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Margaret K.Y. Mak, Oron Levin, Joseph Mizrahi and Christina W.Y. Hui-Chan

Calculation of joint torques during the rising phase of sit-to-stand motion is in most cases indeterminate, due to the unknown thighs/chair reaction forces in addition to the other sources of uncertainties such as joint positioning and anthropometric data. In the present study we tested the reliability of computation of the joint torques from a five-segment model; we used force plate data of thighs/chair and feet/ground reaction forces, in addition to kinematic measurements. While solving for joint torques before and after seat-off, differences between model solutions and measured data were calculated and minimized using an iterative algorithm for the reestimation of joint positioning and anthropometric properties. The above method was demonstrated for a group of six normal elderly persons.

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Robert K. Jensen and Paula Fletcher

The segment principal moments of inertia of a sample of 7 elderly males and 12 elderly females were estimated using a model based on stacked elliptical cylinders at 2-cm intervals. Apart from the thigh, all male parameters were larger than female parameters. The largest differences were for the lower trunk and hand and for the forearm. The inertia parameters of the thigh for the males were about 12% smaller than the females. Nonlinear estimations of segment principal moments were then determined. The effect of the differences was tested by cross validating cadaver results against the elliptical model results. The regressions were then cross validated using an independent sample of 6 subjects. The standard errors of fit given as a percentage of the mean, Sf, were smaller than the cross validation results for the cadaver regressions and the differences were attributed to differences between cadavers and living subjects.

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Nobuo Takeshima, Keizo Shimada, Mohammod M. Islam, Hiroaki Kanehisa, Yoshie Ishida and William F. Brechue

To clarify the progression of muscle loss in nursing home residents, frail women (n = 16; age: 85 ± 9 years; residence time: 764 days) were assessed for physical activity, caloric intake, and site-specific muscle thickness (MTH) and subcutaneous fat thickness (SFT) using B-mode ultrasound at nine anatomical sites at four intervals over one year. Height, body weight, and BMI did not change. Physical activity (246 steps/day) and nutritional intake (1,441 kcal, 60.3 g protein/day) were unaltered throughout the study. Subjects experienced a significant, progressive loss of muscle indicated by decrements in anterior upper arm (20%), posterior upper arm (25%), abdomen (20%), subscapular (33%), anterior thigh (15%), posterior thigh (22%), anterior lower leg (11%), posterior lower leg (13%), and forearm (15%) MTH. At study inception, prevalence of sarcopenia was related to muscle loss in the upper leg, while upper body muscle wasting contributed to sarcopenia later and was unrelated to physical activity, nutritional input, or duration of residence.

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Benjamin D. Armstrong, Mitchell L. Cordova, Christopher D. Ingersoll and Nancy F. Lawrence

Context:

Little research has been done evaluating the effects of muscle soreness on a lifting task.

Objective:

To examine the effects of delayed-onset muscle soreness (DOMS) in the thigh musculature on kinematic and kinetic variables associated with the squat-lifting technique.

Design:

Pretest–posttest repeated measures, with treatment as the independent variable (DOMS and no DOMS of the thigh musculature).

Setting:

Research laboratory.

Participants:

Twenty healthy college students.

Intervention:

Subjects were videotaped lifting a 157-N crate before and after DOMS inducement.

Main Outcome Measures:

A 2-dimensional sagittal-plane video analysis was used to calculate 7 kinematic and kinetic variables.

Results:

DOMS had no effect on L5/S1 torque and shear or compression, hip torque and range of motion, or knee torque and range of motion during lifting.

Conclusions:

DOMS does not appear to alter kinematic and kinetic variables associated with the squat-lifting technique.

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Susan Vincent Graser, Robert P. Pangrazi and William J. Vincent

Background:

The purpose was to determine if waist placement of the pedometer effected accuracy in normal, overweight, and obese children, when attaching the pedometer to the waistband or a belt.

Methods:

Seventy-seven children (ages 10-12 y) wore five pedometers on the waistband of their pants and a belt at the following placements: navel (NV), anterior midline of the right thigh (AMT), right side (RS), posterior midline of the right thigh (PMT), and middle of the back (MB). Participants walked 100 steps on a treadmill at 80 m · min−1.

Results:

The RS, PMT, and MB sites on the waistband and the AMT and RS sites on the belt produced the least error.

Conclusions:

Of these sites the RS placement is recommended because of the ease of reading the pedometer during activity. Using a belt did not significantly improve accuracy except for normal weight groups at the NV placement site.

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John P. Miller, James C. Vailas, Ronald V. Croce, Robert Confessore and Kerriann Catlaw

This study examined the effects of (a) functional knee braces on thigh muscle EMG and (b) physical activity and leg shape on knee brace migration. Ten female college ice hockey players were fitted with a strap-secured functional knee brace (SSB) and a hard-shell functional knee brace with strapping. Participants performed a side-step maneuver, a treadmill ran, and an obstacle course. Significant differences were noted in hamstring and quadriceps EMG median frequency (mfEMG) while wearing the SSB compared with the control condition. Significant downward shifts were noted in hamstring mfEMG for both braces when compared with the control condition. There was greater brace migration for the obstacle course for both brace types. No relation was found between leg shape and the amount of migration. This study suggests that custom-fitted functional knee braces alter the motor unit recruitment patterns of the thigh musculature during physical activity and that they do not migrate significantly during physical activity.

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Kenneth J. Richter

A 57-year-old patient who was on Coumadin was placed on a very vigorous sports medicine rehabilitation program for a left hemiparesis. His prothrombin was stable at 16 seconds with a control of 12.4 seconds. After doing knee flexion and extension exercises on an isokinetic machine, he developed an extensive posterior thigh ecchymosis. Rehabilitation clinicians need to be aware of the possibility of such a complication in an anticoagulated patient.

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William L. Siler and Philip E. Martin

In order to compare fast and slow runners with respect to the relative timing of the compensations they make to maintain a given running velocity during a prolonged effort, coordinate data were collected periodically for 9 fast and 10 slow volunteers performing a treadmill run to volitional exhaustion at a speed approximating their 10-km race pace. Statistically significant but small changes were noted in the average stride length, range of motion at the thigh, maximum thigh flexion, maximum knee extension, maximum knee flexion, and head-neck-trunk segment (HNT) angle at maximum thigh extension. No statistically significant differences were detected, however, with regard to the relative timing of the compensations demonstrated by the two groups. It was concluded that runners demonstrate subtle compensations in running pattern as they approach volitional exhaustion. In addition, it was concluded that the performance level of the runners as reflected by the ranges of 10-km run performance used in this investigation does not affect the relative timing of the compensations. Finally, it appears that some individuals are more sensitive to the effects of fatigue as evidenced by extreme compensations in running pattern.

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Mary Ridgway, Carol Pope and Jerry Wilkerson

The purpose of this study was to identify factors affecting efficiency of wheelchair propulsion by male subjects in the 800-m racing event. High-speed films were taken of finalists (n=31) at the 1986 National Wheelchair Track and Field Championships. Kinematic data were calculated on the head, trunk, upper arm, elbow, and thigh in addition to cycle velocity (wheelchair velocity), cycle duration, cycle rate, cycle distance, and percentage of propulsion and recovery. In general, fastest cycle velocities, rates, and greatest distances occurred in the higher classes. During propulsion, head movement was greatest in Classes II/III (13.9°) and trunk movement was greatest in Classes IV/V (7.8°). Additionally, the higher classes exhibited greater movement at the shoulder and elbow than did Classes IA/IB. The thighs were closest to the trunk in Classes IA/IB and were farthest from the trunk in Classes IV/V. Movement of the trunk and head, as well as positioning of the thighs during wheelchair racing, may help in propulsion and with aerodynamics.

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John A. Nyland, Dean P. Currier, J. Michael Ray and Mitchell J. Duby

This paper discusses function changes during an accelerated rehabilitation program at 6, 10, and 52 weeks postsurgery for a college athlete following anterior cruciate ligament reconstruction/meniscectomy of the left knee. The effects of combined pulsed electromagnetic field (PEMF) and neuromuscular electrical stimulation (NMES) on knee extensor torque, thigh girth, and pain level are presented. PEMF-NMES decreased stimulation pain by 76%. Knee extensor isometric torque increased by 23%, and thigh girth decreased less than 5% at 6 weeks. Knee extensor isokinetic torque was 13% and 3% deficient at 90°/s and 240°/s, and standing single-leg broad jump distance was 19% deficient at 10 weeks. Knee extensor isokinetic torque was 1% and 1.5% greater at 90°/s and 240°/s, and standing single-leg broad jump distance was 11% deficient at 52 weeks. Knee anterior laxity was 2 mm at 10 weeks and 3 mm at 52 weeks. PEMF-NMES appears to comfortably enhance knee extensor torque gains and diminish thigh girth loss. Despite early return to practice, functional deficit remained and anterior laxity was increased at 52 weeks.