PubMed Health⌕ Search

Biomedical subjects

J R Basford

Publications and source records attributed to J R Basford.

At least 19 recordsLinked to original sources
PubMed2003

Muscle endurance and power spectrum of the triceps brachii in wheelchair marathon racers with paraplegia.

OBJECTIVE: To investigate differences in triceps brachii endurance and electrical activity between elite marathon and recreational wheelchair athletes with paraplegia. DESIGN AND METHODS: Nine male elite wheelchair athletes between 20 and 46 years of age (average 29.0 +/- 8.2 years) with complete (ASIA-A) T4-L1 paraplegia were compared to a group of six male height- and weight-matched recreational wheelchair athletes with similar ages and injuries. Right triceps brachii maximum voluntary contraction (MVC), as well as the duration of the ability to maintain a 50% MVC were determined for all subjects. Median frequency (MF) and mean power frequency (MPF) were evaluated with fast Fourier transform spectrum analysis. MF and MPF rates of change were calculated and compared with the Student's t-test. SETTING: : Department of Rehabilitation Medicine, University of Occupational and Environmental Health, Japan. RESULTS: Right triceps brachii MVCs of the marathoners (42.4 +/- 8.8 N m (range 33-55 N m)) and recreational athletes (41.6 +/- 9.3 N m (range 32-56 N m)) did not differ significantly (P = 0.63). Endurance, however, did. All of the athletes, but none of the control subjects, were able to maintain a 50% MVC contraction of the right triceps brachii for 2 min (the average contraction duration in the latter group was 75.5+/-16.2 s). MF and MPF of the triceps brachii decreased linearly in both groups, but the slopes in the marathoners (-8.9 +/- 4.6 (-3.8 to -16.4) and -9.7 +/- 4.6 (-4.0 to -17.2)%/min, respectively) were statistically less steep than those in the recreational athletes (-22.3 +/- 8.2 (-9.6 to -31.4) and -21.2 +/- 6.4 (-11.4 to -28.6)%/min, respectively). CONCLUSION: Elite marathoners and active wheelchair users have similar triceps brachii strength. The marathoner's triceps brachii, however, display a significantly improved endurance and a slower decline of MF and MPF with time than do those of their recreational athlete control group.

Adult↗
PubMed2001

Training-related changes in the maximal rate of torque development and EMG activity.

This study monitored the effects of a short-term elbow flexor training program on surface electromyographic (SEMG) spike activity. The experimental paradigm consisted of three test sessions separated by 2-week intervals. At the beginning of each session, participants (N=13) performed five maximal effort isometric contractions of the elbow flexors to serve as baseline. After 5 min of rest, the participants then engaged in a 30-trial isometric fatigue protocol during which maximal elbow flexion torque was measured with a load-cell, and the maximal rate of change in the torque (dtau/dt(max)) was obtained from the differentiated torque-time curve. Bipolar electrodes were used to monitor the SEMG spike activity of the biceps brachii. Mean spike amplitude (MSA) and mean spike frequency (MSF) were calculated for the torque development and constant-torque phases of the isometric contraction, termed Segment 1 and Segment 2, respectively. Mean power frequency (MPF) was also calculated for Segment 2. The five baseline contractions of the second and third sessions were compared with those of the first session and analyzed for training-related changes. Training increased dtau/dt(max) but failed to change maximal elbow flexion torque or MSA. However, there was an increase in the MSF during the torque development phase of the contraction (Segment 1). Both MSA and MSF were greatest during the constant-torque phase of the isometric contraction (Segment 2). There was a strong linear correlation (r=0.90, P<0.05) between MSF and MPF during (Segment 2). We hypothesize that the increase in dtau/dt(max) is due to enhanced motor-unit rate-coding. The demonstrated correlation between MSF and MPF measures will allow investigators to use spike analysis to examine the frequency content of the SEMG signal under non-stationary conditions.

Biomechanical Phenomena↗
PubMed2001

The reversal of antagonists facilitates the peak rate of tension development.

OBJECTIVE: The present study was designed to test the effects of the reversal of antagonists on the peak rate of tension development (dF/dt(max)) of the elbow extensors. DESIGN: Experimental, with matched controls. SETTING: A biomechanics research laboratory. PARTICIPANTS: Twenty-six healthy women without a history of upper extremity injury or neurologic disorder, randomly assigned to experimental (n = 13) or control (n = 13) groups. INTERVENTIONS: Two groups of healthy subjects followed identical exercise protocols, except that the control group performed maximal isometric contractions of the elbow extensors and the experimental group executed a maximal isometric elbow flexion contraction immediately before a maximal elbow extension contraction. Both groups performed 5 cycles of a 2-second contraction with 22-second rest periods between agonist muscle contractions and were evaluated at 4 test sessions spaced 2 weeks apart. MAIN OUTCOME MEASURES: All measurements were done with the shoulder and elbow at 90 degrees of flexion in the sagittal plane to ensure reproducibility. A load cell was used to measure elbow extension moment and to calculate the peak rate of tension development (dF/dt(max)). Biceps and triceps brachii surface electromyographic activity was monitored concurrently. The electromyographic measures were mean spike (peak-to-peak) amplitude and mean spike frequency of the biceps and triceps brachii activity. RESULTS: Intraclass dF/dt(max) and electromyographic reliability was good (r > or = .72) in both groups. Because biceps electromyographic measures were considerably less reliable (r < or = .53), they were not included in our analysis. While dF/dt(max) increased quadratically in both groups (p <.05), the experimental group was on average 36.1Nm. s(-1) (63%) greater across sessions 2 to 4 (p <.05). In contrast, triceps electromyographic activity did not differ significantly between groups (p >.05). The means averaged across groups exhibited a quadratic increase from session 1 to session 4: 91microV or 48% for mean spike amplitude (p <.05) and 7Hz or 16% for mean spike frequency (p <.05). CONCLUSIONS: The greater dF/dt(max) for the experimental group was not associated with increased electromyographic activity. The experimental group appeared to use the biomechanic properties of the pretensioned extensor muscle-tendon complex, rather than neurologic biasing, to accomplish its power gains.

Analysis of Variance↗
PubMed2001

A historical perspective of the popular use of electric and magnetic therapy.

OBJECTIVES: To review the history of the therapeutic use of static electric and magnetic fields and to understand its implications for current popular and medical acceptance of these and other alternative and complementary therapies. DATA SOURCES: Comprehensive MEDLINE (1960-2000) and CINAHL (1982-2000) computer literature searches by using key words such as electricity, magnetism, electromagnetic, therapy, medicine, EMF, history of medicine, and fields. Additional references were obtained from the bibliographies of the selected articles. In addition, discussions were held with curators of medical history museums and supplemental searches were made of Internet sources through various search engines. STUDY SELECTION: Primary references were used whenever possible. In a few instances, secondary references, particularly those requiring translations of early texts, were used. DATA SYNTHESIS: The use of electric and magnetic forces to treat disease has intrigued the general public and the scientific community since at least the time of the ancient Greeks. The popularity of these therapies has waxed and waned over the millennia, but at all times the popular imagination, often spurred by dynamic and colorful practitioners of pseudoscience, has been more excited than the medical or political establishment. In fact, a pattern seems to reappear. In each era, unsophisticated public acceptance is met first with medical disdain, then with investigation, and, finally, with a failure to find objective evidence of efficacy. This pattern continues today with the public acceptance of magnetic therapy (and alternative and complementary medicine in general) far outstripping acceptance by the medical community. CONCLUSION: The therapeutic implications of applying electrical and magnetic fields to heal disease have continually captured the popular imagination. Approaches thousands of years apart can be remarkably similar, but, in each era, proof has been lacking and the prevailing medical establishment has remained unconvinced. Interest persists today. Although these agents may have a future role in the healing of human disease, their history and a minimal scientific rationale makes it unlikely that the dichotomy between the hopes of the public and the medical skepticism will disappear.

Advertising↗
PubMed2001

Neural adaptations to fatigue: implications for muscle strength and training.

PURPOSE: This paper investigates the neural mechanisms responsible for the increase in strength that occurs during serial isometric contractions. METHODS: A three-session design was used. Thirteen subjects (N = 13) were asked to perform five maximal isometric elbow extension strength trials to serve as baseline. After a 5-min rest, the subjects were administered a 30-trial fatigue protocol. This process was repeated two more times at 2-wk intervals. Elbow extension torque and surface electromyography (EMG) of the triceps and biceps brachii were monitored concurrently. The criterion measures were elbow extension torque, root-mean-square EMG amplitude, and mean power frequency (MPF). RESULTS: Intraclass reliability ranged from good to excellent. Within each experimental session, the fatigue protocol resulted in a decrease in maximal isometric elbow extension torque as well as biceps and triceps EMG amplitude and MPF (P < 0.05). However, the mean of the 30 trials and the magnitude of the linear decrease in elbow extension torque increased across the three sessions (P < 0.05). Biceps and triceps EMG amplitude increased and MPF decreased as the number of sessions increased (P < 0.05). CONCLUSIONS: These findings suggest that the fatigue protocol served as a training stimulus to down regulate motor-unit firing frequency.

Adult↗
PubMed2000

Laser therapy: a randomized, controlled trial of the effects of low intensity Nd:YAG laser irradiation on lateral epicondylitis.

OBJECTIVE: To assess the effectiveness of low intensity laser therapy in the treatment of lateral epicondylitis. DESIGN: A double-masked, placebo-controlled, randomized clinical trial. SETTING: A physical medicine and rehabilitation clinic. PARTICIPANTS: Fifty-two ambulatory men and women (age range, 18-70 yr) with symptomatic lateral epicondylitis of more than 30 days in duration and a normal neurologic examination. INTERVENTION: Subjects were bloc randomized into 2 groups with a computer-generated schedule. All underwent irradiation for 60 seconds at 7 points along the symptomatic forearm 3 times weekly for 4 weeks by a masked therapist. The sole difference between the groups was that the probe of a 1.06-microm continuous wave laser emitted 204 mW/cm2 (12.24 J/cm2) for the treated subjects and was inactive for the control subjects. Subjects were assessed at the beginning, midpoint (session 6), and end (session 12) of treatment, as well as at follow-up 28 to 35 days after their last treatment. MAIN OUTCOME MEASURES: Pain in last 24 hours, tenderness to palpation, and patient's perception of change (benefit). RESULTS: The treated and untreated groups were well matched demographically. Masking was maintained for subjects and therapists; however, the groups did not vary to a statistically significant extent in terms of the main outcome measures either during treatment or at follow-up. Secondary outcome variables, such as grasp and pinch strength, medication use, and pain with grasp and pinch, also failed to statistically differ significantly between the groups. No significant treatment side effects were noted. CONCLUSION: Treatment with low intensity 1.06-microm laser irradiation within the parameters of this study was a safe but ineffective treatment of lateral epicondylitis. Further research seems warranted in this controversial area.

Adolescent↗
PubMed1999

Laser therapy: a randomized, controlled trial of the effects of low-intensity Nd:YAG laser irradiation on musculoskeletal back pain.

OBJECTIVE: To assess the effectiveness of low-intensity laser therapy in the treatment of musculoskeletal low back pain. DESIGN: A double-masked, placebo-controlled, randomized clinical trial. SETTING: A physical medicine and rehabilitation clinic. PARTICIPANTS: Sixty-three ambulatory men and women between the ages of 18 and 70yrs with symptomatic nonradiating low back pain of more than 30 days' duration and normal neurologic examination results. INTERVENTION: Subjects were bloc randomized into two groups with a computer-generated schedule. All underwent irradiation for 90 seconds at eight symmetric points along the lumbosacral spine three times a week for 4 weeks by a masked therapist. The sole difference between the groups was that the probes of a 1.06 microm neodymium:yttrium-aluminum-garnet laser emitted 542mW/cm2 for the treated subjects and were inactive for the control subjects. MAIN OUTCOME MEASURES: Subject's perception of benefit, level of function as assessed by the Oswestry Disability Questionnaire, and lumbar mobility. RESULTS: The treated group had a time-dependent improvement in two of the three outcome measures: perception of benefit and level of function. These results were most marked at the midpoint evaluation (p < .005, p < .01) and end of treatment (p < .017, p < .001) but tended to lessen at the 1-month follow-up (p < .10, p < .004). Lumbar mobility did not differ between the groups at any time. All tests were two-sample t tests with unequal variances. CONCLUSIONS: Treatment with low-intensity 1.06 microm laser irradiation produced a moderate reduction in pain and improvement in function in patients with musculoskeletal low back pain. Benefits, however, were limited and decreased with time. Further research is warranted.

Adolescent↗
PubMed1999

Evaluation of consultation-based rehabilitation for hospitalized cancer patients with functional impairment.

OBJECTIVE: To evaluate prospectively the effect of consultation-based interdisciplinary rehabilitation in hospitalized cancer patients. PATIENTS AND METHODS: Three hundred forty-one hospitalized patients with cancer were referred to the Cancer Adaptation Team (interdisciplinary rehabilitation services) over an 8-month period. Functional status at enrollment and dismissal was evaluated with a Barthel Mobility Index and Karnofsky Performance Status scale. Quality-of-life parameters were evaluated with specifically designed questionnaires. RESULTS: Two hundred ninety patients met the inclusion criteria. One hundred eighty-nine survived and completed the study. Significant functional improvement was observed between enrollment and dismissal on both functional indexes (P< or =.001). Quality-of-life questionnaires, while limited by low completion rate, showed significant improvement on multiple parameters. CONCLUSION: Significant functional gains were observed in hospitalized cancer patients who received interdisciplinary rehabilitation services on a consultation basis.

Activities of Daily Living↗
PubMed1998

A randomized controlled evaluation of low-intensity laser therapy: plantar fasciitis.

OBJECTIVE: To determine whether low-intensity laser irradiation, a widespread but controversial physical therapy agent, is an effective treatment of plantar fasciitis. DESIGN: A randomized, double-blinded, placebo-controlled clinical study. SETTING: A sports medicine clinic. SUBJECTS: Thirty-two otherwise healthy individuals with plantar fasciitis of more than 1 month's duration. INTERVENTION: Dummy or active irradiation with a 30 mW .83 microm GaAlAs continuous-wave infrared (IR) diode laser three times a week for 4 weeks. MEASUREMENTS: Morning pain, pain with toe walking, tenderness to palpation, windlass test response, medication consumption, and orthotic use were evaluated immediately before the study, as well as at the midpoint and end of treatment. Subjects were also evaluated at a follow-up 1 month after their last treatment. RESULTS: No significant differences were found between the groups in any of the outcome measures either during treatment or at the 1-month follow-up. Treatment, however, was well tolerated and side effects were minimal. CONCLUSIONS: Low-intensity IR laser therapy appears safe but, at least within the parameters of this study, is not beneficial in the treatment of plantar fasciitis.

Adult↗
PubMed1997

Reversal of antagonists: effect of elbow extension strength and endurance.

OBJECTIVE: To evaluate the reversal of elbow antagonists designed to facilitate the extensors relative to agonist-only contractions of the extensors, while using a protocol previously demonstrated to result in an increase in strength through motor learning. DESIGN: Two-group convenience sample composed of healthy subjects. SETTING: Clinic research laboratory. SUBJECTS: Twenty-eight healthy women without a history of upper extremity injury or neurologic disorder. MEASUREMENTS: Elbow extension strength and endurance were measured during maximal effort isometric reversal of the elbow antagonists (experimental group) and elbow extension only (control group) resistance exercise. Biceps brachii short head (BBS), triceps brachii lateral head (TLAT), and triceps brachii long head (TLNG) electromyographic (EMG) activity was measured concurrently. RESULTS: There were no significant differences between groups for either elbow extension strength, BBS, TLAT, or TLNG EMG activity. The experimental and control groups exhibited a significant linear (p < .01) and quadratic (p < .01) increase in baseline strength of 5.2N.m (30.5%). EMG activity from each muscle group increased linearly (p < .01) across all test sessions. Similar results were observed for elbow extension strength and biceps and triceps EMG activity during fatigue testing. CONCLUSIONS: The reversal of antagonists technique was not superior to agonist-only resistance exercise, nor did it interfere with the acquisition of muscular strength or endurance through motor learning.

Adult↗
PubMed1997

Influences of cane length on the stability of stroke patients.

The purpose of this study was to investigate the influence of cane length on the standing and walking stability of stroke patients. Ten stroke patients were used as subjects and evaluated by using two different cane lengths based on the measurements of the distance from distal wrist crease to the ground (WC cane), and the distance from greater trochanter to ground (GT cane). Force plates were used to determine the center of pressure (COP). The maximum sways, the total travel distances, and the mean travel speeds of the COP were analyzed for each patient standing and walking with and without canes. It was found that the total travel distance and the mean travel speed of the COP in the medial-lateral (M-L) direction were significantly lower when standing with a cane than when standing without one. It was also found that the values of these parameters and the maximum sways of the COP in both anterior-posterior (A-P) and M-L directions were significantly lower when standing with the WC cane than when standing with the GT cane. No significant difference was found in the maximum M-L sway, the total travel distance, and the mean travel speed of the COP in walking. These results suggest that the standing stability of stroke patients is improved by using canes, especially by using a WC cane, although no significant influence of using canes on the walking stability was detected. Based on the results of this study, the vertical distance from the wrist crease to ground is recommended as the appropriate cane length for stroke patients.

Adult↗
PubMed1995

Low intensity laser therapy: still not an established clinical tool.

The surgical, ophthalmological, and dermatological applications of high power lasers are well known and easily understood. What is neither as well known nor as easily understood is that lasers at powers that are orders of magnitude smaller have also been used in the laboratory and clinic for nearly 30 years to modulate cell function, lessen pain, and accelerate healing of soft tissue injuries. This article analyzes the rationale of this approach, examines the utility of laser therapy in its most common clinical applications, reviews and synthesizes the findings, and concludes that although laboratory findings seem authentic, clinical utility remains unestablished.

Biophysical Phenomena↗
PubMed1993

Effects of 830 nm continuous wave laser diode irradiation on median nerve function in normal subjects.

The presence, magnitude, and nature of the effect that low intensity laser irradiation has on nerve function, growth, and repair constitute a contentious area of research. We have addressed one aspect of this controversy by systematically examining the influence of 830 nm laser radiation on median nerve function. In particular, we investigated median nerve motor and sensory distal latencies, action potential amplitudes, action potential areas, and conduction velocities as well as dorsal hand skin temperatures in 33 normal subjects in a double-blinded, randomized controlled study. All subjects received identical treatment: 30 seconds of "irradiation" at 10 points over the course of the right median nerve (five sites on the forearm and five sites distal to the wrist crease) with either an active (1.2 J/point) or inactive (0 J/point) 40 mW 830 nm continuous wave IR laser diode. Latencies, conduction velocities, amplitudes, areas, and skin temperatures were collected bilaterally at a baseline immediately prior to irradiation and at intervals of 1, 5, 10, 15, 20, and 30 minutes following treatment. Analysis of the results reveals that motor and sensory distal latencies were decreased in the treated limbs of the laser-treated group relative to the control group by 3-4% (P < .016 and .046, respectively, rank sum test). No significant differences in these quantities were found between the limbs within either group. Similarly, no alterations of action potential amplitudes, action potential areas, forearm conduction velocities, or skin temperatures were detected within or between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1993

Laser therapy: scientific basis and clinical role.

The ability of laser irradiation to destroy tissue is well known. Less well known is the fact that the same radiation, at much lower intensities, can non-destructively alter cellular function. This latter phenomenon, which occurs in the absence of significant heating, is now a basis for the conservative treatment of a variety of musculoskeletal, neurological, and soft tissue conditions in many parts of the world. This review first examines the 25-year history and scientific basis of "laser therapy." Clinical applications are discussed and the reasons for its relative lack of acceptance in the US are examined. The article concludes with an overview of current research and the impact it will have on laser therapy's role in US clinical practice.

Animals↗
PubMed1990

Does low-intensity helium-neon laser irradiation alter sensory nerve active potentials or distal latencies?

The effect of 1 mW helium neon continuous-wave (0.633 microns) laser irradiation on superficial radical sensory and median sensory nerve function was examined in a double-blind, controlled study involving 40 volunteers. No differences in action potential amplitudes, distal latencies, or forearm skin temperatures were found between the treated and control groups either at the time of irradiation or at subsequent evaluations 15 and 30 minutes later. As a result, we are unable to confirm reports that low-energy lasers of this power and wavelength alter nerve function.

Action Potentials↗
PubMed1990

Clinical evaluation of the rocker bottom crutch.

One hundred fifty hospitalized patients referred to a physical therapy department for crutch walking instruction were evaluated in a randomized, controlled crossover study with "rocker bottom" and conventional axillary crutches. A large training effect was observed with each crutch, but no significant differences (all P greater than .05) of gait speed, stride length, heart rate, stability, or feeling of security were noted between the groups. Thus, rocker bottom crutches, despite potential stability and energy conservation benefits, were found to be no more effective than conventional axillary crutches in this hospital setting.

Aged↗