HANDEDNESS INFLUENCES PASSIVE SHOULDER RANGE OF MOTION IN NONATHLETE ADULT WOMEN

Objective: The Purpose of this study was to determine whether handedness influences bilateral shoulder range of motion in nonathlete adult women. Methods: This was an observational Study. Shoulder range of motion (flexion, abduction, horizontal adduction, extension, external and internal rotation) was passively and bilaterally measured in 50 female, right-handed, and healthy university students, ranging from 20 to 29 years of age, who were not practicing repetitive activities with the upper limbs at the time Of this study. The assessment was performed with a universal goniometer, twice for each subject by the same examiner. irst and second measurements were correlated using the intraclass correlation coefficient, which was high for all movements and ranged from 0.80 to 0.97. The Student t test and Wilcoxon test were used to compare the range of motion between the dominant and nondominant shoulders and the mean differences between the 2 sides. The effect of size vias alpha = .05. Results: There is statistically significance difference between the 2 sides when the rotational range of motion is compared the dominant shoulder presented increased external rotation (mean, 4.74 degrees; 95% confidence interval, 1.61-7.87) and decreased internal rotation (mean, 3.52 degrees; 95% confidence interval, 1.64-5.4) compared to the opposite Shoulder. Conclusion: Dominance should be considered when shoulder rotation is evaluated even in nonathlete adult women. (J Manipulative Physiol Ther 2009;32:149-153)

Efeitos do alongamento e do aquecimento no desempenho isocinético e na atividade eletromiográfica do músculo bíceps femoral ensaio clínico randomizado

To evaluate the effects of warm-up and stretching, singly or combined, on isokinetic performance and electromyographic activity of the biceps femoris. Materials and methods: Sixty-four volunteers of both sexes, with mean age of 23,1 ± 3,5 years and mean body mass index of 23,5 ± 2,5 Kg/m2 were randomly assigned into 4 groups: control, warm-up (stationary bicycle for 10 minutes), stretching (4 sets of 30 seconds of hamstring muscles static stretching) and warm-up + stretching. All the volunteers were submitted to evaluation pre and post-intervention of the muscle latency time and biceps femoris RMS and the passive torque, peak torque and power of the hamstring muscles. Results: The warm-up + stretching group had reduction of muscle latency time. There was a reduction of RMS during passive torque evaluation in stretching group. The RMS during isometric evaluation was reduced in all experimental groups. The RMS during eccentric evaluation showed reduction in control and warm-up + stretching groups. The passive torque and the eccentric peak torque had no significant differences pre to post-intervention in any group. There was reduction in isometric peak torque in all groups. Conclusion: The warm-up and stretching, when applied in combination can reduce the muscle latency time; stretching protocol promoted neural changes; the protocols used did not alter the muscle viscoelastic properties

Efeito do tempo de repouso após fadiga induzida no desempenho neuromuscular do quadríceps femoral: ensaio clínico, controlado, randomizado, cego

Objective: To evaluate the effect of different resting periods, after induced muscle fatigue, in the quadriceps femoris neuromuscular performance, in healthy subjects. Methods: Sixty-four volunteers, of both genders, with an average of 21,8 ± 1,7 years and mean body mass index of 24,2 ± 3,7 Kg/m2 were randomly assigned into 4 groups: control group (was not induced fatigue); Experimental Group 1 (Exp. 1 1 minute of rest after fatigue); Experimental Group 3 (Exp. 3 3 minutes of rest after fatigue) and Experimental Group 5 (Exp. 5 5 minutes of rest after fatigue). The subjects were evaluated to the knee´s joint position sense (JPS), followed by 5 flexion-extension knee concentric isokinetic contractions at 60°/s, with concomitant recording of median frequency (Fmed) of rectus femoris (RF), vastus lateralis (VL) and vastus medialis (VM). Then they underwent a muscle fatigue protocol (30 flexion-extension knee concentric contractions at 60°/s) and were reevaluated on the isokinetic performance, Fmed and JPS. Blood lactate levels were measured before initial assessment, immediately after the fatigue protocol and 5 minutes after the end of the rest period. Results: The adoption of 3 minutes of rest was sufficient to restore the initial conditions for the peak torque normalized by body weight and the VL and VM Fmed. The joint position sense returned to its initial values with 1 minute rest. The lactate concentration remained high regardless of the adopted rest period. Conclusion: The use of 3-minute rest period is sufficient for the reestablishment of the neuromuscular parameters to the pre fatigue values.

Eccentric torque-producing capacity is influenced by muscle length in older healthy adults

Considering the importance of muscle strength to functional capacity in the elderly, the study investigated the effects of age on isokinetic performance and torque production as a function of muscle length. Eleven younger (24.2±2.9years) and seventeen older men (62.7±2.5years) were subjected to concentric and eccentric isokinetic knee extension/flexion at 60°.s-1 and 120°.s-1 through a functional range of motion. The older group presented lower peak torque (Nm) than the young group for both isokinetic contraction types (age effect, p<0.001). Peak torque deficits in the older group were near 30% and 29% for concentric and eccentric contraction, respectively. Concentric peak torque was lower at 120.s-1 than at 60.s-1 for both groups (angular velocity effect, p<0.001). Eccentric knee extension torque was the only exercise tested that showed an interaction effect between age and muscle length (p<0.001), which suggested different torque responses to the muscle length between groups. Compared with the young group, the eccentric knee extension torque was 22% to 56% lower in the older group, with the deficits being lower in the shortened muscle length (22-27%) and higher (33-56%) in stretched muscle length. In older men, the production of eccentric knee strength seems to be muscle length-dependent. At more stretched positions, older subjects lose the capacity to generate eccentric knee extension torque. More studies are needed to assess the mechanisms involved in eccentric strength preservation with aging and its relationship with muscle length.

Efeito tardio do kinesio taping na função do membro inferior e no desempenho neuromuscular do quadríceps femoral de mulheres saudáveis: ensaio clínico e randomizado

Introduction: Kinesio Taping (KT) has been used in healthy people to improve neuromuscular performance, however, few studies have evaluated its chronic effects, despite being suggested. Objective: To analyze the chronic effects of KT on neuromuscular performance of the quadriceps, the oscillation of the center of pressure and lower limb function in healthy women. Methods: blinded, randomized, controlled trial, composed of 60 women (mean age 21.9 ± 3.3 years and BMI 22.3 ± 2.2 kg / m2) submitted to the evaluation of oscillation of the center of pressure through the baropodometry, the lower limb function by the hop test, isokinetic knee performance, the electromyographic activity of the vastus lateralis (VL) and joint position sense of the knee (JPS). Then, participants were randomly divided into three groups of twenty: control - did not apply the KT; placebo - application of KT without tension on the quadriceps; Kinesio Taping - application of KT with tension in the same muscle group. The evaluations were conducted in five moments: prior to application of KT, immediately after the application, 24h, 48h after application and 24 hours after its removal (72h). SPSS 20.0 was used for statistical analysis. The KS test was used to verify the data normality, the Levene test for homogeneity of variances and a mixed-model ANOVA 3x5 to check intra and inter-group differences. Results: there was no difference in peak torque, the power, nor the electromyographic activity or SPA (p> 0.05) between groups. The displacement speed of center of pressure reduced immediately after the application on kinesio taping group (p <0.001), but with no differences between the groups (p = 0.28). There was a reduction in the time of peak torque among the three groups in the evaluations after KT application (p <0.001) and an increase in single hop in all groups (p <0.001), but with no differences between them. Conclusion: KT can not change, in a chronic way, the lower limb function, the oscillation of the center of pressure, the isokinetic performance, the JPS of the knee and the electromyographic activity of VL muscle in healthy women.

Efeitos imediatos da plataforma vibratória no desempenho neuromuscular do quadríceps femoral, após reconstrução do LCA: ensaio controlado, randomizado e cego

Objective: to investigate the immediate effect of the vibrating platform on the neuromuscular performance of the quadriceps femoris and on the postural oscillation of subjects submitted to Anterior Cruciate Ligament (ACL) reconstruction. Materials and methods: this study is a randomized and blind clinical trial. Forty-four male volunteers (average age of 27,4 ±6,2 IMC of 26,85± 3,8 Kg/m² and post surgery timeframe of 17± 1,4 weeks) were randomized into two groups: OFF platform (n=22, protocol of exercise over the vibrating platform off) and ON platform (n=22 protocol of exercise over the vibrating platform on, 50Hz frequency and 4mm of amplitude). All volunteers were submitted to assessment the isokinetic evaluation of the quadriceps femoris (isometric and isokinetic at 60°/s) and of the electromyography activity of the muscles Vasto Lateralis (VL) and Vasto Medialis (VM), besides the postural oscillation (baropodometry) in two distinct moments: before and immediately after the intervention protocol. The data was analyzed through the SPSS 20.0 software, with a 5% significance level. To verify the homogeneity of the groups it was used an ANOVA one way, and a ANOVA mixed model to compare the intra and inter groups. Results: it was observed differences between the pre and the post, to latero lateral velocity, isometric torque peak and total work in comparison with intragroup. However, it wasn’t verified any difference in comparing the intergroup in the preevaluation and in the post-evaluation protocol over the vibrating platform. Conclusion: the use of the vibrating platform doesn’t change as an immediate manner the isokinetic performance of the quadriceps femoris, the electromyography activity of the VL and the VM, also doesn’t interfere with the postural oscillation of individuals that were submitted to the ACL reconstruction.

Análise do desempenho muscular do quadríceps e dos isquiotibiais em função da série temporal e da amplitude de movimento de atletas amadoras de futsal feminino = : Analysis of muscle performance of the quadriceps and hamstrings as a function of the times series and range of motion of amateurfemale futsal athletes

Universidade Estadual de Campinas . Faculdade de Educação Física

Predicting sprint running times from isokinetic and squat lift tests: A regression analysis

This study examined the relationship between isokinetic hip extensor/hip flexor strength, 1-RM squat strength, and sprint running performance for both a sprint-trained and non-sprint-trained group. Eleven male sprinters and 8 male controls volunteered for the study. On the same day subjects ran 20-m sprints from both a stationary start and with a 50-m acceleration distance, completed isokinetic hip extension/flexion exercises at 1.05, 4.74, and 8.42 rad.s(-1), and had their squat strength estimated. Stepwise multiple regression analysis showed that equations for predicting both 20-m maximum velocity nm time and 20-m acceleration time may be calculated with an error of less than 0.05 sec using only isokinetic and squat strength data. However, a single regression equation for predicting both 20-m acceleration and maximum velocity run times from isokinetic or squat tests was not found. The regression analysis indicated that hip flexor strength at all test velocities was a better predictor of sprint running performance than hip extensor strength.

Effect of the movement speed of resistance training exercises on sprint and strength performance in concurrently training elite junior sprinters

The aim of this study was to determine the effects of 7 weeks of high- and low-velocity resistance training on strength and sprint running performance in nine male elite junior sprint runners (age 19.0 +/- 1.4 years, best 100 m times 10.89 +/- 0.21 s; mean +/- s). The athletes continued their sprint training throughout the study, but their resistance training programme was replaced by one in which the movement velocities of hip extension and flexion, knee extension and flexion and squat exercises varied according to the loads lifted (i.e. 30-50% and 70-90% of 1-RM in the high- and low-velocity training groups, respectively). There were no between-group differences in hip flexion or extension torque produced at 1.05, 4.74 or 8.42 rad . s(-1), 20 m acceleration or 20 m 'flying' running times, or 1-RM squat lift strength either before or after training. This was despite significant improvements in 20 m acceleration time (P < 0.01), squat strength (P< 0.05), isokinetic hip flexion torque at 4.74 rad . s(-1) and hip extension torque at 1.05 and 4.74 rad . s(-1) for the athletes as a whole over the training period. Although velocity-specific strength adaptations have been shown to occur rapidly in untrained and non-concurrently training individuals, the present results suggest a lack of velocity-specific performance changes in elite concurrently training sprint runners performing a combination of traditional and semi-specific resistance training exercises.

Isokinetic assessment of the flexor-extensor balance of the knee in athletes with total rupture of the anterior cruciate ligament

The purpose of this study was to assess the flexor-extensor group of muscles of the knee in young athletes diagnosed with a total rupture of the anterior cruciate ligament (ACL). Eighteen knees of 18 athletes (14 men and 4 women) with an average age of 21.6 years (range 16-32 years) were assessed with a Cybex 6000 model isokinetic apparatus. The average interval between occurrence of the injury and assessment was 10.2 months (range 2 - 48 months). There was an associated meniscal injury in eight of the knees. Athletes with any other kind of associated injury, limitation, or blockage of the movement of the joint, significant pain during the exam, or interval between injury and exam of less than two months were excluded from the study. The parameters studied were the peak torque-velocity and flexor-extensor relationships at the constant angular velocities of 60°/sec and 240°/sec. Previous warming-up was done by means of an ergometric bicycle and adaptation with 3 submaximal repetitions. The contra-lateral side, which presented no injury, was used as control. Peak torque (PT) at the constant velocity of 60°/sec was greater than that at 240°/sec for knees with and without injuries. However, there was no significant difference between the injured and uninjured sides at 60°/sec or at 240°/sec. The average value for the flexor-extensor relationship at 60°/sec on the injured was 60% (( 6), compared to 57% (( 10) on the contra-lateral side. At 240°/sec, the average value was 75% ((10) on the injured side, and 65% ((12) on the contra-lateral side. In conclusion, despite the complete rupture of the ACL of one knee, the average values for the flexor-extensor relationship were similar on the injured and uninjured sides at the velocity of 60°/sec. As the velocity increased, an increase in the values for the flexor-extensor relationship of the knee also occurred, indicating a tendency of the performance of the flexor muscle group to approach that of the extensor muscle group, and this tendency was more pronounced on the side of the injury.

Isokinetic rotator muscles fatigue in glenohumeral joint instability before and after Latarjet surgery: a pilot prospective study.

We aimed to analyze the changes in isokinetic internal (IR) and external (ER) rotator muscles fatigue (a) in patients with non-operated recurrent anterior instability, and (b) before and after shoulder surgical stabilization with the Bristow-Latarjet procedure. Thirty-seven patients with non-operated unilateral recurrent anterior post-traumatic instability (NG) were compared with 12 healthy subjects [control group (CG)]. Twenty patients with operated recurrent anterior instability group (OG) underwent isokinetic evaluation before and 3, 6, and 21 months after Bristow-Latarjet surgery. IR and ER muscles strength was evaluated with Con-Trex® dynamometer, with subjects seated and at a 45° shoulder abduction angle in scapular plane. IR and ER muscle fatigue was determined after 10 concentric repetitions at 180° · s(-1) through the fatigue index, the percent decrease in performance (DP), and the slope of peak torque decrease. There were no differences in rotator muscles fatigue between NG and CG. In OG, 3 months post-surgery, IR DP of operated shoulder was significantly (P < 0.001) higher than presurgery and 6 and 21 months post-surgery. Rotator muscles fatigability was not associated with recurrent anterior instability. After surgical stabilization, there was a significantly higher IR fatigability in the operated shoulder 3 months post-surgery, followed by recovery evidenced 6 months post-surgery and long-term maintenance over 21 months.

The effects of stretching on the flexibility, muscle performance and functionality of institutionalized older women

Stretching has been widely used to increase the range of motion. We assessed the effects of a stretching program on muscle-tendon length, flexibility, torque, and activities of daily living of institutionalized older women. Inclusion/exclusion criteria were according to Mini-Mental State Examination (MMSE) (>13), Barthel Index (>13) and Lysholm Scoring Scale (>84). Seventeen 67 ± 9 year-old elderly women from a nursing home were divided into 2 groups at random: the control group (CG, N = 9) participated in enjoyable cultural activities; the stretching group (SG, N = 8) performed active stretching of hamstrings, 4 bouts of 1 min each. Both groups were supervised three times per week over a period of 8 weeks. Peak torque was assessed by an isokinetic method. Both groups were evaluated by a photogrammetric method to assess muscle-tendon length of uni- and biarticular hip flexors and hamstring flexibility. All measurements were analyzed before and after 8 weeks by two-way ANOVA with the level of significance set at 5%. Hamstring flexibility increased by 30% in the SG group compared to pre-training (76.5 ± 13.0° vs 59.5 ± 9.0°, P = 0.0002) and by 9.2% compared to the CG group (76.5 ± 13.0° vs 64.0 ± 12.0°, P = 0.0018). Muscle-tendon lengths of hip biarticular flexor muscles (124 ± 6.8° vs 118.3 ± 7.6°, 5.0 ± 7.0%, P = 0.031) and eccentric knee extensor peak torque were decreased in the CG group compared to pre-test values (-49.4 ± 16.8 vs -60.5 ± 18.9 Nm, -15.7 ± 20%, P = 0.048). The stretching program was sufficient to increase hamstring flexibility and a lack of stretching can cause reduction of muscle performance.

Effect of L-carnitine on exercise performance in patients with mitochondrial myopathy

Exercise intolerance due to impaired oxidative metabolism is a prominent symptom in patients with mitochondrial myopathy (MM), but it is still uncertain whether L-carnitine supplementation is beneficial for patients with MM. The aim of our study was to investigate the effects of L-carnitine on exercise performance in MM. Twelve MM subjects (mean age±SD=35.4±10.8 years) with chronic progressive external ophthalmoplegia (CPEO) were first compared to 10 healthy controls (mean age±SD=29±7.8 years) before they were randomly assigned to receive L-carnitine supplementation (3 g/daily) or placebo in a double-blind crossover design. Clinical status, body composition, respiratory function tests, peripheral muscle strength (isokinetic and isometric torque) and cardiopulmonary exercise tests (incremental to peak exercise and at 70% of maximal), constant work rate (CWR) exercise test, to the limit of tolerance [Tlim]) were assessed after 2 months of L-carnitine/placebo administration. Patients with MM presented with lower mean height, total body weight, fat-free mass, and peripheral muscle strength compared to controls in the pre-test evaluation. After L-carnitine supplementation, the patients with MM significantly improved their Tlim (14±1.9 vs 11±1.4 min) and oxygen consumption ( V ˙ O 2 ) at CWR exercise, both at isotime (1151±115 vs 1049±104 mL/min) and at Tlim (1223±114 vs 1060±108 mL/min). These results indicate that L-carnitine supplementation may improve aerobic capacity and exercise tolerance during high-intensity CWRs in MM patients with CPEO.