Delayed Muscle Soreness Research Articles

(486) Changes in physical activity and its association with pain-related negative affect and pain sensitivity before and after exercise-induced low back pain

This study examined changes in physical activity (PA) after exercise-induced delayed muscle soreness (DOMS) in healthy subjects. Additionally, we investigated the extent to which pain-related negative affect is associated with objective measures of PA, and the relationship between PA and measures of pain sensitivity. Thirty-seven pain-free volunteers (Females=22, age=24.6±5 y/o) participated. Subjects wore an activity monitor 12 hours/day for 10 days. PA variables used for analysis were total activity, mean activity counts per minute, and peak activity count. Subjects completed the fear of pain questionnaire and the pain catastrophizing scale. Pain sensitivity was measured using pressure pain threshold (PPT) and heat pain threshold and tolerance. DOMS was induced 5 days after baseline testing. Subjects were tested again 48 hours later and were asked to rate their worst pain experienced within the last 48 hours using the numeric rating scale (NRS). Pearson’s correlation moments were used to examine the association among variables of interest. Paired sample t-test compared levels of PA pre- and post-DOMS. Before DOMS total PA was associated only with fear (r=-0.389; p=0.017). Positive associations between total PA and PPT (r=0.527; p=0.001), heat pain threshold (r=0.452; p=0.005), and heat pain tolerance (r=0.319; p=0.054) were observed. After DOMS subjects reported pain of 24.1±21.7 on the NRS. Peak activity count decreased after DOMS from 9641±5229 to 7859±4571 (p=0.001) and mean activity counts decreased from 470.3±205.9 to 408.2±165.5 (p=0.003). Results from this study suggest that fear of pain but not catastrophizing is an important psychological factor that influences PA in healthy subjects. Additionally, higher levels of PA activity may enhance descending pain modulatory systems that could protect against pain conditions. Finally, PA intensity after DOMS was reduced as shown by a decrease in mean activity counts per minute and peak PA. This study examined changes in physical activity (PA) after exercise-induced delayed muscle soreness (DOMS) in healthy subjects. Additionally, we investigated the extent to which pain-related negative affect is associated with objective measures of PA, and the relationship between PA and measures of pain sensitivity. Thirty-seven pain-free volunteers (Females=22, age=24.6±5 y/o) participated. Subjects wore an activity monitor 12 hours/day for 10 days. PA variables used for analysis were total activity, mean activity counts per minute, and peak activity count. Subjects completed the fear of pain questionnaire and the pain catastrophizing scale. Pain sensitivity was measured using pressure pain threshold (PPT) and heat pain threshold and tolerance. DOMS was induced 5 days after baseline testing. Subjects were tested again 48 hours later and were asked to rate their worst pain experienced within the last 48 hours using the numeric rating scale (NRS). Pearson’s correlation moments were used to examine the association among variables of interest. Paired sample t-test compared levels of PA pre- and post-DOMS. Before DOMS total PA was associated only with fear (r=-0.389; p=0.017). Positive associations between total PA and PPT (r=0.527; p=0.001), heat pain threshold (r=0.452; p=0.005), and heat pain tolerance (r=0.319; p=0.054) were observed. After DOMS subjects reported pain of 24.1±21.7 on the NRS. Peak activity count decreased after DOMS from 9641±5229 to 7859±4571 (p=0.001) and mean activity counts decreased from 470.3±205.9 to 408.2±165.5 (p=0.003). Results from this study suggest that fear of pain but not catastrophizing is an important psychological factor that influences PA in healthy subjects. Additionally, higher levels of PA activity may enhance descending pain modulatory systems that could protect against pain conditions. Finally, PA intensity after DOMS was reduced as shown by a decrease in mean activity counts per minute and peak PA.

Gene Expression in Circulating White Blood Cells Following Eccentric Exercise

Strenuous, unaccustomed exercise involving eccentric (muscle-lengthening) actions (ECC) can produce muscle damage, characterized by delayed muscle soreness and prolonged losses in strength and range of motion. The initial mechanical damage caused by ECC is followed by repair and regeneration. An increase in circulating white blood cells (WBCs) after ECC is followed by waves of inflammatory cells that infiltrate the muscle and play a range of roles, including clean up of damaged debris and signaling to promote remodeling. Following a second, or repeated, bout of ECC, there is less soreness and reduced losses in strength and range of motion, as well as an attenuated peripheral inflammatory response. These responses are collectively known as the "repeated bout effect." The mechanisms driving this effect are poorly understood; however, it has been suggested that the attenuated inflammatory response may play a role. PURPOSE: To identify alterations in global gene expression in circulating WBCs via microarray analysis following an initial and repeated bout of ECC. METHODS: Six healthy, sedentary men aged 23.5 +/- 1.7 years participated. These subjects performed 24 maximal ECC of the elbow flexors. After 2 weeks, subjects repeated the exercise. WBCs were isolated from blood drawn at the same time of day at 3 visits (baseline and 6 hours after each bout). Gene expression of WBCs was measured using Affymetrix GeneChip Human Genome U133A 2.0 Arrays and analyzed using RM ANCOVA (age and BMI covariates; p<0.02) in Partek Genomics Suite. RESULTS: Following bout 1, 189 genes were upregulated and 142 downregulated. Following the second bout, a greater number of genes had altered expression, with 745 genes upregulated and 305 downregulated. Expression of 169 genes was altered differentially between bouts. Genes upregulated after bout 2 but not bout 1 included several members of the JAK/STAT pathway (e.g. JAK3: 6-fold; STAT5B: 1.4-fold; STAT6: 1.4-fold) and several actin-related genes (PDLIM7: 2.1-fold and ARPC4: 1.4-fold). CONCLUSIONS: Gene expression in WBCs was selectively altered in response to a repeated bout of ECC, including those in the JAK/STAT pathway and several actin-related genes. These genes may play a role in the repeated bout effect. This study was made possible by the Vermont Genetics Network through Grant Number P20 RR16462 from the INBRE Program of the National Center for Research Resources (NCRR), a component of the National Institutes of Health (NIH). Its contents are solely the responsibility of the authors and do not necessarily represent the official views of NCRR or NIH.

Effects of High Dose Fish Oil Supplementation on Delayed Onset Muscle Soreness and Inflammatory Markers

Delayed muscle soreness (DOMS) is caused, in part, by muscle damage associated with the eccentric component of exercise and this muscle damage can result in an inflammatory response by the body. Fish oil rich in eicosapaetonic acid (EPA) and docosahexeoric acid (DHA) have been shown to have anti-inflammatory properties. However, studies have not investigated the impact of consuming a high dose offish oil for a prolonged period of time on DOMS. The purpose of this study was to determine the effects of high dose fish oil supplementation on DOMS and the associated muscle inflammatory response. The control group (CON; n=10) consumed 3.45 grams of wheat germ and the experimental group (FO; n=10) received 3.0 grams fish oil per day for 65 days. On Day 60, participants performed eccentric muscle contractions at an angular velocity of 60°-sec -1 through 20° to 90° of knee flexion until exhaustion. Perceived muscular soreness, isometric strength, and muscle inflammatory markers were measured before exercise and at 8, 24,48, 72, 96 and 120 hours post-exercise. We found no significant differences between the CON and FO groups for all variables. The data suggests the fish oil had no effect on inflammatory markers and the signs and symptoms of DOMS when compared to a placebo.

Building Muscle Is a Pain

Bradykinin released during exercise stimulates nerve growth factor production by muscle, which sensitizes pain nerves and leads to delayed muscle soreness.

Physiological Background of Muscular Pain During Skiing and Delayed Muscle Soreness after Skiing

Physiological Background of Muscular Pain During Skiing and Delayed Muscle Soreness after Skiing During intensive skiing, at each turn, in particular towards the end of the turning steering phase, eccentric work of the lower limb muscles occurs (predominantly of the quadriceps femoris), which is the direct cause of damage within muscle cells. A few or more than ten hours after intensive physical effort the symptoms of delayed onset muscle soreness may appear, which is mainly a result of the micro-damage within the myocytes. The following procedure can be proposed for prevention of muscle soreness for skiers: around a week before first day of skiing in the season, skiers should perform a series of intensive physical exercises involving eccentric contractions, thus inducing delayed muscular soreness. The exercises may involve for example: downhill running, preferably down a steep slope, running down stairs, deep knee bend jumps, deep knee bend jumps over an obstacle, jumping to the ground from a certain height, sit-ups on one or both feet, etc. The exercises should lead considerable local fatigue, in particular of the lower limb muscles, so that muscle soreness occurs on the second day, in particular in the frontal part of the thighs. After approximately two days the pain will alleviate, while after a week the strength of the muscles will return to its pre-exercise condition. This should considerably reduce, or even remove, delayed muscle soreness after skiing, which will not only help skiers use their time more effectively but will also be crucial to the skiers' safety.

Eccentric Exercise Alters The Kinematic Structure Of Pointing Movements

It is known that the performance of eccentric muscle contractions often leads to delayed muscle soreness accompanied by declines in strength and isometric force steadiness. However, the effect of eccentric exercise on the performance of a dynamic motor task is not clear. PURPOSE: To examine the effects of a bout of eccentric exercise on kinematic measures related to accuracy (i.e. submovements) during spatially-constrained pointing movements. METHODS: 17 untrained subjects (10 M, 7 F; 26 ± 3 yrs.) performed 20 rapid discrete elbow-extension pointing movements with their right arm before, immediately after (fatigue and muscle damage), and 24-hours after (muscle damage only) fatiguing eccentric exercise on a isokinetic dynamometer. Endpoint (fingertip) movement kinematics were obtained for each pointing trial and examined for secondary submovements indentified by zero crossings in the tangential velocity and acceleration profiles. RESULTS: MVC force declined by 44% immediately after eccentric exercise and remained depressed (22%) 24-hrs after the exercise indicating the existence of muscle damage. Movement times were slower and peak velocity decreased immediately after, and only partially recovered 24-hrs after the exercise compared with before (222 ± 40, 248 ± 37 and 238 ± 42ms, P<0.05; 3.4 ± 0.6, 3.1 ± 0.6 and 3.3± 0.7m/s, P<0.01). Only 8% of the trials exhibited submovements before the eccentric exercise, however that number grew to 87% of trials immediately afterward and 29% of trials 24 hrs after. In those trials requiring submovements, subjects traveled 85 ± 8, 64 ± 6 and 72 ± 11% (P<0.001) of the total movement time before using a secondary submovement. CONCLUSIONS: These results demonstrate that kinematic measures associated with movement accuracy are altered from eccentric exercise and only partially restored after 24 hrs.

The Effects of Ibuprofen on Delayed Muscle Soreness and Muscular Performance After Eccentric Exercise

The Effects of Ibuprofen on Delayed Muscle Soreness and Muscular Performance After Eccentric Exercise

MRI EVALUATION OF HEAT AND STRETCH AS TREATMENTS FOR MUSCLE DAMAGE AFTER ECCENTRIC EXERCISE

Delayed muscle soreness (DMS) is the sensation of pain and/or discomfort experienced 24 - 48 hours after eccentric exercise (ECC). Magnetic resonance imaging (MRI) studies have shown that muscles subjected to ECC exercise exhibit an increase in T2 relaxation time post-exercise that parallels the development of pain and damage associated with DMS. Post-exercise static stretching and/or the application of superficial heat have been suggested as a method to alleviate DMS. PURPOSE: To examine the effects of topical heat and/or static stretch treatments on T2 relaxation time, muscle swelling, isometric strength, and pain following ECC exercise. METHODS: Thirty two untrained male subjects performed intense ECC knee extension exercise, followed by two weeks of treatment (heat, stretch, heat plus stretch) or no treatment (control, n = 8/group). Isometric strength testing, pain ratings, and T2-weighted images (TR/TE = 1500/30,60) of the thigh were performed before and at 2, 3, 4, 8, and 15 d. RESULTS: ECC exercise produced muscle damage in all groups as evidenced by the large increase in T2 and muscle swelling, and from the decrease in isometric strength in the first few days after the exercise. Independent of treatment, pain ratings and muscle swelling recovered to baseline by 15 d, although isometric strength remained lower (77 ± 4 vs. 95 ± 3 kg pre-exercise, mean ± SE) and T2 values higher (32.2 ± 0.8 vs. 28.6 ± 0.2 ms). T2, swelling, pain and the deficit in strength on day 15 were not different between the treatment groups. CONCLUSION: The similar time course and magnitude of the T2 changes and pain ratings in the days following ECC exercise demonstrates that therapeutic application of superficial heat and/or static stretching did not enhance the recovery of damaged muscle nor did it alleviate the soreness. (Supported by a gift from Proctor and Gamble)

Plasma creatine kinase responses of 18- to 30-yr-old African-American men to eccentric exercise.

The primary aim was to describe the response of plasma creatine kinase (CK) activity in a sample of African-American men after a bout of eccentric exercise. The study also described signal intensity changes detected by MR in the musculature of the right lower leg. Subjects were 20 male volunteers of African descent (age = 24 +/- 4 [mean +/- SD] yr). Each walked backward for 60 min at 3 km x h(-1) down a 23% grade. Venous blood was sampled before exercise, immediately (0 d) after and 1, 2, 4, and 7 d after exercise for plasma CK assay. Soreness in the plantar flexor muscles was evaluated in 18 subjects at selected times during the 7 d postexercise. Injury to the plantar flexor muscles was evaluated by magnetic resonance imaging (MRI). The subjects had high baseline plasma CK activity (187 +/- 127 IU x L(-1); 163 +/- 70 IU x L(-1) with one outlier excluded) compared with typical clinical norms. As a group, CK activity was increased (P < 0.05) 4 d (980 +/- 1331 IU L(-1)) and 7 d (1022 +/- 1031 IU L(-1)) postexercise, compared with preexercise. Eleven (55%) of the subjects had large, delayed increases in plasma CK activity ("hyperresponses"). As a group, the plasma CK response was similar to responses of comparison Caucasian subjects. All subjects reported delayed muscle soreness; there was no association between soreness and plasma CK. Every subject showed MRI evidence of injury to plantar flexor muscles postexercise but varying in degree and time course. Plasma CK activity correlated to MRI signal intensity (rho = 0.445). Results suggest that changes in plasma CK activity and skeletal muscle injury in African-American men after eccentric exercise do not differ from the responses of Caucasians.

AGE-RELATED DIFFERENCES IN THE PANCREATIC ??-CELL RESPONSE TO HYPERGLYCEMIA FOLLOWING ECCENTRIC EXERCISE

136 Eccentric exercise results in delayed muscle soreness, muscle damage, insulin resistance, and increased insulin secretion in young individuals. The purpose of this investigation was to determine if older subjects differ from young subjects, in the pancreatic β-cell response to glucose following eccentric exercise. Hyperglycemic clamps (180 min, 10.0 mM) were performed on 8 young (age, 22 ± 1 yrs; body mass index, BMI, 23.4 ± 1.9 kg·m-2.; waist-to-hip ratio, WHR, 0.83 ± 0.02) and 8 older (age, 66 ± 2; BMI, 25.5 ± 1.2; WHR, 0.91 ± 0.01) sedentary healthy men with normal glucose tolerance, without exercise (CON) and 48 h after a single bout of eccentric exercise (ECC; leg extension and chest press, 10 sets X 10 reps, 100% 3-RM). ECC resulted in a 3-to-7-fold increase in muscle soreness ratings at 36 h in all subjects, and elevated (P< 0.02) plasma creatine kinase (CK) concentrations 48 h after ECC in young(1179 ± 480 vs. 58 ± 17 IU·I-1.; ECC vs. CON) and older subjects (629 ± 418 vs. 49 ± 15). Pancreatic β-cell secretion was similar in all subjects during CON clamps. When ECC was compared to CON, the first phase (0-10 min) C-peptide area under the curve (AUC) increased (P < 0.05) in young (4.2 ± 0.4 vs. 3.7 ± 0.6 nmol·I-1·min), but not among older subjects (3.2 ± 0.7 vs. 3.5 ± 0.7). The first phase C-peptide AUC response to ECC was significantly different (P < 0.02) between young and older subjects. Individual peak C-peptide concentrations were lower (P < 0.05) after ECC in older subjects (0.93 ± 0.16 vs. 1.12 ± 0.11 nmol·I-1), suggesting reduced first phase pancreatic β-cell secretion. In addition, first phase insulin-to-C-peptide molar ratios suggest opposite trends (P = 0.05) in insulin and/or C-peptide clearance for young and older subjects. Furthermore, the C-peptide AUC response to ECC was inversely related to WHR (r = -0.62, P < 0.02 and r = -0.66, P < 0.0006; first and second (10-180 min) phase, respectively). In conclusion, although all subjects experienced muscle soreness and apparent muscle damage after eccentric exercise, older subjects did not exhibit the increase in pancreaticβ-cell response to hyperglycemia that was observed among young subjects. Furthermore, abdominal adiposity may account for some of the age-related differences in pancreatic β-cell secretion following eccentric exercise.

THE EFFECTS OF IBUPROFEN ON DELAYED MUSCLE SORENESS AFTER ECCENTRIC EXERCISE840

The purpose of this study was to examine the effects of ibuprofen (an anti-inflammatory drug) on delayed muscle soreness, induced by eccentric exercise. Nineteen subjects age (x±s) 24.6±3.3 yr., height 176.2±11.1 cm. weight 77.3±18.7 kg and body fat 17.2±4.2% performed eccentric leg curl exercise in order to induce muscle pain in the hamstrings. Thereafter 10 subjects randomly received a placebo (double blind) and 9 an ibuprofen pill of 400 mg every 8 hours within a period of 48 hours. Blood samples of 15 ml for the measurement of creatine kinasse (CK) and white blood cells (WBC) were taken after 4-6, 24 and 48 hours of exercise. The maximal strength (1-RM), as well as the power and the range of motion decreased significantly (p<0.05) after 24 hours and after 48 hours of exercise in both the placebo and the ibuprofen group. Perceived pain increased in both groups after 24 and 48 hours (p<0.05), although the ibuprofen group yielded a significantly lower value (p<0.05) after 24 hours. The WBC were significantly increased after 4-6 hours (p<0.05). The CK values of the ibuprofen group were also significantly lower (p<0.05) after 24 and 48 hours revealing a significant interaction with the placebo group. The anti-inflammatory drug used in the present study relieved the pain and facilitated the repair of muscle damage induced by eccentric exercise. These results permit athletes to follow an eccentric exercise program in order to enhance their athletic performance.

Delayed muscle soreness. The inflammatory response to muscle injury and its clinical implications.

Delayed onset muscle soreness (DOMS) is a sensation of discomfort that occurs 1 to 2 days after exercise. The soreness has been reported to be most evident at the muscle/tendon junction initially, and then spreading throughout the muscle. The muscle activity which causes the most soreness and injury to the muscle is eccentric activity. The injury to the muscle has been well described but the mechanism underlying the injury is not fully understood. Some recent studies have focused on the role of the cytoskeleton and its contribution to the sarcomere injury. Although little has been confirmed regarding the mechanisms involved in the production of delayed muscle soreness, it has been suggested that the soreness may occur as a result of mechanical factors or it may be biochemical in nature. To date, there appears to be no relationship between the development of soreness and the loss of muscle strength, in that the timing of the two events is different. Loss of muscle force has been observed immediately after the exercise. However, by collecting data at more frequent intervals a second loss of force has been reported in mice 1 to 3 days post-exercise. Future studies with humans may find this second loss of force to be related to DOMS. The role of inflammation during exercise-induced muscle injury has not been clearly defined. It is possible that the inflammatory response may be responsible for initiating, amplifying, and/or resolving skeletal muscle injury. Evidence from the literature of the involvement of cytokines, complement, neutrophils, monocytes and macrophages in the acute phase response are presented in this review. Clinically, DOMS is a common but self-limiting condition that usually requires no treatment. Most exercise enthusiasts are familiar with its symptoms. However, where a muscle has been immobilised or debilitated, it is not known how that muscle will respond to exercise, especially eccentric activity.

Isokinetic Eccentric Exercise

The development of active isokinetic dynamometers has allowed the assessment of muscular moment under eccentric activations that have different characteristics to concentric actions. It is well documented that at a given angular velocity the eccentric moment is greater than the corresponding concentric moment. The moment-velocity relationship under eccentric conditions has been investigated, with conflicting results. Particularly, eccentric moment was reported to remain similar to, or to increase or decrease with, increasing angular velocity. As with concentric actions, the reliability of isokinetic eccentric measurements is influenced by a number of factors such as gravity, preload force and testing position. The velocity-specific effects of eccentric training have not been extensively investigated. Based on current knowledge, eccentric exercise does not appear to be velocity-specific. Although the mode specificity of both concentric and eccentric exercises have been investigated, the resultant observations are conflicting. Eccentric training has been found to improve both concentric and eccentric strength: yet, it has also been reported to improve only concentric or eccentric strength. The reciprocal muscle group ratios under eccentric actions were found not to be influenced by angular velocity, but the significant role of the eccentric/concentric moment ratio of each muscle has not been examined thoroughly. It is well documented that eccentric activations are associated with delayed muscle soreness and muscle damage. A limited number of studies have reported that isokinetic eccentric efforts may result in a lower amount of muscle soreness compared with other exercise modalities. Isokinetic dynamometers provide some unique characteristics for rehabilitation applications. Examination of the clinical application of eccentric exercise is limited. Consequently, the use of this exercise modality in prevention and assessment of musculoskeletal injuries should be investigated further.

Effects of Isokinetic Soreness-Inducing Exercise on Blood Levels of C-Reactive Protein and Creatine Kinase

This study examined whether acute inflammation was the mechanism underlying delayed muscle soreness (DMS) by assessing the effect of soreness-inducing exercise on blood levels of C-reactive protein (CRP), an acute inflammation marker. Sixteen female college students (= 20.6 +/- 2.6 years) performed three sets of 35 isokinetic contractions of the knee flexors and extensors at 120 degrees /set on a Biodex isokinetic dynamometer. Group 1 (N = 8) exercised eccentrically and Group 2 (N = 8) concentrically at an intensity of 80% of a concentric 120 degrees /set peak torque. Pre-exercise and 1, 24, 48 and 72 hours postexercise, DMS of the quadriceps femoris (QF) and hamstrings (HA) were assessed and blood samples were collected for creatine kinase (CK), an indicator of muscle damage, and CRP, which was measured by a radial immunodiffusion procedure. The mean CK values 72 hours postexercise were 14,856 and 360 IU/L for groups 1 and 2, respectively. No significant elevations of CRP occurred in either group. ANOVAs using a split plot factorial design found Group 1 to have significantly larger logarithmic CK elevations, ranked QF soreness, and ranked HA soreness than Group 2. In contrast to myocardial infarct patients and marathon runner investigations, this study did not demonstrate abnormal elevations of CRP when increases in CK were induced. With high-repetition submaximal isokinetic exercise, eccentric contractions induce higher levels of muscle damage and DMS than concentric contractions. Further, the hamstrings are more susceptible to DMS than the quadriceps femoris when eccentric isokinetic exercise is performed at the same relative intensity. J Orthop Sports Phys Ther 1992;16(5):208-214.

Effects of downhill running on the responses to an oral glucose challenge.

Because muscle damage from eccentric exercise has been associated with alterations in muscle glycogen metabolism, this study determined the effects of exercise on the insulin and glucose responses to an oral glucose tolerance test (OGTT). In a repeated-measures design, 11 subjects undertook either no exercise, 2 min of isokinetic leg exercise, or 50 min of level or downhill running. No exercise was performed and diet was controlled during the 48 hrs after the treatments and before the OGTT. Ratings of muscle soreness and CK activity were significantly elevated 48 hrs after downhill running. Level running also increased CK activity but did not induce muscle soreness. Isokinetic exercise did not affect either one. Blood glucose responses to the OGTT were similar among the treatments. In contrast, the insulin responses to the OGTT following downhill running were significantly increased. These results suggest that eccentric exercise associated with downhill running that results in delayed muscle soreness is associated with the development of a mild insulin-resistant condition.

The Effect of Eccentric Strength Training at Various Speeds on Concentric Strength of the Quadriceps and Hamstring Muscles

This study investigated the effect of eccentric training on concentric strength of the quadriceps and hamstring muscles. The dominant legs of 43 college-age males were pretested concentrically using the KIN-COM(R) at speeds of 60 and 180 degrees /sec. Twenty-eight treatment subjects trained eccentrically at one of the testing speeds for a period of eight weeks; the remainder served as the control group. Prior to each training session, the subjects gave a subjective evaluation of muscle soreness. Delayed muscle soreness did not affect the subjects' ability to train eccentrically. A concentric posttest was taken to determine any treatment effects. The quadriceps muscle did not show any significant change after eccentric training. Eccentric training at 60 and 180 degrees /sec significantly increased the concentric strength of the hamstrings. Eccentric training does appear to be effective in developing concentric strength in the hamstrings. The speed of eccentric training was not a factor in concentric conditioning. J Orthop Sports Phys Ther 1991;13(5):226-230.

Effects of Miometric and Pliometric Muscle Actions on Delayed Muscle Soreness

Effects of Miometric and Pliometric Muscle Actions on Delayed Muscle Soreness

Comparison of Quadriceps Isokinetic Eccentric and Isokinetic Concentric Data Using a Standard Fatigue Protocol

. The purpose of the study was to compare fatigue development in concentric vs. eccentric muscular activation in the quadriceps of 15 healthy human subjects, controlling as many of the dynamic variables as possible. An isokinetic testing protocol was used, with knee joint angular velocity limited to 180 deg/sec, and with 40 repetitions through a range of motion of 75 deg constituting the fatigue-developing exercise. Quadriceps torque was measured via a robotic dynamometer, IEMG of the rectus femoris muscle was recorded, and a subjective pain rating scale was used to assess delayed muscle soreness following fatiguing exercise for concentric and eccentric tests. Eccentric peak torque to body weight ratio was greater than the concentric ratio (1.25 vs. 0.66, p < .001), significant torque fatigue developed in both eccentric and concentric tests (30.3% and 13.7%), and significant decline in IEMG occurred in both eccentric and concentric tests (17.0% and 15.1 %). The eccentric declines in torque and IEMG were not significantly different than the concentric declines. There was no clear difference in the pain reports associated with the two different exercise modes. Delayed onset muscle soreness was rated as mild (3 on scale of 10) at most during the 72-h surveillance period. It is concluded that the development of fatigue through eccentric muscular activation may stress the contractile mechanism less than that associated with concentric muscular contraction, and that standard clinical

Effects of Miometric and Pliometric Muscle Actions on Delayed Muscle Soreness

The acute effects of miometric muscle actions (MMA) and pliometric muscle actions (PMA) of the quadriceps were studied in 24 healthy untrained females. Group 80/80 (n=12) performed three sets of MMA-only (shortening muscle actions) knee extensions until fatigue, alternated with three sets of contralateral PMA-only (lengthening muscle actions) exercise with a similar resistance (80 percent 1 RM) for the same number of repetitions. The 80/120 group (n=12) followed the identical MMA protocol, but used 120 percent 1 RM to fatigue for the contralateral PMAs. Subjects returned approximately 48 hours after the initial exercise session to attempt to repeat or surpass their initial performance. Group 80/120 reported significantly higher (p < 0.01) delayed onset muscle soreness (DOMS) following PMAs 24, 48 and 72 hours post exercise. Group 80/80 reported similar DOMS for MMA and PMA limbs. There was no significant difference in the number of repetitions performed between the initial and 48-hour exercise sessions in either group. Contrary to the preponderance of professional opinion, these data suggest that when similar resistances are used, PMAs per se do not induce greater DOMS. However, greater resistive forces, which are often encountered during PMAs, can induce greater DOMS.

Does Postexercise Static Stretching Alleviate Delayed Muscle Soreness?

In brief: Twenty-three subjects performed a 30-minute step test to induce delayed muscle soreness (DMS) in the eccentrically contracting thigh and calf muscles. A regimen of static stretching performed after the test did not alleviate DMS; there was neither temporary relief of pain immediately after stretching nor a general reduction in pain during the three-day postexercise period. Serum creatine kinase level-a commonly used marker of muscle damage-was elevated after exercise and the strength of the sore thigh muscles was reduced; stretching did not affect these responses. These results contradict claims of the benefits of static stretching for relief of exercise-induced DMS.