Nutritional ketosis improves exercise metabolism in patients with very long-chain acyl-CoA dehydrogenase deficiency.

A maladaptive shift from fat to carbohydrate (CHO) oxidation during exercise is thought to underlie myopathy and exercise-induced rhabdomyolysis in patients with fatty acid oxidation (FAO) disorders. We hypothesised that ingestion of a ketone ester (KE) drink prior to exercise could serve as an alternative oxidative substrate supply to boost muscular ATP homeostasis. To establish a rational basis for therapeutic use of KE supplementation in FAO, we tested this hypothesis in patients deficient in Very Long-Chain acyl-CoA Dehydrogenase (VLCAD). Five patients (range 17-45 y; 4 M/1F) patients were included in an investigator-initiated, randomised, blinded, placebo-controlled, 2-way cross-over study. Patients drank either a KE + CHO mix or an isocaloric CHO equivalent and performed 35 minutes upright cycling followed by 10 minutes supine cycling inside a Magnetic Resonance scanner at individual maximal FAO work rate (fatmax; approximately 40% VO2 max). The protocol was repeated after a 1-week interval with the alternate drink. Primary outcome measures were quadriceps phosphocreatine (PCr), Pi and pH dynamics during exercise and recovery assayed by in vivo 31 P-MR spectroscopy. Secondary outcomes included plasma and muscle metabolites and respiratory gas exchange recordings. Ingestion of KE rapidly induced mild ketosis and increased muscle BHB content. During exercise at FATMAX, VLCADD-specific plasma acylcarnitine levels, quadriceps glycolytic intermediate levels and in vivo Pi/PCr ratio were all lower in KE + CHO than CHO. These results provide a rational basis for future clinical trials of synthetic ketone ester supplementation therapy in patients with FAO disorders. Trial registration: ClinicalTrials.gov. Protocol ID: NCT03531554; METC2014.492; ABR51222.042.14.

Computer and internet use among people with long-standing spinal cord injury: a cross-sectional survey in the Netherlands.

STUDY DESIGN: Cross-sectional survey OBJECTIVES: To describe computer and Internet use (other than for work or study) among people with long-standing spinal cord injury (SCI), examine associations between demographic and lesion characteristics and Internet use, and examine associations between Internet use and mental health, participation, and life satisfaction. SETTING: Community, The Netherlands METHODS: Participants were 265 individuals living with SCI for at least 10 years, who were 18-35 at the onset of SCI, aged 28-65 at the time of the study and wheelchair-user. Scales for General and Health-related Internet use were developed. RESULTS: Nearly all (97.7%) participants had Internet access and 98.4% of those used it daily or weekly. Of those with tetraplegia, 47.4% had assistive devices for computer use. General Internet use, such as following news and online banking, was very frequent. Websites with information on general health or accessibility were typically visited a few times a year. Three-quarters never visited websites of other individuals with SCI or foreign websites with information on SCI. General Internet use was associated with male gender, younger age, and higher education. Participants with tetraplegia scored higher on Health-related Internet use compared to participants with paraplegia. Health-related Internet use was associated with worse participation, but not with the other psychosocial variables. CONCLUSION: Internet has become part of daily life of people with SCI in the Netherlands. However, only one association between Internet use and indicators of psychosocial functioning was found. Possible underuse of adaptive devices and of SCI-specific websites warrant further investigation.

Patterns of changes in wheelchair exercise capacity after spinal cord injury.

OBJECTIVES: (1) To identify different patterns of changes in wheelchair exercise capacity in the period between the start of active spinal cord injury (SCI) rehabilitation and 5 years after discharge; (2) to examine the pattern determinants of the change in wheelchair exercise capacity. DESIGN: Prospective cohort study. Measurements were recorded at the start of active inpatient rehabilitation, 3 months after the start, at discharge of inpatient rehabilitation, 1 year after discharge, and 5 years after discharge. SETTING: Eight rehabilitation centers. PARTICIPANTS: Persons with SCI (N=130; age range, 18-65y), who were wheelchair-dependent, at least for long distances. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Wheelchair exercise capacity: peak power output (W). RESULTS: We found 4 different patterns of the change of peak power output (mean ± SD): (1) a pattern with high and progressive scores (33% of total study group): high progressive scores (start of rehabilitation: 49±15W to 5 years after discharge: 77±17.2W); (2) a pattern of improvement during inpatient rehabilitation and deterioration after inpatient rehabilitation (12%): progressive scores during inpatient rehabilitation with deteriorating scores after discharge (start of rehabilitation: 29±8.7W, to discharge: 60±8.4W, to 5 years after discharge: 39±13.1W); (3) a pattern with low and only slightly progressive scores (52%): low progressive scores (start of rehabilitation: 20±10.1W to 5 years after discharge: 31±15.9W); and (4) a pattern with low scores during inpatient rehabilitation and a sharp rise after discharge (3%): low inpatient scores with strong progressive scores after discharge (start of rehabilitation: 29±15.5W to 5 years after discharge: 82±10.6W). A logistic regression of factors that may distinguish between patterns with high and progressive scores and patterns with low and only slightly progressive scores revealed that older age, being a woman, having a tetraplegic lesion, and low functional status were associated with patterns with low and only slightly progressive scores. The pattern of improvement during inpatient rehabilitation and deterioration after inpatient rehabilitation showed more neuropathic pain and lower sports participation than patterns with high and progressive scores. CONCLUSIONS: For the vast majority of patients, wheelchair exercise capacity after SCI shows a positive trend and can be described in distinct patterns that are dependent on personal, lesion, and functional characteristics.

[Sport performance with a prosthesis]. / Sporten met een prothese.

Technology is a contributory factor to sporting success in many Paralympic sports. This article is about upper and lower limb prostheses that are used in sports. The characteristics of lower limb prosthesis can be modified to respond to predictable leg movements such as with running. Conventional mechanical lower limb prostheses do not respond well to unexpected movements. There are upper limb prostheses that have been adapted for a broad range of sports including fishing, cycling, kayaking, skiing, baseball and even mountain climbing. Techniques are being developed that enable a more natural movement of the prosthesis to occur, such as targeted muscle reinnervation. These techniques are currently still in the experimental stage. The training schedule of the sportsperson must be balanced against his or her tolerance level to avoid mechanical overstrain, not only around the stump but also on the unaffected side. Lower limb prostheses that lead to top sporting successes, such as with running, have resulted in discussions about distorted competition. No upper limb prostheses have led to similar discussions.

Different level, but a similar day pattern of physical activity in workers and sick-listed people with chronic nonspecific musculoskeletal pain.

OBJECTIVE: To investigate whether physical activity (PA) levels and day patterns of sick-listed workers with chronic nonspecific musculoskeletal pain (CMP) admitted for multidisciplinary rehabilitation are different from those of workers with CMP. DESIGN: Cross-sectional. SETTING: Outpatient rehabilitation center and general community. PARTICIPANTS: A convenience sample of sick-listed patients with CMP (n=27) referred for multidisciplinary pain rehabilitation, and a volunteer sample of workers with CMP (n=107; <5% sick leave in year before participation). INTERVENTION: Participants wore an accelerometer for 5 to 7 consecutive days. MAIN OUTCOME MEASURE: PA, expressed as activity counts. All analyses were corrected for confounders. RESULTS: PA levels of workers with CMP were higher than those of sick-listed patients (P=.01). After correction for confounders, work status explained 3.5% of the variance observed in activity counts (F(change)=5.27, P=.024). In the mornings, group status significantly contributed to the variance in mean activity counts (F(change)=5.32, P=.02). In afternoons (F(change)=3.29, P=.07) and evenings (F(change)=2.41, P=.12), the effect of group status on PA level was nonsignificant. No significant interaction was observed between time and group status (Wilks' λ=.92, F(14,104)=.66, P=.80). CONCLUSIONS: Workers with CMP have a higher PA level compared with sick-listed patients. The PA day pattern did not differ significantly between the 2 groups.

The effects of high custom made shoes on gait characteristics and patient satisfaction in hemiplegic gait.

OBJECTIVE: To determine the effects of a temporary high custom made orthopaedic shoe on functional mobility, walking speed, and gait characteristics in hemiplegic stroke patients. In addition, interference of attentional demands and patient satisfaction were studied. DESIGN: Clinical experimental study. SETTING: University Medical Centre. PARTICIPANTS: Nineteen stroke patients (12 males; mean age 55 years (standard deviation (SD) 10 years); mean time post onset 3.6 months (SD 1.4 months)) with a spastic paresis of the lower extremity. MAIN OUTCOME MEASURES: Functional mobility was assessed with the timed up and go test, walking speed and gait characteristics were measured with clinical gait analysis and performed with and without a verbal dual task. Patient satisfaction was determined with a questionnaire. RESULTS: Walking with the high orthopaedic shoe resulted in improved functional mobility (22%; p<.001), walking speed (37%; p<.001) and gait characteristics compared to walking with normal shoes. The dual task interfered with functional mobility during walking. The interference was equally big for normal shoes as for the orthopaedic shoe. Patients evaluated walking with the high orthopaedic shoe as an improvement (p<.001). An average of 84% reported improvements in foot lifting, swing progression, taking weight, confidence while walking, safety, walking distance and walking speed. CONCLUSION: In the early recovery phase after stroke, when regaining walking ability, a temporary high orthopaedic shoe can improve hemiplegic gait, even with dual task interference.

Recovery of life satisfaction in persons with spinal cord injury during inpatient rehabilitation.

OBJECTIVE: To determine the course of life satisfaction of persons with spinal cord injury and its determinants during inpatient rehabilitation and up to 1 yr after discharge. DESIGN: Prospective cohort study of 222 persons with spinal cord injury. Measurements at the start of active rehabilitation, after 3 mos, at discharge, and 1 yr after discharge. Questions about current life satisfaction and current life satisfaction compared with life satisfaction before spinal cord injury were asked and analyzed, and the sum score Life Satisfaction Total of these questions was analyzed using a multilevel regression analysis. Person and injury characteristics and secondary impairments at each measurement were analyzed as possible determinants of the Life Satisfaction Total score. RESULTS: Estimated Life Satisfaction Total scores improved from 5.3 (SE, 0.16) at the start of active rehabilitation up to 6.5 (0.17) at discharge and remained stable (6.5; 0.16) during the first year after discharge. Significant determinants of a positive course of life satisfaction were less pain, fewer secondary impairments, and better functional status. CONCLUSIONS: Life satisfaction already improves during inpatient rehabilitation. Functional status, pain, and secondary impairments must be treated adequately in multidisciplinary rehabilitation.

Changes and determinants of life satisfaction after spinal cord injury: a cohort study in the Netherlands.

OBJECTIVE: To determine the impact of spinal cord injury (SCI) on life satisfaction of persons with SCI 1 year after discharge of inpatient rehabilitation. DESIGN: A cohort study. Life satisfaction before SCI was retrospectively measured at the start of active rehabilitation. One year after discharge from inpatient rehabilitation, current life satisfaction was measured. SETTING: Eight rehabilitation centers in The Netherlands. PARTICIPANTS: Persons (N=147) aged 18 to 65 and wheelchair-dependent at least for long distances. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: The Life Satisfaction Questionnaire. RESULTS: Mean satisfaction with life +/- SD as a whole was 5.3+/-0 before SCI and 4.3+/-1.3 one year after inpatient rehabilitation. Sexual life, self-care, and vocational situation showed the largest impact of SCI (P<.05), whereas the social relationships domains appeared to be the least affected. Decrease of life satisfaction after SCI was larger when using the retrospective ratings than when using general population scores. Significant determinants of life satisfaction after SCI were high lesion level (beta=.31, P<.05), pain (beta=.19, P<.05), and secondary impairments (beta=.22, P<.05). CONCLUSIONS: Life satisfaction decreased in persons with SCI. Level of lesion and suffering secondary impairments or pain were associated with low life satisfaction 1 year after discharge from inpatient rehabilitation.

Underlying mechanisms of improving physical activity behavior after rehabilitation.

BACKGROUND: Regular physical activity is beneficial for the health and functioning of people with a disability. Effective components of successful physical activity promotion interventions should be identified and disseminated. PURPOSE: To study the underlying mechanisms of the combined sport stimulation program "Rehabilitation & Sports" (R&S) and daily physical activity promotion program "Active after Rehabilitation" (AaR). METHOD: Subjects in four rehabilitation centers received R&S + AaR (n = 284). Subjects in six control centers (n = 603) received usual care. Physical activity and its determinants were assessed with questionnaires at seven weeks before and nine weeks and one year after rehabilitation. RESULTS: Variables that were determinants of the intervention-induced improvement in physical activity behavior at both follow-up measurements were attitude, the perceived benefits "improved health and reduced risk of disease," "better feeling about oneself," and "improved fitness," and the barrier "limited environmental possibilities." The percentage change in the intervention coefficient caused by these determinants ranged from -35.3% to -16.3% and from -28.4% to -11.3% at nine weeks and one year after rehabilitation, respectively. CONCLUSION: Personalized tailored counseling interventions can improve physical activity behavior in people with a disability by targeting both personal and environmental determinants of physical activity behavior.

Prospective analysis of lipid profiles in persons with a spinal cord injury during and 1 year after inpatient rehabilitation.

OBJECTIVES: To investigate the course of lipid profiles during and 1 year after inpatient rehabilitation of persons with spinal cord injury, and to determine which personal, lesion, and lifestyle characteristics influence the changes in lipid profiles over time and among subjects. DESIGN: Multilevel regression analysis of measurement points during and after rehabilitation. SETTING: Eight rehabilitation centers in The Netherlands. PARTICIPANTS: People with complete and incomplete paraplegia and tetraplegia (N=180). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides (TG), and the TC/HDL ratio. RESULTS: We found a significant decrease in TG and TC/HDL during inpatient rehabilitation and a significant increase in HDL during and after inpatient rehabilitation. TC and LDL, however, showed unfavorable increases after clinical discharge. The changes in HDL and LDL over time differed between lesion groups. An increase in the body mass index (BMI) led to an unfavorable change in all lipid profiles. Older participants showed higher TC, LDL, and HDL concentrations. Women and participants who consumed some alcohol, or who were more active 1 year after discharge, had more favorable HDL levels. CONCLUSIONS: Lipid profiles improved during inpatient rehabilitation but deteriorated somewhat after clinical discharge. Controlling one's BMI seems important in diminishing the risk for unfavorable lipid profiles.

The Physical Activity Scale for Individuals with Physical Disabilities: test-retest reliability and comparison with an accelerometer.

BACKGROUND: The objective was to determine the test-retest reliability and criterion validity of the Physical Activity Scale for Individuals with Physical Disabilities (PASIPD). METHODS: Forty-five non-wheelchair dependent subjects were recruited from three Dutch rehabilitation centers. Subjects' diagnoses were: stroke, spinal cord injury, whiplash, and neurological-, orthopedic- or back disorders. The PASIPD is a 7-d recall physical activity questionnaire that was completed twice, 1 wk apart. During this week, physical activity was also measured with an Actigraph accelerometer. RESULTS: The test-retest reliability Spearman correlation of the PASIPD was 0.77. The criterion validity Spearman correlation was 0.30 when compared to the accelerometer. CONCLUSIONS: The PASIPD had test-retest reliability and criterion validity that is comparable to well established self-report physical activity questionnaires from the general population.

Successfully improving physical activity behavior after rehabilitation.

PURPOSE: To determine the effects of the physical activity promotion programs Rehabilitation & Sports (R&S) and Active after Rehabilitation (AaR) on sport and daily physical activity 1 year after in- or outpatient rehabilitation. DESIGN: Subjects in intervention rehabilitation centers were randomized into a group receiving R&S only (n = 315) and a group receiving R&S and AaR (n = 284). Subjects in six control centers (n = 603) received usual care. SETTING: Ten Dutch rehabilitation centers. SUBJECTS: Subjects consisted of 1202 rehabilitation patients. Most frequent diagnoses were stroke, neurological disorders, and back disorders. INTERVENTION: Both the sport stimulation program (R&S) and the daily physical activity promotion program (AaR) consisted of personalized tailored counseling. MEASURES: Two sport outcomes and two daily physical activity outcomes were assessed with questionnaires at baseline and 1 year after rehabilitation. ANALYSIS: Multilevel analyses comparing both intervention groups to the control group. RESULTS: The R&S program showed no significant effects. Intention-to-treat analyses in the R&S + AaR group showed borderline significant improvements in one sport (odds ratio [OR] = 1.66, p = .02) and both physical activity outcomes (OR = 1.68, p = .01 and regression coefficient = 10.78, p = .05). On-treatment analyses in the R&S + AaR group showed similar but stronger effects. CONCLUSIONS: The combination of the R&S and AaR programs improved physical activity behavior and sport participation 1 year after in- or outpatient rehabilitation. The R&S program alone did not have any effects.

Rapid and extensive arterial adaptations after spinal cord injury.

OBJECTIVE: To assess the time course of adaptations in leg vascular dimension and function within the first 6 weeks after a spinal cord injury (SCI). DESIGN: Longitudinal study design. SETTING: University medical center and rehabilitation clinic. PARTICIPANTS: Six men were studied serially at 1, 2, 3, 4, and 6 weeks after SCI. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Diameter, blood flow, and shear rate levels of the common femoral artery (CFA), superficial femoral artery (SFA), brachial artery, and carotid artery were measured with echo Doppler ultrasound (diameter, blood flow, shear rate). Endothelial function in the SFA was measured with flow-mediated dilation (FMD). In addition, leg volume and blood pressure measurements were performed. RESULTS: Femoral artery diameter (CFA, 25%; SFA, 16%; P<.01) and leg volume (22%, P<.01) decreased simultaneously, and these reductions were largely accomplished within 3 weeks postinjury. Significant increases were observed for basal shear rate levels (64% increase at week 3; 117% increase at week 6; P<.01), absolute FMD responses (8% increase at week 3, 23% increase at week 6; P<.05) and relative FMD responses (26% increase at week 3, 44% increase at week 6; P<.001). CONCLUSIONS: Our findings show a rapid onset of adaptations in arterial dimension and function to extreme inactivity in humans. Vascular adaptations include extensive reductions in femoral diameter and leg volume, as well as increased basal shear rate levels and FMD responses, which all appear to be largely accomplished within 3 weeks after an SCI.

Course of gross mechanical efficiency in handrim wheelchair propulsion during rehabilitation of people with spinal cord injury: a prospective cohort study.

OBJECTIVE: To investigate the course of mechanical efficiency of handrim wheelchair propulsion during rehabilitation of subjects with (in)complete paraplegia and tetraplegia. DESIGN: Subjects were tested at the start of active rehabilitation (t1), 3 months later (t2), and when discharged from inpatient rehabilitation (t3). They performed two 3-minute submaximal treadmill exercise blocks in a wheelchair. SETTING: Eight rehabilitation centers in the Netherlands. PARTICIPANTS: Ninety-two people with (in)complete paraplegia and tetraplegia. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Mechanical efficiency values were calculated for each block. The course of mechanical efficiency was investigated using test occasions (t1 -t3), completeness and level (paraplegia or tetraplegia) of the lesion, and power output as independent variables in a multilevel regression analysis. RESULTS: Mechanical efficiency significantly increased between t1 and t2 only. After adding level and completeness of the lesion and their interactions with time to the model, block 2 showed that subjects with paraplegia had a significantly higher mechanical efficiency than subjects with tetraplegia. Subjects with tetraplegia improved more between t1 and t2 . Differences in mechanical efficiency between subjects with paraplegia and tetraplegia could not be explained by differences in absolute and relative power output levels. CONCLUSIONS: Results showed a significant improvement in mechanical efficiency during the first 3 months of active rehabilitation. Subjects with paraplegia showed a higher mechanical efficiency than did subjects with tetraplegia, whereas the latter showed more improvement between t1 and t2 .

Physical activity for people with a disability: a conceptual model.

The promotion of a physically active lifestyle has become an important issue in health policy in first-world countries. A physically active lifestyle is accompanied by several fitness and health benefits. Individuals with a disability can particularly benefit from an active lifestyle: not only does it reduce the risk for secondary health problems, but all levels of functioning can be influenced positively. The objective of this article is to propose a conceptual model that describes the relationships between physical activity behaviour, its determinants and functioning of people with a disability. The literature was systematically searched for articles considering physical activity and disability, and models relating both topics were looked for in particular. No models were found relating physical activity behaviour, its determinants and functioning in people with a disability. Consequently, a new model, the Physical Activity for people with a Disability (PAD) model, was constructed based on existing models of disability and models of determinants of physical activity behaviour. The starting point was the new WHO Model of Functioning and Disability, part of the International Classification of Functioning, Disability and Health (ICF), which describes the multidimensional aspects of functioning and disability. Physical activity behaviour and its determinants were integrated into the ICF model. The factors determining physical activity were based mainly on those used in the Attitude, Social influence and self-Efficacy (ASE) model. The proposed model can be used as a theoretical framework for future interventions and research on physical activity promotion in the population of people with a disability. The model currently forms the theoretical basis for a large physical activity promotion trial in ten Dutch rehabilitation centres.

Mechanical loading of the low back and shoulders during pushing and pulling activities.

The objective of this study was to quantify the mechanical load on the low back and shoulders during pushing and pulling in combination with three task constraints: the use of one or two hands, three cart weights, and two handle heights. The second objective was to explore the relation between the initial and sustained exerted forces and the mechanical load on the low back and shoulders. Detailed biomechanical models of the low back and shoulder joint were used to estimate mechanical loading. Using generalized estimating equations (GEE) the effects were quantified for exerted push/pull forces, net moments at the low back and shoulders, compressive and shear forces at the low back, and compressive forces at the glenohumeral joint. The results of this study appeared to be useful to estimate ergonomics consequences of interventions in the working constraints during pushing and pulling. Cart weight as well as handle height had a considerable effect on the mechanical load and it is recommended to maintain low cart weights and to push or pull at shoulder height. Initial and sustained exerted forces were not highly correlated with the mechanical load at the low back and shoulders within the studied range of the exerted forces.

Time course of arterial vascular adaptations to inactivity and paralyses in humans.

PURPOSE: The aim of the present study was to assess the time course of vascular adaptations to inactivity and paralyses in humans. The spinal cord-injured (SCI) population offers a unique "human model of nature" to assess peripheral vascular adaptations and its time course to extreme inactivity and paralyses. METHODS: Arterial diameters and red blood cell velocity of the carotid artery (CA), common femoral artery (FA), and brachial artery (BA) were measured using echo Doppler ultrasound. Fifteen SCI persons with lesions varying from 6 wk to 13 months postinjury participated in a cross-sectional study (SCI-CS), 6 SCI individuals were included for longitudinal measurements (SCI-L) at weeks 6, 8, 12, 16, 20, and 24 after the trauma, and 16 able-bodied individuals served as a control group (C). RESULTS: Within 6 wk after the SCI, diameter (SCI-CS: 0.68 +/- 0.09 cm, SCI-L: 0.67 +/- 0.04 cm, C: 0.95 +/- 0.07 cm) and blood flow (SCI-CS: 299 +/- 112 mL x min(-1), SCI-L 279: +/- 52 mL x min(-1), C: 405 +/- 97 mL x min(-1)) of the femoral artery were significantly reduced (P < 0.001), and local femoral wall shear rate was almost doubled in SCI-CS and SC-L compared with C (P < 0.001). No further changes in femoral arterial properties were observed between week 6 and 13 months postinjury in SCI-L as well as SCI-CS. Carotid and brachial artery diameter and flow were similar in SCI and C and did not change between 6 wk and 13 months after the injury. CONCLUSION: We conclude that the process of vascular adaptations to inactivity and paralyses in humans seems to be largely completed within weeks.

Low-back and shoulder complaints among workers with pushing and pulling tasks.

OBJECTIVES: Low-back and shoulder complaints were examined in relation to self-reported and objectively assessed exposure to work-related pushing and pulling. METHODS: Workers from several companies (eg, nursing homes and flower auctions) with pushing and pulling tasks and, as reference, workers without physically demanding tasks were invited to participate. Altogether 829 workers initially received a questionnaire, of whom 459 responded both initially and after 1 year of follow-up. Initially, self-reported exposure to pushing and pulling was assessed by questionnaire. Furthermore, a representative sample of 131 workers was observed at work using TRAC (task recording and analysis on computer) to assess exposure to pushing and pulling objectively. For exposure to pushing and pulling, the workers were classified into a reference group and medium and high exposure groups. Initially and in the follow-up, the 12-month prevalence of low-back and shoulder complaints was assessed. Complaints reported in the follow-up were separately used as dependent variables to calculate prevalence rate ratios (PR) in a Cox's proportional hazard regression analysis. RESULTS: The adjusted PR values were not significant for low-back complaints. For shoulder complaints, both the medium and high exposure groups showed significant adjusted PR values for self-reported exposure and observed duration of pushing and pulling when compared with the reference group (PR range 2.18-4.86). For the observed frequency of pushing and pulling, only the medium exposure group showed a significant PR, of 3.95. CONCLUSIONS: The findings suggest a rather strong relationship between pushing and pulling and shoulder complaints. The evidence for a relationship between pushing and pulling and low-back complaints is limited.

Normative values and determinants of physical capacity in individuals with spinal cord injury.

We reanalyzed data from five studies with similar or identical methodology performed by our laboratory to define normative values and determinants of physical capacity in individuals with tetraplegia and paraplegia. Each study consisted of a graded wheelchair exercise test to determine peak oxygen uptake and maximal power output and could additionally include a wheelchair sprint test to determine short-term (anaerobic) power output and/or an isometric strength test. The combined subject population included 166 individuals (20 women), varying considerably for age, body mass, lesion level, time since injury, and activity level. Ranges in physical capacity parameters were extensive and normative values for individuals with tetraplegia and paraplegia were established. These physical capacity norms could be used for evaluation of fitness status and training or therapeutic interventions. Multiple regression procedures indicated that 48-80% of the variance in physical capacity could be explained by lesion level and completeness, activity level, gender, age, body mass, and time since injury. Although physical capacity is largely determined by factors that cannot be altered, such as lesion level, age, and gender, changeable factors such as activity level and body mass play an additional role.