Eccentric Exercise Protocol Research Articles

Novel method for evaluation of subtalar joint alignment under weight-bearing conditions using laser beam

Baseline testing comparing thosewithAchilles tendinopathy to healthy controls showed a clear difference between the groups (p≥ 0.001 for symptomatic and non-symptomatic sides) whilst after rehabilitation there is no statistical difference on the symptomatic or non-symptomatic leg (p= 0.103 and p= 0.332). Conclusion(s): This was the first study to determine how an eccentric exercise regime for the Plantarflexors affects endurance capacity in those with Achilles tendinopathy. This study highlighted significant differences in endurance capacity prior to the intervention, these deficits were resolved after the completion of an eccentric regime. This study also highlights that eccentric rehabilitation regimes alter endurance capacity in both legs despite only being performed on one leg. Implications: Eccentric exercise protocols appear to correct endurance capacity of those with tendinopathy, further studies need to determine if this is critical to good clinical outcomes.

Short-Wave Diathermy Pretreatment and Inflammatory Myokine Response After High-Intensity Eccentric Exercise.

Various modalities have been used to pretreat skeletal muscle to attenuate inflammation. To determine the effects of short-wave diathermy (SWD) preheating treatment on inflammation and stress markers after eccentric exercise. Controlled laboratory study. University laboratory setting. Fifteen male (age = 22 ± 4.9 years, height = 179.75 ± 9.56 cm, mass = 82.22 ± 12.67 kg) college-aged students. Seven participants were selected randomly to receive 40 minutes of SWD heat treatment (HT), and 8 participants served as the control (CON) group and rested without SWD. Both groups completed 7 sets of 10 repetitions of a high-intensity eccentric exercise protocol (EEP) at 120% of the 1-repetition maximum (1-RM) leg extension. We biopsied muscles on days 1, 3 (24 hours post-EEP), and 4 (48 hours post-EEP) and collected blood samples on days 1, 2 (4 hours post-EEP), 3, and 4. We determined 1-RM on day 2 (24 hours post-SWD) and measured 1-RM on days 3 and 4. We analyzed the muscle samples for interleukin 6 (IL-6), tumor necrosis factor α, and heat shock protein 70 and the blood for serum creatine kinase. We found a group × time interaction for intramuscular IL-6 levels after SWD (F2,26 = 7.13, P = .003). The IL-6 decreased in HT (F1,6 = 17.8, P = .006), whereas CON showed no change (P > .05). We found a group × time interaction for tumor necrosis factor α levels (F2,26 = 3.71, P = .04), which increased in CON (F2,14 = 7.16, P = .007), but saw no changes for HT (P > .05). No group × time interactions were noted for 1-RM, heat shock protein 70, or creatine kinase (P > .05). The SWD preheating treatment provided a treatment effect for intramuscular inflammatory myokines induced through high-intensity eccentric exercise but did not affect other factors associated with intense exercise and inflammation.

Adaptation of local muscle blood flow and surface electromyography to repeated bouts of eccentric exercise.

The aim of this randomized controlled crossover study was to investigate the effect of a bout of unaccustomed eccentric exercise (ECC) followed by a consecutive bout of the same intensity on local muscle blood flow, amplitude, and frequency of the electromyographic (EMG) signal from the exercised tibialis anterior muscle. Sixteen healthy male participants (age, 25.7 (0.6) years; body mass index 24.8 (1) kg·m(-2) participated in this study. Two identical bouts of high-intensity ECC were performed on the tibialis anterior muscle 7 days apart. Control sessions involving no exercise were performed 4 weeks either before or after the exercise sessions. Changes in local total blood flow [ΔtHb], EMG root mean square, and median power frequency were recorded during isometric maximum voluntary contraction of ankle dorsiflexion. Measurements were performed before, immediately after, and the day after both ECCs (ECC1 and ECC2). The participants rested quietly in a chair in the control session. Eccentric exercise 1 led to a significant decrease in [ΔtHb] on the day after (p ≤ 0.05), whereas ECC2 did not. Median power frequency decreased significantly in ECC2 compared with ECC1 (p < 0.01). Root mean square was unchanged in all the instants. The present study showed that adaptation is depicted in the local muscle blood flow and the frequency contents of the EMG after an unaccustomed ECC inducing muscle soreness. These alterations provide a potential mechanism for a rapid adaptation, which decreases susceptibility of the muscle to develop further soreness in the subsequent ECC bout.

(469) Treatment preference, equipoise and expectations: what you expect is what you get

Expected pain-relief from treatment is associated with positive clinical outcomes in patients with musculoskeletal pain. Less widely studied is the preference of the provider and patient for one type of treatment approach over others. The purpose of this study was to evaluate the extent to which these variables, the type of treatment received, and expectations for pain relief influenced pain intensity in an experimental model of low back pain. Healthy individuals were randomly assigned to receive manipulation (MAN), mobilization (MOB), or therapeutic touch (TT) 48 hours after an eccentric exercise protocol designed to induce acute low back pain. General linear modeling (GLM) was used to evaluate the contributions of expected pain relief, subject and provider treatment preference, and treatment received to pain relief immediately following MAN, MOB, or TT. Pain intensity was measured using the 101-point Numerical Pain Rating Scale. Data from 65 subjects (75.4% female, mean age 22.8) and 3 providers comprised the sample. No group differences existed in pre- and post-intervention pain intensity scores. Two providers expected SMT to provide the greatest pain relief and one did not have a preference. Twenty-four subjects (36.9%) had no treatment preference, four (6.2%) preferred MAN, 17 (26.2%) preferred MOB, and 20 (30.8%) preferred TT. GLM results indicated that subject expectation for pain relief significantly predicted pain relief (Waldχ2= 72.8, p<0.001). A significant interaction existed between treatment received and whether preference matched treatment; specifically, when a provider and subject had no preference about treatment, MAN was associated with pain relief (Waldχ2= 4.2, p=0.04). These data extend previous work related to expectations for pain relief to an acute model of low back pain. Our results suggest that an individual’s expectations for pain relief strongly predicted pain outcomes. Future work should extend these findings beyond the immediate time point.

The Effects of Pre-Exercise Ginger Supplementation on Muscle Damage and Delayed Onset Muscle Soreness.

Ginger possesses analgesic and pharmacological properties mimicking non-steroidal antiinflammatory drugs. We aimed to determine if ginger supplementation is efficacious for attenuating muscle damage and delayed onset muscle soreness (DOMS) following high-intensity resistance exercise. Following a 5-day supplementation period of placebo or 4 g ginger (randomized groups), 20 non-weight trained participants performed a high-intensity elbow flexor eccentric exercise protocol to induce muscle damage. Markers associated with muscle damage and DOMS were repeatedly measured before supplementation and for 4 days following the exercise protocol. Repeated measures analysis of variance revealed one repetition maximum lift decreased significantly 24 h post-exercise in both groups (p < 0.005), improved 48 h post-exercise only in the ginger group (p = 0.002), and improved at 72 (p = 0.021) and 96 h (p = 0.044) only in the placebo group. Blood creatine kinase significantly increased for both groups (p = 0.015) but continued to increase only in the ginger group 72 (p = 0.006) and 96 h (p = 0.027) post-exercise. Visual analog scale of pain was significantly elevated following eccentric exercise (p < 0.001) and was not influenced by ginger. In conclusion, 4 g of ginger supplementation may be used to accelerate recovery of muscle strength following intense exercise but does not influence indicators of muscle damage or DOMS.

Blood flow after exercise-induced muscle damage.

The most common modality used to address acute inflammation is cryotherapy. Whereas pain decreases with cryotherapy, evidence that changes occur in perfusion of skeletal muscle is limited. We do not know whether ice attenuates the increases in perfusion associated with acute inflammation. To examine the effects of repeated applications of ice bags on perfusion of the gastrocnemius muscle after an eccentric exercise protocol. Controlled laboratory study. Laboratory. Eighteen healthy participants (3 men, 15 women; age = 22.2 ± 2.2 years, height = 166.0 ± 11.9 cm, mass = 69.4 ± 25.0 kg). To induce eccentric muscle damage, participants performed 100 unilateral heel-lowering exercises off a step to the beat of a metronome. A randomized intervention (cryotherapy, sham, control) was applied to the exercised lower extremity immediately after the protocol and again at 10, 24, and 34 hours after the protocol. Baseline perfusion measurements (blood volume, blood flow, and blood flow velocity) were taken using contrast-enhanced ultrasound of the exercised leg. Perfusion was reassessed after the first intervention and 48 hours after the protocol as percentage change scores. Pain was measured with a visual analog scale at baseline and at 10, 24, 34, and 48 hours after the protocol. Separate repeated-measures analyses of variance were used to assess each dependent variable. We found no interactions among interventions for microvascular perfusion. Blood volume and blood flow, however, increased in all conditions at 48 hours after exercise (P < .001), and blood flow velocity decreased postintervention from baseline (P = .041). We found a time-by-intervention interaction for pain (P = .009). Visual analog scale scores were lower for the cryotherapy group than for the control group at 34 and 48 hours after exercise. Whereas eccentric muscle damage resulted in increased blood flow, ice did not decrease muscle perfusion 48 hours after exercise. Therefore, ice does not seem to decrease muscle perfusion when blood flow is elevated, as it would be during inflammation.

Combination of eccentric exercise and neuromuscular electrical stimulation to improve quadriceps function post-ACL reconstruction

BackgroundNeuromuscular electrical stimulation (NMES) has been shown to reduce quadriceps activation failure (QAF), and eccentric exercise has been shown to lessen muscle atrophy post-ACL reconstruction. Given that these are two critical components of quadriceps strength, intervention combining these therapies may be effective at reinstituting quadriceps function post-reconstruction. Thus, the aim of this study was to evaluate the effectiveness of a combined NMES and eccentric exercise intervention to improve the recovery of quadriceps activation and strength post-reconstruction. MethodsThirty-six individuals post-injury were placed into four treatment groups (N&E, NMES and eccentrics; E-only, eccentrics only; N-only, NMES-only; and STND, standard of care) and ten healthy controls participated. N&E and N-only received the NMES protocol 2× per week for the first 6weeks post-reconstruction. N&E and E-only received the eccentric exercise protocol 2× per week beginning 6weeks post-reconstruction. Quadriceps activation was assessed via the superimposed burst technique and quantified via the central activation ratio. Quadriceps strength was assessed via maximal voluntary isomeric contractions (Nm/kg). Data was gathered on three occasions: pre-operative, 12-weeks-post-surgery and at return-to-play. ResultsNo differences in pre-operative measures existed (P>0.05). E-only recovered quadriceps activation better than N-only or STND (P<0.05). N&E and E-only recovered strength better than N-only or the STND (P<0.05) and had strength values that were similar to healthy at return-to-play (P>0.05). ConclusionEccentric exercise was capable of restoring levels of quadriceps activation and strength that were similar to those of healthy adults and better than NMES alone.Level of evidence: Level 3, Parallel longitudinal study

A new exercise protocol to cause delayed onset muscle soreness in quadriceps femoris muscle and analyzing its effects on vertical jump height in amateur sportswomen

Introduction and goals: Delayed onset muscle soreness normally appears right after eccentric exercise and between the first 24 to 48 hours after exercise reaches its highest level. The symptoms totally disappear after 7 to 10 days. After recovery, power and efficiency of the muscle increase and this power raise, results in improvement of a sport skill like vertical jump. The aim of this article was studying the effects of eccentric exercise of quadriceps femoris muscle on vertical jump height in nonprofessional sportswomen. Material and method: This study was performed on 10 amateur sportswomen. In two test sessions performed right after the exercise and 10 days after that, quadriceps femoris muscle force, one repetition maximum (1RM), height of four types of single leg squat, double leg squat, countermovement, and drop jump ,and the amount of muscle soreness was examined. Data analyzing with SPSS software and paired T- test was done. Results: Isometric force of the quadriceps femoris muscle and the height of vertical jump decreased right after performing the eccentric exercise. The isometric force and the 1RM of quadriceps femoris muscle increased 10 days after performing eccentric exercise (P< o.o5). The jump that was mostly affected was single leg squat jump. Discussion: Performing eccentric exercise increases the muscle force and this force raise can enhance sport skill efficiency like vertical jump. The eccentric exercise protocol in this study was new and although its intensity was medium, it had positive effects on muscle force and vertical jump height. Key words: Delayed Onset Muscle Soreness, Quadriceps femoris, Vertical jump.

Musculoskeletal stiffness during hopping and running does not change following downhill backwards walking

Eccentric contractions that provide spring energy can also cause muscle damage. The aim of this study was to explore leg and vertical stiffness following muscle damage induced by an eccentric exercise protocol. Twenty active males completed 60 minutes of backward-walking on a treadmill at 0.67 m/s and a gradient of − 8.5° to induce muscle damage. Tests were performed immediately before; immediately post; and 24, 48, and 168 hours post eccentric exercise. Tests included running at 3.35 m/s and hopping at 2.2 Hz using single- and double-legged actions. Leg and vertical stiffness were measured from kinetic and kinematic data, and electromyography (EMG) of five muscles of the preferred limb were recorded during hopping. Increases in pain scores (over 37%) occurred post-exercise and 24 and 48 hours later (p < 0.001). A 7% decrease in maximal voluntary contraction occurred immediately post-exercise (p = 0.019). Changes in knee kinematics during single-legged hopping were observed 168 hours post (p < 0.05). No significant changes were observed in EMG, creatine kinase activity, leg, or vertical stiffness. Results indicate that knee mechanics may be altered to maintain consistent levels of leg and vertical stiffness when eccentric exercise-induced muscle damage is present in the lower legs.

Phototherapy in skeletal muscle performance and recovery after exercise: effect of combination of super-pulsed laser and light-emitting diodes.

Recent studies with phototherapy have shown positive results in enhancement of performance and improvement of recovery when applied before exercise. However, several factors still remain unknown such as therapeutic windows, optimal treatment parameters, and effects of combination of different light sources (laser and LEDs). The aim of this study was to evaluate the effects of phototherapy with the combination of different light sources on skeletal muscle performance and post-exercise recovery, and to establish the optimal energy dose. A randomized, double-blinded, placebo-controlled trial with participation of 40 male healthy untrained volunteers was performed. A single phototherapy intervention was performed immediately after pre-exercise (baseline) maximum voluntary contraction (MVC) with a cluster of 12 diodes (4 of 905nm lasers-0.3125mW each, 4 of 875nm LEDs-17.5mW each, and 4 of 670nm LEDs-15mW each- manufactured by Multi Radiance Medical™) and dose of 10, 30, and 50J or placebo in six sites of quadriceps. MVC, delayed onset muscle soreness (DOMS), and creatine kinase (CK) activity were analyzed. Assessments were performed before, 1min, 1, 24, 48, 72, and 96h after eccentric exercise protocol employed to induce fatigue. Phototherapy increased (p < 0.05) MVC was compared to placebo from immediately after to 96h after exercise with 10 or 30J doses (better results with 30J dose). DOMS was significantly decreased compared to placebo (p < 0.05) with 30J dose from 24 to 96h after exercise, and with 50J dose from immediately after to 96h after exercise. CK activity was significantly decreased (p < 0.05) compared to placebo with all phototherapy doses from 1 to 96h after exercise (except for 50J dose at 96h). Pre-exercise phototherapy with combination of low-level laser and LEDs, mainly with 30J dose, significantly increases performance, decreases DOMS, and improves biochemical marker related to skeletal muscle damage.

Benefits of Decumanum Phlebodium intake on the muscle damage in the response to intense physical exercise in sedentary subjects

Intense physical exercise provoke muscle damage, that in sedentary people can increase cardiovascular risk. Phlebodium decumanum (PD) has shown to have immunomodulator effects in models of moderate intense physical activities in well conditioned groups. To evaluate the PD effects during eccentric exercise, as a model of muscle inflammation protocol, on a sedentary population with cardiovascular risk. This is an experimental, double-blind, multigroup randomized study. Experimental Group 1 (n = 17)received PD, 9 doses of 400 mg (total amount 3.6 g) every 8 hours during 3 days, and Control Group 2 (n = 16)received a placebo. All the subjects performed two treadmill ergoespirometry tests: first, a modified Bruce protocol to discard ischemic responses during exercise and to evaluate VO2max before the experimental phase;and second, with an eccentric protocol (14% descending ramp test) during 10 minutes in stable state at 70-80%VO2max, as experimental inflammatory protocol.We compared intra and inter groups to evaluate differences in the pre and post-test differences results on blood muscle damage variables. The study shown statistically significant differences in all pre-post intra-groups results in muscle damage variables (CK, LDH and Myoglobin, but not in Cardiac Troponin), and in functional lower-limb test (SJand CMJ). The comparison of inter-group results shown less muscle damage and less functional lower-limb deterioration in Group 1 compared with Control group, with statistical significance in both cases. Differences in handgrip dynamometry were no statistically significant. The eccentric exercise protocol in that study has proven to be a good model to induce muscle and functional damage in sedentary people. Short PD treatment has shown to reduce muscle and functional acute damages compared with placebo control group in this specific population.

(528) The influence of fear of pain on activity-induced exacerbation of delayed onset muscle pain

Little is known regarding the influence of fear of pain on acute exacerbations of pain during activity, which is reported in several chronic pain conditions. Thus, the purpose of this study was to investigate the influence of fear of pain on pain perception during activity and at rest after induced delayed onset muscle pain (DOMP) of the bicep. Forty-two young healthy adults completed 2 consecutive days of testing. On Day 1, subjects completed the State-Trait Anxiety Inventory –Trait version (STAI-T), the Pain Catastrophizing Scale (PCS), and the Fear of Pain Questionnaire (FPQ-III). Then, subjects performed an eccentric exercise protocol of the non-dominant elbow flexors to induce DOMP. At baseline and 24 hours after the eccentric exercise protocol, bicep pain was assessed at rest and during elbow flexion, and extension. Subjects were then randomly assigned to perform 20 minutes of either standardized activity of the painful muscles (elbow flexion/extension with a 1lb dumbbell), non-standardized activity of the painful muscles (elbow flexion/ extension while playing Nintendo Wii Boxing), or quiet rest. Subjects rated their worst pain during the activity/rest. Step-wise regression models considered baseline pain measures and scores on the STAI-T, PCS, and FPQ-III as predictors of DOMP at rest and elbow flexion/extension 24 hours later. Bivariate correlations examined the relationship between fear of pain and worst pain during 20 minutes of activity or rest. FPQ-III scores significantly predicted DOMP at rest (b=.481) and pain during elbow extension (b=.445), and were significantly related to worst pain during 20 minutes of rest (r=.853) and standardized elbow flexion/extension activity (r=.733). These results confirm the influence of fear of pain on DOMP while at rest and provide novel evidence showing that greater fear of pain is also associated with greater activityinduced exacerbations of DOMP, with the exception of pain reported while playing Wii Boxing.

Effect of Whole-Body Periodic Acceleration on Exercise-Induced Muscle Damage after Eccentric Exercise

To examine the effects of whole-body periodic acceleration (pGz) on exercise-induced-muscle-damage (EIMD) -related symptoms induced by unaccustomed eccentric arm exercise. Seventeen active young men (23.4 ± 4.6 y) made 6 visits to the research facility over a 2-wk period. On day 1, subjects performed a 1-repetition-maximum (1RM) elbow-flexion test and were randomly assigned to the pGz (n = 8) or control group (n = 9). Criterion measurements were taken on day 2, before and immediately after performance of the eccentric-exercise protocol (10 sets, 10 repetitions using 120% 1RM) and after the recovery period. During subsequent sessions (24, 48, 72, and 96 h) these data were collected before pGz or passive recovery. Measurements included isometric strength (maximal voluntary contraction [MVC]), blood markers (creatine kinase, myoglobin, IL-6, TNF-α, TBARS, PGF2α, protein carbonyls, uric acid, and nitrites), soreness, pain, circumference, and range of motion (ROM). Significantly higher MVC values were seen for pGz throughout the recovery period. Within-group differences were seen in myoglobin, IL-6, IL-10, protein carbonyls, soreness, pain, circumference, and ROM showing small negative responses and rapid recovery for the pGz condition. Our results demonstrate that pGz can be an effective tool for the reduction of EIMD and may contribute to the training-adaptation cycle by speeding up the recovery of the body due to its performance-loss-lessening effect.

Effects of anatabine and unilateral maximal eccentric isokinetic muscle actions on serum markers of muscle damage and inflammation

The purpose of this study was to examine the effects of anatabine supplementation in conjunction with unilateral, maximal eccentric isokinetic muscle actions on serum markers of muscle damage and pro-inflammatory cytokines in humans. Seventeen men (mean±S.D. age=22.4±3.2 yrs) participated in this double-blinded, placebo-controlled, crossover study. Participants were randomly assigned to two 10-day conditions (anatabine and placebo) separated by a 2–4 week washout period. After seven days of supplementation, blood was sampled immediately prior to PRE, immediately following POST, and 24, 48, and 72h after 6 sets of 10 repetitions of unilateral, maximal eccentric isokinetic forearm flexion exercise. Concentrations of serum creatine kinase, lactate dehydrogenase, myoglobin, high sensitivity c-reactive protein, and TNF-α were measured. Creatine kinase, myoglobin, and lactate dehydrogenase increased (P<0.05), while high sensitivity c-reactive protein and TNF-α did not change (P>0.05) after the eccentric exercise during both conditions. Lactate dehydrogenase was higher (P<0.05) during the anatabine condition. The primary findings of this study were two-fold: (a) anatabine had no beneficial effects on traditional markers of muscle damage (creatine kinase, lactate dehydrogenase, and myoglobin) compared to placebo after the eccentric exercise protocol, and (b) the eccentric exercise protocol did not elicit increase in the pro-inflammatory cytokines (c-reactive protein and TNF-α). Future studies are needed to examine the effects of anatabine on naturally-occurring inflammation that is common with aging or obesity. Furthermore, additional research is needed to examine the relationship between muscle damage and inflammation after eccentric exercises of different modes, durations, and intensities.

In Memoriam

In Memoriam

Effects of load magnitude, muscle length and velocity during eccentric chronic loading on the longitudinal growth of the vastus lateralis muscle.

The present study investigated the longitudinal growth of the vastus lateralis muscle using four eccentric exercise protocols with different mechanical stimuli by modifying the load magnitude, lengthening velocity and muscle length at which the load was applied. Thirty-one participants voluntarily participated in this study in two experimental and one control group. The first experimental group (N=10) exercised the knee extensors of one leg at 65% (low load magnitude) of the maximum isometric voluntary contraction (MVC) and the second leg at 100% MVC (high load magnitude) with 90 deg s(-1) angular velocity, from 25 to 100 deg knee angle. The second experimental group (N=10) exercised one leg at 100% MVC, 90 deg s(-1), from 25 to 65 deg knee angle (short muscle length). The other leg was exercised at 100% MVC, 240 deg s(-1) angular velocity (high muscle lengthening velocity) from 25 to 100 deg. In the pre- and post-intervention measurements, we examined the fascicle length of the vastus lateralis at rest and the moment-angle relationship of the knee extensors. After 10 weeks of intervention, we found a significant increase (~14%) of vastus lateralis fascicle length compared with the control group, yet only in the leg that was exercised with high lengthening velocity. The findings provide evidence that not every eccentric loading causes an increase in fascicle length and that the lengthening velocity of the fascicles during the eccentric loading, particularly in the phase where the knee joint moment decreases (i.e. deactivation of the muscle), seems to be an important factor for longitudinal muscle growth.

The effect of eccentric exercise-induced delayed-onset muscle soreness on positioning sense and shooting percentage in wheelchair basketball players.

Eccentric exercise is defined as a type of exercise in which the muscle produces power by extending. In contrast to isometric and concentric exercises, eccentric muscle activity is much more effective mechanically; however, it may expose the muscle to soreness. Delayed-Onset Muscle Soreness (DOMS) emerges a couple of hours after an eccentric activity, especially in individuals who are not used to this kind of exercise, and causes a temporary decrease in muscle performance, joint movement angle and muscle power, and also a temporary increase in the blood creatine kinase (CK) activity. This study investigates the effect of DOMS on the upper extremities motor performance by conducting an eccentric exercise load on the elbow flexor muscles. Cross sectional study. The study included 10 wheelchair basketball players. First, the participants underwent blood CK activity, positioning sense, muscle pain, shooting performance measurements tests at the base, and after 30 minutes and 24 and 48 hours. Then, one week later, the one-repetition-maximums of biceps curls were determined in order to define the intensity of the eccentric exercise. An eccentric exercise protocol which would cause DOMS was applied to all players. All tests were replaced with acute exhaustive eccentric exercise; the same tests were repeated in the same order after the exercise. Blood CK activity was measured by taking an earlobe capillary blood sample. The muscle pain level was measured by using a Visual Analogue Scale (VAS). Positioning sense loss was assessed via goniometer at 30º, 60° and 90° degrees horizontally. The study found a statistically significant increase in blood CK activity and positioning sense loss, and a decrease in the pressure-pain threshold, as well as the shooting percentages in the exercise group when compared with the control. These findings suggest that DOMS negatively affects the upper extremities motor performance of wheelchair basketball players at least 48 hours after eccentric exercise.

Ameliorative Effects of Caffeic Acid Phenethyl Ester on an Eccentric Exercise-Induced Skeletal Muscle Injury by Down-Regulating NF-κB Mediated Inflammation

Background and Purpose: Caffeic acid phenethyl ester (CAPE), a phenolic compound isolated from propolis, displays a variety of biological activities. The aim is to examine the protective effect and mechanisms of CAPE on an eccentric exercise-induced muscle injury model. Experimental Approach: An intermittent downhill eccentric exercise protocol was used. The oxidative tissue injury and expression of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), interleukin-1ß (IL-1ß), monocyte chemotactic protein-1 (MCP-1), and activation of nuclear factor-κB (NF-κB) were examined. CAPE was applied in a dose of 5 and 10 mg/kg/day, p.o. Key Results: The eccentric exercise induced remarkable skeletal muscle damage uncovered by a dramatic elevation of creatine kinase in the serum and severe degenerative myopathy. These pathophysiological changes were accompanied by an upregulation of the inflammatory responses including protein nitrotyrosylation, poly-ADP-ribose-polymerase (PARP) upregulation, lipid peroxidation as measured by malondialdehyde (MDA) formation, and leukocyte infiltration as measured by myeloperoxidase (MPO). The inflammatory responses primarily resulted from enhanced expression of COX2, iNOS, and production of IL-1ß and MCP-1, possibly through activation of NF-κB. All these pathological changes were suppressed by treatment of CAPE. Conclusions and Implications: Our results indicate that CAPE exhibits protective effects against eccentric exercise-induced skeletal muscle damage in rats by blocking the NF-κB-dependent activation of the inflammatory responses.

Achilles Tendinopathy Modulates Force Frequency Characteristics of Eccentric Exercise

Previous research has demonstrated that ground reaction force (GRF) recorded during eccentric ankle exercise is characterized by greater power in the 8- to 12-Hz bandwidth when compared with that recorded during concentric ankle exercise. Subsequently, it was suggested that vibrations in this bandwidth may underpin the beneficial effect of eccentric loading in tendon repair. However, this observation has been made only in individuals without Achilles tendinopathy. This research compared the force frequency characteristics of eccentric and concentric exercises in individuals with and without Achilles tendinopathy. Eleven male adults with unilateral midportion Achilles tendinopathy and nine control male adults without tendinopathy participated in the research. Kinematics and GRF were recorded while the participants performed a common eccentric rehabilitation exercise protocol and a concentric equivalent. Ankle joint kinematics and the frequency power spectrum of the resultant GRF were calculated. Eccentric exercise was characterized by a significantly greater proportion of spectral power between 4.5 and 11.5 Hz when compared with concentric exercise. There were no significant differences between limbs in the force frequency characteristics of concentric exercise. Eccentric exercise, in contrast, was defined by a shift in the power spectrum of the symptomatic limb, resulting in a second spectral peak at 9 Hz, rather than 10 Hz in the control limb. Compared with healthy tendon, Achilles tendinopathy was characterized by lower frequency vibrations during eccentric rehabilitation exercises. This finding may be associated with changes in neuromuscular activation and tendon stiffness that have been shown to occur with tendinopathy and provides a possible rationale for the previous observation of a different biochemical response to eccentric exercise in healthy and injured Achilles tendons.

Eccentric Exercise Protocols for Patella Tendinopathy: Should we Really be Withdrawing Athletes from Sport? A Systematic Review

The 2007 review by Visnes and Bahr concluded that athletes with patella tendinopathy should be withdrawn from sport whilst engaging in eccentric exercise (EE) rehabilitation programs. However, deprivation of sport is associated with a number of negative psychological and physiological effects. Withdrawal from sport is therefore a decision that warrants due consideration of the risk/benefit ratio. The aim of this study was to determine whether sufficient evidence exists to warrant withdrawal of athletes from sport during an eccentric exercise rehabilitation program. A systematic review of the literature was performed to identify relevant randomised trials. Data was extracted to determine whether athletes were withdrawn from sport, what evidence was presented to support the chosen strategy and whether this affected the clinical outcome. Seven studies were included. None of these reported high quality evidence to support withdrawal. In addition, three studies were identified in which athletes were not withdrawn from sport and still benefited from EE. This review has demonstrated that there is no high quality evidence to support a strategy of withdrawal from sport in the management of patella tendinopathy.