Biomedical subjects

T L Baxter

Publications and source records attributed to T L Baxter.

8 recordsLinked to original sources

PubMed1998

Tracking control in the nonparetic hand of subjects with stroke.

OBJECTIVE: To examine in subjects with stroke using their nonparetic side how different levels of stimulus-response (S-R) compatibility, which require different levels of information processing, affect manual tracking control. DESIGN: Descriptive study comparing finger movement tracking performance under S-R-compatible and S-R-incompatible conditions between subjects with stroke and healthy controls. Four two-factor analysis of variance tests with one independent factor (group, gender, laterality, or order) and one repeated measures factor (position) comprised the data analysis. SETTING: University-based research setting. PATIENTS: Forty subjects with chronic stroke: 20 right hemiplegia (average age, 65.2+/-2.3 yrs); 20 left hemiplegia (average age, 68.6+/-2.3 yrs). Fifty-one healthy controls: 24 using nondominant hand (average age, 68.6+/-2.1 yrs); 27 using dominant hand (average age, 68.7+/-2.0 yrs). All were right-handed. MAIN OUTCOME MEASURE: Tracking accuracy index (AI), based on root-mean-square error normalized to scale of each subject's tracking target. RESULTS: In S-R-incompatible condition, AI of subjects with stroke was not significantly different from controls (F[1, 89]=1.73, p=.19). In S-R-compatible condition, AI of control subjects was significantly better than subjects with stroke (F[1, 89]=14.3, p=.0003). CONCLUSION: Manual tracking is impaired in nonparetic hand of subjects with stroke, suggesting that information processing, distinctly separate from motor weakness, may be an underestimated problem impairing controlled movements in individuals with stroke.

Adult↗

PubMed1998

Name or hum that tune: feeling of knowing for music.

This is the first reported research that explores the feeling of knowing (FOK) for musical stimuli. Subjects attempted to recall melodies and titles of musical pieces, made FOK ratings when recall failed, and then had a recognition test. With instrumental music (Experiment 1), more titles were recalled when melodies were given as cues than vice versa. With songs whose lyrics were not presented (Experiment 2), however, more melodies were recalled than were titles. For nonrecalled items, although the overall levels of recognition did not differ, FOK ratings were higher for titles than for melodies in Experiment 1, and the opposite pattern occurred in Experiment 2. In both experiments, the FOK ratings predicted melody recognition more accurately than they did title recognition.

Adult↗

PubMed1998

The breast and sports: issues for the clinician.

Although a number of recent reviews have focused on the effects of exercise and sports on menstrual function, minimal emphasis has been placed on how the breast is affected. Increasing numbers of female athletes are participating in previously male-dominated contact sports; the effect on overall breast health from medium-to-high impact activities remains to be seen. This article reviews the basic anatomy and embryology of breast tissue, outlines various problems of the breast that the adolescent athlete may encounter, and offers management strategies for such problems.

Adolescent↗

PubMed1988

Professional ice hockey players: physiologic, anthropometric, and musculoskeletal characteristics.

Twenty-seven players from a National Hockey League (NHL) team were evaluated for maximal aerobic power, body composition, and muscle strength and flexibility upon reporting to training camp. Aerobic power was determined with a maximal treadmill exercise test. Body composition was determined by underwater weighing. Muscle strength of the internal and external shoulder rotator muscles and the knee flexors and extensors were determined isokinetically at 30 degrees/sec. Strength of the hip adductors was determined isometrically. The average (+/- standard error) maximal oxygen consumption (VO2max) for all players was 53.4 +/- 0.8 ml x kg-1 x min-1. When players were grouped by their usual playing positions (Goalies = G, n = 4; Forwards = F, n = 15; and Defensemen = D, n = 8) there were no differences in VO2 max, resting or maximal heart rate, and exercise test duration. Although G (77.7 +/- 3.2 kg) were significantly lighter than D (88.5 +/- 1.9 kg) and F (86.1 +/- 1.9 kg), there were no significant differences between player positions in height or percentage of body fat (9.2 +/- 0.9%). Measures of absolute muscle strength and muscle strength adjusted for body weight were similar for G, F, and D. Goalies, however, had significantly more flexibility in the hip and groin musculature than F and D. Although team averages for muscle strength and flexibility were normal and symmetric, ten players (37%) exhibited significant musculoskeletal strength and flexibility deficits.

Adult↗

PubMed1988

Quantitative muscle testing in childhood dermatomyositis.

Sixteen children with dermatomyositis were followed longitudinally by quantitative muscle testing between 1972 and 1982. The time to achievement of normal muscle strength measured quantitatively was significantly delayed (p less than .001) compared to the time muscle strength was clinically assessed as normal by manual muscle testing. A significant difference was also found between the time normal muscle strength was measured and normal muscle enzymes were achieved (p less than .05). Quantitative muscle testing is a useful adjunct to clinical assessment of muscle strength and determination of muscle enzymes in the therapeutic management of patients with dermatomyositis.

Adolescent↗

PubMed1987

Strength testing with a portable dynamometer: reliability for upper and lower extremities.

This study was designed to determine intraobserver and interobserver reliability of maximal muscle strength for upper and lower extremity muscle groups. Four healthy subjects were tested with a portable muscle dynamometer on two separate occasions by three separate examiners to determine maximal isometric strength of lateral pinch between thumb and index finger, elbow flexion, elbow extension, shoulder flexion, hip flexion, hip extension, hip abduction, knee flexion, and ankle dorsiflexion. A break test was also used to evaluate the strength of cervical flexor muscles and extensor hallucis longus. Pearson correlation coefficients for inter- and intraexaminer testing was good for upper extremity test values from 0.85 to 0.99. The variation coefficient of the methodology error (CV) in all upper extremity muscle tests was between 5.1% and 8.3%. These results seemed reliable for clinical muscle strength testing. However, correlation coefficients for lower extremity testing were poor, with values ranging from -0.20 to 0.96. The CV in these tests was much greater than in the upper extremities and ranged from 11.3% to 17.8%. Both break tests also had high CV, with each being greater than 17%. Our results demonstrate that although the dynamometer is reliable for testing upper extremity muscle groups, it is unreliable for testing lower extremity muscle groups. Further work is needed to evaluate muscle strength quantitatively in the clinical setting in an accurate, valid, and reliable manner.

Arm↗

PubMed1987

Musculoskeletal profile of male collegiate soccer players.

Twenty-five collegiate soccer players were evaluated for lower extremity flexibility and muscle strength at the end of preseason training and before the onset of the collegiate soccer season on two successive seasons. The purpose of the evaluation was to determine whether symmetry was present in their legs and whether deficits in flexibility or strength would affect the susceptibility to hamstring or groin muscle strain injuries. The mean (+/- SE) flexibility of the dominant leg for hip abduction was 41 degrees +/- 1.2 degree; for hip flexion, 76 degrees +/- 1.9 degree; for hip extension, 174 degrees +/- 0.7 degree; and for ankle dorsiflexion, 33 degrees +/- 1.3 degree. The mean (+/- SE) isokinetic torque of the dominant leg (tested at 30 degrees per second) for knee extension was 214 +/- 8 newton meters and for flexion was 128 +/- 4 newton meters, while isometric strength for hip flexion was 315 +/- 8 newtons and for ankle plantar flexion was 1721 +/- 58 newtons. No significant differences were found between the dominant and nondominant legs in flexibility or strength. During this study no hamstring or groin strain injuries occurred. The lack of leg muscle strain injuries appeared to be directly related to the initiation of a controlled warmup and stretching program and underlines the importance of this in injury prevention. Interestingly, more than 50% (13 of 25) of the players were found to have significant deficits in one or more specific muscle groups. Two athletes sustained low back strain injuries and one athlete had a knee sprain injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1981

Muscle formation in Ehlers-Danlos syndrome.

Ehlers-Danlos Syndrome (EDS) is a familial connective tissue disorder characterized by marked joint hypermobility, skin hyperdistensibility and fragility. To determine the influence of connective tissue hyperdistensibility on muscle function, a young woman with classic EDS underwent extensive muscle function testing which included a controlled strengthening exercise program. Quantitative muscle strength testing revealed generalized muscle weakness characteristic of this disease. The strength-length relationship curve for quadriceps was shifted, implying an increased series elastic component of muscle. No inherent muscle abnormality was evident from electromyography and serum enzyme evaluation. Unusual fluctuation in maximal isometric strength output curves was found in all tested groups. A functional proprioceptive deficit was demonstrated and found correctable with training and visual compensation. Reduced joint proprioception, plus the tendency for minor subluxations from daily activities, resulted in a learned motor pattern that emphasized short jerky motions rather than sustained precise muscular contractions. From these findings, muscle function in EDS was hypothesized to be affected by connective tissue distensibility.

Adult↗