Summary:
ABSTRACT
Leg length discrepancy is a skeletal asymmetry that a large portion of the population exhibits (Soukka, 1991). However, mild descrepancy, in terms of centimeters, is not de- tected by clinicians. It is usually found by chance after people develop some weakness or clinical syndrome due to their demanding daily life, work duties or sports activities, in which bending and rotational loads, prolonged standing etc are often. Leg length discrepancy is categorized as anatomical and functional (Knutson, 2005). However, both types impact the body by varying the pattern of posture and movement and therefore the distribution of loads on it (Levan- gie, 1999). Compensatory strategies are adopted in both conditions to avoid discomfort and clinical syndromes (Baylis WJ, 1988). However, these strategies are likely to cause muscle imbalances and skeletal deviations, which in turn can lead to skeletal diseases, such as osteoarthritis (Golightly et al., 2007). There is no unanimity by clinicians whether mild leg length discrepancy needs equation, and whether degree threshold for causing negative effects on the human body exists. The present study investigates the effects of leg length discrepancy on postural control and body movement in walking and running. In this study, a special rubber shoe was applied to 30 young adults without musculoskeletal problems or painful syndromes. The somatometric characteristics, the thorough musculoskeletal assessment of the participants and the obtaining of data on their health and level of physical activities were carried out with the use of similar equipment and questionnaires before starting the research process. The EMG activity recording of the erector spinae in the thoracic and lumbar spine as well as the hip abductor was performed with a biosignal recording system during walking and running on instrumented treadmill. The subjects walked at a speed of 5.6 km/h, 8.1 km/h on a flat surface (0º) without application but also with the application special rubber shoe each time with a different height. One-way repeated measures ANOVA, Two-way repeated measures ANOVA were used to statistically analyze the results. No effect was found at the muscles’ EMG activity being investigated as the size of the leg length discrepancy. However, changes were observed in steps’ length and duration, in contact and swing phase during both walking and running. Changes were also noted in stride length, stride width, stride du- ration as well as gait cadence during walking while the same parameters did not change during running. Significant effects were also noted in ground responses during walking and running.
Keywords:
leg length inequality, gait analysis, walking, running, postural balance
