Flexibility development in sprinters using EMG biofeedback and relaxation training

This study compared the effectiveness of electromyographic (EMG) biofeedback and relaxation treatment in producing flexibility increases at the hip joint. Retention of flexibility gains and changes in sprinting performance were also examined. Fifteen male and 15 female athletes, predominantly sprinters, were matched according to age, sex, and flexibility and were randomly assigned to one of three groups. The control group received only the testing, the biofeedback group received visual and auditory EMG training, and the relaxation group received modified PMR and imagery exercises. Subjects in the two experimental groups were given eight twice-weekly 10-minute sessions and then were retested for flexibility. Retention of flexibility was reassessed 2 and 4 weeks later. Sprint performance improved for all groups. EMG biofeedback and relaxation treatment methods were no more effective than stretching exercises used by the control group for improving flexibility during the treatment period, but they did produce evidence of superior flexibility gains in the retention period. This may be important as flexibility has been reported to be related to the incidence of injuries.     

The response of manual motor functioning in Parkinsonians to frontal EMG biofeedback and progressive relaxation

The purpose of the current investigation was to determine the effects of frontal EMG biofeedback and progressive relaxation training on manual motor functioning in Parkinsonians. Twenty patients were matched and randomly assigned to two groups. All subjects were administered a brief manual motor assessment. The experimental group then underwent weekly sessions of frontal EMG and relaxation training for a period of 15 weeks. At the conclusion of the training period, both experimental and control groups were again administered the manual motor tasks. The results indicated that Parkinsonian patients are capable of significantly lowering frontal EMG activity levels. The motor task results, however, yielded no statistically significant differences between the two groups as a result of the biofeedback training.     

Effectiveness of multiple muscle-site EMG biofeedback and relaxation training in reducing the aversiveness of cancer chemotherapy

A 44-year-old female cancer patient was given progressive muscle relaxation training and multiple muscle-site EMG biofeedback to reduce the conditioned negative responses she had apparently developed to her chemotherapy treatments. Following three baseline chemotherapy sessions, the patient was given relaxation training and biofeedback during four consecutive chemotherapy treatments and was asked to practice her relaxation skills daily in the hospital or at home. After the patient felt able to relax on her own, relaxation training and biofeedback were terminated and three follow-up sessions were held. Results indicated that during the chemotherapy sessions in which the patient received relaxation training and biofeedback, she showed reductions in physiological arousal (EMG, pulse rate, systolic blood pressure, and diastolic blood pressure) and reported feeling less anxious and nauseated. Moreover, these changes were maintained during the follow-up sessions. These results suggest that relaxation training plus multiple muscle-site biofeedback may be an effective adjunctive procedure for reducing some of the adverse side effects of cancer chemotherapy.     

Feedback delays and relaxation expectancies in EMG biofeedback

The use of noncontingent feedback controls in studies of the efficacy and process of electromyographic (EMG) biofeedback may yield results confounded by differential expectancies for relaxation. Furthermore, the role of expectancies in producing psychological and physical relaxation as well as reducing muscle activity is unclear. This study investigated the effects of feedback delays and induced relaxation expectancies on EMG activity and experienced relaxation. One hundred four non-clinical subjects participated in one auditory frontal EMG biofeedback training session. Subjects were assigned to one of four computerized feedback delay conditions (0.0037, 0.7493, 2.2481, 6.7444 s) and to one of two relaxation expectancy conditions (positive or negative). During 20 minutes of biofeedback training, all groups decreased frontal activity. Feedback delays interacted with training epochs in affecting EMG; the longest delay group reduced frontal activity more slowly than the shortest delay group during training. Positive relaxation expectancies produced greater experienced relaxation than did negative relaxation expectancies. Instrumental and expectancy factors in EMG biofeedback appear to operate independently of each other by reducing physiological activity and producing psychological relaxation respectively.     

Feedback delays and relaxation expectancies in EMG biofeedback

The use of noncontingent feedback controls in studies of the efficacy and process of electromyographic (EMG) biofeedback may yield results confounded by differential expectancies for relaxation. Furthermore, the role of expectancies in producing psychological and physical relaxation as well as reducing muscle activity is unclear. This study investigated the effects of feedback delays and induced relaxation expectancies on EMG activity and experienced relaxation. One hundred four non-clinical subjects participated in one auditory frontal EMG biofeedback training session. Subjects were assigned to one of four computerized feedback delay conditions (0.0037, 0.7493, 2.2481, 6.7444 s) and to one of two relaxation expectancy conditions (positive or negative). During 20 minutes of biofeedback training, all groups decreased frontal activity. Feedback delays interacted with training epochs in affecting EMG; the longest delay group reduced frontal activity more slowly than the shortest delay group during training. Positive relaxation expectancies produced greater experienced relaxation than did negative relaxation expectancies. Instrumental and expectancy factors in EMG biofeedback appear to operate independently of each other by reducing physiological activity and producing psychological relaxation respectively.This study was completed by the first author under the direction of the second author in partial fulfillment of the requirements for the Master of Arts degree. We gratefully acknowledge the computerization advice and assistance provided by Larry Wheeler, and the assistance in data collection provided by Dawn Dexter and Michael Winstanley.     

The effect of stressful life events on EMG biofeedback and relaxation training in the treatment of anxiety

The present study evaluated the effect of frontal EMG biofeedback and relaxation training on a group of 20 anxious patients experiencing stressful life events. The patients were divided into two groups, high and low in stress, based on their life change score on the Recent Life Changes Questionnaire. Patients were evaluated at pre, post, and 6-week follow-up. Treatment consisted of 10 sessions of biofeedback-assisted relaxation. Results indicated that the high stress group showed pre to post changes on anxiety, depression, symptoms, and EMG, while low stress showed no change. Post to follow-up comparisons showed maintenance of improvement for the high stress group and no change for low stress. From pre to follow-up assessment, the high stress group showed significant changes. Both groups reported internal attributions following biofeedback and relaxation training. The high stress group attributed their improvement to the belief they were in control of their minds and bodies, while the low stress group most frequently reported the effort put into the task. The results indicate support for a cognitive explanation for some of biofeedback's effects.     

Biofeedback-assisted EMG relaxation for urinary retention and incontinence

A 27-year-old woman with chronic urinary retention and incontinence since infancy was treated for 8 months with frontal electromyographic relaxation training. Urinary control and sensations of bladder fullness were obtained for the first time in the patient's history. Residual urine readings showed marked improvement. Application of EMG biofeedback to other bladder disorders is discussed.     

Is group progressive relaxation training as effective with hyperactive children as individual EMG biofeedback treatment?

This study examined whether group progressive relaxation training was as effective as individual EMG biofeedback training in facilitating the academic achievement and self-control of 45 hyperactive elementary school children. Academic achievement was assessed with the Gates-MacGinities Reading Tests, and self-control was measured with the Nowicki-Strickland and the Teacher Rating scales. Eight sessions were scheduled at weekly intervals. Progressive relaxation was conducted in groups of seven or eight and was induced with a commercial audiocassette program. EMG training augmented frontalis biofeedback with those taped exercises. A placebo group listened to taped children's stories. Multivariate analysis of variance indicated no significant differences among the three contrast groups when all dependent variables were considered together. However, univariate F values and discriminant analysis disclosed locus of control to be significantly more internal for the progressive relaxation condition. Also, differences between the two relaxation and the placebo groups, though not statistically significant, were all in the expected direction. While the relative efficacy of group progressive relaxation could not be established conclusively, the data appeared sufficiently positive to warrant further investigation of this cost-effective prospective intervention.The opinions expressed by the authors are not necessarily those of their respective institutions.     

Generalization of EMG biofeedback training

Five young adults received audio biofeedback training to reduce trapezius EMG levels while they engaged in reading in an office, seated at a table. A multiple-baseline-across subjects design was employed in two separate studies. After training, all subjects demonstrated reduced EMG levels while reading in a home or library setting. The first study suggested that subjects reduced EMG levels by minimizing movements and altering their postures; the second study systematically demonstrated changes in such behavior, which was correlated with EMG levels. The data provide evidence that EMG biofeedback resulted in response generalization across several motoric classes, and in stimulus generalization from the training setting to the natural environment. The importance of assessing generalization is discussed.     

Generalization of EMG biofeedback training

Five young adults received audio biofeedback training to reduce trapezius EMG levels while they engaged in reading in an office, seated at a table. A multiple-baseline-across subjects design was employed in two separate studies. After training, all subjects demonstrated reduced EMG levels while reading in a home or library setting. The first study suggested that subjects reduced EMG levels by minimizing movements and altering their postures; the second study systematically demonstrated changes in such behavior, which was correlated with EMG levels. The data provide evidence that EMG biofeedback resulted in response generalization across several motoric classes, and in stimulus generalization from the training setting to the natural environment. The importance of assessing generalization is discussed.     

The relationship between muscle discrimination ability and response to relaxation training in three kinds of headaches

Accurate discrimination of changes in physiological response has been noted as an important element in learning to control that response. Using a magnitude production procedure involving forearm isometric contractions, it was found that the ability to discriminate muscle tension varied across headache groups, with the no-headache control group (r=.76) being most accurate, followed by the tension group (r=.68), the mixed tension and migraine group (r=.60), and finally the migraine group (r=.51). The most important result, however, was that muscle discrimination ability significantly predicted clinical outcome from treatment by relaxation training for tension headache subjects (r=.50) but did not predict outcome for migraine or mixed headache subjects.This research was supported by a grant from NINCDS, NS-15235.     

Effects of noncontingent feedback on EMG training, EMG responses, and subjective experience

Various types of noncontingent feedback have been used as control procedures in EMG training; however, their effects on such training have received little attention. Experiment 1 in the present study examined the effects of noncontingent feedback on EMG training, and Experiment 2 assessed the effects of feedback characteristics on EMG responses. In Experiment 1, three noncontingent feedback groups (yoked control, randomly fluctuating tones, and decreasing tones) and one contingent group underwent 20 minutes of training for frontal EMG decreases. Procedures in Experiment 2 were identical to those in Experiment 1 except that subjects were instructed merely to listen to the feedback tones. Results of Experiment 1 indicated that contingent and noncontingent fluctuating feedback groups achieved significantly lower EMG levels than noncontingent decreasing and yoked control groups. In Experiment 2, however, no differences in EMG activity were found among groups. In both experiments, groups did not differ in terms of subjective variables such as frustration, suspiciousness about the tone, or length of time attending to the tone. Results of these two experiments suggest that differences in EMG responses to various types of noncontingent feedback result from interactions between characteristics of the feedback stimulus and instructions to decrease the stimulus.     

Effects of noncontingent feedback on EMG training,EMG responses,and subjective experience

Various types of noncontingent feedback have been used as control procedures in EMG training; however, their effects on such training have received little attention. Experiment 1 in the present study examined the effects of noncontingent feedback on EMG training, and Experiment 2 assessed the effects of feedback characteristics on EMG responses. In Experiment 1, three noncontingent feedback groups (yoked control, randomly fluctuating tones, and decreasing tones) and one contingent group underwent 20 minutes of training for frontal EMG decreases. Procedures in Experiment 2 were identical to those in Experiment 1 except that subjects were instructed merely to listen to the feedback tones. Results of Experiment 1 indicated that contingent and noncontingent fluctuating feedback groups achieved significantly lower EMG levels than noncontingent decreasing and yoked control groups. In Experiment 2, however, no differences in EMG activity were found among groups. In both experiments, groups did not differ in terms of subjective variables such as frustration, suspiciousness about the tone, or length of time attending to the tone. Results of these two experiments suggest that differences in EMG responses to various types of noncontingent feedback result from interactions between characteristics of the feedback stimulus and instructions to decrease the stimulus.This research was supported by Ohio University Research Grants No. 9147 and No. 9155 to the first author.     

Hypnotizability and spatial attentional functions

Many theories of hypnotic responding have proposed that differences in hypnotic trait rely on differences in frontal attentional functions. Evidence of hypnotizability-related attentional abilities are, however, very scant. This study was designed to investigate the relationship between hypnotizability and executive control components of attention in the spatial domain. We chose the Attention Network Test that enables to analyze alerting, orienting and executive control functions by measuring reaction times (RTs) to targets cued for different locations in space. According to Posner theory, alerting, orienting and executive control effects were found in both groups. No differences between highly susceptible (Highs) and low susceptible individuals (Lows) on executive control functions were found. However, in Highs alerting was significantly smaller than in Lows and Highs were significantly faster than Lows in the no and central cue conditions. These findings suggest that Highs would be endowed with a basal higher efficiency in achieving and maintaining their readiness to respond to incoming stimuli. This relation between hypnotizability and alerting, is discussed in terms of a possible more efficient noradrenergic activity driven by frontal attentional systems.     

Cognitive and physiologic responses to EMG biofeedback and three types of pseudofeedback during a muscular relaxation task

Four groups of normal human subjects were tested for their ability to reduce frontal muscle tension levels during presentation of veridical auditory biofeedback or auditory pseudofeedback. A double-blind methodology was used. Three groups of subjects assigned to the pseudofeedback conditions received a feedback signal that was not contingent on EMG activity but that followed one of three different patterns. One group received a truly random signal, the second received a signal that gradually increased in frequency (apparent failure), and the third received a signal that gradually decreased in frequency (apparent success). Dependent measures included both physiologic (frontal and neck EMG) and subjective reactions to the relaxation task. The different patterns of pseudofeedback did produce reliably different subjective responses, suggesting that the manipulations succeeded in producing unequal nonspecific effects that were unrelated to the feedback contingency specifically. However, these differential subjective effects were not strongly reflected in the physiologic responses since the differences in EMG levels among the four groups did not differ significantly at any stage of training. An analysis of the integrity of the double-blind procedure showed that although experimenters were effectively kept blind to group assignment, subjects' responding suggested a response bias as well as the possibility that the double-blind was breached. The utility of the double-blind methodology in biofeedback experiments is discussed and suggestions for future research are offered.     

The effects of EMG feedback training during problem solving

The present case study investigated the effects of competing task demands on biofeedback training to reduce frontalis muscle tension. Baseline levels of frontalis muscle tension were recorded for relaxation and problem solving. The subject was trained to decrease muscle tension with biofeedback for the problem-solving task alone. The results indicated that EMG training during problem solving was successfully accomplished. Frontalis muscle tension during relaxation baseline did not change as a result of reductions in muscle tension during problem-solving feedback training. This suggests that the decrease of muscle tension cannot be attributed to reductions in overall muscle tension levels. Instead, training was specific to the problem-solving feedback phases. Additionally, it was found that accuracy in problem-solving did not decline as a result of simultaneous feedback training. Thus EMG biofeedback training can be accomplished and exercised without disruption of ongoing mental activity.