Search PubMed⌕ Search

Biomedical subjects

T M Cook

Publications and source records attributed to T M Cook.

At least 19 recordsLinked to original sources
PubMed1995

The effect of foot orthotics on three-dimensional kinematics of the leg and rearfoot during running.

Foot orthotics have been used successfully in the treatment of musculoskeletal symptoms associated with structural variations of the foot. Their effectiveness has been primarily addressed through two-dimensional, frontal plane motion studies of the subtalar joint in individuals considered "clinical pronators." Recent evidence suggests that assessment of tibial axial rotation in combination with frontal plane analysis of calcaneal inversion/eversion may provide improved understanding of subtalar joint function. The purpose of this study was to examine the effects of semi-rigid foot orthotics on three-dimensional lower limb kinematics in 20 recreational runners presenting with distinct structural foot characteristics. Radiographic measurements were used to classify subjects into a low or high rearfoot profile group. The results of the kinematic analysis showed a significant orthotic effect for rotations occurring from heel contact to peak tibial internal rotation, as well as in the coupling relationship between tibial axial rotation and calcaneal inversion/eversion. Both groups responded similarly with a mean reduction of 2 degrees in tibial internal rotation. No differences were found for the frontal plane rotations for either group when orthotics were worn. The findings suggest that the maximum effect of orthotics may be realized in the first 50% of stance and related to the changes in tibial axial rotation.

Biomechanical Phenomena↗
PubMed1994

Effects of stair-stepping exercise direction and cadence on EMG activity of selected lower extremity muscle groups.

Step ergometry has become a popular treatment mode in cardiovascular fitness and knee rehabilitation programs. The following study describes the effects of forward stair stepping at 35 and 95 steps/minute and forward and retrograde stair stepping at 60 steps/minute on the mean electromyographic (EMG) activity of the gluteus maximus, rectus femoris, vastus medialis, semimembranosus/semitendinosus, and gastrocnemius muscles. Thirty-three subjects without prior lower extremity pathology participated in the study. Analysis of variance was used to compare mean EMG activity during the knee extension phase of the different stepping conditions. Significant differences (p < 0.05) in mean EMGs of gluteus maximus, rectus femoris, vastus medialis, and gastrocnemius were noted across all cadences. The semimembranosus/semitendinosus EMG activity displayed a single significant difference between the cadences of 35 and 95. The comparison between forward and retrograde stepping identified only one significant difference in mean EMG (semimembranosus/semitendinosus). The effects of cadence on EMG activity should be considered when developing conditioning or rehabilitation programs for the lower extremity. Faster cadences result in increased peak activity of shorter duration for the gluteus maximus, quadriceps, and gastrocnemius. There is no apparent difference in EMG activity of the hamstrings due to cadence. Also, noting the minimal activation that occurs, stair-stepping exercise would not be recommended for strengthening of the hamstrings musculature.

Adolescent↗
PubMed1994

Active surveillance for the control of cumulative trauma disorders: a working model in the newspaper industry.

Health and risk factor surveillance is a critical aspect of an effective ergonomics process. Physical therapists are becoming increasingly involved in many components of the ergonomics process, including health and risk factor surveillance. The purpose of this study was to develop and implement a multistaged active surveillance program for the management and control of cumulative trauma disorders. The surveillance program was established at three newspaper companies consisting of 1,150 employees. This study focused on the first three stages of the multistage surveillance model, which incorporates the use of symptom and job factor questionnaires, specific anatomical surveys, and clinical detection tests. The results of the study indicated that 1) musculoskeletal symptoms in the back, neck, and hands accounted for the majority of reported missed work among the newspaper workers; 2) production workers had a higher prevalence of musculoskeletal symptoms than office workers; and 3) the prevalence of probable carpal tunnel syndrome among the newspaper workers was 1.5%.

Adolescent↗
PubMed1994

Vibration sensibility testing in the workplace. Day-to-day reliability.

Loss of vibration sensibility has been suggested as an early indicator of peripheral compression neuropathy, including carpal tunnel syndrome. Although vibration sensibility has been used frequently to evaluate carpal tunnel syndrome, the day-to-day reliability of vibration measurements in an industrial population measured at the workplace has not been assessed. Vibration sensibility testing was performed at the university ergonomics laboratory on 50 volunteers (100 hands) and at a newspaper company on 50 workers (100 hands). Vibration perception and disappearance thresholds were measured on two occasions separated by 3 to 5 days. Student's t tests indicated no significant differences between the first and second tests or between the two groups. Pearson product-moment correlations for test-retest reliability were lower in the industry group but were relatively high despite the less than optimal testing conditions. Our findings suggest that vibration sensibility measurements are reliable from day to day not only in the laboratory but also in the workplace.

Adult↗
PubMed1993

Effects of seated posture on erector spinae EMG activity during whole body vibration.

The purpose of this study was to evaluate the electromyographic (EMG) response of the erector spinae to whole body vibration in three different unsupported seated postures: neutral upright, forward lean, and posterior lean. Subjects were 11 healthy college-age men. EMG was collected using bipolar surface electrodes placed bilaterally over the erector spinae at the L4 level. A modified chair with attached accelerometer was affixed to an induction type vibrator. Subjects were vibrated vertically at 4.5 Hz and 6.21 m.s-2 RMS. Data were collected in each of the three postures for 30 s pre- and post-vibration and for 2 min during vibration. Mean EMG values were determined for each sampling period and compared using ANOVA. The mean value for anterior lean was significantly larger (p < 0.05) than that for posterior lean and neutral. EMG data analysed by triggered averaging showed a phase-dependent response to the vibratory cycle for the forward leaning and neutral upright postures. The results of this study indicate that the magnitude of the vibration synchronous response of the erector spinae musculature is dependent upon body posture. This response may be an important factor in the onset of muscular fatigue and the increased incidence of back disorders among individuals exposed to whole body vibration.

Adult↗
PubMed1992

An electromyographic analysis of hip abductor muscle activity when subjects are carrying loads in one or both hands.

Forces produced at the hip joint as a result of hip abductor muscle contractions while carrying loads reach several times body weight (BW). Physical therapists often advise patients with hip osteoarthritis in ways to minimize these forces as a means of reducing the pain associated with carrying loads. The purpose of this study was to use surface electromyography (EMG) to quantify the relative demands placed on the hip abductors while carrying loads in one hand or in both hands. Thirty asymptomatic college-aged subjects walked while carrying loads of 10% and 20% of BW unilaterally and loads of 10%, 20%, and 40% of BW bilaterally. Signals from foot switches allowed a computer to average the EMG data over the phase of gait when the foot was in complete contact with the ground. All EMG data were normalized to a percentage of the EMG voltage produced during no-load walking (%EMG). Our prime dependent variable was the %EMG averaged over both hip sides of all subjects' multiple walking trials. Our major analysis involved a multifactorial analysis of variance for repeated measures with method of carry (unilateral or bilateral) and load as the two main independent variables. Results demonstrated that both the amount of the load and the method of load carry made a significant difference in regard to the amount of hip abductor EMG produced. Of particular note was the fact that the bilateral 20% of BW condition produced statistically less %EMG (when averaged over both sides) than did the unilateral 20% of BW condition. Persons with hip disease should be aware that hip joint forces may be reduced by the bilateral method of carrying loads.

Adult↗
PubMed1992

Lumbar support thickness: effect on seated buttock pressure in individuals with and without spinal cord injury.

We compared the effects of different lumbar support thicknesses on seated buttock pressure in individuals with and without spinal cord injury (SCI). Eighteen subjects with SCI (SCI group) and 18 subjects without SCI (control group) were seated on a pressure-sensing transducer incorporated into an adjustable chair. The output was calibrated so that eight pressure intervals (colors) were displayed. The lumbar support thickness was adjusted to 0, 2.5, 5, and 7.5 cm, and the highest and lowest seated buttock pressures were analyzed. External measurements of the hip angle were taken for each lumbar support condition. High reliability of repeated seated test positions was found (intraclass correlation coefficient = .93). The 5- and 7.5-cm-thick lumbar supports caused a decrease in the highest pressure areas in the control group, but no change in the SCI group. The hip angle was increased with each increment in lumbar support thickness in both groups, but the SCI group's hip angle was consistently less than that of the control group for each lumbar support condition. The results of this study suggest that in individuals with chronic paralysis (greater than or equal to 3 years), the use of a wheelchair lumbar support has a negligible effect on seated buttock pressure.

Adult↗
PubMed1991

Electromyographic activity of selected leg musculature in subjects with normal and chronically sprained ankles performing on a BAPS board.

The purpose of this study was to evaluate the magnitude and temporal features of tibialis anterior, peroneus longus, and gastrocnemius muscle activity during exercises performed on a Biomechanical Ankle Platform System (BAPS) board by subjects with normal and chronically sprained ankles. Fourteen participants in each of the two groups rotated the platform in both clockwise and counterclockwise directions at self-selected velocities. Trials were completed with both medium- and large-sized hemispheres under the platform while electromyographic surface recordings were made from the three muscles of interest. Electromyographic values, normalized within individuals as a percentage of maximal voluntary isometric contraction (MVIC), ranged from 20% to 80% of MVIC. An analysis of variance for the average myoelectric signals from all three muscles revealed no differences between the two groups. Effects of direction and hemisphere size were shown for all muscles. The large hemisphere produced significantly greater average activity and a more pronounced effect on the tibialis anterior muscle. The data provide information on the level of muscle activity required for conditions used in this study and may assist the physical therapist with making judgments about the use of this device in rehabilitation programs.

Adult↗
PubMed1991

Characterization of a gyrB mutation responsible for low-level nalidixic acid resistance in Neisseria gonorrhoeae.

Nalidixic acid-resistant derivatives of Neisseria gonorrhoeae WR302 were identified and categorized into two classes on the basis of their susceptibilities to this antimicrobial agent. The MIC of nalidixic acid for the derivative strain MUG116 was fourfold greater than that for its isogenic parental strain WR302 (2 versus 0.5 micrograms/ml, respectively). MUG324 was significantly more resistant to nalidixic acid (greater than 64 micrograms/ml). The MICs of other antimicrobial agents known to interact with either the gyrA or gyrB gene products were determined. Although the nalidixic acid MIC for MUG116 increased, no significant increases in the MICs of other agents that interact with the gyrA gene product were seen. The MICs of all agents that interact with the gyrA gene product were significantly increased for MUG324. The gene that imparts low-level nalidixic acid resistance was cloned from strain MUG116. The DNA sequence of this gene was determined, and by comparing the deduced amino acid sequence with sequences of proteins in data bases, this protein was found to be approximately 70% homologous with the gyrB gene product of Escherichia coli.

Amino Acid Sequence↗