Propulsion biomechanics do not differ between athletic and nonathletic manual wheelchair users in their daily wheelchairs

The purpose of this study was to investigate whether athletic and nonathletic manual wheelchair users (MWU) display differences in kinetic and kinematic variables during daily wheelchair propulsion. Thirty-nine manual wheelchair users (athletic n = 25; nonathletic n = 14) propelled their own daily living wheelchair on a roller ergometer at two submaximal speeds for three minutes (1.11 m s−1 and 1.67 m s−1). A 10 camera Vicon motion capture system (Vicon, Motion Systems Ltd. Oxford, United Kingdom) collected three-dimensional kinematics of the upper limbs and thorax at 200 Hz during the final minute of each propulsion trial. Kinetics, kinematics and kinematic variability were compared between athletic and nonathletic groups. Kinematic differences were investigated using statistical parametric mapping. Athletic MWU performed significantly greater physical activity per week compared to nonathletic MWU (920 ± 601 mins vs 380 ± 147 mins, respectively). However, no significant biomechanical differences between athletic and nonathletic MWU were observed during either propulsion speed. During the 1.11 m s−1 trial wheelchair users displayed a stroke frequency of 53 ± 12 pushes/min and a contact angle of 92.5 ± 16.2°. During the 1.67 m s−1 trial the mean stroke frequency was 64 ± 22 pushes/min and contact angle was 85.4 ± 13.6°. Despite the hand being unconstrained during the recovery phase the magnitude of joint kinematic variability was similar across both glenohumeral and scapulothoracic joints during recovery and push phases. To conclude, although athletic MWU participate in more physical activity per week they adopt similar strategies to propel their daily living wheelchair. Investigations of shoulder pain and dailywheelchair propulsion do not need to distinguish between athletic and nonathletic MWU

Alterations in shoulder kinematics are associated with shoulder pain during wheelchair propulsion sprints

The study purpose was to examine the biomechanical characteristics of sports wheelchair propulsion and determine biomechanical associations with shoulder pain in wheelchair athletes. Twenty wheelchair court-sport athletes (age: 32 +/- 11 years old) performed one submaximal propulsion trial in their sports-specific wheelchair at 1.67 m/s for 3 min and two 10 s sprints on a dual-roller ergometer. The Performance Corrected Wheelchair User's Shoulder Pain Index (PC-WUSPI) assessed shoulder pain. During the acceleration phase of wheelchair sprinting, participants propelled with significantly longer push times, larger forces, and thorax flexion range of motion (ROM) than both the maximal velocity phase of sprinting and submaximal propulsion. Participants displayed significantly greater peak glenohumeral abduction and scapular internal rotation during the acceleration phase (20 +/- 9 degrees and 45 +/- 7 degrees) and maximal velocity phase (14 +/- 4 degrees and 44 +/- 7 degrees) of sprinting, compared to submaximal propulsion (12 +/- 6 degrees and 39 +/- 8 degrees). Greater shoulder pain severity was associated with larger glenohumeral abduction ROM (r = 0.59, p = 0.007) and scapular internal rotation ROM (r = 0.53, p = 0.017) during the acceleration phase of wheelchair sprinting, but with lower peak glenohumeral flexion (r = -0.49, p = 0.030), peak abduction (r = -0.48, p = 0.034), and abduction ROM (r = -0.44, p = 0.049) during the maximal velocity phase. Biomechanical characteristics of wheelchair sprinting suggest this activity imposes greater mechanical stress than submaximal propulsion. Kinematic associations with shoulder pain during acceleration are in shoulder orientations linked to a reduced subacromial space, potentially increasing tissue stress

The longitudinal relationship between shoulder pain and altered wheelchair propulsion biomechanics of manual wheelchair users

The purpose of this study was to investigate the longitudinal association between within-subject changes in shoulder pain and alterations in wheelchair propulsion biomechanics in manual wheelchair users. Eighteen (age 33 ± 11 years) manual wheelchair users propelled their own daily living wheelchair at 1.11 m.s-1 for three minutes on a dual-roller ergometer during two laboratory visits (T1 and T2) between 4 and 6 months apart. Shoulder pain was assessed using the Performance Corrected Wheelchair User's Shoulder Pain Index (PC-WUSPI). Between visits mean PC-WUSPI scores increased by 5.4 points and varied from - 13.5 to + 20.9 points. Of the eighteen participants, nine (50%) experienced increased shoulder pain, seven (39%) no change in pain, and two (11%) decreased pain. Increasing shoulder pain severity correlated with increased contact angle (r = 0.59, P = 0.010), thorax range of motion (r = 0.60, P = 0.009) and kinetic and kinematic variability. Additionally, increasing shoulder pain was associated with reductions in peak torque (r = -0.56, P = 0.016), peak glenohumeral abduction (r = -0.69, P = 0.002), peak scapular downward rotation (r = -0.68, P = 0.002), and range of motion in glenohumeral flexion/extension and scapular angles. Group comparisons revealed that these biomechanical alterations were exhibited by individuals who experienced increased shoulder pain, whereas, propulsion biomechanics of those with no change/decreased pain remained unaltered. These findings indicate that wheelchair users exhibit a protective short-term wheelchair propulsion biomechanical response to increases in shoulder pain which may temporarily help maintain functional independence

Scapular kinematic variability during wheelchair propulsion is associated with shoulder pain in wheelchair users

The purpose of this study was to investigate whether wheelchair propulsion biomechanics differ between individuals with different magnitudes of shoulder pain. Forty (age 36 11 years) manual wheelchair users propelled their own daily living wheelchair at 1.11 m.s(-1) for three minutes on a dual-roller ergometer. Shoulder pain was evaluated using the Performance Corrected Wheelchair User's Shoulder Pain Index (PC-WUSPI). Correlation analyses between spatio-temporal, kinetic and upper limb kinematic variables during wheelchair propulsion and PC-WUSPI scores were assessed. Furthermore, kinematic differences between wheelchair users with no or mild shoulder pain (n = 33) and moderate pain (n = 7) were investigated using statistical parametric mapping. Participant mean PC-WUSPI scores were 20.3 +/- 26.3 points and varied from zero up to 104 points. No significant correlations were observed between kinetic or spatio-temporal parameters of wheelchair propulsion and shoulder pain. However, lower inter-cycle variability of scapular internal/external rotation was associated with greater levels of shoulder pain (r = 0.35, P = 0.03). Wheelchair users with moderate pain displayed significantly lower scapular kinematic variability compared to those with mild or no pain between 17 and 51% of the push phase for internal rotation, between 31-42% and 77-100% of the push phase for downward rotation and between 28-36% and 53-65% of the push phase for posterior tilt. Lower scapular variability displayed by wheelchair users with moderate shoulder pain may reflect a more uniform distribution of repeated subacromial tissue stress imposed by propulsion. This suggests that lower scapular kinematic variability during propulsion may contribute towards the development of chronic shoulder pain. (C) 2020 Elsevier Ltd. All rights reserved

Editorial: Adapted sports:Wheeled-mobility, exercise and health

Editorial on the Research Topic Adapted sports: wheeled-mobility, exercise and health by Vegter RJK, Veeger DHEJ, Goosey-Tolfrey VL and Leicht CA. (2002) Front. Rehabilit. Sci. 3: 1015179. doi: 10.3389/fresc.2022.1015179.</p

A novel push-pull central-lever mechanism reduces peak forces and energy-cost compared to hand-rim wheelchair propulsion during a controlled lab-based experiment

BACKGROUND: Hand-rim wheelchair propulsion is straining and mechanically inefficient, often leading to upper limb complaints. Previous push–pull lever propulsion mechanisms have shown to perform better or equal in efficiency and physiological strain. Propulsion biomechanics have not been evaluated thus far. A novel push–pull central-lever propulsion mechanism is compared to conventional hand-rim wheelchair propulsion, using both physiological and biomechanical outcomes under low-intensity steady-state conditions on a motor driven treadmill. METHODS: In this 5 day (distributed over a maximum of 21 days) between-group experiment, 30 able-bodied novices performed 60 min (5 × 3 × 4 min) of practice in either the push–pull central lever wheelchair (n = 15) or the hand-rim wheelchair (n = 15). At the first and final sessions cardiopulmonary strain, propulsion kinematics and force production were determined in both instrumented propulsion mechanisms. Repeated measures ANOVA evaluated between (propulsion mechanism type), within (over practice) and interaction effects. RESULTS: Over practice, both groups significantly improved on all outcome measures. After practice the peak forces during the push and pull phase of lever propulsion were considerably lower compared to those in the handrim push phase (42 ± 10 & 46 ± 10 vs 63 ± 21N). Concomitantly, energy expenditure was found to be lower as well (263 ± 45 vs 298 ± 59W), on the other hand gross mechanical efficiency (6.4 ± 1.5 vs 5.9 ± 1.3%), heart-rate (97 ± 10 vs 98 ± 10 bpm) and perceived exertion (9 ± 2 vs 10 ± 1) were not significantly different between modes. CONCLUSION: The current study shows the potential benefits of the newly designed push–pull central-lever propulsion mechanism over regular hand rim wheelchair propulsion. The much lower forces and energy expenditure might help to reduce the strain on the upper extremities and thus prevent the development of overuse injury. This proof of concept in a controlled laboratory experiment warrants continued experimental research in wheelchair-users during daily life

Biomechanical and physiological differences between synchronous and asynchronous low intensity handcycling during practice-based learning in able-bodied men

BACKGROUND: Originally, the cranks of a handcycle were mounted with a 180° phase shift (asynchronous). However, as handcycling became more popular, the crank mode switched to a parallel mounting (synchronous) over the years. Differences between both modes have been investigated, however, not into great detail for propulsion technique or practice effects. Our aim is to compare both crank modes from a biomechanical and physiological perspective, hence considering force and power production as a cause of physiological outcome measures. This is done within a practice protocol, as it is expected that motor learning takes place in the early stages of handcycling in novices. METHODS: Twelve able-bodied male novices volunteered to take part. The experiment consisted of a pre-test, three practice sessions and a post-test, which was subsequently repeated for both crank modes in a counterbalanced manner. In each session the participants handcycled for 3 × 4 minutes on a leveled motorized treadmill at 1.94 m/s. Inbetween sessions were 2 days of rest. 3D forces, handlebar and crank angle were measured on the left hand side. Kinematic markers were placed on the handcycle to monitor the movement on the treadmill. Lastly, breath-by-breath spirometry combined with heart-rate were continuously measured. The effects of crank mode and practice-based learning were analyzed using a two way repeated measures ANOVA, with synchronous vs asynchronous and pre-test vs post-test as within-subject factors. RESULTS: In the pre-test, asynchronous handcycling was less efficient than synchronous handcycling in terms of physiological strain, force production and timing. At the post-test, the metabolic costs were comparable for both modes. The force production was, also after practice, more efficient in the synchronous mode. External power production, crank rotation velocity and the distance travelled back and forwards on the treadmill suggest that asynchronous handcycling is more constant throughout the cycle. CONCLUSIONS: As the metabolic costs were reduced in the asynchronous mode, we would advise to include a practice period, when comparing both modes in scientific experiments. For handcycle users, we would currently advise a synchronous set-up for daily use, as the force production is more effective in the synchronous mode, even after practice

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

Determining and Controlling External Power Output During Regular Handrim Wheelchair Propulsion

The use of a manual wheelchair is critical to 1% of the world's population. Human powered wheeled mobility research has considerably matured, which has led to improved research techniques becoming available over the last decades. To increase the understanding of wheeled mobility performance, monitoring, training, skill acquisition, and optimization of the wheelchair-user interface in rehabilitation, daily life, and sports, further standardization of measurement set-ups and analyses is required. A crucial stepping-stone is the accurate measurement and standardization of external power output (measured in Watts), which is pivotal for the interpretation and comparison of experiments aiming to improve rehabilitation practice, activities of daily living, and adaptive sports. The different methodologies and advantages of accurate power output determination during overground, treadmill, and ergometer-based testing are presented and discussed in detail. Overground propulsion provides the most externally valid mode for testing, but standardization can be troublesome. Treadmill propulsion is mechanically similar to overground propulsion, but turning and accelerating is not possible. An ergometer is the most constrained and standardization is relatively easy. The goal is to stimulate good practice and standardization to facilitate the further development of theory and its application among research facilities and applied clinical and sports sciences around the world