Browsing by Author "Arnold, Sarah"

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    Muscle activation patterns during functional movements in transtibial amputees
    (Stellenbosch : Stellenbosch University, 2018-11) Arnold, Sarah; Ferreira, Suzanne; Derman, Wayne; Runciman, Phoebe; Stellenbosch University. Faculty of Education. Dept. of Sport Science.
    ENGLISH ABSTRACT: Functional movement capabilities of individuals with unilateral transtibial amputations are altered due to muscle loss and prosthesis limitations compared to healthy, typical individuals. The extent of the adaptions made during functional activities is however, unknown. The purpose of the study was to gain a better understanding of unilateral transtibial amputees (UTTA) muscle activation levels during functional activities. A systematic review (article one) relating to the gait and balance of UTTA was completed. It revealed the need for research relating to muscle activation and movement strategies during functional activities. Stage two of the Van Mechelen model was addressed through biomechanical analysis during single leg balance (SLB) and sit-to-stand-to-sit (SiStSi) tasks through muscle activation and biomechanical analysis. The study included 12 UTTA (34±10 years) and 13 able-bodied controls (CON) (34±11 years). The average time since amputation was 10±7 years. Each UTTA made use of their personal prosthesis for the observational testing. The participants were required to perform a unilateral SLB task followed by 10 continuous SiStSi movements. Muscle activation was measured for seven muscle groups using surface electromyography (EMG) together with a three dimensional biomechanical analysis. The results of article two relates to the single leg balance activity. Significantly greater muscle activation levels were found for the lumbar erector spinae (LES), gluteus medius (Gmed), gluteus maximus (Gmax), biceps femoris (BF) and vastus lateralis (VL) (p<0.05) for the affected side (AF) in comparison with the unaffected side (UN) and CON. Greater hip flexion moment and concentric hip power were observed for AF (p<0.05) while hip and knee flexion was greater than UN and CON (p<0.05). No significant differences were found for the knee and ankle joint moments during SLB (p>0.05). The SiStSi results are discussed in article three. Lower muscle activation levels were found for VL of AF compared to UN and CON, with greater activation levels of the tibialis anterior (TA) for UN than CON (p<0.05). The peak hip moment for AF during the SiSt was greater than UN and CON (p<0.05). Significantly greater hip power and hip flexion were identified for UTTA compared to CON (p<0.05), while the knee and ankle joint moments and powers were greater for UN than AF and CON (p<0.05). Lastly, vertical ground reaction force (vGRF) was significantly higher for UN than AF (p<0.05) The main findings included greater muscle activation of the muscles surrounding the hip joint of UTTA during the SLB and the SiStSi activities. Joint overloading was noted for the UN knee as well as overcompensation by the UN ankle during the SiStSi. Lastly, asymmetry was observed in the vGRF between the AF and UN sides during the SiStSi.