Physical Activity Levels, Correlates, and All-Cause Mortality Risk in People Living With Different Health Conditions.

BACKGROUND: To better understand physical activity behavior and its health benefits in people living with health conditions, we studied people with and without 20 different self-reported health conditions with regard to (1) their physical activity levels, (2) factors correlated with these physical activity levels, and (3) the association between physical activity and all-cause mortality. METHODS: We used a subsample (n = 88,659) of the Lifelines cohort study from the Netherlands. For people living with and without 20 different self-reported health conditions, we studied the aforementioned factors in relation to physical activity. Physical activity was assessed with the Short Questionnaire to Assess Health-Enhancing Physical Activity Questionnaire, and mortality data were obtained from the Dutch death register. RESULTS: People with a reported health condition were less likely to meet physical activity guidelines than people without a reported health condition (odds ratios ranging from 0.55 to 0.89). Higher body mass index and sitting time, and lower self-rated health, physical functioning, and education levels were associated with lower odds of meeting physical activity guidelines across most health conditions. Finally, we found a protective association between physical activity and all-cause mortality in both people living with and without different health conditions. CONCLUSION: People living with different health conditions are generally less physically active compared with people living without a health condition. Both people living with and without self-reported health conditions share a number of key factors associated with physical activity levels. We also observed the expected protective association between physical activity and all-cause mortality.

Feasibility of preoperative and postoperative physical rehabilitation for cardiac surgery patients - a longitudinal cohort study.

BACKGROUND: This study aimed to determine the feasibility of a preoperative and postoperative (in- and outpatient) physical rehabilitation program, the Heart-ROCQ-pilot program. METHODS: This cohort study included patients undergoing cardiac surgery (including coronary artery bypass graft surgery, valve surgery, aortic surgery, or combinations of these surgeries) and participated in the Heart-ROCQ-pilot program. Feasibility involved compliance and characteristics of bicycle and strength training sessions in the three rehabilitation phases. RESULTS: Of the eligible patients, 56% (n = 74) participated in the program (41% of exclusions were due to various health reasons). On average across the rehabilitation phases, the compliance rates of bicycle and strength training were 88% and 83%, respectively. Workload to heart rate (W/HR) ratio and total absolute volume load for bicycle and strength training, respectively, improved in each rehabilitation phase (P < 0.05). The W/HR-ratio was higher during the last postoperative session compared to the first preoperative session (0.48 to 0.63 W/beat, P < 0.001) and similar to the last preoperative session (0.65 to 0.64 W/beat, P < 0.497). During less than 1% of the bicycle sessions, patients reported discomfort scores of 5 to 6 (scale 0-10, with higher scores indicating a higher level). CONCLUSIONS: The Heart-ROCQ-pilot program was feasible for patients awaiting cardiac surgery. Patients were very compliant and were able to safely increase the training load before surgery and regained this improvement within eight weeks after surgery.

Measurement properties of device-based physical activity instruments in ambulatory adults with physical disabilities and/or chronic diseases: a scoping review.

BACKGROUND: People with physical disabilities and/or chronic diseases tend to have an inactive lifestyle. Monitoring physical activity levels is important to provide insight on how much and what types of activities people with physical disabilities and/or chronic diseases engage in. This information can be used as input for interventions to promote a physically active lifestyle. Therefore, valid and reliable physical activity measurement instruments are needed. This scoping review aims 1) to provide a critical mapping of the existing literature and 2) directions for future research on measurement properties of device-based instruments assessing physical activity behavior in ambulant adults with physical disabilities and/or chronic diseases. METHODS: Four databases (MEDLINE, CINAHL, Web of Science, Embase) were systematically searched from 2015 to April 16th 2023 for articles investigating measurement properties of device-based instruments assessing physical activity in ambulatory adults with physical disabilities and/or chronic diseases. For the majority, screening and selection of eligible studies were done in duplicate. Extracted data were publication data, study data, study population, device, studied measurement properties and study outcome. Data were synthesized per device. RESULTS: One hundred three of 21566 Studies were included. 55 Consumer-grade and 23 research-grade devices were studied on measurement properties, using 14 different physical activity outcomes, in 23 different physical disabilities and/or chronic diseases. ActiGraph (n = 28) and Fitbit (n = 39) devices were most frequently studied. Steps (n = 68) was the most common used physical activity outcome. 97 studies determined validity, 11 studies reliability and 6 studies responsiveness. CONCLUSION: This scoping review shows a large variability in research on measurement properties of device-based instruments in ambulatory adults with physical disabilities and/or chronic diseases. The variability highlights a need for standardization of and consensus on research in this field. The review provides directions for future research.

Fatigue in children and adolescents after burns: evaluating the problem using longitudinal data.

PURPOSE: Describe prevalence and severity of fatigue in children and adolescents with burns during six months after hospital discharge, identify potential explanatory variables, and examine the relationship with exercise capacity. MATERIALS AND METHODS: Fatigue was assessed using the Pediatric-Quality-of-Life-Inventory-Multidimensional-Fatigue-Scale (PedsQL-MFS) at discharge, and six weeks, three-, and six months after discharge. PedsQL-MFS scores ≥1 SD below the age-group specific non-burned reference mean were considered to signify fatigue. RESULTS: Twenty-two children and adolescents (13 boys/9 girls, age 6-18 years, with burns covering 2-34% of total body surface area) were included. The prevalence of fatigue decreased from 65% (11/17) at discharge to 28% (5/18) six months after discharge. At group level, fatigue severity decreased over time, reaching healthy reference values from six weeks after discharge and beyond. At individual level, the course of fatigue severity varied widely. Fatigue severity at six months after discharge could not be predicted by age, sex, or burn severity (p = 0.51, p = 0.58, p = 0.95, respectively). The association with exercise capacity was weak (r = 0.062-0.538). CONCLUSIONS: More than a quarter of pediatric burn patients reported fatigue six months after discharge. Further research in larger populations is required, including also the impact of burn-related fatigue on daily functioning and quality of life.Trial registration number: OND1353942Implications for rehabilitationFatigue should be recognized as a potential consequence of (pediatric) burns, even several months post burnFatigue should be assessed regularly after discharge in all children and adolescents with burns, as it seems not possible to predict its severity from age, sex, or burn severity characteristicsThe weak association between exercise capacity and self-reported fatigue suggests that burn-related fatigue is not simply a consequence of a reduced exercise capacity.

The impact of lower-limb function on upper-limb pull and push strength in elite handcycling athletes.

This study investigated the impact of performing a closed kinetic chain with the lower limbs on isometric upper-limb pull and push strength. Sixty-two elite handcyclists were assessed with the Manual Muscle Test and allocated to groups with partial to normal (LLF) or no lower-limb (no-LLF) function. Both groups performed upper-limb strength measurements under two kinetic-chain conditions. During the closed-chain condition, the lower limbs were attached to two footrests, providing horizontal and vertical support. During the open-chain condition, the footrests were removed and the limbs were supported vertically by a horizontal plate. Repeated-measures ANOVA were conducted to investigate main effects (open vs. closed chain, LLF vs. no-LLF) and their interaction. During pull, LLF performed better (p < 0.001, +11%) by pushing against the footrests. However, this increase in pulling strength during a closed-chain condition was not observed in the no-LLF. Therefore, findings suggest an advantage for the least impaired athletes by being able to perform lower-limb closed chains during pulling. Handcyclists with LLF can maximise pulling performance by adjusting the footrests. The classification system should consider the implications of these findings on the allocation of athletes with different levels of LLF and/or on the equipment regulation.

Changes in body satisfaction during and after a 5-month handcycle training period and associations with physical capacity and body composition in individuals with a physical impairment.

PURPOSE: To investigate: (1) changes in body satisfaction during five months of handcycle training and one year after the training period; (2) whether longitudinal changes are dependent on sex, waist circumference and severity of the physical impairment; (3) associations between changes in physical capacity or body composition, and body satisfaction. MATERIALS AND METHODS: Individuals (N = 143) with health conditions such as spinal cord injury filled out the Adult Body Satisfaction Questionnaire: at the start of the training (T1), directly after the training period (T2); and four months (T3) and one year after the training period (T4). At T1 and T2, physical capacity was determined with an upper-body graded exercise test, and waist circumference was measured. Handcycling classification was used as a proxy for the severity of impairment. RESULTS: Multilevel regression analyses showed that body satisfaction significantly increased during the training period and significantly decreased back to pre-training levels at follow-up. Individuals with more severe impairments showed a larger decrease at T4. Improvements in physical capacity and waist circumference were significantly associated with improvements in body satisfaction. CONCLUSIONS: Body satisfaction significantly increased during the training period, but significantly decreased during follow-up. Additional efforts might be necessary to keep individuals engaged in long-term exercise.

Body image disturbances are frequently described in individuals with a physical impairment.An increase in body image can be achieved by improvements in physical capacity and waist circumference as a consequence of training.It is important to keep individuals engaged in exercise, as body satisfaction decreases after termination of the training period.For individuals with severe physical impairments additional efforts are necessary to keep them engaged in exercise.

Development of a Portable Low-Cost System for the Metrological Verification of Wheelchair Roller Ergometers.

Wheelchair ergometers are widely used in research, clinical practice, and sports environments. The majority of wheelchair ergometers are roller systems that allow for wheelchair propulsion in the personal wheelchair on one or two (instrumented) rollers. Oftentimes these systems are only statically calibrated. However, wheelchair propulsion is dynamic by nature, requiring a dynamic validation process. The aim of the current project was to present a low-cost portable system for the dynamic metrological verification of wheelchair roller ergometers, based on an instrumented reference wheel. The tangential force on the roller is determined, along with its uncertainty, from the reference wheel properties, and compared with the force measured by the ergometer. Uncertainty of this reference wheel system was found to be lower than the one of the ergometer used, indicating that this novel approach can be used for the metrological verification of ergometers.

Force-velocity profiling of elite wheelchair rugby players by manipulating rolling resistance over multiple wheelchair sprints.

This study investigated the effect of increased rolling resistance on wheelchair sprint performance and the concomitant force-velocity characteristics. Thirteen wheelchair rugby (WCR) athletes completed five 15 s wheelchair sprints in their own rugby wheelchair on an instrumented dual-roller wheelchair ergometer. The first sprint was performed against a close to overground resistance and in each of the following sprints, the resistance increased with 80% of that resistance. A repeated-measures ANOVA examined differences between sprints. Subsequently, linear regression analyses examined the individual force-velocity relations and then, individual parabolic power output curves were modeled. Increased rolling resistance led to significantly lower velocities (-36%), higher propulsion forces (+150%) and higher power outputs (+83%). These differences were accompanied by a lower push frequency, higher push time, yet a constant recovery time and contact angle. The modeled linear regressions (R2 = 0.71 ± 0.10) between force and velocity differed a lot in slope and intercept among individual athletes. The peak of the power output parabola (i.e., the optimal velocity) occurred on average at 3.1 ± 0.6 ms-1 . These individual force-velocity profiles can be used for training recommendations or technological changes to better exploit power generation capabilities of the WCR athletes' musculoskeletal system.

Handrim Wheelchair Propulsion Technique in Individuals With Spinal Cord Injury With and Without Shoulder Pain: A Cross-sectional Comparison.

OBJECTIVE: The aim of this study was to compare handrim wheelchair propulsion technique between individuals with spinal cord injury with and without shoulder pain. DESIGN: A cross-sectional study including 38 experienced handrim wheelchair users with spinal cord injury was conducted. Participants were divided into the "shoulder pain" ( n = 15) and "no-shoulder pain" ( n = 23) groups using the Local Musculoskeletal Discomfort scale. Kinetic and spatiotemporal aspects of handrim wheelchair propulsion during submaximal exercise on a motor-driven treadmill were analyzed. Data were collected using a measurement wheel instrumented with three-dimensional force sensors. RESULTS: After correction for confounders (time since injury and body height), linear regression analyses showed that the pain group had a 0.30-sec (95% confidence interval, -0.5 to -0.1) shorter cycle time, 0.22-sec (95% confidence interval, -0.4 to -0.1) shorter recovery time, 15.6 degrees (95% confidence interval, -27.4 to -3.8) smaller contact angle, and 8% (95% confidence interval, -15 to 0) lower variability in work per push compared with the no-pain group. Other parameters did not differ between groups. CONCLUSIONS: This study indicates that individuals with spinal cord injury who experience shoulder pain propel their handrim wheelchair kinematically differently from individuals with spinal cord injury without shoulder pain. This difference in propulsion technique might be a pain-avoiding mechanism aimed at decreasing shoulder range of motion.

Psychosocial factors of physical activity among people with disabilities: Prospective cohort study.

PURPOSE/OBJECTIVE: This study aimed to (a) explore the associations between psychosocial factors and physical activity behavior in people with physical disabilities and/or chronic diseases, both between and within persons over time; and (b) examine whether these associations differ for people initiating and people maintaining physical activity behavior. RESEARCH METHOD/DESIGN: Data of 1,256 adults with physical disabilities and/or chronic diseases enrolled in the prospective cohort study Rehabilitation, Sports, and Active lifestyle (ReSpAct) were analyzed. Self-reported physical activity and four main psychosocial factors (i.e., self-efficacy, attitude, motivation, social support) were measured with questionnaires 3-6 weeks before discharge (T0) and 14 (T1), 33 (T2), and 52 (T3) weeks after discharge from rehabilitation. Hybrid multilevel regression models (corrected for age, sex, education level, diagnosis, counseling support) were used. RESULTS: Multivariable significant between-subject associations were found for self-efficacy (std ß = .094; 95% CI [0.035, 0.153]) and intrinsic motivation (std ß = .114; [0.036, 0.192]). Multivariable significant within-subject associations were found for identified regulation (std ß = -.038; [-0.072, -0.005]) and intrinsic motivation (std ß = .049; [0.016, 0.082]). Effect modification of initiating or maintaining physical activity was found for the between-subject association of attitude (p = .035). No significant associations were found for social support, amotivation, external regulation, and introjected regulation. CONCLUSION/IMPLICATIONS: This study is the first that explored the between- and within-subject associations between psychosocial factors and physical activity over time in a large cohort of adults with physical disabilities and/or chronic diseases. The findings indicate the importance of intrinsic motivation, identified regulation, and self-efficacy in initiating and maintaining physical activity behavior. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Muscle strength trajectories and their association with postoperative health-related quality of life in patients undergoing coronary artery bypass grafting surgery: a prospective cohort study.

BACKGROUND: Patients with sarcopenia have a higher risk of poor recovery after coronary artery bypass grafting (CABG). Little is known about the impact of changes in muscle strength (the primary indicator for sarcopenia) on health-related quality of life (HR-QoL). This study aimed to (1) identify subgroups with different muscle strength trajectories, (2) identify differences in preoperative risk factors among trajectory group membership, and (3) explore their prognostic value on postoperative HR-QoL in patients undergoing CABG. METHODS: In this prospective observational study 131 patients undergoing elective CABG completed grip strength tests and HR-QoL questionnaires. Latent Class Growth Mixture Modelling (LCGMM) was used to identify clinically relevant trajectories (> 5% of study population) for weight-normalised grip strength, measured at admission, 3 days, and 6 months after surgery. Differences between trajectory group membership at baseline were evaluated. The impact of trajectory group membership on postoperative HR-QoL was evaluated with multiple linear regression models. RESULTS: Due to low numbers (n = 15), female patients were excluded from LCGMM and subsequent statistical analyses. In males (n = 116), we identified two main weight-normalised grip strength trajectories: a "stable average" trajectory with a slight decline immediately post-surgery and recovery to preoperative levels (n = 85) and a "high" trajectory with a considerable immediate decline after surgery but followed towards a higher level of recovery compared to preoperative level (n = 27). The "stable average" patients were older (68 vs. 57 years; P = 0.003), had more diabetes (27% vs. 4%; P = 0.01) and had a higher BMI (27.8 vs. 24.8; P = 0.005) compared to the "high" group. After correction for age, diabetes, and baseline HR-QoL, group trajectory membership was not associated with postoperative HR-QoL, yet an increase in individual change scores of weight-normalised grip strength was associated with a better postoperative HR-QoL. We also identified one small trajectory group (n = 4, ≤ 5%). CONCLUSIONS: This study showed two relevant weight-normalised grip strength trajectories in male patients undergoing CABG, varying in important preoperative risk factors. While change scores of grip strength per weight did predict postoperative HR-QoL, the trajectory subgroups could not predict postoperative HR-QoL. Future research should focus on female patients, reacting potentially different on CABG and/or rehabilitation treatment. Trial registration NCT03774342, 12-12-2018.

External and Internal Work Load During a Mountain Time Trial in Trained Handcyclists Versus a World-Class Handcyclist and Determinants of Performance.

OBJECTIVES: The aims of the study were to evaluate the external and internal work load of trained handcyclists during a mountain time trial, to compare the results with a world-class handcyclist, and to identify time trial performance determinants. DESIGN: Ten trained and one world-class handcyclists performed a graded exercise test to determine power output and heart rate at the (first and second) ventilatory thresholds and exhaustion. Power output and heart rate were continuously measured during the race. RESULTS: The mean absolute power output during the race (119 ± 21 vs. 203 W, P < 0.001) was lower in the trained handcyclists compared with the world-class handcyclist. The absolute and relative heart rate during the race (86 ± 7% vs. 88%, P = 0.40) and relative power output during the race (66 ± 10% vs. 62%, P = 0.24) were similar. Trained handcyclists cycled significantly less time at a power output between first and second ventilatory thresholds (48% vs. 64%, P = 0.02) and more at a power output greater than second ventilatory threshold (34% vs. 11%, P = 0.005). Power output at the second ventilatory threshold showed the strongest correlation with finish time ( r = -0.78) and peak power output with mean power output of the race ( r = 0.90). CONCLUSIONS: The laboratory outcome peak power output and power output at the second ventilatory threshold are important performance determinants for longer time trials in handcyclists, and it is, therefore, important to improve these outcomes with training. Because the trained handcyclists cycled most of the race in intensity zones 2 and 3, it is recommended to incorporate these zones also in the training.

Associations between meeting exercise guidelines, physical fitness, and health in people with spinal cord injury.

PURPOSE: (1) To estimate the proportion of Dutch wheelchair users with spinal cord injury (SCI) who meet different SCI exercise guidelines; (2) to evaluate which demographic and lesion characteristics are associated with meeting these guidelines; (3) whether meeting these guidelines is associated with physical fitness and health. MATERIALS AND METHODS: Based on the PASIPD questionnaire items, participants were allocated to meeting two SCI aerobic exercise guidelines, which differ in exercise load. Differences in personal, lesion, fitness, and health characteristics between groups were tested with a one-way ANOVA. Multiple regression analyses were performed to evaluate if meeting guidelines was associated with better fitness and health. Statistical significance was accepted at p < 0.05. RESULTS: Of the 358 included participants, 63.1% met at least one aerobic exercise guideline. Being female, older age, having tetraplegia, and lower educational level were associated with a lower likelihood to meet the aerobic exercise guidelines. Meeting aerobic exercise guidelines showed a positive association with all respiratory and exercise capacity parameters. Limited associations were found between meeting exercise guidelines and health. CONCLUSIONS: Meeting exercise guidelines was associated with better respiratory functions and exercise capacity with additional fitness and some body composition benefits in higher exercise activity levels.IMPLICATIONS FOR REHABILITATIONMeeting SCI exercise guidelines are associated with better respiratory functions and exercise capacity with additional fitness and body composition benefits when higher exercising at higher activity levels, emphasizing the value and importance of regular exercise in individuals with SCI.

Toward a Standardized and Individualized Laboratory-Based Protocol for Wheelchair-Specific Exercise Capacity Testing in Wheelchair Athletes: A Scoping Review.

ABSTRACT: Previous studies on handrim wheelchair-specific (an)aerobic exercise capacity in wheelchair athletes have used a diversity of participants, equipment, and protocols. Therefore, test results are difficult to compare among studies. The first aim of this scoping review is to provide an overview of the populations studied, the equipment and protocols used, and the reported outcomes from all laboratory-based studies on wheelchair-specific exercise capacity in wheelchair athletes. The second aim is to synthesize these findings into a standardized, yet individualized protocol. A scoping literature search resulted in 10 anaerobic and 38 aerobic protocols. A large variety in equipment, protocol design, and reported outcomes was found. Studies that systematically investigated the influence of protocol features are lacking, which makes it difficult to interpret and compare test outcomes among the heterogeneous group of wheelchair athletes. Protocol design was often dependent on a priori participant knowledge. However, specific guidelines for individualization were missing. However, the common protocol features of the different studies were united into guidelines that could be followed when performing standardized and individualized wheelchair-specific exercise capacity tests in wheelchair athletes. Together with guidelines regarding reporting of participant characteristics, used equipment, and outcome measures, we hope to work toward more international agreement in future testing.

A Scoping Review on Shoulder Injuries of Wheelchair Tennis Players: Potential Risk-Factors and Musculoskeletal Adaptations.

Wheelchair tennis players are prone to develop shoulder injuries, due to the combination of wheelchair propulsion, overhead activities and daily wheelchair activities. A methodical literature search was conducted to identify articles on shoulder complaints in wheelchair tennis, wheelchair sports and tennis. The aims were to identify (1) type of shoulder complaints; (2) possible risk factors for the development of shoulder injuries; (3) musculoskeletal adaptations in the shoulder joint in wheelchair tennis players. Fifteen papers were included in this review, five on wheelchair tennis, three on wheelchair sports and seven on tennis. Type of shoulder complaints were acromioclavicular pathology, osteoarthritic changes, joint effusion and rotator cuff tears. Possible risk factors for the development of shoulder injuries in wheelchair tennis are overhead movements, repetitive activation of the anterior muscle chain and internal rotators, as well as a higher spinal cord injury level. Muscular imbalance with higher values for the internal rotators, increase in external range of motion, decrease in internal range of motion and reduced total arc of motion were the most common proposed musculoskeletal adaptations due to an unbalanced load. These presented risk factors and musculoskeletal adaptations might help researchers, coaches and wheelchair tennis players to prevent shoulder injuries.

Evaluation of a standardized test protocol to measure wheelchair-specific anaerobic and aerobic exercise capacity in healthy novices on an instrumented roller ergometer.

This study aims to evaluate whether a test protocol with standardized and individualized resistance settings leads to valid wheelchair Wingate tests (WAnT) and graded exercise tests (GXT) in healthy novices. Twenty able-bodied individuals (10M/10F, age 23 ± 2 years, body mass 72 ± 11 kg) performed an isometric strength test, sprint test, WAnT and GXT on a wheelchair ergometer. Using a previously developed set of regression equations, individuals' isometric strength outcome was used to estimate the WAnT result (P30est), from which an effective individual WAnT resistance was derived. The subsequently measured WAnT outcome (P30meas) was used to estimate the GXT outcome (POpeakest) and to scale the individual GXT resistance steps. Estimated and measured outcomes were compared. The WAnT protocol was considered valid when maximal velocity did not exceed 3 m·s-1; the GXT protocol was considered valid when test duration was 8-12 min. P30est did not significantly differ from P30meas, while one participant did not have a valid WanT, as maximal velocity exceeded 3 m·s-1. POpeakest was 10% higher than POpeakmeas, and six participants did not reach a valid GXT: five participants had a test duration under 8 min and one participant over 12 min. The isometric strength test can be used to individually scale the WAnT protocol. The WAnT outcome scaled the protocol for the GXT less accurately, resulting in mostly shorter-than-desired test durations. In conclusion, the evaluated standardized and individualized test protocol was valid for the WAnT but less valid for the GXT among a group of novices. Before implementing the standardized individual test protocol on a broader scale, e.g. among paralympic athletes, it should be evaluated among different athletic wheelchair-dependent populations.

Split-belt walking: An experience that is hard to forget.

BACKGROUND: The common paradigm to study the adaptability of human gait is split-belt walking. Short-term savings (minutes to days) of split-belt adaptation have been widely studied to gain knowledge in locomotor learning but reports on long-term savings are limited. Here, we studied whether after a prolonged inter-exposure interval (three weeks), the newly acquired locomotor pattern is subject to forgetting or that the pattern is saved in long-term locomotor memory. RESEARCH QUESTION: Can savings of adaptation to split-belt walking remain after a prolonged inter-exposure interval of three weeks? METHODS: Fourteen healthy adults participated in a single ten-minute adaptation session to split-belt walking and five-minute washout to tied-belt walking. They received no training after the first exposure and returned to the laboratory exactly three weeks later for the second exposure. To identify the adaptation trends and quantify saving parameters we used Singular Spectrum Analysis, a non-parametric, data-driven approach. We identified trends in step length asymmetry and double support asymmetry, and calculated the adaptation volume (reduction in asymmetry over the course of adaptation), and the plateau time (time required for the trend to level off). RESULTS: At the second exposure after three weeks, we found substantial savings in adaptation for step length asymmetry volume (61.6-67.6% decrease) and plateau time (76.3 % decrease). No differences were found during washout or in double support asymmetry. SIGNIFICANCE: This study shows that able-bodied individuals retain savings of split-belt adaptation over a three-week period, which indicates that only naïve split-belt walkers should be included in split-belt adaptation studies, as previous experience to split-belt walking will not be washed out, even after a prolonged period. In future research, these results can be compared with long-term savings in patient groups, to gain insight into factors underlying (un)successful gait training in rehabilitation.

Association between upper-limb isometric strength and handcycling performance in elite athletes.

This study investigated the association among isometric upper-limb strength of handcyclists and sport-specific performance outcomes. At two international events, 62 athletes were tested on upper-limb strength, measured with an isometric-strength setup and with Manual Muscle Test (MMT). Horizontal force (Fz), effectiveness, rate of development, variability, and asymmetries were calculated for upper-limb pull and push. Performance measures were mean (POmean) and peak (POpeak) 20-s sprint power output and average time-trial velocity (TTvelocity). Regression models were conducted to investigate which pull and push strength variables associated strongest with performance measures. Additional regression analyses were conducted with an MMT sum score as predictor. Push and pull Fz showed the strongest associations with all outcomes. Combined push and pull Fz explained (p < .001) 80-81% of variance of POmean and POpeak. For TTvelocity, only push Fz was included in the model explaining 29% of the variance (p < .001). MMT models revealed weaker associations with sprint PO (R2 = .38-.40, p < .001) and TTvelocity (R2 = .18, p = 0.001). The findings confirmed the relevance of upper-limb strength on handcycling performance and the significance of ratio-scaled strength measures. Isometric strength outcomes are adequate sport-specific indicators of impairment in handcycling classification, but future research should corroborate this notion and its potential to discriminate between sports classes.

Physical activity behaviour up to 1 year post-rehabilitation among adults with physical disabilities and/or chronic diseases: results of the prospective cohort study ReSpAct.

BACKGROUND: Little is known of physical activity behaviour among adults with a disability and/or chronic disease during and up to 1 year post-rehabilitation. We aimed to explore (1) dose characteristics of physical activity behaviour among adults with physical disabilities and/or chronic diseases during that period, and (2) the effects of personal characteristics and diagnosis on the development of physical activity over time. METHODS: Adults with physical disabilities and/or chronic diseases (N=1256), enrolled in the Rehabilitation, Sports and Active lifestyle study, were followed with questionnaires: 3-6 weeks before (T0) and 14 (T1), 33 (T2) and 52 (T3) weeks after discharge from rehabilitation. Physical activity was assessed with the adapted version of the Short Questionnaire to ASsess Health enhancing physical activity. Dose characteristics of physical activity were descriptively analysed. Multilevel regression models were performed to assess physical activity over time and the effect of personal and diagnosis characteristics on physical activity over time. RESULTS: Median total physical activity ranged from 1545 (IQR: 853-2453) at T0 to 1710 (IQR: 960-2730) at T3 min/week. Household (495-600 min/week) and light-intensity (900-998 min/week) activities accrued the most minutes. Analyses showed a significant increase in total physical activity moderate-intensity to vigorous-intensity physical activity and work/commuting physical activity for all time points (T1-T3) compared with baseline (T0). Diagnosis, age, sex and body mass index had a significant effect on baseline total physical activity. CONCLUSION: Physical activity is highly diverse among adults with physical disabilities and/or chronic diseases. Understanding this diversity in physical activity can help improve physical activity promotion activities.

Interobserver and intraobserver reliabilities of determining the ventilatory thresholds in subjects with a lower limb amputation and able-bodied subjects during a peak exercise test on the combined arm-leg (Cruiser) ergometer.

The first (VT1) and second ventilator (VT2) (anaerobic) thresholds are used to individually prescribe exercise training programs. The purpose of this research was to analyze inter- and intraobserver reliabilities of determining VT1 and VT2 in subjects with lower limb amputation (LLA) and able-bodied (AB) subjects during a peak exercise test on the arm-leg (Cruiser) ergometer. Previously published data of exercise tests on the Cruiser ergometer of subjects with LLA ( n = 17) and AB subjects ( n = 30) were analyzed twice by two observers. The VT1 and VT2 were determined based on ventilation plots. Differences in determining the VT1 and VT2 between the observers for the first and second analyses were analyzed. To quantify variation in measurement a variance component analysis was performed. Bland-Altmann plots were made, and limits of agreement were calculated. The number of observations in which thresholds could not be determined differed significantly between observers and analysis. Variation in VT1 between and within observers was small (0-1.6%) compared with the total variation, for both the subjects with an LLA and AB subjects. The reliability coefficient for VT1 was more than 0.75, and the limits of agreement were good. In conclusion, based on the results of this study on a population level, VT1 can be used to prescribe exercise training programs after an LLA. In the current study, the determination of VT2 was less reliable than VT1. More research is needed into the clinical application of VT1 and VT2 during a peak exercise test on the Cruiser ergometer.