The role of endogenous opioids in moderate exercise training-induced enhancement of the secondary antibody response in mice.

BACKGROUND AND PURPOSE: Moderate exercise training (60%-80% of maximal oxygen uptake) enhances the secondary antibody response. The mechanism underlying this enhancement, however, has not been determined. In moderate doses, endogenous opioids such as enkephalins enhance antibody response. Furthermore, serum concentrations of endogenous opioids increase in response to exercise, and training programs augment this effect. Therefore, the enhancement of the secondary antibody response induced by moderate exercise may be brought about, in part, by endogenous opioids. The purpose of this study was to examine the effects of naltrexone (an opioid antagonist) on the enhancement of secondary antibody response induced by moderate exercise in young mice. SUBJECTS AND METHODS: C57BL/6 mice immunized to human serum albumin (HSA) were randomly assigned to 1 of 3 groups: naltrexone, placebo, or control (received no intervention). Then, the mice in each group were randomly assigned to either an exercise group (treadmill running at 15 m/min, 0ø slope, 5 days per week for 8 weeks) or a non-exercise group. At the end of 8 weeks, booster immunization was given, and the mice in the exercise group continued to exercise. Ten days later, when high levels of antibodies are produced in secondary antibody response, anti-HSA antibodies in serum were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: With naltrexone implantation, mice that exercised showed a depression of secondary antibody response as compared with mice that exercised and either received a placebo or did not receive any intervention. DISCUSSION AND CONCLUSION: Endogenous opioids may play a role in the enhancement of the secondary antibody response observed after moderate exercise.

Assessing Wolf motor function test as outcome measure for research in patients after stroke.

BACKGROUND AND PURPOSE: The Wolf Motor Function Test (WMFT) is a new time-based method to evaluate upper extremity performance while providing insight into joint-specific and total limb movements. This study addresses selected psychometric attributes of the WMFT applied to a chronic stroke population. METHODS: Nineteen individuals after stroke and with intact cognition and sitting balance were age- and sex-matched with 19 individuals without impairment. Subjects performed the WMFT and the upper extremity portion of the Fugl-Meyer Motor Assessment (FMA) on 2 occasions (12 to 16 days apart), with scoring performed independently by 2 random raters. RESULTS: The WMFT and FMA demonstrated agreement (P<0.0001) between raters at each session. WMFT scores for the dominant and nondominant extremities of individuals without impairment were different (P0.05) from the dominant and nondominant extremities of individuals without impairment. The WMFT and FMA scores were related (P<0.02) for the more affected extremity in individuals after stroke. CONCLUSIONS: The interrater reliability, construct validity, and criterion validity of the WMFT, as used in these subject samples, are supported.

The effects of intense physical exercise on secondary antibody response in young and old mice.

BACKGROUND AND PURPOSE: Based largely on data from young subjects, intense physical exercise is believed to suppress immune function. In addition, immune function, including secondary antibody response, declines with advancing age. Therefore, intense exercise in old subjects may further suppress the secondary antibody response. The purpose of this in vivo study was to investigate the effects of intense physical exercise on secondary antibody response in young (6-8 weeks) and old (22-24 months) C57BL/6 mice. SUBJECTS AND METHODS: Data were obtained from 22 young and 18 old C57BL/6 mice that were immunized to human serum albumin (HSA) and randomly divided into 3 groups. Two groups were exposed to a single bout of intense exercise to exhaustion and immediately boosted with an injection of HSA. The first group did not exercise further, but the second group continued with daily bouts of intense exercise to exhaustion for 9 days. The third group (control group) did not undergo intense exercise, but received the booster injection of HSA at the same time as the other groups. Ten days after the HSA booster injection, when high level of antibodies are produced in secondary antibody response, serum anti-HSA antibodies were measured by enzyme-linked immunosorbent assay. RESULTS: Young mice did not show suppression of secondary antibody response following intense exercise. However, old mice, exposed to a single bout of intense exercise, had an enhanced response similar to the response seen in young control mice. CONCLUSION AND DISCUSSION: The widely accepted hypothesis of immunosuppression resulting from intense exercise may not be true for old mice.

Decline in spontaneous activity of group Aalphabeta sensory afferents after sciatic nerve axotomy in rat.

Changes are observed in the strength of central synaptic transmission and the firing behavior of primary afferents damaged by peripheral nerve injury. To clarify the relationship between synaptic strength and amount of spontaneous activity, firing behavior was studied in adult, male Sprague-Dawley rats in which sciatic nerve afferents were axotomized. Intra-axonal recordings were taken from Aalphabeta afferents within 7 h (acute, n = 309), at 3 days (n = 228), or at 10 days (n = 230) after sciatic nerve cut. The proportion of spontaneously discharging afferents fell from 22% in the acute group to < or = 13% in chronic groups. Thus, neither the progressive decline in the strength of central synaptic transmission from cut primary afferents nor the altered sensation observed after nerve cut can be explained by chronic changes in spontaneous activity of cut Aalpha/Abeta afferents.

Establishing the reliability and validity of measurements of walking time using the Emory Functional Ambulation Profile.

BACKGROUND AND PURPOSE: The Emory Functional Ambulation Profile (E-FAP) measures time to walk in different environments and accounts for use of assistive devices. This study assessed the reliability and validity of walking time measurements using these components. SUBJECTS: Twenty-eight subjects who had strokes and 28 subjects without impairment were recruited. METHODS: The E-FAP, Berg Balance Test, Functional Reach Test, and Timed 10-Meter Walk Test were administered in random order during a single data collection session. RESULTS: Interrater reliability for the total E-FAP was > or = .997. Subjects without impairment performed better on all 4 tests than did subjects who had strokes. Increased times on the E-FAP correlated with poor performance on the Berg Balance Test and slow gait speeds on the Timed 10-Meter Walk Test in the subjects who had strokes. The E-FAP scores and the Functional Reach Test scores were not correlated. CONCLUSION AND DISCUSSION: The E-FAP can be administered easily and inexpensively. Because the E-FAP scores differentiated subject groups and correlated with known measures of function, the E-FAP may be a clinically useful measure of ambulation.

Determining consistency of elbow joint threshold angle in elbow flexor muscles with spastic hypertonia.

BACKGROUND AND PURPOSE: Threshold angle, the point in passive range of motion where a muscle response or torque change is elicited, may be a potentially valid measure of hypertonus. Because the relationship of initial muscle length to threshold angle has not been addressed previously, this preliminary study examined whether starting elbow joint position and speed of stretch to elbow flexor muscles affect threshold angle. SUBJECTS: Five subjects with stroke-induced hypertonia of the elbow flexor muscles participated. METHODS: Two starting angles and two designated stretch speeds were applied randomly by a torque motor at each of three testing sessions. RESULTS: Starting angle, subject, and session affected threshold angle. A 90-degree starting angle at a stretch speed of approximately 1.0 radian/s produced the most consistent threshold angles between sessions within subjects, and threshold angle was relatively consistent for some subjects, irrespective of speed. CONCLUSION AND DISCUSSION: If future research indicates that these data can be generalized, the use of threshold angle as a consistent measure of hypertonia will require comparison within individuals, use of a consistent starting angle, and a movement condition of a 90-degree starting angle and an approximate movement speed of 1.0 radian/s across sessions.

The effect of two types of foot orthoses on rearfoot mechanics.

Little experimental data exist regarding the comparative biomechanical of various foot orthoses. This study evaluated the comparative effect of biomechanical orthoses and over-the-counter arch supports on controlling rearfoot pronation. Twenty-four patients with forefoot varus deformity were studied while walking on a treadmill. Two-dimensional, videotape motion analysis was used for studying rearfoot mechanics with three experimental conditions: 1) shoes only, 2) shoes plus arch supports, and 3) shoes plus biomechanical orthoses. The variables studied were: maximum pronation, calcaneal eversion, maximum pronation velocity, time-to-maximum pronation, and total pronation. No difference was noted in maximum pronation, calcaneal eversion, and total pronation between the three conditions. The data for maximum pronation velocity and time-to-maximum pronation were not reliable. Based on the results of this study, padded arch supports nor biomechanical orthoses can be preferentially recommended for their ability to control maximum pronation, calcaneal eversion, and total pronation during walking. Additional research is necessary to: 1) identify the biomechanical effects that are responsible for the clinical success of foot orthoses, and 2) determine better designs for controlling rearfoot movement.

Posture in patients with shoulder overuse injuries and healthy individuals.

Assessment of posture is an integral component of patient evaluation with shoulder overuse injuries. However, the professional literature contains relatively few studies that have assessed the relationship between posture, function, and injury. The purpose of this study was to determine the relationship and differences in postural variables within and between subjects with overuse injuries to the shoulder of healthy subjects. Thirty patient subjects and 30 healthy subjects matched for age and gender were recruited. Scapular protraction and rotation, forward head position, midthoracic curvature, and passive humeral elevation in the plane of the scapula were measured randomly in standing. All measurement techniques were standardized and validated. Intrarater and interrater reliability for all clinical measures were established before data collection. Forward head position was significantly greater (p < .001) in the patient group than the healthy group; humeral elevation was significantly greater (p < .001) in the healthy group than in the patient group and in the uninvolved shoulders (p < .01) than the involved shoulders within the patient group. Scapular protraction, rotation, midthoracic curvature, and scapular symmetry were not significantly different between groups. Scapula protraction and rotation were significantly related (p < .05) in the patient group. No other postural variables were related. Conclusions regarding the influence of posture to shoulder injury are inconclusive based on several confounding variables that may have affected the outcome.

Contralateral and long latency effects of human biceps brachii stretch reflex conditioning.

Results from previous studies on monkeys and human subjects have demonstrated that the biceps brachii spinal stretch reflex (SSR) can be operantly conditioned. The extent to which conditioning paradigms influence contralateral SSRs or longer latency responses in the same limb has not been examined. Nine subjects were given 10 training sessions to either increase or decrease the size of their biceps brachii SSR. Group changes were compared to the mean of six baseline (control) sessions. Both groups showed progressive SSR changes over the training sessions. Up-trained subjects increased their SSR responses by an average of 135.3% above baseline, with the last three sessions showing a 237.5% increase, while down-trained subjects reduced their average SSR responses by 43.4%, with a 52.7% reduction over the last three sessions. ipsilateral longer latency responses showed average changes of 68.9% and -68.7% for up- and down-trainers, respectively. As in the case of SSRs, these responses changed progressively over sessions, with a 131.5% increase seen in the last three up-training sessions and an 82.4% reduction over the same period for down-trainers. Correlation coefficients between SSR and longer latency responses were high (R = 0.90, up-trainers; R = 0.87, down-trainers). Contralateral SSR and longer latency responses, measured in the absence of feedback and at least 10 min after ipsilateral conditioning, showed directional changes that were similar to the trained side, but their magnitudes were not as profound. Collectively, these data suggest that unilateral SSR conditioning affects spinal circuits controlling contralateral SSRs and influences longer latency responses.

The frontal plane relationship of the forefoot to the rearfoot in an asymptomatic population.

Physical therapists use biochemical orthotics to treat symptoms attributed to structural abnormalities of the feet. The purpose of this study was to determine the prevalence of forefoot varus, valgus, and neutral positions in a healthy population, and to compare forefoot positions between genders, legs, and age groups. Nonprobability sampling was used to obtain 120 healthy subjects. A repeated-measures, one-group design was used. A forefoot measuring device and a goniometer were used to measure the forefoot-rearfoot frontal plane relationship. Of the 234 measured feet, 86.67% had a varus, 8.75% had a valgus, and 4.58% had a neutral forefoot-rearfoot relationship. No significant difference in position was found between genders or legs within subjects. A certain amount of forefoot varus or valgus may be characteristic of a healthy population; however, future studies should include children and adolescents to determine if forefoot positions are acquired or congenital.

Overcoming limitations in elbow movement in the presence of antagonist hyperactivity.

BACKGROUND AND PURPOSE: A traditional perspective on rehabilitation of patients with abnormal muscular hyperactivity presumes that relaxation should be facilitated prior to recruitment of antagonists, if effective movement about a joint is to occur. The purpose of the study was to determine the effect of training weak triceps brachii muscles, with hyperactivity present in the opposing biceps brachii muscles, on elbow function in individuals at least 1 year poststroke. SUBJECTS: Sixteen patients with chronic stroke were randomly assigned to receive electromyographic biofeedback to retrain the triceps muscle (n = 8) or to receive conventional movement training (n = 8). METHODS: Both groups participated in 5 baseline and 10 training sessions involving tasks requiring elbow extension. Preintervention and postintervention measurements included elbow extension range of motion, triceps and biceps muscle electromyographic activity during performance of elbow extension, resisted elbow extension, and a reaching task. RESULTS: Two-sample t-test results of between-group comparisons for each variable were not significant. One-sample t-test results of within-group comparisons showed significant increases in triceps muscle mean electromyographic activity during two of the three tasks for the feedback group, but not for the nonfeedback group. Passive and active range of motion in both groups increased significantly, although biceps muscle co-contraction persisted. CONCLUSION AND DISCUSSION: These results suggest that functional improvements at the elbow may have been due to biomechanical (peripheral) rather than neuromuscular (central) changes about the joint. Furthermore, these preliminary data indicate that patients with stroke may be trained to increase movement without first being trained to specifically inhibit hyperactivity in muscles.

Immediate effects of the toe spreader on the tonic toe flexion reflex.

BACKGROUND AND PURPOSE: The purpose of the study was to determine whether the use of a toe spreader to inhibit the tonic toe flexion reflex (TTFR) immediately alters temporal-distance gait characteristics, plantar surface contact, or muscle activity in the limb exhibiting the TTFR of subjects with hemiparesis secondary to supraspinal lesion. SUBJECTS: Eighteen adults with hemiparesis secondary to supraspinal lesions served as subjects for the standing portion of the study. Sixteen of the subjects participated in the gait portion of the study. METHODS: The study was a randomized, within-subject, between-conditions comparison consisting of standing and gait phases, with four conditions for each phase (shoe off, toe spreader off/on, shoe on, toe spreader off/on). Measures performed were ink footprint gait analysis and integrated electromyography from the limb exhibiting the TTFR. RESULTS: Presence of the TTFR was reduced significantly with the use of the toe spreader. Velocity and cadence were increased significantly by use of the toe spreader. CONCLUSION AND DISCUSSION: The toe spreader may be a useful treatment option for improving gait. The clinical significance of these findings, however, will depend on the functional context of toe-spreader use.

The Landau reaction in fullterm and preterm infants at four months of age.

Twelve normal fullterm infants and 11 low-risk preterm infants were assessed at four months of age. Assessments included a Three-Component-Scale for the Landau reaction, the Touwen Scale for the Landau reaction, the Bayley Scales of Infant Development Motor Scale, and the Movement Assessment of Infants Muscle Tone Scale. A statistically significant relationship was found between gestational age (preterm vs. fullterm birth) and scores on the hip and kicking subcomponents on the Three-Component-Scale for the Landau reaction, and also between gestational age at birth and scores on the summary of tone-extremities and total risk score items on the Movement Assessment of Infants. Although preterm and fullterm infants may not show differences in scores on motor developmental level assessments, variations in postural reactions and muscle tone may be present at four months of age.

The effect of a forearm strap on wrist - extensor strength*.

Thirty subjects with no pathology of the right elbow were tested using an isokinetic dynamometer to measure wrist extensor strength. Subjects were tested under control and experimental conditions with and without a forearm strap. Tests were conducted at 30 and 120 degrees /sec. Results were plotted on separate graphs using a sequential trials method. No difference in strength was noted at the slower speed. A statistically significant increase in strength with the strap was found at 120 degrees /sec. It was concluded that, in these subjects, the forearm strap made no difference in strength at the slower speed, but significantly increased strength at the faster speed. Facilitation due to sensory stimulation of the skin and pressure on the muscle belly was offered as an explanation. Further research is needed in this area. J Orthop Sports Phys Ther 1984;6(3):184-189.