Trapezius activity and intramuscular balance during isokinetic exercise in overhead athletes with impingement symptoms.

We compared normalized trapezius muscle activity and intramuscular balance ratios between overhead athletes with impingement symptoms and non-injured athletes during isokinetic abduction and external rotation movements. Thirty-nine overhead athletes with chronic impingement symptoms and 30 non-injured athletes participated in the study. Electromyographic activity of upper, middle, and lower trapezius was measured during isokinetic abduction and external rotation, using surface electrodes. The results show a significant increase of upper trapezius activity during both movements in the patient group, with decreased activity in the lower trapezius during abduction, and in the middle trapezius during external rotation. Analysis of the intramuscular activity ratios revealed muscle imbalance on the injured side of the patient group for upper/middle trapezius and upper/lower trapezius during abduction, and for all three muscle activity ratios during external rotation. These results confirm the presence of scapular muscle imbalances in patients with impingement symptoms and emphasize the relevance of restoration of scapular muscle balance in shoulder rehabilitation.

Statistical modelling of fatigue-related electromyographic median frequency characteristics of back and hip muscles during a standardized isometric back extension test.

The purpose of the present study was to evaluate which statistical model - linear, logarithmic, quadratic or exponential - best described the fatigue-related electromyographic (EMG) changes of back and hip muscles. Twenty healthy volunteers performed a modified Biering-Sorensen test. The EMG activity of the latissimus dorsi (LD), longissimus thoracis pars thoracis (LTT) and lumborum (LTL), iliocostalis lumborum pars thoracis (ILT) and lumborum (ILL), multifidus (MF), gluteus maximus (GM) and biceps femoris (BF) was measured bilaterally using surface electrodes. Higher R(2) values were found for the quadratic models (p<0.05 for all muscles), and lower R(2) values for the logarithmic models (p<0.05 for LTT, LTL, ILL, MF and GM). The exponential models generated higher R(2) values compared to the linear ones for the LTT, LTL and MF (all p<0.05). Further analyses revealed, however, that these models did not add useful additional information, and therefore would only increase the complexity. The findings of the current study validate the use of simple linear regression techniques when studying fatigue-related EMG median frequency characteristics of back and hip muscles during isometric contractions.

Evaluation of isokinetic force production and associated muscle activity in the scapular rotators during a protraction-retraction movement in overhead athletes with impingement symptoms.

OBJECTIVES: To determine if the muscle force and electromyographic activity in the scapular rotators of overhead athletes with impingement symptoms showed differences between the injured and non-injured sides. METHODS: Isokinetic peak force was evaluated during protraction and retraction of the shoulder girdle, with simultaneous recording of electromyographic activity of the three trapezius muscles and the serratus anterior muscle, in 19 overhead athletes with impingement symptoms. RESULTS: Paired t tests showed significantly lower peak force during isokinetic protraction at high velocity (p<0.05), a significantly lower protraction/retraction ratio (p<0.01), and significantly lower electromyographic activity in the lower trapezius muscle during isokinetic retraction on the injured side than on the non-injured side (p<0.05). CONCLUSION: These results confirm that patients with impingement symptoms show abnormal muscle performance at the scapulothoracic joint.

Treating sensory impairments in the post-stroke upper limb with intermittent pneumatic compression. Results of a preliminary trial.

OBJECTIVE: To evaluate the efficacy of intermittent pneumatic compression (IPC) in treating sensory impairments in the hemiplegic upper limb in stroke patients. DESIGN: Twenty-three stroke patients were enrolled in a randomized, controlled preliminary trial that compared the application of intermittent pneumatic compression with a passive treatment strategy. SETTING: Four Belgian day centres for treatment of neurological disabilities. Four acute and rehabilitation care wards specialized in neurological treatment. SUBJECTS: Twenty-three stroke patients. INTERVENTIONS: The experimental group (n = 11) received standard physiotherapy combined with intermittent pneumatic compression treatment (10 cycles of 3 minutes with a peak of 40 mmHg) for their hemiplegic upper limb. The control group (n = 12) received supplementary to their conventional physiotherapy a placebo treatment, namely sham short-wave therapy on the hemiplegic shoulder for 30 minutes. MAIN OUTCOME MEASURES: Sensory impairments were clinically assessed at three occasions over a period of four weeks using the Nottingham Sensory Assessment scale. RESULTS: Both groups improved in somatosensation over time, but the experimental group improved more than the control group (p= 0.036) or 81.1% improvement versus 30.9%. CONCLUSIONS: The use of intermittent pneumatic compression in the rehabilitation of stroke patients may be of clinical importance for the restoration of sensory function.

Does taping influence electromyographic muscle activity in the scapular rotators in healthy shoulders?

Although taping techniques are commonly used in addition to exercise programmes in the rehabilitation of shoulder instability and secondary subacromial or internal impingement, few studies exist on the effect of taping on the muscle activity of the scapular rotators. The purpose of our study was to examine the influence of one particular tape on muscular activity in scapular muscles. Twenty healthy shoulders were examined with surface EMG recordings on the three parts of trapezius and serratus anterior muscle during dynamic full range of motion abduction and forward flexion. The movement direction, and tape and no-tape conditions were randomized. The statistical analyses with ANOVA repeated Measures (GLM model) showed significant differences among the means between the four muscles (P<0.05), two movement directions (P<0.05), applied resistance (P<0.01), and movement period (P<0.01). However, no significant difference was observed based on the application of tape. The results of our investigation revealed no significant influence of tape application on EMG activity in the scapular muscles in healthy subjects. Future research will be necessary to examine other parameters of neuromuscular control in order to determine possible proprioceptive changes in muscle recruitment with tape application.

Differences in electromyographic activity in the multifidus muscle and the iliocostalis lumborum between healthy subjects and patients with sub-acute and chronic low back pain.

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.

Intra-operator and inter-operator reliability of surface electromyography in the clinical evaluation of back muscles.

As a prerequisite to the use of a test battery based on electromyographic (EMG) analysis of the paraspinal muscles for identifying and remedying back muscle dysfunction, the intra- and inter-operator reliability was assessed. Fifteen volunteers underwent EMG tests on three occasions. The test subjects were asked to perform 22 exercises, subdivided into four categories: coordination, stabilization, balance and strength exercises. The time interval between the tests was one week. The myoelectric signals of the multifidus (MF) and iliocostalis lumborum pars thoracis (ICLT) were analysed with regard to amplitude (averaged EMG) and frequency (zero cross rate). The results indicated that the reliability was better for the MF than for the ICLT, and also for exercises at higher loads (strength exercises). In the intra-operator condition, the reproducibility of the averaged EMG was good (ICC>0.75), except for the balance exercises (ICC = 0.40-0.74). In general, the averaged EMG in the inter-operator condition and the zero cross rate in both the intra- and inter-operator conditions are less or poorly reliable. These results demonstrate that when back muscle function is evaluated during coordination, stabilization and strength exercises, only the averaged EMG parameter has acceptable reproducibility over time when assessed by the same operator.

Effects of three different training modalities on the cross sectional area of the lumbar multifidus muscle in patients with chronic low back pain.

OBJECTIVES: To determine the effect of different training schedules on the cross sectional area (CSA) of the lumbar multifidus muscle in patients with chronic low back pain. METHODS: Each of 59 nine patients was randomly assigned to one of three programmes: 10 weeks of stabilisation training (group 1; n = 19); 10 weeks of stabilisation training combined with dynamic resistance training (group 2; n = 20); 10 weeks of stabilisation training combined with dynamic-static resistance training (group 3; n = 20). Before and after 10 weeks of training, multifidus CSAs were measured from standard computed tomography images at three different levels (upper end plate of L3 and L4, and lower end plate of L4). RESULTS: The CSA of the multifidus muscle was significantly increased at all levels after training in group 3. In contrast, no significant differences were found in groups 1 and 2. CONCLUSIONS: General stabilisation exercises and dynamic intensive lumbar resistance training have no significant effect on the CSA of the lumbar multifidus muscle in patients with chronic low back pain. The static holding component between the concentric and eccentric phase was found to be critical in inducing muscle hypertrophy during the first 10 weeks. Treatment consisting of stabilisation training combined with an intensive lumbar dynamic-static strengthening programme seems to be the most appropriate method of restoring the size of the multifidus muscle.

A functional subdivision of hip, abdominal, and back muscles during asymmetric lifting.

STUDY DESIGN: An experimental study of muscle recruitment patterns during asymmetric lifting in healthy individuals. OBJECTIVE: To investigate muscle recruitment patterns during asymmetric lifting, representing a common daily living activity, to determine whether systematic differences exist between functioning of the local and global muscle systems. SUMMARY OF BACKGROUND DATA: The normal function of the local muscle system is to provide sufficient segmental stability to the spine. The global muscle system provides general trunk stabilization and enables the static and dynamic work necessary for daily living and sports activities. Current knowledge about these two muscle groups appears to be specifically derived from anatomic findings and experiments conducted under artificial circumstances. To the authors' knowledge, the recruitment patterns of both muscle groups have not been investigated in daily living activities. METHODS: Twenty-nine healthy individuals performed different variants of asymmetric lifting activities. Electromyographic data were collected from seven hip, abdominal, and back muscle pairs. In addition, trunk kinematics were measured by means of an ultrasonic movement analysis system. RESULTS: The left and right obliquus internus, rectus femoris, and multifidus showed symmetric co-contraction in all variants of activities. In contrast, significant left/right differences were observed in the external oblique, gluteus maximus, iliocostalis lumborum pars thoracis, and latissimus dorsi. CONCLUSIONS: The results of this study show a symmetric activation of the local muscles during the performance of low-load, asymmetric lifting tasks, which suggests that these muscles play a stabilizing role during these manoeuvres. The global muscles, however, hand show asymmetric patterns of activation during the same tasks, supporting their role as global stabilizers and prime movers.

The effects of three different training modalities on the cross-sectional area of the paravertebral muscles.

The purpose of this study was to determine the effect of different training schedules on the cross-sectional area (CSA) of the paravertebral muscles (PA) in chronic low back pain (CLBP) patients. To achieve this goal 59 patients were randomly assigned to three different 10-week rehabilitation programs: stabilization training (group 1, n=19), stabilization training combined with dynamic resistance training (group 2, n=20) and stabilization training combined with dynamic-static resistance training (group 3, n=20). The CSA of the PA was derived from standard computerized tomography (CT) images at three different levels. The CSA of the PA was found to increase statistically in group 2 (upper end-plate of L4) and group 3 (upper end-plate of L3 and lower end-plate of L4). In contrast, no statistical differences over time were found in group 1. Since stabilization exercises have no effect on the CSA of the PA, intensive lumbar resistance training seems to be necessary to restore the size of the PA in CLBP patients with atrophied back muscles. No systematic difference in hypertrophy between dynamic and dynamic-static strengthening training modes was found.

Pain relief in labour by transcutaneous electrical nerve stimulation (TENS).

For several years Transcutaneous Electrical Nerve Stimulation (TENS) has been used in the management of chronic and acute pain. The aim of this trial was to determine its effectiveness in providing pain relief during labour as well as its influence on the incidence of requests for epidural analgesia. The experimental group (receiving TENS by a burst - conventional obstetric TENS-apparatus) and the control population (not receiving TENS) consisted of 24 and 35 women respectively. In the experimental group the TENS application was switched off for a period of 15 min. The 24 women were asked to point out the intensity of their pain on a visual analogue scale before, during and after this temporary interruption. Two days postpartum the parturient's satisfaction was evaluated by two questions, a procedure which revealed that 96% degree of satisfaction. The incidence of epidural analgesia in the experimental group was compared to the control-group. During TENS application the pain scores were significantly lower (p<0.0001), but no statistically significant difference in incidence of epidural analgesia was found between the experimental group and the control group.

CT imaging of trunk muscles in chronic low back pain patients and healthy control subjects.

Increasing documentation on the size and appearance of muscles in the lumbar spine of low back pain (LBP) patients is available in the literature. However, a comparative study between unoperated chronic low back pain (CLBP) patients and matched (age, gender, physical activity, height and weight) healthy controls with regard to muscle cross-sectional area (CSA) and the amount of fat deposits at different levels has never been undertaken. Moreover, since a recent focus in the physiotherapy management of patients with LBP has been the specific training of the stabilizing muscles, there is a need for quantifying and qualifying the multifidus. A comparative study between unoperated CLBP patients and matched control subjects was conducted. Twenty-three healthy volunteers and 32 patients were studied. The muscle and fat CSAs were derived from standard computed tomography (CT) images at three different levels, using computerized image analysis techniques. The muscles studied were: the total paraspinal muscle mass, the isolated multifidus and the psoas. The results showed that only the CSA of the multifidus and only at the lowest level (lower end-plate of L4) was found to be statistically smaller in LBP patients. As regards amount of fat, in none of the three studied muscles was a significant difference found between the two groups. An aetiological relationship between atrophy of the multifidus and the occurrence of LBP can not be ruled out as a possible explanation. Alternatively, atrophy may be the consequence of LBP: after the onset of pain and possible long-loop inhibition of the multifidus a combination of reflex inhibition and substitution patterns of the trunk muscles may work together and could cause a selective atrophy of the multifidus. Since this muscle is considered important for lumbar segmental stability, the phenomenon of atrophy may be a reason for the high recurrence rate of LBP.

Failure of therapeutic ultrasound in healing burn injuries.

Experimental observations suggest that therapeutic ultrasound stimulates wound healing. Despite the controversy concerning its efficiency, this procedure is commonly implemented. To study the effect of this treatment in burns, we conducted a randomized control trail in 20 Fischer rats. Two groups of 10 animals each were studied, In group 1 the experimental burn was treated with pulsed ultrasound (SATA 0.25 W/cm2), in group 2 with continuous ultrasound (0.3 W/cm2). No stimulating effect of ultrasound could be demonstrated in these two groups, monitored by histological examination and a size index. These results discourage the clinical administration of therapeutic ultrasound to enhance the healing of burns.

Low-power laser and healing of burns: a preliminary assay.

A randomized preliminary study of 20 female Fischer rats was conducted to assess the effect of laser on healing in burns. Clinical use for this purpose seemed to be widely accepted and implemented, despite the few substantiating research reports. Two burns were inflicted on each animal; one was treated, and the other was left untreated. Two groups of 10 animals each were randomly organized. In group 1, the experimental burn was treated with a helium-neon laser; in group 2, with a gallium- arsenide laser. In neither group could any major stimulating effect be demonstrated on the basis of observation and a size index. The low statistically significant smaller size index in group 1 on day 20, in comparison with the controls, is intriguing but is of no relevance in view of the complete healing process. The practical feasibility and the weak differential power arouse doubts about the effectiveness of laser for this matter.