575 resultados para Isometric Dynamometry
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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OBJECTIVE: To compare the strength generated by the rotator muscles of the shoulder joint between the right upper limb and left upper limb among healthy individuals. METHODS: To evaluate the muscle strength of upper limbs from isometric contractions in the horizontal direction (rotation) an isometric dynamometer was used, equipped with transducers, signal conditioning, a data acquisition board, and finally, a computer. Study participants were 22 male military subjects, aged between 18 and 19 years old, body mass between 57.7 and 93.0 kg (71.8 ± 9.45 kg) and height between 1.67 and 1.90 m (1.75 ± 0.06 m), healthy and without clinical diseases or any type of orthopedic injury in the muscle skeletal system. RESULTS: The internal rotation in the right upper limb (RUL) was higher than the average strength of internal rotation in the left upper limb (LUL) (p = 0.723). The external rotation strength in RUL was lower than the average strength of external rotation in the LUL (p=0.788). No statistical difference was observed by comparing the strength values of all isometric strength tests. CONCLUSION: For the sample and methodology used to assess muscle strength, there was no statistical difference between the strength generated by the muscles of the rotator cuff of the right and left upper limbs. Experimental Study.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The aim of this study is to characterize some population biology parameters of P. squamosissimus, A. altiparanae and S. maculatus, the dominant fish species of the Santa Bárbara river, a tributary of the Nova Avanhandava reservoir, low Tietê river. Fish samplings were performed monthly between September/2002 and August/2003, using gill nets with different mesh sizes. Females of all species have larger standard lengths than males (Mann-Whitney, p < 0.0001), and are more frequent in superior size classes (Kolmogorov-Smirnov, p < 0.0001). All populations presented isometric growth, but differences between males and females were observed. Only P. squamosissimus presented a gender ratio different from 1:1, with a higher proportion of males (1:2, X2, p < 0.05). The onset of gonadal maturation occurs at 15 cm in P. squamosissimus, 9 cm in S. maculatus and at 8.9 cm in A. altiparanae. In all species populations, the adults predominate over juveniles. The allometric condition factor (K) of P. squamosissimus and S. maculatus presented higher values in the periods from March-May and June-August, and A. altiparanae in the period from March-May (Kruskal-Wallis, p < 0.05). These results indicate that the populations successfully exploit the lentic environment, and present life cycle tactics adapted to their particular means of environment occupation.
Quantitative end qualitative analysis of the electrical activity of rectus abdominis muscle portions
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The purpose of this study was to investigate the electrical behavior pattern of the Rectus abdominis muscle by qualitative and quantitative analysis of the electromyographic signal obtained from its superior, medium and inferior portions during dynamic and static activities. Ten voluntaries (aged X = 17.8 years, SD = 1.6) athletic males were studied without history of muscle skeletal disfunction. For the quantitative analysis the RMS (Root Mean Square) values obtained in the electromyographic signal during the isometric exercises were normalized and expressed in maximum voluntary isometric contraction percentages. For the qualitative analysis of the dynamic activity the electromyographic signal was processed by full-wave rectification, linear envelope and normalization (amplitude and time), so that the resulting curve of the processed signal was submitted to descriptive graphic analysis. The results of the quantitative study show that there is not a statistically significant difference among the portions of the muscle. Qualitative analysis demonstrated two aspects: the presence of a common activation electric pattern in the portions of Rectus abdominis muscle and the absence of significant difference in the inclination angles in the electrical activity curve during the isotonic exercises.
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To study racemic bupivacaine, non-racemic bupivacaine and ropivacaine on myocardial contractility. Isolated Wistar papillary muscles were submitted to 50 and 100 mM racemic bupivacaine (B50 and B100), non-racemic bupivacaine (NR50 and NR100) and ropivacaine (R50 and R100) intoxication. Isometric contraction data were obtained in basal condition (0.2 Hz), after increasing the frequency of stimulation to 1.0 Hz and after 5, 10 and 15 min of local anesthetic intoxication. Data were analyzed as relative changes of variation. Developed tension was higher with R100 than B100 at D1 (4.3 ± 41.1 vs -57.9 ± 48.1). Resting tension was altered with B50 (-10.6 ± 23.8 vs -4.7 ± 5.0) and R50 (-14.0 ± 20.5 vs -0.5 ± 7.1) between D1 and D3. Maximum rate of tension development was lower with B100 (-56.6 ± 38.0) than R50 (-6.3 ± 37.9) and R100 (-1.9 ± 37.2) in D1. B50, B100 and NR100 modified the maximum rate of tension decline from D1 through D2. Time to peak tension was changed with NR50 between D1 and D2. Racemic bupivacaine depressed myocardial contractile force more than non-racemic bupivacaine and ropivacaine. Non-racemic and racemic bupivacaine caused myocardial relaxation impairment more than ropivacaine.
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Chronic obstructive pulmonary disease (COPD) is associated with autonomic dysfunctions that can be evaluated through heart rate variability (HRV). Resistance training promotes improvement in autonomic modulation; however, studies that evaluate this scenario using geometric indices, which include nonlinear evaluation, thus providing more accurate information for physiological interpretation of HRV, are unknown. This study aimed to investigate the influence of resistance training on autonomic modulation, using geometric indices of HRV, and peripheral muscle strength in individuals with COPD. Fourteen volunteers with COPD were submitted to resistance training consisting of 24 sessions lasting 60 min each, with a frequency of three times a week. The intensity was determined as 60% of one maximum repetition and was progressively increased until 80% for the upper and lower limbs. The HRV and dynamometry were performed at two moments, the beginning and the end of the experimental protocol. Significant increases were observed in the RRtri (4·81 ± 1·60 versus 6·55 ± 2·69, P = 0·033), TINN (65·36 ± 35·49 versus 101·07 ± 63·34, P = 0·028), SD1 (7·48 ± 3·17 versus 11·04 ± 6·45, P = 0·038) and SD2 (22·30 ± 8·56 versus 32·92 ± 18·78, P = 0·022) indices after the resistance training. Visual analysis of the Poincare plot demonstrated greater dispersion beat-to-beat and in the long-term interval between consecutive heart beats. Regarding muscle strength, there was a significant increase in the shoulder abduction and knee flexion. In conclusion, geometric indices of HRV can predict improvement in autonomic modulation after resistance training in individuals with COPD; improvement in peripheral muscle strength in patients with COPD was also observed.
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The aims of this study were to evaluate aspects of balance, ankle muscle strength and spatiotemporal gait parameters in individuals with diabetic peripheral neuropathy (DPN) and verify whether deficits in spatiotemporal gait parameters were associated with ankle muscle strength and balance performance. Thirty individuals with DPN and 30 control individuals have participated. Spatiotemporal gait parameters were evaluated by measuring the time to walk a set distance during self-selected and maximal walking speeds. Functional mobility and balance performance were assessed using the Functional Reach and the Time Up and Go tests. Ankle isometric muscle strength was assessed with a handheld digital dynamometer. Analyses of variance were employed to verify possible differences between groups and conditions. Multiple linear regression analysis was employed to uncover possible predictors of gait deficits. Gait spatiotemporal, functional mobility, balance performance and ankle muscle strength were affected in individuals with DPN. The Time Up and Go test performance and ankle muscle isometric strength were associated to spatiotemporal gait changes, especially during maximal walking speed condition. Functional mobility and balance performance are damaged in DPN and balance performance and ankle muscle strength can be used to predict spatiotemporal gait parameters in individuals with DPN.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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To analyze strength and integrated electromyography (IEMG) data in order to determine the neuromuscular efficiency (NME) of the vastus lateralis (VL) and biceps femoris (BF) muscles in patients with anterior cruciate ligament (ACL) injuries, during the preoperative and postoperative periods; and to compare the injured limb at these two times, using the non-operated limb as a control. EMG data and BF and VL strength data were collected during three maximum isometric contractions in knee flexion and extension movements. The assessment protocol was applied before the operation and two months after the operation, and the NME of the BF and VL muscles was obtained. There was no difference in the NME of the VL muscle from before to after the operation. On the other hand, the NME of the BF in the non-operated limb was found to have increased, two months after the surgery. The NME provides a good estimate of muscle function because it is directly related to muscle strength and capacity for activation. However, the results indicated that two months after the ACL reconstruction procedure, at the time when loading in the open kinetic chain within rehabilitation protocols is usually started, the neuromuscular efficiency of the VL and BF had still not been reestablished.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The aim of this study was to investigate the effect of recovery time after quadriceps muscle fatigue on gait in young adults. Forty young adults (20-40 years old) performed three 8-m gait trials at preferred velocity before and after muscle fatigue, and after 5, 10 and 20min of passive rest. In addition, at each time point, two maximal isometric voluntary contractions were preformed. Muscle fatigue was induced by repeated sit-to-stand transfers until task failure. Spatio-temporal, kinetic and muscle activity parameters, measured in the central stride of each trial, were analyzed. Data were compared between before and after the muscle fatigue protocol and after the recovery periods by one-way repeated measures ANOVA. The voluntary force was decreased after the fatigue protocol (p<0.001) and after 5, 10 and 20min of recovery compared to before the fatigue protocol. Step width (p<0.001) and RMS of biceps femoris (p<0.05) were increased immediately after the fatigue protocol and remained increased after the recovery periods. In addition, stride duration was decreased immediately after the fatigue protocol compared to before and to after 10 and 20min of rest (p<0.001). The anterior-posterior propulsive impulse was also decreased after the fatigue protocol (p<0.001) and remained low after 5, 10 and 20min of rest. We conclude that 20min is not enough to see full recovery of gait after exhaustive quadriceps muscle fatigue.
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The goal of the present study was to investigate possible differences towards strenght recovery measured by different methods and running economy (RE), after one session of downhill running (DR), in order to induce muscle damage (MD). Our hypothesis is that the strenght recovery measured by jumps is more alike RE markers, due to the measures' specificity. Ten male subjects, ages 18 to 30, apparently healthy, without any experience with strenght training at least 6 months before the tests took place in this study. After going to the lab twice (to familiarize themselves with the protocols, and determine their maximum oxygen consumption/running speeds), they went to the lab five times in the following week, in order to collect all the variables before, immediately after, and 24, 48, 72 and 96 hours in. The variables obtained were: stride frequency (SF), stride lenght (SL), oxygen volume (VO2), carbon dioxide volume (VCO2), ventilation (VE), lactate blood concentration ([Lac]), isometric peak torque (IPT), subjective pain perception (SPP), effort perception (EP), medial-portion circumference (CIR), knee movement extent (EXT), torque development rate (TDR), counter movement jump and squat jump height (HCM and HS), strenght development rate of both jumps (SDCM and SDS), and maximum soil strenght reaction (SRCM and SRS). Changes over time in all variables were verified by one way variancy analysis. Differences between the strenght measures were verified by two way variancy analysis. When significant effects were verified, Tuckey's post-hoc were applied. The significancy level taken on this study was p < 0,05. Of all indirect muscle damage markers, IPT, SPP and TDR were the only ones in which ocurred significant changes. We couldn't find the moments where this happened for TDR with the post-hoc used. On RE markers, VO2, [Lac] and VE suffered significant effects over time. About the jumps variables, only SDCM and HCM presented significant...
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Among the numerous possibilities of physical exercise, it has been recommended that stretching routines should be incorporated into training programs focused on the elderly population, and that these routines should be preferentially performed on the same strength or aerobic training session. However, studies have shown that muscle strength production can be acutely impaired if it is preceded by static stretching exercises (AE). Although there seems to be a relationship between the number of stretched muscles and strength response, no studies were found examining such relationship in the same study, simultaneously. Thus, the objective of this study is to analyze the acute effect of stretching of different muscle groups on strength performance in older women. Nineteen physically active older women participated in the study (67.8 ± 5.3 years, 68.9 ± 12.4 kg, 157.2 ± 6.4 cm)-usar ponto final em inglês e não vírgula. The participants visited the lab for six consecutive days, three of which were intended to familiarization. Over the next three days, all the participants performed the experimental conditions: control; quadriceps stretching alone and complete stretching, involving the major extensors muscle groups of knees and hips. Both the two stretching conditions were realized with three series of 30s (total volume of 90 seconds for each exercise). All experimental conditions was be performed with an interval of at least 24 hours and order of execution was be randomized. The force transducer was connected to a leg press apparatus, where the isometric force time curve and electromyographic activity of the vastus medial and vastus lateralis were recorded. Measurements were registered immediately after each experimental condition, during five seconds. Statistical analysis comprised descriptive procedures and the One way ANOVA test for repeated measures (p<0.05). No statistically significant differences between the control and the two...
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Several methods are used towards delayed onset muscle soreness appraisal. This study's goal was to investigate, amongst three commonly adopted methods, which one would be the most effective (the one that shows higher values) in the quantification of this phenomenon. 10 male subjects, of age 22.8 ± 3.1 years old, weight 80 ± 12.4 kg, height 174 ± 0.07 cm, without recent experience with strength training (lower limbs) and/or running took place in this study. All subjects carried out a muscle damage induction protocol, which consisted of 30 minute downhill running (-16% or -9.09º) at 80% speed compared to their maximum oxygen consumption. Muscle damage determinants such as isometric peak torque, knee joint range of motion and circumference of the medial portion of the thight were measured before, during, 24, 48, 72 and 96 hours after downhill running. The subjective pain perception was measured simultaneously with the other determinants through three different tests: sitting on and getting up of a chair; climbing and descending from a 45cm step; and self thigh palpation. After going through all subjective pain perception tests, the subjects filled out a visual analog scale with their perception of pain. Muscle damage changes over time were compared through variance analysis (ANOVA) one way for repeated measures. Subjective pain perception values obtained in all three different tests were compared through two way ANOVAs for repeated numbers. The significance level adopted in this study was z ≤ 0.05. The results showed that the step test was the on which better evaluated the delayed onset muscle soreness. No significant differences were found through the ADM and CIR recovery markers. Downhil running determined reduced of PTI (~22.4%). Significant links between pain were obtained for both subjective pain perception tests starting at 24 and 48 hours, where the highest registered average happened in the step test after 48h, with high...