An investigation into the relationships between strength, flexibility and anthropometric discrepancies, on lower limbs asymmetry in athletes

Aldukhail, AM 2015, An investigation into the relationships between strength, flexibility and anthropometric discrepancies, on lower limbs asymmetry in athletes , PhD thesis, University of Salford.

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Assessment of bilateral asymmetry (BA) in lower-limbs is crucial in the field of sport rehabilitation as it stands on the physical capabilities of athletes. Clinicians, in their daily practice, aim to objectively standardise their measurements when assessing athletes’ performance or produce norms. Such norms, enable assessors to track athletes’ performance in order to optimise it or on the other hand, to correct their BA as precautionary measure from risk of injury due to improper loading on the musculoskeletal system. Therefore, four main studies were conducted in this thesis to investigate the relationship between key criteria in lower limbs. The first study has sat thresholds for BA and once exceeded the athlete is doomed to be asymmetric. Thresholds were calculated based on the average of absolute asymmetry value percentage (AAV%) in sub-elite athletes [n=139]. An auxiliary study [n=63] was conducted within study one to examine the effect of different loads on the criteria of countermovement jump (CMJ) across jump sets. In study two, threshold norms of elite-athletes were established for four sport-specific groups and, a novel descriptive statistical approach (threshold boundary) was executed to examine the differences between them. In study three [n=144], the relationships between the criteria of CMJ and key criteria in lower limbs were examined based on a novel descriptive statistical approach called agreement in diagnosis of asymmetry. Furthermore, an investigation was conducted also, to examine the effect of manipulating leg length on the force platform profile across different sets of CMJ trials. Lastly, in study four, an investigation was conducted to examine the association between two functional tasks (CMJ and running) by using the asymmetry agreement statistical methodology [n=144]. BA were found throughout all tests and was clinically diagnosed using threshold percentage (Threshold% = mean of AAV% + SD). Moderate to high levels of association were found between criteria. The results from this thesis (0.8-38.1%) indicate that arbitrary percentages of 15% for BA in lower limbs found in literature do not reflect typical thresholds in athletes . Lastly, future studies should be conducted to define how detrimental these asymmetries in term of performance and injury risk. Keywords: biomechanics, asymmetry, imbalance, athletes, lower limbs and threshold.

Item Type: Thesis (PhD)
Schools: Schools > School of Health Sciences
Funders: Non funded research
Depositing User: AM Aldukhail
Date Deposited: 20 Mar 2017 08:44
Last Modified: 27 Aug 2021 23:31

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