Development and Evaluation of Assessment Methods to Permit Evidence-based Classification in Paralympic Athletics

Classification in Paralympic Athletics aims to minimise the impact of impairment on the outcome of competition so that athletes compete against those who experience a similar degree of difficulty in performing an activity. This will ensure that success in Paralympic competition is determined by the same factors as non-disabled athletics – talent, motivation, and training. To achieve an evidence-based system of classification requires the development of valid, reliable methods to assess impairment and activity limitation, and the quantification of how much impairment impacts athletic performance. The overall aim of this thesis is to contribute towards the development of an evidence-based system of classification for Paralympic Athletics through the development and evaluation of methods to assess muscle strength and a test battery of supplementary activity limitation tests for running. The focus of chapters two, three, four and five is strength assessment. Chapter 2 reviews the relevant scientific literature, providing a definition of strength and an overview of neurological, morphological, psychological and assessment characteristics which affect strength assessment and the mechanisms by which strength can be impaired and improved. Requirements for methods of assessing strength impairment for the purposes of classifying athletes are reviewed and it is concluded that multi-joint isometric tests are the most appropriate. Chapter 3 provides a detailed description of equipment and protocols for 10 strength tests – five upper body strength tests, two trunk strength tests and three lower body tests – that are consistent with the criteria proposed in Chapter 2. The tests feature a purpose-built isometric strength testing rig comprising a rigid frame, and a fully adjustable, wheelchair accessible seat which permits anthropometrically standardised positioning relative to an S-type load cell. Study 1 is presented in Chapter 4. The purpose of Study 1 was to evaluate the validity and reliability of the novel muscle strength tests in non-disabled participants and determine if body size was a significant predictor of strength in these tests. Sixty-three males and fifty-five females attended a one hour testing session in which anthropometric measures and strength tests were performed. Seventeen participants returned for a second session within 10 days to allow analysis of reliability. Normal performance ranges were developed to allow results of athletes with a disability to be meaningfully interpreted in future studies. Analysis demonstrated that reliability was acceptable in all tests. The results also showed that no single anthropometric measure was predictive of strength performance; however individual anthropometric measures were identified for each test of strength. Multiple regression indicated that more than 10% of the variance in three upper body, and one lower body strength test for males and two upper body strength tests for females could be explained by anthropometric measures. This will require the measurement of chest depth, shoulder breadth, sitting height and femur breadth in males, and humerus length, humerus breadth and forearm length in females, for future use of these tests in classification. Study 2 is presented in Chapter 5. The purpose of this study was evaluating the relationship between strength and wheelchair racing performance in thirteen international-level athletes with a spinal cord injury. Participants completed four upper body strength tests. Performance was evaluated on a wheelchair ergometer and on the track. Participants were designated as ‘full trunk strength’ or ‘not full trunk strength’ based on manual muscle testing scores. Analysis showed the contribution of trunk strength to performance was not significantly greater in athletes with full trunk strength as opposed to those without full trunk strength. It was also demonstrated that the relationship between trunk strength and performance was higher in the conditions of increased resistance seen on the wheelchair ergometer as compared to the track. The focus of Chapter 6 is not strength evaluation but evaluation of athletic performance. While an evaluation of the relationship between impairment and performance will allow the impact of impairment on performance to be determined, issues of training and non-compliance must be considered in classification. The aim of Study 3 was to identify a battery of tests that are predictive of running performance. Sixty-seven non-disabled participants completed a performance test and five alternative activity limitation tests (standing Broad Jump, 4 Bounds, 10m Skip, Running in Place and Split Jumps). Nine participants returned within 14 days to allow for evaluation of reliability. Reliability was high for all tests. Pearson’s correlations with 30m Sprint were moderate to strong for Standing Broad Jump, 4 Bounds and 10m Skip, but weaker for Split Jumps and Running in Place. Multiple regression indicated that Standing Broad Jump, 4 Bounds and 10m Skip explained 75% of variance in running performance. Normal performance ranges for the test battery were provided. This thesis has contributed significantly towards the development of an evidence-based system of classification in Paralympic athletics. A review of literature determined multi-joint, isometric strength tests to be suitable for classification. Following the development and description of these protocols, an evaluation of the psychometric properties of the strength test battery was performed in Study 1. The second study provided an evaluation of the relationship between trunk strength impairment and performance in wheelchair racing. This will provide a necessary method and stimulus for research that should, in future, determine the impact of strength impairment on all Paralympic activities. The supplementary activity limitation test battery developed for running in study three was valid and reliable and provides a method for the development of test batteries for other fundamental activities in Paralympic athletics.