vendex and Acute-Disease

Bed rest is usually considered an efficient treatment for acute low back pain. However, the optimal duration of bed rest is still being discussed. The recommended periods vary from 2 days to 2 weeks. The duration of optimum length is an important topic given the economical and physiological drawbacks of prolonged inactivity. The purpose of this work is to measure objectively the efficacy of two different durations of bed rest through a dynamometric measure of trunk function. Some 51 male patients, students or self-employed, being treated for acute low back pain were randomized into two groups. Group I was prescribed a bed rest period of 3 days and group II, a period of 7 days. We used a multi-axis isoinertial trunk testing dynamometric device (Isostation B200, Isotechnologies, USA). Patients were all assessed on day 1 and also on day 5 for group I or on day 9 for group II. The variables measured in the sagittal plane were isometric torques in flexion and extension, unresisted range of motion, average dynamic torques and average velocities. Patients were also asked to fill in a visual analogue pain scale on both assessment days. The improvement of all performance measures were important and highly significant (P < 0.001) in both groups. The results of the functional testing and the visual analogue pain scale showed no significant differences between the groups. In these relatively young and motivated patients, a duration of bed rest of 3 days resulted in the same objective functional improvement of trunk function and pain rating as a period of 7 days. This shorter duration should be considered as preferable, given the same objective results but important physiological and economical advantages.

Topics: Activities of Daily Living; Acute Disease; Adolescent; Adult; Bed Rest; Humans; Low Back Pain; Male; Middle Aged; Movement; Outcome Assessment, Health Care; Pain Measurement; Range of Motion, Articular; Time Factors; Tomography, X-Ray Computed; Torque; Young Adult

We examined changes in the variability, frequency composition, and complexity of force signal from subacute to chronic stage of stroke during maintenance of isometric knee extension and compared these parameters between chronic stroke and healthy subjects. The sample included 15 healthy (65±8 years) and 23 chronic stroke subjects (65±14 years, 6-112 months post-stroke) of whom 10 (64±15 years) were also examined 11-22 days post-stroke (subacute stage). The subjects performed isometric knee extension at 10%, 20%, 30%, and 50% of peak torque for 10s (two trials each). Coefficient of variation (CV) was used as a measure of force variability. The median frequency and relative power in the 0-3, 4-6, and 8-12 Hz bands were obtained through a power spectrum analysis of the force signal. The signal complexity was quantified using the sample entropy (SampEn). The longitudinal analysis revealed a significant decrease in CV from subacute to chronic stage across all contraction levels (P<0.001) but no significant changes in the frequency and entropy parameters. Comparison between the chronic stroke and control subjects revealed no significant difference in CV across the force levels (P>0.05) but significantly decreased median frequency (P<0.01), with the relative power increased in 0-3 Hz band and decreased in 4-6 and 8-12 Hz bands in both paretic and non-paretic legs (P<0.001). SampEn was also significantly decreased in chronic stroke, bilaterally (P<0.001). These results indicate a shift toward lower frequencies and a less complex physiological process underlying force control in chronic stroke. The overall results suggest the improvement in force variability from subacute to chronic stroke but without normalization in the frequency composition and complexity of the force signal. Thus, disordered structure of the force signal remains a marker of impaired motor control long after stroke occurrence despite apparent recovery in force variability.

Topics: Acute Disease; Adult; Aged; Aged, 80 and over; Chronic Disease; Entropy; Female; Humans; Isometric Contraction; Knee; Longitudinal Studies; Male; Middle Aged; Muscle, Skeletal; Stroke; Time Factors; Torque

Muscle fatigue prevents repetitive use of paralyzed muscle after spinal cord injury (SCI).. This study compared the effects of hybrid patterns of muscle stimulation in individuals with acute and chronic SCI.. Individuals with chronic (n = 11) or acute paralysis (n = 3) underwent soleus muscle activation with a constant (CT) or doublet (DT) stimulation train before and at various times after a fatigue protocol.. The chronically paralyzed soleus was highly fatigable with a fatigue index (FI) of 19% ± 6%, whereas the acutely paralyzed soleus was fatigue resistant (FI = 89% ± 8%). For the chronically paralyzed group, the DT protocol caused less than 5% improvement in peak and mean force relative to the CT protocol before fatigue; however, after fatigue the DT protocol caused an increase in peak and mean force (>10%), compared with the CT protocol (P < .05). As the chronically paralyzed muscle developed low-frequency fatigue, the DT protocol became more effective than the CT protocol (P < .05). The DT protocol increased the rate of torque development before fatigue (42% ± 78%), after fatigue (62% ± 52%), and during recovery (87% ± 54% to 101% ± 56%; P < .05). The acutely paralyzed group showed minimal change in peak and mean torque with the DT protocol.. Chronic reduced activity is associated with muscle adaptations (slow to fast) that render the muscle more amenable to force enhancement through doublet train activation after fatigue. These findings are applicable to patients using neuromuscular stimulation.

Topics: Acute Disease; Adult; Chronic Disease; Electric Stimulation Therapy; Female; Humans; Male; Muscle Fatigue; Muscle, Skeletal; Paralysis; Spinal Cord Injuries; Time Factors; Torque; Young Adult

To investigate whether low FiO2 affects muscle oxygenation and the rate of decline in peak torque (DR) during isokinetic knee extension, subjects performed 50 isokinetic knee extensions at 180 degrees /s and at 0.5 Hz while inhaling low O2 gas (12 %O2; H) or air (N). Muscle oxygenation kinetics was assessed by near-infrared spectroscopy, and whole-body V.O2 and HR were measured. We calculated total-, oxy- and deoxy-hemoglobin/myoglobin concentrations (TotalHb/Mb, OxyHb/Mb, DeoxyHb/Mb), and the slopes of the change in OxyHb/Mb during exercise. SpO2 decreased in H while DR and V.O2 did not differ between the conditions. During exercise, OxyHb/Mb was lower in H than in N, and DeoxyHb/Mb was higher in H than in N. TotalHb/Mb began to increase from the resting level earlier in H. HR was higher during the latter half of the exercise in H. The slopes of the change in OxyHb/Mb were the same in the two conditions. Our results show that low FiO2 decreases SpO2 and muscle oxygenation during maximal isokinetic knee extension. However, low SpO2 and muscle oxygenation did not affect the rates of decline of peak torque. These results suggest that the decline in peak torque occurs for reasons other than O2 availability.

Topics: Acute Disease; Adult; Humans; Hypoxia; Japan; Kinetics; Knee Joint; Male; Muscle Strength; Muscle, Skeletal; Oxygen Consumption; Spectroscopy, Near-Infrared; Torque

Healthy untrained men (age 20.4+/-1.7 years, n=20) volunteered to participate in an experiment in order to establish dynamics of indirect symptoms of skeletal muscle damage (ISMD) (decrease in maximal isometric voluntary contraction torque (MVCT) and torque evoked by electrostimulation at different frequencies and at different quadriceps muscle length, height (H) of drop jump (DJ), muscle soreness and creatine kinase (CK) activity in the blood) after 100 DJs from 0.75 m height performed with maximal intensity with an interval of 20s between the jumps (stretch-shortening exercise, SSE). All ISMDs remained even 72 h after SSE (P<0.01-0.001). The muscle experienced greater decrease (P<0.01) in torque evoked by electrostimulation (at low stimulation frequencies and at short muscle length in particular) after SSE than neuromuscular performance (MVCT and H of DJ) which demonstrated secondary decrease (P<0.01) in neuromuscular performance during the first 48 h after SSE. Within 24-72 h after the SSE the subjects felt an acute muscle pain (5-7 points approximately) and the CK activity in the blood was significantly increased up to 1200 IU/L (P<0.001). A significant correlation between decrease in MVCT and H of DJ 24-48 h after SSE on the one hand and muscle soreness registered within 24-48 h after SSE on the other was observed, whereas correlation between the other indirect symptoms of skeletal muscle damage was not significant.

Topics: Acute Disease; Adult; Analysis of Variance; Biomarkers; Creatine Kinase; Electric Stimulation; Heart Rate; Humans; Isometric Contraction; Male; Muscle Fatigue; Muscle Stretching Exercises; Muscular Diseases; Pain; Physical Endurance; Quadriceps Muscle; Reflex, Stretch; Torque

The present study was carried out to examine possible mechanisms of back muscle dysfunction by assessing a stabilising and a torque-producing back muscle, the multifidus (MF) and the iliocostalis lumborum pars thoracis (ICLT), respectively, in order to identify whether back pain patients showed altered recruitment patterns during different types of exercise. In a group of healthy subjects (n=77) and patients with sub-acute (n=24) and chronic (51) low back pain, the normalised electromyographic (EMG) activity of the MF and the ICLT (as a percentage of maximal voluntary contraction) were analysed during coordination, stabilisation and strength exercises. The results showed that, in comparison with the healthy subjects, the chronic low back pain patients displayed significantly lower (P=0.013) EMG activity of the MF during the coordination exercises, indicating that, over the long term, back pain patients have a reduced capacity to voluntarily recruit the MF in order to obtain a neutral lordosis. In contrast, during the stabilisation exercises, no significant differences between patients and controls were found for the normalised EMG activity of the two muscles. These findings indicated that, during low-load exercises, no insufficiencies in back muscle recruitment were evident in either subacute or chronic back pain patients. During the strength exercises, the normalised activity of both back muscles was significantly lower in chronic low back pain patients (P=0.017 and 0.003 for the MF and ICLT, respectively) than in healthy controls. Pain, pain avoidance and deconditioning may have contributed to these lower levels of EMG activity during intensive back muscle contraction. The possible dysfunction of the MF during coordination exercises and the altered activity of both muscles during strength exercises may be of importance in symptom generation, recurrence or maintenance of low back pain.

Topics: Acute Disease; Adult; Back; Chronic Disease; Electromyography; Exercise Therapy; Female; Humans; Low Back Pain; Male; Middle Aged; Muscle Contraction; Muscle, Skeletal; Torque; Volition

A correlative design using stepwise regression analysis.. To explore the variation in spinal isometric strength that can be accounted for by anticipation of pain, sensory perception of pain, functional disability belief, and the fear-avoidance belief in chronic low back pain patients.. Several biobehavioral factors contribute to the persistence of pain behavior in chronic patients. Recent studies suggest a need to explore the relation between reduced physical performance and the sensory and cognitive perception of pain.. Sixty-three patients with chronic low back pain 20 to 56 years of age participated in this study. Visual Analogs Scales, the Fear-Avoidance Belief questionnaire, and the Disability Belief questionnaire were used to measure the sensory and cognitive dimensions of pain. Spinal isometric strength was measured by the Medx lumbar extension machine.. Analysis of variance and the stepwise regression analysis demonstrated that anticipation of pain and the fear-avoidance belief about physical activity significantly predicted variation in the spinal isometric strength deficit P < 0. 001. True pain experienced during the testing and answers to the Disability Belief questionnaire were not related.. The results of this study strongly support the hypothesis that spinal physical capacity in chronicity is not explained solely by the sensory perception of pain. The anticipation of pain and the fear-avoidance belief about physical activities were the strongest predictors of the variation in physical performance.

Topics: Acute Disease; Adult; Avoidance Learning; Fear; Female; Humans; Isometric Contraction; Low Back Pain; Lumbosacral Region; Male; Middle Aged; Pain Measurement; Regression Analysis; Torque

To evaluate the relation between variability of the torque curves and factors such as age, gender, measurement speeds, and period from low back pain (LBP) onset at isokinetic trunk strength testing.. Observational.. Hospital.. One hundred forty-three consecutive LBP patients (acute, subacute, and chronic) who received physical therapy, and 200 healthy volunteer subjects.. The variability of the torque curves is an indicator of consistency of effort, and was measured as the coefficient of variance (CV) at different measurement speeds in isokinetic trunk flexion/extension strength testing.. The CV was lower in men than in women at the faster measurement speed. LBP patients had higher CV values than healthy subjects. The CV was different according to gender and measurement speed, but not different according to age and periods from LBP onset.. The CV was affected by measurement speed and gender, but not by age or period from LBP onset. Because the CV was higher in LBP patients than in healthy subjects, this value may be usable as an adjunctive index of LBP.

Topics: Abdomen; Acute Disease; Adolescent; Adult; Age Factors; Aged; Aged, 80 and over; Case-Control Studies; Chronic Disease; Female; Humans; Isotonic Contraction; Low Back Pain; Male; Middle Aged; Muscle Weakness; Range of Motion, Articular; Sex Factors; Thorax; Torque

We analyzed the twitch and summated torque (tetanus) during repetitive activation and recovery of the human soleus muscle in individuals with spinal cord injury. Thirteen individuals with complete paralysis (9 chronic, 4 acute) had the tibial nerve activated every 1,500 ms with a 20-Hz train (7 stimuli) for 300 ms and a single pulse at 1,100 ms. The stimulation protocol lasted 3 min and included 120 twitches and 120 tetani. Minimal changes were found for the acute group. The chronic group showed a significant reduction in the torque and a significant slowing of the contractile speeds of both the twitch and tetanus. The decrease in the peak twitch torque was significantly greater than the decrease in the peak tetanus torque early during the fatigue protocol for the chronic group. The twitch time to peak and half relaxation time were prolonged during fatigue, which was associated with improved fusion of the tetanus torque. At the end of the fatigue protocol, the decrease in the peak twitch torque was not significantly different from the decrease in the peak tetanus torque. After 5 min of rest, the contractile speeds recovered causing the tetanus to become unfused, but the tetanus torque became less depressed than the twitch torque. The differential responses for the twitch and the tetanus suggest an interplay between optimal fusion created from contractile speed slowing and excitation contraction coupling compromise. These issues make the optimal design of functional electrical stimulation systems a formidable task.

Topics: Acute Disease; Adolescent; Adult; Chronic Disease; Electric Stimulation; Female; Humans; Male; Middle Aged; Muscle Contraction; Muscle Fatigue; Muscle Fibers, Fast-Twitch; Muscle Fibers, Slow-Twitch; Muscle, Skeletal; Paralysis; Time Factors; Torque

Plain lateral radiographs in a neutral position were studied in ten acute thoracolumbar burst fractures produced by high speed impact on three vertebrae human cadaveric spine segments. Six linear geometric parameters were measured on each film. The ratio of each value in the neutral injured to the intact condition was correlated linearly with the motion parameters obtained from post-traumatic three-dimensional flexibility data (neutral zone NZ; range of motion ROM). Anterior unit height (vertebra+adjacent discs) had the highest correlation with the neutral zone and flexibility in all directions, especially flexion-extension (NZ, R2 = 0.93; flexion ROM, R2 = 0.86; extension ROM, R2 = 0.79) lateral bending (NZ, R2 = 0.83; ROM, R2 = 0.90) and right axial rotation (NZ, R2 = 0.53; ROM, R2 = 0.86). The deformation ratio (average height to depth) correlated most with the neutral zone in left axial rotation (R2 = 0.91) and right lateral bending (R2 = 0.92). Due to the high correlations obtained, these parameters should be evaluated in clinical situations to assess their effectiveness in predicting the instability of burst fractures. Ultimately, prospective clinical studies are required to verify their clinical utility.

Topics: Acceleration; Acute Disease; Adult; Aged; Cadaver; Compressive Strength; Female; Fractures, Comminuted; Humans; Least-Squares Analysis; Linear Models; Lumbar Vertebrae; Male; Middle Aged; Pliability; Predictive Value of Tests; Radiography; Range of Motion, Articular; Spinal Fractures; Thoracic Vertebrae; Torque