (40). Nieman et al. (2005) tested the relationship between plasma CPK, DOMS and various plasma cytokines. These researchers found that muscle damage, post-race DOMS and IL-6, IL-10 were positively correlated. The increase in the cytokines was greatest for IL-6 (125-fold), corresponding with a 112-fold increase in CPK (13). In our study increase in IL-6 in GIBE in comparison with the other groups was less and this may be related to the anti-inflammatory effect of ginger. It seems that one hour, was enough for ginger to affect on cytokine’s release. After muscular damaged, the sarcolema disruption allows muscle proteins such as CK to be released from the fiber into the blood stream (41, 42). The increased level of CPK confirmed occurrence of DOMS. After eccentric exercise, CPK changed significantly in GIAE and PL but not in GIBE that was similar to previous studies (43-45). The main symptoms of DOMS are pain, decrease in range of motion, decrease in muscle strength and swelling (13,15). Swelling is often associated with acute inflammation. Many studies using humans to investigate an association between DOMS and swelling. Loss of function and strength is associated with loss of force generating capacity (12) . Our findings of increased thigh muscle volume and decreases hip ROM and isometric strength, clearly showed that the exercise protocol resulted in muscle damage, but ginger couldn’t ameliorate these symptoms. Ginger and DHA (docosahexaenoic acid) (15, 46), and vitamin C (45) didn’t change arm volume and elbow ROM after EE. The increase in isometric strength of thigh 1 hour after exercise may be due to better use of dynamometer. Similar to Drager et al. study, the decrease in ROM was associated with decrease in isometric strength and this suggests that muscular tightness can impair maximum isometric force production (46). Although the changes in these variables weren’t statistically significance, but it showed that ginger had a positive effect on GBE in comparison with GIAE and PL. In summery the results of the present study suggest that ginger extract could reduce pain and inflammation caused by eccentric exerciseIt could be used as an effective herbal in healing DOMS.