DEEP AND SUPERFICIAL TRUNK MUSCLE ACTIVATION DURING WHEELCHAIR PROPULSION

Efficient manual wheelchair propulsion is essential for persons with spinal cord injury (SCI), in their activities of daily life as well as for their participation in physical training and sports. The aim of this study in progress is to investigate the coordination of upper body muscles during wheelchair propulsion in persons with SCI at different spinal levels. Particular attention will be paid to the ability of persons with thoracic SCI, clinically classified as “complete”, to activate and coordinate their abdominal muscles

Stakträning effektivt för ryggmärgsskadade

En ryggmärgsskada leder till ett ökat stillasittande. Risken är då stor att drabbas av till exempel hjärt- och kärlsjukdomar. Många får också överbelastningsbesvär från skuldra och arm av ett liv i rullstol. Med högintensiv intervallträning i den nyutvecklade sittstakergometer går det att minska problemen

Performance and trainability in paraplegics : motor function, shoulder muscle strength and sitting balance before and after kayak ergometer training

Background Spinal cord injury (SCI) results in a complete or partial loss of motor and/or sensory function below the injury level. An SCI causes extensive functional impairment compelling many persons to wheelchair usage. Maintaining an adequate strength and control of trunk and shoulder muscles becomes essential, as the majority of every day tasks will be performed in a sitting position. Moreover, physical exercise is crucial to avoid risks connected with a sedentary life-style. Therefore, it becomes important to find suitable, effective, and attractive physical activities to retain and even improve motor functions achieved during rehabilitation. Ideally, such a training activity should be versatile and have the potential to improve several capacities beneficial to everyday life and thereby increase the independence of persons with SCI. Kayak paddling appears to fulfil several of the criteria for such an activity. Objectives The overall aims were to see if, and to what extent, a period of training on a modified kayak ergometer could influence functional performance as well as specific qualities, such as, shoulder muscle strength and sitting balance control in a group of postrehabilitated persons with thoracic SCI. An additional aim was to understand more about the availability of the trunk muscles in a person with a clinically complete thoracic SCI and how the trunk muscles are used to maintain upright sitting in response to balance perturbations. Methods Ten adult post-rehabilitated persons with thoracic SCI performed 30 sessions of kayak ergometer training for a 10-week period, with progressively increased intensity and balance demand in the medio-lateral direction. Pre- and post-training measurements included performance in functional wheelchair tests, maximal voluntary shoulder muscle strength, and trunk stability in response to support-surface translations. Electromyographic (EMG) recordings from deep and superficial trunk muscles were obtained in a sub-sample of two subjects, one with a high thoracic SCI and one able-bodied person. Results There were significant improvements with training in functional performance, shoulder muscle strength, and the ability to maintain an upright sitting posture in response to balance perturbations in the group of persons with SCI. The EMG results revealed that the person with a high thoracic SCI, clinically classified as complete, was still able to activate trunk muscles below the injury, both in maximal voluntary efforts and in response to balance perturbations, but the response pattern differed from that of the ablebodied. Conclusions The improvements in test-performance observed with the kayak ergometer training in the persons with SCI should enhance their capacity to master similar challenges in everyday life, which, in turn, might lead to a greater independence. The pilot data on muscle activation highlight the importance of including examination of trunk muscle function in persons with thoracic SCI in relation to injury classification, prognosis, and training prescription

Positive Effects of Kayak and Kayak Ergometer Training by people with Paraplegia

Background Spinal cord injury (SCI) results in a complete or partial loss of motor and/or sensory function below the injury level. An SCI causes extensive functional impairment compelling many persons to wheelchair usage. Maintaining an adequate strength and control of trunk and shoulder muscles becomes essential, as the majority of every day tasks will be performed in a sitting position. Moreover, physical exercise is crucial to avoid risks connected with a sedentary life-style. Therefore, it becomes important to find suitable, effective, and attractive physical activities to retain and even improve motor functions achieved during rehabilitation. Ideally, such a training activity should be versatile and have the potential to improve several capacities beneficial to everyday life and thereby increase the independence of persons with SCI. Kayak paddling appears to fulfil several of the criteria for such an activity. Objectives The overall aims were to see if, and to what extent, a period of training on a modified kayak ergometer could influence functional performance as well as specific qualities, such as, shoulder muscle strength and sitting balance control in a group of post-rehabilitated persons with thoracic SCI. Methods Ten adult post-rehabilitated persons with thoracic SCI performed 30 sessions of kayak ergometer training for a 10-week period, with progressively increased intensity and balance demand in the medio-lateral direction. Pre- and post-training measurements included performance in functional wheelchair tests, maximal voluntary shoulder muscle strength, and trunk stability in response to support-surface translations. Results There were significant improvements with training in functional performance, shoulder muscle strength, and the ability to maintain an upright sitting posture in response to balance perturbations in the group of persons with SCI. Conclusions The improvements in test-performance observed with the kayak ergometer training in the persons with SCI should enhance their capacity to master similar challenges in everyday life, which, in turn, might lead to a greater independence

Isometric, dynamic, and manual muscle strength measures and their association with cycling performance in elite para-cyclists.

OBJECTIVE: Para-cycling classification aims to generate fair competition by discriminating between levels of activity limitation. This study investigated the relationship between lower limb Manual Muscle Tests (MMT) with ratio-scaled measures of isometric and dynamic strength, and of the ratio-scaled measures with cycling performance. DESIGN: Fifty-six para-cyclists (44 males, 12 females) with leg impairments performed isometric and dynamic strength tests: leg push and pull, and an all-out 20 s sprint. MMT results were obtained from the classification database (n = 21) and race speeds from time trials (n = 54). RESULTS: Regression analyses showed significant associations of MMT with isometric push (R2 = .49), dynamic push (R2 = .35), and dynamic pull (R2 = .28). Isometric strength was significantly correlated with dynamic push (ρ = .63) and pull (ρ = .54). The isometric and dynamic tests were significantly associated with sprint power and race speed (R2 = .16-.50). CONCLUSION: The modified MMT and ratio-scaled measures were significantly associated. The significant relation of isometric and dynamic strength with sprint power and race speed maps the impact of lower limb impairments on para-cycling performance. MMT and the isometric and dynamic measures show potential for use in para-cycling classification

Para-cycling race performance in different sport classes.

Purpose: The para-cycling classification system, consisting of five classes (C1-C5) for bicycling (C5 athletes having least impairments), is mostly based on expert-opinion rather than scientific evidence. The aim of this study was to determine the differences in race performance between para-cycling classes. Methods: From official results of the men's 1 km time trials for classes C1-C5 of seven Union Cycliste Internationale World Championships and Paralympics, median race speed of the five fastest athletes in each class was calculated (n = 175). Para-cycling results were expressed as a percentage of able-bodied performance using race results from the same years (n = 35). To assess differences between consecutive classes, Kruskal-Wallis tests with Mann-Whitney U post hoc tests were performed, correcting for multiple testing (p < 0.013). Results: Para-cyclists in C1 reached 75% (median ± interquartile range = 44.8 ± 4.2 km/h) and in C5 90% (53.5 ± 2.9 km/h) of able-bodied race speed (59.4 ± 0.9 km/h). Median race speed between consecutive classes was significantly different (χ2 = 142.6, p < 0.01), except for C4 (52.1 ± 2.8 km/h) and C5 (U = 447.0, p = 0.05). Conclusion: Current para-cycling classification does not clearly differentiate between classes with least impairments.IMPLICATIONS FOR REHABILITATIONThe current classification system is not evidence-based and does not clearly differentiate between relevant groups of para-cyclists.An evidence-based para-cycling classification system is essential for a fair and equitable competition.Fair competition will make it more interesting and increase participation.Para-cycling can inspire everyone with and even those without disabilities to be physically active

Cortical and vestibular stimulation reveal preserved descending motor pathways in individuals with motor-complete spinal cord injury.

OBJECTIVE: To use a combination of electrophysiological techniques to determine the extent of preserved muscle activity below the clinically-defined level of motor-complete spinal cord injury. METHODS: Transcranial magnetic stimulation and vestibular-evoked myogenic potentials were used to investigate whether there was any preserved muscle activity in trunk, hip and leg muscles of 16 individuals with motor-complete spinal cord injury (C4-T12) and 16 able-bodied matched controls. RESULTS: Most individuals (14/16) with motor-complete spinal cord injury were found to have transcranial magnetic stimulation evoked, and/or voluntary evoked muscle activity in muscles innervated below the clinically classified lesion level. In most cases voluntary muscle activation was accompanied by a present transcranial magnetic stimulation response. Furthermore, motor-evoked potentials to transcranial magnetic stimulation could be observed in muscles that could not be voluntarily activated. Vestibular-evoked myogenic potentials responses were also observed in a small number of subjects, indicating the potential preservation of other descending pathways. CONCLUSION: These results highlight the importance of using multiple electrophysiological techniques to assist in determining the potential preservation of muscle activity below the clinically-defined level of injury in individuals with a motor-complete spinal cord injury. These techniques may provide clinicians with more accurate information about the state of various motor pathways, and could offer a method to more accurately target rehabilitation

Assessment of abdominal muscle function in individuals with motor-complete spinal cord injury above T6 in response to transcranial magnetic stimulation.

Objective: To use transcranial magnetic stimulation and electromyography to assess the potential for preserved function in the abdominal muscles in individuals classified with motor-complete spinal cord injury above T6. Subjects: Five individuals with spinal cord injury (C5-T3) and 5 able-bodied individuals. Methods: Transcranial magnetic stimulation was delivered over the abdominal region of primary motor cortex during resting and sub-maximal (or attempted) contractions. Surface electromyography was used to record motor-evoked potentials as well as maximal voluntary (or attempted) contractions in the abdominal muscles and the diaphragm. Results: Responses to transcranial magnetic stimulation in the abdominal muscles occurred in all spinal cord injury subjects. Latencies of muscle response onsets were similar in both groups; however, peak-to-peak amplitudes were smaller in the spinal cord injury group. During maximal voluntary (or attempted) contractions all spinal cord injury subjects were able to elicit electromyography activity above resting levels in more than one abdominal muscle across tasks. Conclusion: Individuals with motor-complete spinal cord injury above T6 were able to activate abdominal muscles in response to transcranial magnetic stimulation and during maximal voluntary (or attempted) contractions. The activation was induced directly through corticospinal pathways, and not indirectly by stretch reflex activations of the diaphragm. Transcranial magnetic stimulation and electromyography measurements provide a useful method to assess motor preservation of abdominal muscles in persons with spinal cord injury

Interrater Reliability of the New Sport-Specific Evidence-Based Classification System for Para Va'a.

The purpose of this study was to examine the interrater reliability of a new evidence-based classification system for Para Va'a. Twelve Para Va'a athletes were classified by three classifier teams each consisting of a medical and a technical classifier. Interrater reliability was assessed by calculating intraclass correlation for the overall class allocation and total scores of trunk, leg, and on-water test batteries and by calculating Fleiss's kappa and percentage of total agreement in the individual tests of each test battery. All classifier teams agreed with the overall class allocation of all athletes, and all three test batteries exhibited excellent interrater reliability. At a test level, agreement between classifiers was almost perfect in 14 tests, substantial in four tests, moderate in four tests, and fair in one test. The results suggest that a Para Va'a athlete can expect to be allocated to the same class regardless of which classifier team conducts the classification

Kinematic and kinetic performance variables during paddling among para-kayak athletes with unilateral above or below knee amputation

In para-kayak, athletes with unilateral above knee amputation (AK) and athletes with below knee amputation (BK) compete in the same class. This has been questioned since previous research have shown that the legs are important for paddling performance. The purpose was therefore to examine differences in kinematic and kinetic performance variables between AK and BK para-kayak athletes and the amputated (A) and non-amputated (NA) sides. Eleven AK and six BK athletes on international level participated. 3D kinematic and kinetic data were collected for the body, seat, footrest and paddle during kayak ergometer paddling. There were no significant differences between the groups in main performance variables such as power output or paddle force. Differences between the groups were only seen in the hip joint in flexion range of motion, flexion and extension angular velocity and flexion moment where BK demonstrated larger values. The NA side demonstrated greater values compared to the A side in posterior force at the seat and in hip flexion moment. As there were no significant differences between the groups in the majority of the examined key performance variables, the results suggest that athletes with unilateral AK and BK amputation may be able to compete in the same class.At the time of Johanna Rosen's dissertation, the paper was submitted and under review.Funded by International Canoe Federation (ICF) and Swedish Research Council for Sport Science (CIF)</p