Reduction In Muscle Stiffness Research Articles

Effect of a Repeated Sprint Ability test on the muscle contractile properties in elite futsal players

The aim of this study was to evaluate the effect of a repeated sprint ability (RSA) test on the contractile properties of the muscles in elite futsal players. A total of 20 elite players completed the RSA test (7 × 30 m), and the contractile response from the rectus femoris (RF) and biceps femoris (BF) of both legs were analysed pre and post through tensiomyography. There was a significant increment in 30-m times from the third sprint onwards (p < 0.05). The percent decrement in sprint ability (RSADEC) with respect to the first sprint was significantly higher in the last sprint. The players did not show evidence of lateral asymmetry in any of the muscle groups analysed after the RSA test (p > 0.05). Following the RSA test there was a significant reduction in the delay time (Td) in RF, a significant decrement in half-relaxation time (Tr) in the RF, and a significant reduction in sustain time (Ts) in the RF and BF of both legs. The maximum radial displacement of the muscle belly (Dm) increased (1.6 mm; effect size = 0.75; p < 0.05) in the RF after the RSA test, indicating reduced muscle stiffness and the ability to generate strength rapidly. The decrement in performance during the RSA test was significantly correlated with changes in contraction time (Tc) in RF and BF, Td in BF, and Dm in RF (p < 0.05). The RSA test generated alterations in the contractile properties of the RF and BF in elite players. However, futsal players did not present asymmetries in any muscular parameters. The baseline contractile muscle parameters could be an important factor related to performance of players during repeated high-intensity actions.

Adaptations in the passive mechanical properties of skeletal muscle to altered patterns of use.

The aim of this mini-review is to describe the present state of knowledge regarding the effects of chronic changes in the patterns of muscle use (defined as changes lasting >1 wk), including muscle stretching, strengthening, and others, on the passive mechanical properties of healthy human skeletal muscles. Various forms of muscle stretch training and some forms of strength training (especially eccentric training) are known to strongly impact the maximum elongation capacity of muscles in vivo (i.e., maximum joint range of motion), largely by increasing our ability to tolerate higher stretch loads. However, only small effects are observed in the passive stiffness of the muscle-tendon unit (MTU) or the muscle itself, although a reduction in muscle stiffness has been observed in the plantar flexors after both stretching and eccentric exercise interventions. No changes have yet been observed in viscoelastic properties such as the MTU stress-relaxation response, although a minimum of evidence indicates that hysteresis during passive stretch-relaxation cycles may be reduced by muscle stretching training. Importantly, data exist for relatively few muscle groups, and little is known about the effects of age and sex on the adaptive process of passive mechanical properties. Despite the significant research effort afforded to understanding the effects of altered physical activity patterns on the maximum range of motion at some joints, further information is needed before it will be possible to develop targeted physical activity interventions with the aim of evoking specific changes in passive mechanical properties in individuals or in specific muscles and muscle groups.

Human recombinant hyaluronidase injections for upper limb muscle stiffness in individuals with cerebral injury: A case series

Introduction: Spasticity, muscle stiffness, and contracture cause severe disability after central nervous system injury. However, current treatment options for spasticity produce muscle weakness which can impede movement and do not directly address muscle stiffness. Here we propose that the accumulation of hyaluronan within muscles promotes the development of muscle stiffness and report that treatment with the enzyme hyaluronidase increases upper limb movement and reduces muscle stiffness without producing weakness.

Active versus local vibration warm-up effects on knee extensors stiffness and neuromuscular performance of healthy young males

ObjectivesTo compare the effects of local-vibration and active warm-up on knee extensors muscle stiffness and neuromuscular performance. DesignExperimental crossover study. MethodsThirteen participants performed three 15-min warm-up protocols of control (CON), active (ACT) and local-vibration (LV) in separate testing session. Passive stiffness of vastus lateralis (VL) and vastus medialis (VM) by shear wave elastography and neuromuscular performance were assessed before and 2-min after each condition. ResultsA decrease in muscle stiffness was reported after ACT for VL (−16.0±6.6%; p<0.001) and VM (−10.2±8.7%; p=0.03) while no changes were reported after CON (p=0.46 and p=0.34 for VL and VM, respectively) and LV (p=0.07 and p=0.46 for VL and VM, respectively). Maximal jump performances increased during squat (+8.5±6.6%; p<0.001) and countermovement jump (+5.2±5.8%; p<0.001) after ACT while no changes were reported after CON and LV during squat (p=0.16 and p=0.81, respectively) and countermovement jump (p=0.18 and p=0.31, respectively). We further report that each condition was ineffective to inducing changes in maximal voluntary isometric contraction force (p=0.18), rate of force development (p=0.92), twitch parameters (p>0.05) as well as central modulations as reported by the unchanged voluntary activation level (p=0.24) and maximal electromyography (EMG) recorded from the VL (p=0.44). ConclusionsThe active warm-up acutely reduced muscle stiffness and increased muscle performance during maximal dynamic tasks. With regard to LV, further studies are required to determine optimal parameters (frequency, amplitude, duration) to significantly increase muscle performance.

Imaging muscle stiffness post-stroke

Post-stroke spasticity develops a result of CNS injury, but secondary non-neural changes can contribute to upper limb muscle stiffness. The hylauronan hypothesis postulates that an increase in the concentration of hyaluronan, a glycosaminoglycan (GAG) in the extra-cellular matrix (ECM) of muscles, may contribute to muscle stiffness in spastic patients. This study sought to provide imaging evidence of the hyaluronan hypothesis. Five post-stroke patients (3 males, 2 females, age = 46 ± 15) and five healthy control subjects (3 males, 2 females, age = 27 ± 2) underwent Dixon based water-fat imaging and 3D-T1rho relaxation mapping of upper arm muscles were used to determine intramuscular GAG content. The MRI was study was conducted on a 3 T clinical scanner (Prisma, Siemens Healthcare, Germany). Following the MRI, the patients underwent off-label intramuscular hyaluronidase injections (Hylenex, Halozyme Therapeutics, Inc.) for clinical treatment. Post-injection MRIs were conducted approximately two weeks after the treatment. Two tailed student t -tests were used for comparing the groups. A paired t -test was used for the pre- and post-injection comparison. Following the hyaluronidase injections patients reported significant relief from muscle stiffness and showed increased arm movement. The hyaluronan concentration in the biceps and triceps was significantly higher in patients pre-injection, and was reduced post-injection. Note the change in muscle shape from triangular to more circular as in controls post-injection in the patient. 3D T1ρ mapping of the muscle can be used to detect intramuscular GAG content (hyaluronan) non-invasively. The muscle micro-environment can contribute to muscle stiffness, and injections of the enzyme hyaluronidase can be used to restore normal muscle microenvironment and reduce muscle stiffness post-stroke.

Stretching of voluntarily-activated muscles evokes greater acute and chronic adaptive changes than (traditional) static stretching

Purpose: To determine whether acute (single session) and chronic (prolonged training) increases in joint range of motion(ROM) are greater if muscles are voluntarily activated before being stretched (i.e. active muscle stretching) when compared to traditional, static stretching. Methods: In experiment 1, 18 physically-active subjects completed two static (SS1, SS2) and active (AMS1, AMS2) calf muscle stretch sessions, with each session separated by 48–72h. SS sessions comprised 5 sets of 30-s static stretches, whilst AMS comprised 5 sets of 10 repetitions of 3-s stretches imposed on maximally contracted muscle (both interventions=150s). In experiment 2, 13 subjects performed twice-weekly AMS for 6 weeks (5×12 repetitions, 3-s maximally-active muscle stretches 10◦/s, 20◦ plantarflexion to 10◦ dorsiflexion) on an isokinetic dynamometer. Maximal isometric plantarflexor strength, dorsiflexion ROM, peak passive tension, and muscle, tendon and muscle-tendon unit (MTU) stiffness were measured using isokinetic dynamometry, real-time ultrasound and 3D motion analyses before and after both the acute (experiment 1) and chronic (experiment 2) interventions. Results: In experiment 1, a significantly greater increase in ROM was observed in AMS (5.9–7.7◦) than SS (2.2–3.0◦), with ROM significantly greater after AMS2 than all other trials (+3.3–5.8◦). A significant ROM increase was already detected after the first set in AMS trials (2.2–3.1◦), and this was similar to the magnitude of change after 5 sets of SS. Similar decreases in the passive moment slope occurred after SS (7.3–11.7%) and AMS (10.1–15.3%), how-ever significant increases in peak passive moment (30.7–34.7%) and elastic energy storage (54.3–68.2%) occurred only after AMS. A significant reduction in maximal isometric strength occurred only after SS1 (6.5%). In experiment 2, plantarflexor MVC (47.1%), dorsiflexion ROM (14.7◦) and stretch tolerance (108%) increased significantly after training, while no change was found in MTU stiffness (passive moment at the same joint angle; 2.5%). A significant decrease in passive muscle stiffness (20.6%) but increase in tendon stiffness (27.7%) was observed. Discussion: A more than 2-fold greater acute increase in ROM was evoked after AMS than SS; the similar results in the second session (SS2 and AMS2) indicate that the finding is not due to muscle damage from unaccustomed training session. A stretch-induced muscle strength decrease was observed after SS but not AMS. After 6-week AMS training, substantial increases in ROM,strength, tendon stiffness and elastic energy storage, but reduction in muscle stiffness, demonstrate that AMS can provide significant physical function benefits whilst reducing risk of muscle injury.

P.18 - The effects of calf massage in boys with Duchenne muscular dystrophy

The hallmark of DMD is progressive weakness and functional difficulties caused by muscle fibrosis resulting in increased stiffness and shortening. A survey in 2012 investigating the use of complementary therapies in our clinic population found that massage was the most commonly used complementary therapy in boys with DMD. This finding prompted this study of the effects of massage on calf muscle length and elasticity, and gait parameters in 20 ambulant boys with DMD (mean 8.75, (SD 2.71) range 6–14 years). The study used a within-subjects randomised controlled cross-over design with a blinded assessor. A ten minute massage was administered by a trained physiotherapist according to a standardised protocol. Muscle stiffness was measured using a myotonometer and muscle length using a goniometer. Spatio-temporal gait parameters were assessed using an electronic walkway and a timed 10m walk/run. Participant perception of muscle stiffness and pain was collected using 10 point visual rating scales. Outcome measures were administered pre- and post-massage. Following a single bilateral calf massage there was a significant reduction in muscle stiffness (-8.65N/m p < 0.001, 95%CI -12.94- -4.36), and a small but statistically significant increase in calf muscle length (soleus 30 p < 0.001, 95%CI 2–4, gastrocnemius 30 p < 0.001, 95%CI 2–4). Of the 16 participants who completed the perception scales, six reported improvement in perceived pain and ten reported a reduction in perceived muscle stiffness. There were no significant changes in gait parameters or 10m walk/run time. Assessment 6–10 days later (mean 7.1(SD 0.55)), found that reduced muscle stiffness (-10.2N/m p < 0.006, 95%CI -17.15- -3.24) and soleus length were maintained (20 p < 0.005, 95%CI 1–4). Massage has positive effects on muscle length and stiffness in ambulant boys with DMD. A further study with larger numbers of participants is needed to validate these findings.

Potensi Ekstrak Etanol Rimpang Jeringau (Acorus calamus L.) Sebagai Spasmolitik

Pain due to smooth muscle stiffness can occur in various circumstances of patients, ranging from normal circumstances such as menstrual pain, to a pathological condition of gastrointestinal infections. To overcome the pain it can be given medication to reduce muscle stiffness as spasmolytics, but there are side effects of the drug. Thus, the need for developing new spasmolytics drugs based on medicinal herbs with fewer side effects. This study was conducted to examine the potential of rhizome extract of jeringau (Acorus calamus L.) that is traditionally used by Dayak tribe to heal upset stomach. Spasmolytic activity of plant extracts tested with isolates organ methods of guinea pig ileum induced by histamine. Result of the study showed 0.3 mg/ml A. calamus rhizomes extract could decrease ileum contraction better than papaverine 0.03 mg/ml (p=0.00). The conclusion of this study is rhizome extract of jeringau (A. calamus) has the potential to be used as spasmolytics in treatment of health problems caused by smooth muscle contraction

Effects of warm-up on hamstring muscles stiffness: Cycling vs foam rolling.

This study investigated the effects of active and/or passive warm-up tasks on the hamstring muscles stiffness through elastography and passive torque measurements. On separate occasions, fourteen males randomly completed four warm-up protocols comprising Control, Cycling, Foam rolling, or Cycling plus Foam rolling (Mixed). The stiffness of the hamstring muscles was assessed through shear wave elastography, along with the passive torque-angle relationship and maximal range of motion (ROM) before, 5, and 30minutes after each experimental condition. At 5minutes, Cycling and Mixed decreased shear modulus (-10.3%±5.9% and -7.7%±8.4%, respectively; P≤.0003, effect size [ES]≥0.24) and passive torque (-7.17%±8.6% and -6.2%±7.5%, respectively; P≤.051, ES≥0.28), and increased ROM (+2.9%±2.9% and +3.2%±3.5%, respectively; P≤.001, ES≥0.30); 30minutes following Mixed, shear modulus (P=.001, ES=0.21) and passive torque (P≤.068, ES≥0.2) were still slightly decreased, while ROM increased (P=.046, ES=0.24). Foam rolling induced "small" immediate short-term decreases in shear modulus (-5.4%±5.7% at 5minutes; P=.05, ES=0.21), without meaningful changes in passive torque or ROM at any time point (P≥.12, ES≤0.23). These results suggest that the combined warm-up elicited no acute superior effects on muscle stiffness compared with cycling, providing evidence for the key role of active warm-up to reduce muscle stiffness. The time between warm-up and competition should be considered when optimizing the effects on muscle stiffness.

Level of functional capacities following soccer-specific warm-up methods among elite collegiate soccer players.

Different methods of warm-up may have implications in improving various aspects of soccer performance. The present study aimed to investigate acute effects of soccer specific warm-up protocols on functional performance tests. This study using randomized within-subject design, investigated the performance of 22 collegiate elite soccer player following soccer specific warm-ups using dynamic stretching, static stretching, and FIFA 11+ program. Post warm-up examinations consisted: 1) Illinois Agility Test; 2) vertical jump; 3) 30 meter sprint; 4) consecutive turns; 5) flexibility of knee. Vertical jump performance was significantly lower following static stretching, as compared to dynamic stretching (P=0.005). Sprint performance declined significantly following static stretching as compared to FIFA 11+ (P=0.023). Agility time was significantly faster following dynamic stretching as compared to FIFA 11+ (P=0.001) and static stretching (P=0.001). Knee flexibility scores were significantly improved following the static stretching as compared to dynamic stretching (P=016). No significant difference was observed for consecutive turns between three warm-up protocol. The present finding showed that a soccer specific warm-up protocol relied on dynamic stretching is preferable in enhancing performance as compared to protocols relying on static stretches and FIFA 11+ program. Investigators suggest that while different soccer specific warm-up protocols have varied types of effects on performance, acute effects of dynamic stretching on performance in elite soccer players are assured, however application of static stretching in reducing muscle stiffness is demonstrated.

Diagnosis and Treatment of` Spasticity and Stiff Muscles

Diagnosis and Treatment of` Spasticity and Stiff Muscles

Human Recombinant Hyaluronidase Injections For Upper Limb Muscle Stiffness in Individuals With Cerebral Injury: A Case Series

Spasticity, muscle stiffness and contracture cause severe disability after central nervous system injury. However, current treatment options for spasticity produce muscle weakness which can impede movement, and do not directly address muscle stiffness. Here we propose that the accumulation of hyaluronan within muscles promotes the development of muscle stiffness, and report that treatment with the enzyme hyaluronidase increases upper limb movement and reduces muscle stiffness without producing weakness. 20 patients with unilateral upper limb spasticity received multiple intramuscular injections of human recombinant hyaluronidase with saline at a single visit. The safety and efficacy of the injections, passive and active movement, and muscle stiffness at eight upper limb joints were assessed at four time points: pre-injection (T0), within 2weeks (T1), within 4–6weeks (T2), and within 3–5months post-injection (T3). There were no clinically significant adverse effects from the injections. Passive movement at all joints, and active movement at most joints increased at T1, and persisted at T2 and T3 for most joints. The modified Ashworth scores also declined significantly over time post-injection. Hyaluronidase injections offer a safe and potentially efficacious treatment for muscle stiffness in neurologically impaired individuals. These results warrant confirmation in placebo-controlled clinical trials.

Flecainide-Responsive Myotonia Permanens With SNEL Onset: A New Case and Literature Review

Sodium channel myotonias are inherited muscle diseases linked to mutations in the voltage-gated sodium channel. These diseases may also affect newborns with variable symptoms. More recently, severe neonatal episodic laryngospasm (SNEL) has been described in a small number of patients. A timely diagnosis of SNEL is crucial because a specific treatment is now available that will likely reduced laryngospasm and improve vital and cerebral outcomes. We report here on an 8-year-old girl who had presented, at birth, with SNEL who subsequently developed myotonia permanens starting at age 3 years. Results of molecular analysis revealed a de novo SCN4A G1306E mutation. The girl was treated with carbamazepine, acetazolamide, and mexiletine, with little improvement; after switching her treatment to flecainide, she experienced a dramatic reduction in muscle stiffness and myotonic symptoms as well as an improvement in behavior.

Effects of Contract-Relax, Static Stretching, and Isometric Contractions on Muscle-Tendon Mechanics.

Loading characteristics of stretching techniques likely influence the specific mechanisms responsible for acute increases in range of motion (ROM). Therefore, the effects of a version of contract-relax (CR) proprioceptive neuromuscular facilitation stretching, static stretching (SS), and maximal isometric contraction (Iso) interventions were studied in 17 healthy human volunteers. Passive ankle moment was recorded on an isokinetic dynamometer, with EMG recording from the triceps surae, simultaneous real-time motion analysis, and ultrasound-imaging-recorded gastrocnemius medialis muscle and Achilles tendon elongation. Subjects then performed each intervention randomly on separate days before reassessment. Significant increases in dorsiflexion ROM (2.5°-5.3°; P < 0.01) and reductions in whole muscle-tendon stiffness (10.1%-21.0%; P < 0.01) occurred under all conditions, with significantly greater changes detected following CR stretching (P < 0.05). Significant reductions in tendon stiffness were observed after CR stretching and Iso (17.7%-22.1%; P < 0.01) but not after SS (P > 0.05), whereas significant reductions in muscle stiffness occurred after CR stretching and SS (16.0%-20.5%; P < 0.01) but not after Iso (P > 0.05). Increases in peak passive moment (stretch tolerance) occurred after Iso (6.8%; P < 0.05), CR stretching (10.6%; P = 0.08), and SS (5.2%; P = 0.08); no difference in changes between conditions was found (P > 0.05). Significant correlations (rs = 0.69-0.82; P < 0.01) were observed between changes in peak passive moment and maximal ROM under all conditions. Although similar ROM increases occur after Iso and SS, changes in muscle and tendon stiffness are distinct. Concomitant reductions in muscle and tendon stiffness after CR stretching suggest a broader adaptive response that likely explains its superior efficacy in acutely increasing ROM. Although mechanical changes appear tissue-specific between interventions, similar increases in stretch tolerance after all interventions are strongly correlated with changes in ROM.

Does long-term passive stretching alter muscle–tendon unit mechanics in children with spastic cerebral palsy?

BackgroundCerebral palsy causes motor impairments during development and many children may experience excessive neural and mechanical muscle stiffness. The clinical assumption is that excessive stiffness is thought to be one of the main reasons for functional impairments in cerebral palsy. As such, passive stretching is widely used to reduce stiffness, with a view to improving function. However, current research evidence on passive stretching in cerebral palsy is not adequate to support or refute the effectiveness of stretching as a management strategy to reduce stiffness and/or improve function. The purpose was to identify the effect of six weeks passive ankle stretching on muscle–tendon unit parameters in children with spastic cerebral palsy. MethodsThirteen children (8–14y) with quadriplegic/diplegic cerebral palsy were randomly assigned to either an experimental group (n=7) or a control group (n=6). The experimental group underwent an additional six weeks of passive ankle dorsiflexion stretching for 15min (per leg), four days per week, whilst the control group continued with their normal routine, which was similar for the two groups. Measures of muscle and tendon stiffness, strain and resting length were acquired pre- and post-intervention. FindingsThe experimental group demonstrated a 3° increase in maximum ankle dorsiflexion. This was accompanied by a 13% reduction in triceps surae muscle stiffness, with no change in tendon stiffness. Additionally, there was an increase in fascicle strain with no changes in resting length, suggesting muscle stiffness reductions were a result of alterations in intra/extra-muscular connective tissue. InterpretationThe results demonstrate that stretching can reduce muscle stiffness by altering fascicle strain but not resting fascicle length.

Objective Assessment of the Rheological Muscle Property in the Treatment of Fibromyalgia.

Fibromyalgia (FM), clinical condition characterized by several signs and symptoms such as widespread pain, trigger point, morning stiffness and extreme tiredness for scarce hours of sleep, is linked to several changes in several brain neurotransmitters, particularly serotonin and norepinephrine. Consequently, the Neural Vegetative System works more and so it generates an exaggerated muscular contraction, sweating and constriction of blood vessels. The aim of our study was to treat a selected group of female patients suffering from FM with duloxetine with physiotherapy. We used two clinical scales (VAS and FIQ) and an objective evaluation such as myometric. The analysis of the data Myoton used during any inspection showed a statistically significant reduction in the values of muscle tone in each district analyzed. This finding was also confirmed by the patients themselves who have experienced a significant welfare and less muscle tension in different locations, as evidenced by data obtained from the clinical scales used by us. In addition, our patients were thought to be satisfied with the improvements not only subjective, but also with the objective witnessed myometry, making them a share of the study and feeling constantly monitored for treatment aimed at a real reduction in muscle stiffness. In conclusion, our study demonstrates combined treatment duloxetine- physiotherapy effectively reduces a symptom often disabling and particularly troublesome in patients with FM as the exaggerated muscle contraction.

Sarcolemmal Biomechanics and Excitability in Malformed Muscle Fibers of Dystrophic Mice

Background: Duchenne muscular dystrophy (DMD), the most common and severe dystrophy, is caused by the absence of dystrophin. Muscle weakness and fragility (i.e. increased susceptibility to damage) are presumably due to structural weakness of the myofiber cytoskeleton, but recent studies suggest that malformed/split myofibers in dystrophic muscle may also play a role. We have previously studied the biomechanical properties of the sarcolemma in single myofibers isolated mechanically from extensor digitorum longus (EDL) muscles in wild-type (WT) and dystrophic (mdx, mouse model for DMD) mice. PURPOSE: We use similar biomechanical methods on enzymatically-dissociated myofibers (both normal and malformed) from the flexor digitorum brevis muscle (FDB) of WT and mdx mice.Methods: FDB muscles were enzymatically-dissociated and plated on specialized coverslips. Suction pressures (P) applied through a pipette to the membrane generated a bleb, which increased in height with increasing P. Larger increases in P ruptured the connections between the sarcolemma and myofibrils (speration P, or SP) and eventually caused the sarcolemma to burst. We also examined excitability using high-speed confocal microscopy and the voltage-sensitive indicator di-8-butyl-amino-naphthyl-ethylene-pyridinium-propyl-sulfonate to assess the action potential (AP).Results: The mechanical results from dissociated FDB myofibers match findings from dissected EDL myofibers, but SP was up to 14-fold higher in the FDB than EDL. SP was 27% lower in mdx myofibers and 50% less in branches of split mdx fibers compared to the trunk. AP amplitude was not altered in between groups, but this work is ongoing.Conclusions: Data indicate a reduction in muscle stiffness, increased sarcolemmal deformability and instability in mdx muscle. This approach corroborates the labor-intensive data obtained from single fiber dissection and allows a facile high throughput model. Findings suggest mechanical differences due to altered morphology, despite comparable excitability.

Massage induces an immediate, albeit short-term, reduction in muscle stiffness.

Using ultrasound shear wave elastography, the aims of this study were: (a) to evaluate the effect of massage on stiffness of the medial gastrocnemius (MG) muscle and (b) to determine whether this effect (if any) persists over a short period of rest. A 7-min massage protocol was performed unilaterally on MG in 18 healthy volunteers. Measurements of muscle shear elastic modulus (stiffness) were performed bilaterally (control and massaged leg) in a moderately stretched position at three time points: before massage (baseline), directly after massage (follow-up 1), and following 3 min of rest (follow-up 2). Directly after massage, participants rated pain experienced during the massage. MG shear elastic modulus of the massaged leg decreased significantly at follow-up 1 (-5.2 ± 8.8%, P = 0.019, d = -0.66). There was no difference between follow-up 2 and baseline for the massaged leg (P = 0.83) indicating that muscle stiffness returned to baseline values. Shear elastic modulus was not different between time points in the control leg. There was no association between perceived pain during the massage and stiffness reduction (r = 0.035; P = 0.89). This is the first study to provide evidence that massage reduces muscle stiffness. However, this effect is short lived and returns to baseline values quickly after cessation of the massage.

Continuous Low-Level Heatwrap Therapy Relieves Low Back Pain and Reduces Muscle Stiffness

Background: Low back pain is a common and costly health care problem. This pilot study evaluated the sensitivity of the 2-stopwatch and Paris plinth methodologies for assessing time-to-onset of pain relief and flexibility, respectively, with continuous, low-level heatwrap therapy. Research Design and Methods: Subjects aged 18 to 55 years with at least moderate baseline acute low back pain were randomly assigned to either heatwrap or oral placebo for 8 hours. Unheated wrap (sham) and oral ibuprofen were included for blinding purposes only. Results: Sixty-one subjects were randomly assigned to either heatwrap (n = 26), oral placebo (n = 25), sham wrap (n = 5), or oral ibuprofen (n = 5). Median time to confirmed first perceptible pain relief and to meaningful pain relief were significantly shorter for the heatwrap group compared with those assigned to oral placebo (96.5 vs < 240.0 min and 215.7 vs > 240.0 min, respectively; P < 0.05 for both). Among subjects receiving the heatwrap, 53.8% reported first perceptible and meaningful relief, compared with 28.0% receiving oral placebo. Subjective measures of pain relief, back stiffness, and global evaluation were more sensitive in detecting treatment differences than the plinth assessments of flexibility, range of motion, and pain. Three adverse events were reported as mild in severity and considered unrelated to study treatment. Conclusions: The 2-stopwatch methodology is a viable approach for assessing onset of analgesia in low back pain; however, the plinth may not be a reliable method for assessing flexibility. Consistent with published studies involving much larger sample sizes, the heatwrap provided significantly faster and sustained pain relief than oral placebo in subjects with acute low back pain. Clinical Trial Identifier: NCT01045993.

Expression of receptors of advanced glycation end product (RAGE) and types I, III and IV collagen in the vastus lateralis muscle of men in early stages of knee osteoarthritis

Alterations in the contractile and non-contractile proteins of the skeletal muscle may reduce muscle function in knee osteoarthritis (OA), and the formation and accumulation of advanced glycation end products, particularly in collagen, can influence the quality of these muscle proteins. The objective of this study was to evaluate the reactivity of types I, III and IV collagen and the expression and localization of receptor for advanced glycation end products (RAGE) in the vastus lateralis (VL) muscle in early stages of knee OA. The hypothesis was that these patients present a higher expression of RAGE and increased immunoreactivity in the collagen. Thirty-five men were divided into two groups: the control group (CG; n = 17) and the osteoarthritis group (OAG; n = 18). All participants were submitted to a biopsy of the VL. The muscle samples were analyzed by immunohistochemistry for collagen and for RAGE and laminin. The expression of RAGE was counted (intracellular, extracellular and total). Student's t-test for independent samples and Mann–Whitney U test were used for the RAGE's intergroup analysis (α ≤ 0.05). A semiquantitative analysis was performed to assess the collagen reactivity. No significant differences were observed in the intracellular, extracellular or total localization of RAGE (p > 0.05). Higher immunoreactivity was observed in the OAG for all types of collagen, with more reactivity for collagen III and IV. We concluded that in the initial stages of knee OA, no differences were observed for RAGE levels between the groups. However, the OAG's higher collagen expression may represent adaptations for reducing muscle stiffness and avoiding injury.