Electromyographic evaluation of the rectus femoris muscle during exercises performed on the leg press

The rectus femoris was analysed in 10 volunteers during knee flexion and extension with the feet in normal, plantar flexion and dorsal flexion positions. Hewlett-Packard surface electrodes, an electromyographic signal amplifier, a computer equipped with an A/D conversion plaque (Model CAD 10/26), software specially designed to record and analyse the signals, Horizontal Leg Press, and electrogoniometers were used. The rectus femoris muscle showed strong potentials at the beginning of knee extension. In the simultaneous bendings of the knee and hip the activity was strong toward the end of the movement. The rectus femoris showed a similar activity both in the upper and lower platforms. As for foot positions, the rectus femoris showed the smallest potentials with the foot in plantar flexion and the largest ones with the foot in dorsal flexion.

Electromyographic behaviour of the gastrocnemius muscle during knee extension and flexion performed on the leg press

The gastrocnemius was analysed in 10 male volunteers during knee flexion and extension with the foot in normal, plantar flexion and dorsal flexion positions. Hewlett-Packard surface electrodes, an electromyographic signal amplifier, a computer equipped with an AID conversion plaque (Model CAD 10/26), a software specially designed to record and analyse the signals, a horizontal leg press, and electrogoniometers were used. The gastrocnemius muscle showed strong potentials at the end of knee extension and beginning of knee flexion. The muscle presented a similar activity both in the zipper and lower platforms. As to bilateral action, the right gastrocnemius presented stronger potentials on the upper platforms, whereas the potentials were bilaterally similar on the lower platforms. As for foot position, the gastrocnemius presented strong potentials when the foot was in plantar flexion. The remaining positions had no effect on the work of the muscle.

Electromyographic evaluation of the upper lip according to the breathing mode: A longitudinal study

The present study aimed at analyzing and comparing longitudinally the EMG (electromyographic activity) of the superior orbicularis oris muscle according to the breathing mode. The sample, 38 adolescents with Angle Class II Division 1 malocclusion with predominantly nose (PNB) or mouth (PMB) breathing, was evaluated at two different periods, with a two-year interval between them. For that purpose, a 16-channel electromyography machine was employed, which was properly calibrated in a PC equipped with an analogue-digital converter, with utilization of surface, passive and bipolar electrodes. The RMS data (root mean square) were collected at rest and in 12 movements and normalized according to time and amplitude, by the peak value of EMG, in order to allow comparisons between subjects and between periods. Comparison of the muscle function of PNB and PMB subjects at period 1 (P1), period 2 (P2) and the variation between periods (Δ) did not reveal statistically significant differences between groups (p < 0.05). However, longitudinal evaluation of the muscle function in PNB and PMB subjects demonstrated different evolutions in the percentage of required EMG for accomplishment of the movements investigated. It was possible to conclude that there are differences in the percentage of electric activity of the upper lip with the growth of the subjects according to the breathing mode.

Electromyographic evaluation of the temporal muscle after the use of interocclusal splints with a vibrating device in individuals with sleep bruxism

This is the first study performed with an interocclusal splint with a vibrating device on patients with sleep bruxism. The purpose of the present study was to evaluate the effectiveness of the splint with vibrating device on patients who suffer from sleep bruxism through computerized electromyography (EMG) of the anterior temporal muscles. Eight male and female patients, ranging in age from 18 to 28 years, with evident signs and symptoms of bruxism were selected. The splint were made for the upper arch. The patients was treated with the interocclusal splint with a vibrating device, and submitted to EMG evaluations of the anterior temporal muscles on both sides. The evaluations were performed at the beginning of treatment and after 21 days of splint use. Electromyography was performed in an isometric contractions measuring of the temporal muscles. The following results obtained revealed that: when closing the mandible (isometric contraction), the anterior temporal muscles had an expressive reduction in electromyographic activity (p. < 0.10), so this splints were considered effective for patients who suffer from sleep bruxism. © 2009 Springer-Verlag.

Influence of upper-body exercise order on hormonal responses in trained men

The aim of this study was to examine acute hormonal responses after different sequences of an upper-body resistance-exercise session. Twenty men completed 2 sessions (3 sets; 70% 1-repetition maximum; 2 min passive rest between sets) of the same exercises in opposite sequences (larger to smaller vs. smaller to larger muscle-group exercises). Total testosterone (TT), free testosterone (FT), testosterone/cortisol (T/C) ratio, sex-hormone-binding globulin (SHBG), growth hormone (GH), and cortisol (C) concentrations were measured before and immediately after each sequence. The results indicate that the GH concentration increased after both sessions, but the increase was significantly greater (p < 0.05) after the sequence in which larger muscle-group exercises were performed prior to the smaller muscle-group exercises. No differences were observed between sessions for TT, FT, SHBG, C, or the T/C ratio at baseline or immediately after resistance exercise. These results indicate that performing larger muscle-group exercises first in an upper-body resistance-exercise session leads to a significantly greater GH response. This may have been due to the significantly greater exercise volume accomplished. In summary, the findings of this investigation support the common prescriptive recommendation to perform larger-muscle group exercises first during a resistance-exercise session.

Influence of exercise order on upper body maximum and submaximal strength gains in trained men

The purpose of this study was to investigate the influence of exercise order on one-repetition maximum (1-RM) and ten-repetition maximum (10-RM) strength gains after 6 weeks of resistance training (RT) in trained men. Sixteen men were randomly assigned into two groups based on the order of exercises performed during training sessions: a group that performed large muscle group exercises first and progressed to small muscle group exercises (LG-SM); while a second group performed the opposite sequence and started with small muscle group exercises and progressed to large muscle group exercises (SM-LG). Four sessions of RT were conducted per week; all exercises were performed for three sets of 8-12 repetitions with 1-min rest intervals between sets. Maximal and submaximal strength were assessed at baseline and after 6 weeks of RT with 1-RM and 10-RM testing for the bench press (BP), lat pulldown (LPD), triceps pulley extension (TE) and biceps curl (BC), respectively. Two-way ANOVA for the 1-RM and 10-RM tests indicated a significant group x time interaction. The 1-RM values significantly increased for all exercises in both groups (P<0.05), but were not significantly different between groups. However, effect size (ES) data indicated that the LG-SM group exhibited a greater magnitude of gains (1-RM and 10-RM) for the BP and LPD exercises. Conversely, ES indicated that the SM-LG group exhibited a greater magnitude of gains (1-RM and 10-RM) for the TE and BC exercises. In conclusion, the results suggest that upper body movements should be prioritized and performed according to individual needs to maximize maximal and submaximal strength. © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine.

Evaluation of rotator cuff muscle strength in healthy individuals

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.

A heat transfer model of the human upper limbs

A steady state multi-segmented heat transfer model of the human upper limbs was developed. The main purpose was to evaluate the impact of blood flow through superficial veins and subcutaneous vascular structures in the palm of the hands over the heat transfer between the limbs and the environment. The distinguishing feature of the model is the inclusion of a detailed circulatory network composed of vessels with diameter larger than 1 mm. The model was validated by comparing its results from exposures to a hot, a neutral, and a cold environment to experimental data presented in the literature. (C) 2011 Elsevier Ltd. All rights reserved.

Creatine but not betaine supplementation increases muscle phosphorylcreatine content and strength performance

We aimed to investigate the role of betaine supplementation on muscle phosphorylcreatine (PCr) content and strength performance in untrained subjects. Additionally, we compared the ergogenic and physiological responses to betaine versus creatine supplementation. Finally, we also tested the possible additive effects of creatine and betaine supplementation. This was a double-blind, randomized, placebo-controlled study. Subjects were assigned to receive betaine (BET; 2 g/day), creatine (CR; 20 g/day), betaine plus creatine (BET + CR; 2 + 20 g/day, respectively) or placebo (PL). At baseline and after 10 days of supplementation, we assessed muscle strength and power, muscle PCr content, and body composition. The CR and BET + CR groups presented greater increase in muscle PCr content than PL ( = 0.004 and = 0.006, respectively). PCr content was comparable between BET versus PL ( = 0.78) and CR versus BET + CR ( = 0.99). CR and BET + CR presented greater muscle power output than PL in the squat exercise following supplementation ( = 0.003 and = 0.041, respectively). Similarly, bench press average power was significantly greater for the CR-supplemented groups. CR and BET + CR groups also showed significant pre- to post-test increase in 1-RM squat and bench press (CR: = 0.027 and < 0.0001; BET + CR: = 0.03 and < 0.0001 for upper- and lower-body assessments, respectively) No significant differences for 1-RM strength and power were observed between BET versus PL and CR versus BET + CR. Body composition did not differ between the groups. In conclusion, we reported that betaine supplementation does not augment muscle PCr content. Furthermore, we showed that betaine supplementation combined or not with creatine supplementation does not affect strength and power performance in untrained subjects.

Weakness of expiratory muscles and pulmonary complications in malnourished patients undergoing upper abdominal surgery

Background and objective: Malnutrition is prevalent in hospitalized patients and causes systemic damage including effects on the respiratory and immune systems, as well as predisposing to infection and increasing postoperative complications and mortality. This study aimed to assess the impact of malnutrition on the rate of postoperative pulmonary complications, respiratory muscle strength and chest wall expansion in patients undergoing elective upper abdominal surgery. Methods: Seventy-five consecutive candidates for upper abdominal surgery (39 in the malnourished group (MNG) and 36 in the control group (CG)) were enrolled in this prospective controlled cohort study. All patients were evaluated for nutritional status, respiratory muscle strength, chest wall expansion and lung function before surgery. Postoperative pulmonary complications (pneumonia, tracheobronchitis, atelectasis and acute respiratory failure) before discharge from hospital were also evaluated. Results: The MNG showed expiratory muscle weakness (MNG 65 +/- 24 vs CG 82 +/- 22 cm H2O; P < 0.001) and decreased chest wall expansion (P < 0.001), whereas inspiratory muscle strength and lung function were preserved (P > 0.05). The MNG also had a higher incidence of postoperative pulmonary complications compared with the CG (31% and 11%, respectively; P = 0.05). In addition, expiratory muscle weakness was correlated with BMI in the MNG (r = 0.43; P < 0.01). The association between malnutrition and expiratory muscle weakness increased the likelihood of postoperative pulmonary complications after upper abdominal surgery (P = 0.02). Conclusions: These results show that malnutrition is associated with weakness of the expiratory muscles, decreased chest wall expansion and increased incidence of pulmonary complications in patients undergoing elective upper abdominal surgery.

Pre- and Postoperative Quantitative Analysis of Contour Abnormalities in Graves Upper Eyelid Retraction

Purpose: One of the most common problems of the surgical management of Graves upper eyelid retraction is the occurrence of eyelid contour abnormalities. In the present study, the postoperative contour of a large sample of eyelids of patients with Graves orbitopathy was measured. Methods: The postoperative upper eyelid contour of 62 eyes of 43 patients with Graves orbitopathy was subjectively classified by 3 experienced surgeons in 3 categories: poor, fair, and good. The shape of the eyelid contours in each category was then measured with a recently developed custom-made software by measuring multiple midpupil eyelid distances each 15 degrees along the palpebral fissure. The upper eyelid contour of 60 normal subjects was also quantified as a control group. Results: The mean ratio between the sum of the lateral and medial midpupil eyelid distances (lateral/medial ratio) was 1.10 +/- 0.11 standard deviation in controls and 1.15 +/- 0.13 standard deviation in patients. Postoperatively, the mean midpupil eyelid distance at 90 degrees was 4.16 +/- 1.13 mm standard deviation. The distribution lateral/medial ratios of the eyelids judged as having good contours was similar to the distribution of the controls with a modal value centered on the interval between 1.0 and 1.10. The distribution of lateral/medial ratios of the eyelids judged as having poor contour was bimodal, with eyelids with low and high lateral/medial ratios. Low lateral/medial ratios occurred when there was a lateral overcorrection, giving the eyelid a flat or a medial ptosis appearance. High lateral/medial ratios were due to a central or medial overcorrection or a lateral peak maintenance. Conclusions: Postoperative upper eyelid contour abnormalities can be quantified by comparing the sum of multiple midpupil eyelid distances of the lateral and medial sectors of the eyelid. Low and high lateral/medial ratios are anomalous and judged as unpleasant. (Ophthal Plast Reconstr Surg 2012;28:429-433)

Relationship between function, strength and electromyography of upper extremities of persons with tetraplegia

Study design: Cross-sectional. Objective: To analyze the relationships between functional tests, arm strength and root mean square of surface electromyography (EMG). Setting: Sao Paulo, Brazil. Methods: Twenty-four individuals with chronic tetraplegia participated. Upper extremity motor score (UEMS), functional independence measure (FIM) motor score, spinal cord independence measure III and capabilities of upper extremity (CUE) were performed. Muscle strength of the right elbow flexors-extensors was assessed using dynamometry and manual muscle test (MMT) and EMG of right biceps and triceps brachii were performed. Spearman's rank correlation coefficients and Mann-Whitney's U-test were used. Results: Functional tests and UEMS correlated strongly among them. UEMS highly correlated with triceps dynamometry and EMG. The dynamometry showed a very high correlation with MMT on the extensor group and a moderate correlation with flexor group. Triceps EMG showed moderate correlation with FIM and CUE. High correlations between triceps EMG and elbow extensors dynamometry and MMT were observed. A significant better performance on functional tests was observed on lower ASIA motor levels. The low-tetraplegia group showed a significant higher score on triceps EMG and dynamometry. Conclusion: Arm strength and EMG seem to be related to functional capabilities and independence in chronic tetraplegia. Spinal Cord (2012) 50, 28-32; doi:10.1038/sc.2011.95; published online 30 August 2011

Large asymmetric hypertrophy of rectus abdominis muscle in professional tennis players

[EN] PURPOSE: To determine the volume and degree of asymmetry of the musculus rectus abdominis (RA) in professional tennis players. METHODS: The volume of the RA was determined using magnetic resonance imaging (MRI) in 8 professional male tennis players and 6 non-active male control subjects. RESULTS: Tennis players had 58% greater RA volume than controls (P = 0.01), due to hypertrophy of both the dominant (34% greater volume, P = 0.02) and non-dominant (82% greater volume, P = 0.01) sides, after accounting for age, the length of the RA muscle and body mass index (BMI) as covariates. In tennis players, there was a marked asymmetry in the development of the RA, which volume was 35% greater in the non-dominant compared to the dominant side (P<0.001). In contrast, no side-to-side difference in RA volume was observed in the controls (P = 0.75). The degree of side-to-side asymmetry increased linearly from the first lumbar disc to the pubic symphysis (r = 0.97, P<0.001). CONCLUSIONS: Professional tennis is associated with marked hypertrophy of the musculus rectus abdominis, which achieves a volume that is 58% greater than in non-active controls. Rectus abdominis hypertrophy is more marked in the non-dominant than in the dominant side, particularly in the more distal regions. Our study supports the concept that humans can differentially recruit both rectus abdominis but also the upper and lower regions of each muscle. It remains to be determined if this disequilibrium raises the risk of injury.

Long-term results after muscle-rib flap transfer for reconstruction of composite limb defects

The authors present the long-term results in a series of 44 cases with post-traumatic bone defects solved with muscle-rib flaps, between March 1997 and December 2007. In these cases, we performed 21 serratus anterior-rib flaps (SA-R), 10 latissimus dorsi-rib flaps (LD-R), and 13 LD-SA-R. The flaps were used in upper limb in 18 cases and in lower limb in 26 cases. With an overall immediate success rate of 95.4% (42 of 44 cases) and a primary bone union rate of 97.7% (43 of 44 cases), and despite the few partisans of this method, we consider that this procedure still remains very usefully for small and medium bone defects accompanied by large soft tissue defects.

Skeletal muscle (1) H MRSI before and after prolonged exercise. I. muscle specific depletion of intramyocellular lipids

Aim of the study was to determine distribution and depletion patterns of intramyocellular lipids (IMCL) in leg muscles before and after two types of standardized endurance exercise. ¹H-magnetic resonance spectroscopic imaging was performed (1) in the thigh of eight-trained cyclists after exercising on an ergometer for 3 h at 52 ± 8% of maximal speed and (2) in the lower leg of eight-trained runners after exercising on a treadmill for 3 h at 49 ± 3% of maximal workload. Pre-exercise IMCL contents were reduced postexercise in 11 out of 13 investigated upper and lower leg muscles (P < 0.015 for all). A strong linear correlation with a slope of ∼0.5 between pre-exercise IMCL content and IMCL depletion was found. IMCL depletion differed strongly between muscles. Absolute and also relative IMCL reduction was significantly higher in muscles with predominantly slow fibers compared to those with fast fibers. Creatine levels and fiber orientation were stable and unchanged after exercise, while trimethyl-ammonium groups increased. This is presented in the accompanying paper. In conclusion, a systematic comparison of metabolic changes in cross sections of the upper and lower leg was performed. The results imply that pre-exercise IMCL levels determine the degree of IMCL depletion after exercise.