Effectiveness of wheelchair skills training for improving manual wheelchair mobility in children and adolescents: protocol for a multicenter randomized waitlist-controlled trial.

BACKGROUND: Self-directed mobility during childhood can influence development, social participation, and independent living later in life. For children who experience challenges with walking, manual wheelchairs (MWCs) provide a means for self-directed mobility. An effective MWC skills training program exists for adults, but controlled trials have not yet been documented in children and adolescents. This paper outlines the protocol for a multi-centre randomized wait-list controlled trial. The primary objective is to test the hypothesis that children and adolescents who receive MWC skills training will have higher MWC skills capacity compared to children and adolescents in the control group who receive usual care. The secondary objectives are to explore the influence of MWC skills training in children and adolescents (MWC use self-efficacy and satisfaction with participation in meaningful activities), and parents (perceived MWC skills); and to measure retention three months later. METHODS: A multi-centre, parallel-group, single-blind randomized wait-list controlled trial will be conducted. A sample of 60 children and adolescents who use MWCs will be recruited in rehabilitation centres, specialized schools, and the communities of three Canadian cities. Participants will be randomized (1:1) to the experimental (Wheelchair Skills Training Program [WSTP]) or wait-list control group (usual care). Performance-based and self-report measures will be completed at baseline (T1), three months (post-intervention, T2), and three months post-intervention (T3). The primary outcome will be MWC skills capacity post-intervention. Secondary outcomes will be MWC use self-efficacy and satisfaction with participation of the child/adolescent, and parent-perceived MWC skills. The WSTP will consist of 12 sessions, 45-60 min each, delivered 1-2 times per week by trained personnel with health professions education. Training will be customized according to the child's baseline skills and participation goals that require the use of the MWC. The wait-list control group will receive usual care for 3 months and then receive the WSTP after completing T2 evaluations. Data will be analysed using ANCOVA (controlling for baseline scores). DISCUSSION: MWC skills training may be one way to improve self-directed mobility and related outcomes for children and adolescents. The results of this multi-centre randomized wait-list controlled trial will allow for the effectiveness of the intervention to be evaluated in a variety of clinical contexts and geographical regions. TRIAL REGISTRATION: ClinicalTrials.gov: NCT05564247, Version October 3, 2022.

Randomized double-blind prospective trial to evaluate the effects of sargramostim versus placebo in a moderate-dose fluorouracil, doxorubicin, and cyclophosphamide adjuvant chemotherapy program for stage II and III breast cancer.

PURPOSE: To determine the effects of sargramostim (recombinant human granulocyte-macrophage colony-stimulating factor [rhu GM-CSF]) on the incidence, duration, and complications of myelosuppression after moderate-dose fluorouracil, doxorubicin, cyclophosphamide (FAC) adjuvant chemotherapy in patients with node-positive breast cancer. PATIENTS AND METHODS: In this randomized, double-blind, placebo-controlled study, 142 women with stage II and III breast cancer were to receive four 21-day cycles of chemotherapy that consisted of fluorouracil 600 mg/ m2 intravenously (IV), doxorubicin 60 mg/m2 IV, and cyclophosphamide 750 mg/m2 IV on day 1, followed by placebo or GM-CSF 250 micrograms/m2/d daily subcutaneously (SC) on days 3 through 15. All patients received prophylactic ciprofloxacin by mouth when the absolute neutrophil count (ANC) was less than 1,000/microL. RESULTS: Eighty-six percent of GM-CSF patients (n = 62) and 96% of placebo patients (n = 69) completed four assessable cycles of treatment on study. Overall, the median duration of severe neutropenia (ANC < 500/microL) was 2.8 days with GM-CSF and 6.8 days with placebo (P < .001); the duration of ANC less than 1,000/microL was 6.0 versus 9.1 days, respectively (P < .001). Hospitalizations for febrile neutropenia were uncommon in either group: GM-CSF, six; placebo, eight. The only other difference in hematologic toxicity was grade 3/4 thrombocytopenia observed with greater frequency in GM-CSF patients than placebo patients in cycles 3 and 4. GM-CSF increased mean the FAC dose-intensity among patients who completed two or more cycles (P < .001). GM-CSF was generally well tolerated and associated with more injection-site reactions, but less mucositis than placebo. There were no deaths on study. CONCLUSION: GM-CSF significantly enhanced ANC recovery after FAC chemotherapy; it decreased the incidence and duration of associated neutropenia and moderately increased the dose-intensity of adjuvant chemotherapy. Whether these effects will ultimately translate into improved long-term outcome remains to be determined.

Mild exercise impedes glycogen repletion in muscle.

Bicycle ergometric exercise was used to deplete glycogen by either 80 or 35% in the vastus lateralis of both legs. Thereafter, subjects from each group rested or maintained single-leg exercise [20% of maximal O2 consumption (Vo2max) for 4 h. All subjects ingested glucose (1.5 g/kg wt; 20% solution) at min 10-12 and min 130-132 of the 4-h period. With bed rest, significant glycogen increases occurred after exhaustive (+36%; P less than 0.05) and nonexhaustive exercise (+13%; P less than 0.05). With single-leg exercise, 1) a diminished glycogen repletion occurred in exercising (+11%; P less than 0.05) and nonexercising (+15%; P less than 0.05) muscle after exhaustive exercise, or 2) further glycogen loss occurred in exercising (-26%; P less than 0.05) and nonexercising muscle (-19%; P less than 0.05) after nonexhaustive exercise. Within both groups, glycogen concentrations did not differ between exercising and nonexercising muscles (P greater than 0.05). Single-leg exercise, not preceded by exercise, provoked differences in glycogen loss in exercising (-47%) and nonexercising (-24%) muscle (P less than 0.05). These experiments demonstrate that mild exercise 1) impedes glycogen resynthesis or 2) provokes glycogen loss in both exercising and nonexercising muscle. These findings cannot be ascribed to circulating glucose and insulin concentrations in these studies.

Locomotor-respiratory coupling during wheelchair propulsion.

Visceral movement due to impact loading is believed to play a role in the locomotor-respiratory coupling (LRC) that has been detected in a number of mammalian species. In the bird and bat species in which LRC has been described, the effect of the wing muscles on the timing of respiration appears to be a dominant influence. To test the hypothesis that LRC occurs in humans propelling wheelchairs (where there is no impact loading and the arms are used for locomotion), we studied 10 wheelchair athletes on a motorized treadmill at three speeds. Each subject's data were analyzed by spectral analysis (based on the fast Fourier transform), which detected apparent LRC (rates within 1% of a single-digit integer ratio) in 12 (40%) of the 30 test settings. However, a control analysis, in which each subject's arm-thrust rates were compared with another subject's breathing rates, revealed apparent (but false) coupling in 8 (27%), not significantly less often (using the chi 2 test). These findings appear to refute the hypothesis that LRC occurs during wheelchair propulsion. These data are consistent with the theory that the visceral piston is important to LRC and suggest that rhythmic arm movements are insufficient to induce the phenomenon in this setting.

Coupling of cardiac and locomotor rhythms.

The pressure within exercising skeletal muscle rises and falls rhythmically during normal human locomotion, the peak pressure reaching levels that intermittently impede blood flow to the exercising muscle. Speculating that a reciprocal relationship between the timing of peak intramuscular and pulsatile arterial pressures should optimize blood flow through muscle and minimize cardiac load, we tested the hypothesis that heart rate becomes entrained with walking and running cadence at some locomotion speeds, by means of electrocardiography and an accelerometer to provide signals reflecting heart rate and cadence, respectively. In 18 of 25 subjects, 1:1 coupling of heart and step rates was present at one or more speeds on a motorized treadmill, generally at moderate to high exercise intensities. To determine how exercise specific this phenomenon is, and to refute the competing hypothesis that coupling is due to vertical accelerations of the heart during locomotion, we had 12 other subjects cycle on an electronically braked bicycle ergometer. Coupling was found between heart rate and pedaling frequency in 10 of them. Cardiac-locomotor coupling appears to be a normal physiological phenomenon, and its identification provides a fresh perspective from which to study endurance.

Failure of accentuated vertical body movements to induce cardiac-locomotor coupling.

Cardiac-locomotor coupling (CLC) has been reported during a variety of rhythmic human activities. One reason postulated for such coupling is that axial movements of the viscera during some activities (the "visceral piston") may enhance expulsion of blood from the heart; if so, accentuated vertical movements of the body should provide a powerful stimulus to coupling. To test this hypothesis, we studied 20 subjects hopping and 20 others skipping rope for greater than or equal to 10 min while electrocardiographic and force-platform signals were recorded, from which we derived the subjects' exercise and heart rates. The incidence and intensity of apparent coupling in the test subjects were compared with those of cross-over controls, where the heart rate of each subject was related to the hopping or skipping rate of a matched subject. Ratios consistent with coupling were seen in 10 (50%) hopping subjects under test conditions and in 13 (65%) under control conditions; among skipping subjects, the incidences were 11 (55%) and 10 (50%). In neither group of subjects was the difference in the incidences or the intensities of apparent CLC statistically significant. Our failure to detect CLC while our subjects were hopping or skipping suggests that the visceral piston is unimportant to the CLC phenomenon.

The influence of foot position on standing balance.

To test the hypothesis that variations in foot position would significantly affect standing balance, we studied ten normal subjects on a Kistler force platform which measured the travel and center of pressure displacement. With the feet together there was substantially more mediolateral (ML) travel than with the axes of the feet 15, 30 or 45 cm apart and the mean ML position of the center of pressure was displaced toward the right; there was no consistent effect on anteroposterior (AP) travel or position. As the right foot was placed 10 and 30 cm forward or back, the least amount of ML and AP travel occurred with the feet even or at 10 cm either direction; the mean AP and ML position moved toward the foot which was placed more posteriorly. Of the five foot angles ranging from toes-out 45 degrees to toes-in 45 degrees, the extent of ML and AP travel was lowest in the toes-out 25 degrees position and greatest in the toes-in 45 degrees position; the mean AP and ML position was farthest forward and to the right with toes-in 45 degrees. These findings have implications for the prosthetic replacement of the lower limbs, sports, ergonomics and postural sway studies.

Effect of limited knee-flexion range on peak hip moments of force while transferring from sitting to standing.

The hypothesis that limiting the knee-flexion range increases the peak hip-extension moment while transferring from sitting to standing was tested by filming (100 fps) ten normal human volunteers. With the knees flexed 105 degrees from full extension (0 degrees) the mean (+/- 1 S.D.) peak hip-extension moment was 142 (+/- 37) Nm. With the knees flexed only 75 degrees subjects threw their arms and trunks forward to a greater extent, with a peak moment of 253 (+/- 65) Nm (p less than 0.0001). If the peak moments rise to a similar degree in patients with arthritis and limited knee-flexion range, they may accelerate hip joint damage or the loosening of hip endoprostheses.

The effect of locomotion speed on the anterior tibial intramuscular pressure of normal humans.

We examined the hypothesis that anterior tibial intramuscular pressure increases with the speed of locomotion. A solidstate pressure transducer was placed near the tip of an intramuscular fluid-filled catheter and each of ten normal subjects walked, jogged and ran barefoot, at 1.5, 2.5 and 3.5 m s-1 respectively, on a treadmill to which they had been previously familiarized. The pressure signals during ten gait cycles from each subject were sampled at 600 Hz and were averaged at each speed. The peak pressures increased in magnitude as a function of increasing locomotion speed, while the mean pressure remained constant.

Flexibility and musculoskeletal symptomatology in female gymnasts and age-matched controls.

Sixty competitive female gymnasts and 35 age-matched nonathletic controls were interviewed for musculoskeletal symptoms and examined for flexibility. A significantly greater number of gymnasts (P less than 0.01) had musculoskeletal symptoms in the wrist, low back, hip, shin, and foot regions than did the controls. The average number of symptomatic regions per subject was significantly greater (P less than 0.001) in gymnasts (6.17) than in controls (2.25). Gymnasts had greater shoulder flexion and horizontal abduction, lumber flexion, hip extension, and toe-touching abilities (P less than 0.001). Controls surpassed gymnasts only in the extent of elbow supination (P less than 0.001). There were no significant differences in lumbar, knee or elbow extension. No statistically significant correlations in flexibility between different body regions were identifiable in gymnasts or controls. The gymnasts with low back discomfort and greater toe-touching ability than those without symptoms. No other consistent and significant relationships between symptomatology and flexibility in a region were found.

Usefulness of footprint-sequence analysis in lower-limb amputees.

Clinicians evaluated the usefulness of footprint-sequence analysis in 25 lower-limb amputees who were all prostheses wearers. The patients walked at a comfortable speed with their usual walking aids along a 2.24-m footprint-recording strip. Each patient's physical therapist and physician indicated on visual-analogue scales how useful they judged both raw and derived data to be in problem solving and as documentation for future comparison. Both groups of clinicians found this type of analysis moderately useful. We found no significant difference, but moderate correlation (r = .61, p less than .01), between their estimates of usefulness for problem solving and for future documentation. They considered the derived data slightly, but significantly, more useful than the raw data (t = 4.20, p less than .001). We found no significant difference or correlation between the estimates of physical therapists and those of physicians. The clinicians ranked pressure distribution, stride width, step length, foot angle, and stride length in order of perceived usefulness. Footprint-sequence analysis appears to be a moderately useful adjunct to the evaluation and documentation of the walking problems of lower-limb amputees. Both raw and derived data should be made available to the physical therapists and physicians caring for these patients.

Participatory research with native community of Kahnawake creates innovative Code of Research Ethics.

Participatory research requires ethical guidelines to incorporate the needs of the partners, i.e., the researchers and the community. This paper describes the background, development and implementation of an innovative Code of Research Ethics developed for a participatory research project with a Native community in Canada. The document ensures that responsibility and control will be shared by both researchers and community throughout the project including joint publication of the results. It defines community control of data, means of resolving dissension at time of publication, incorporation of new researchers and the differences between community-based and academic researchers.

Reliability of walking endurance with an incremental treadmill test.

Treadmill walking endurance is the major outcome measure for intervention studies on patients with intermittent claudication. The measurement properties of this test have not, however, been well documented. We assessed the test-retest reliability of treadmill walking endurance in 10 normal subjects with a mean (+/- 1SD) age of 27.5 (+/- 3.3) years. On four occasions, at intervals of at least one week, each subject walked on a motorized treadmill to the limits of his or her capabilities. With the standard protocol, subjects began at a very low exercise intensity (0.25 m/sec, 0% grade), which increased in either speed or grade at ninety-second intervals through a maximum of fifteen stages to 2.75 m/sec and 20% grade. On the final occasion, 5 of the subjects were tested twice with a fifteen-minute interval, using a truncated protocol starting at stage five (1.25 m/sec, 0% grade). Within-subject standard deviations were low, averaging twenty-three seconds (2.1%). Reliability was very high for the first three tests with the standard protocol (r greater than or equal to 0.98, p less than 0.0001) and for the 5 subjects tested and retested with the short interval and truncated protocol (r = 0.99, p less than 0.0002), while the correlation between the standard protocol and the truncated protocol was somewhat lower (r greater than 0.81, p less than 0.01). For young normal subjects the measurement of walking endurance with an incremental treadmill test is highly reliable, but the limits of reliability need to be considered when conclusions are drawn from such measures.

Coupling between cardiac and locomotor rhythms: the phase lag between heart beats and pedal thrusts.

During some rhythmic exercises, the heart and exercise rates may become coupled (be within 1% of each other). If the intraarterial and skeletal intramuscular pressure cycles were reciprocal, blood flow to exercising muscle should be maximized and cardiac load minimized. In this study the authors tested the hypothesis that, while coupling is present, the phase lag between the pedaling and cardiac contraction cycles is consistent and appropriate. Twenty-seven subjects pedaled, at a frequency natural to them, on an electronically braked bicycle ergometer that held the power output constant regardless of pedaling rate. To assess the phase lag between pedal thrust (two per revolution) and heart beat, pedal-gated plots of the electrocardiography signal were generated throughout the most coupled five-minute work load for each of the 9 subjects in whom the rates were within 1% of each other for at least two consecutive four-second samples taken every fifteen seconds. During this interval of thirty-seconds in which the rates were within 1% of each other, the phase lag of most subjects gradually lengthened and shortened and there was considerable variation among subjects, refuting the authors' hypothesis. The results of this study illustrate the importance of beat-by-beat analysis when studying coupling phenomena. The preliminary assumption, that the coupling between cardiac and locomotor rhythms during cycling was on the basis of a single ischemic muscle group, has apparently been disproven.

The effect of knee-flexion angle on wheelchair turning.

The increasingly popular hyperflexed knee-flexion angle was evaluated to determine its effects on wheelchair turning. Twenty able-bodied subjects were tested comparing the effect of full knee extension and full knee flexion on a number of parameters. We empirically measured the angular velocity of subjects spinning 720 degrees in place, subjects' perceived ease of wheelchair turning, the overall length of the wheelchair, the anteroposterior position of the center of mass (COM), rolling resistance, turning resistance and rear-wheel traction. The combined moment of inertia of the wheelchair and system was modeled. We found that, in comparison with full extension, fully flexing the knees increased angular velocity by 40% and was perceived to be 66% easier by subjects. Overall length decreased by 39%, COM moved rearward 38%, rolling and turning resistance decreased by 21% and 17% respectively, rear-wheel traction increased by 12% and moment of inertia decreased by 42%. All empirically tested parameters were statistically significant (p<0.007). We conclude that the knee-flexion angle has a significant effect on wheelchair turning. The implications of these findings for wheelchair design and prescription will need to be validated on actual wheelchair users and for smaller increments in knee-flexion range.

Preventing occupied wheelchairs from falling down stairs.

The hypothesis was tested that wheelchairs could be prevented from accidentally falling down stairs. A rigid post was attached to the wheelchair frame immediately behind the caster (clearance of 13 mm) such that it would strike the floor just after the casters dropped off an edge. The device was tested by means of a 3-degree ramp at the lower end of which was a level surface that ended with a 11-cm vertical drop. Twenty able-bodied subjects descended the ramp, by gravity alone, from progressively greater distances up the ramp, to determine the threshold at which the speed of the occupied wheelchair (with and without the device in place) was sufficient to induce a forward tip down the step. Forward tips occurred at a mean (+/- 1 SD) threshold speed of 0.77 (+/- 0.06) m/s with the device and at 0.38 (+/- 0.04) m/s without it, a mean difference of 0.39 (+/- 0.07) m/s (p less than 0.0005). This preliminary study suggests that such a wheelchair feature might improve the safety of wheelchairs in conditions involving inadvertent loss of caster support, as when they drop off a stair or ledge.

Wheelchair stability: effect of body position.

When a wheelchair user reaches and leans, the static stability decreases in the direction of the lean and increases in the opposite direction. The purpose of this study was to determine the extent of this effect. We studied 21 nondisabled subjects in a representative wheelchair, measuring the static forward, rear, and lateral stability on a tilting platform. Reaching and leaning away from the tip added stability, with mean increases ranging from 9.1% to 124.3% of the neutral-position values, whereas reaching and leaning toward the tip reduced stability, with mean decreases ranging from 25.2% to 52.3% (p < 0.0001). The stability range ("away" minus "toward") varied from 52.4% to 149.5%. Reaching forward had a greater effect on stability than did reaching back or to the side. Wheelchair users with the ability to control their body positions can profoundly affect the stability of their wheelchairs, a factor that should be considered in wheelchair selection and training.

Mechanical effects of rear-wheel camber on wheelchairs.

Giving the rear wheels of manually propelled wheelchairs negative camber (by angling them such that the bottoms of the wheels are farther apart than the tops) has become increasingly popular, especially among active users. This study's purpose was to evaluate how changing camber affects a wheelchair's mechanics and the extent of these changes. Using a representative wheelchair occupied by an anthropomorphic dummy, we altered the camber from +15 degrees to -15 degrees and measured the effects on nine selected variables. In addition to increasing the wheelchair's track width, negative camber increases the wheelchair's wheelbase and decreases the height of the frame. With negative camber, the center of gravity (CG) of the occupied wheelchair moves backwards. Negative camber causes a backwards tilt of the frame which, in turn, causes toe-out of the rear wheels, a positive caster-inclination angle and an increase in the caster-trail distance. It is apparent that a change in one component of a wheelchair can affect many others, which should be taken into consideration and, where appropriate, compensated for when changing the camber of the wheelchair.

The cardiac-locomotor coupling phenomenon: the contribution of Coleman.

Cardiac-locomotor coupling (entrainment of heart and exercise rates) has been the subject of a number of recent studies. This paper reviews the early work of W. M. Coleman who, in 1921, published the results of his observations on humans and a variety of other species. The animal studies were carried out at the London Zoological Gardens. Coleman's findings remain relevant to those studying entrainment phenomena. They also illustrate the importance and utility of careful observation.

Cardiac-locomotor coupling while finger tapping.

Coupling between cardiac and locomotor rhythms has been identified while people walk, run, hop and cycle at cadences natural to them. To test the hypothesis that cardiac-locomotor coupling occurs during finger tapping, we studied 20 normal subjects tapping a telegraph key at a comfortable rate for 10 min. 15 subjects (75%) coupled significantly at one or more single-digit integer ratio (heart/tapping rate), the most common of which was 1:2. Such coupling should be considered a potentially confounding variable when studying finger tapping in subjects with disease or medication affecting heart rate. Also, the identification of coupling during the repetitive activity of small upper-extremity muscles suggests that neither increases in cardiac load nor impact-loading, two suggested explanations for why coupling occurs, are necessary for the phenomenon.