Secondly, the length of residual femur affects hip muscle strength too. The force can be generated by a muscle is affected by the muscle force magnitude and the distance from the muscle attachment to the axis of rotation (Rassier et al., 1999). For example, the
force can be generated by gluteus maximus is reduced if femur residue length is shorter. Therefore, amputees need to recruit more motor units in order to generate adequate force in walking. This can rationalise energy expenditure on walking increases with higher level amputations (Perry, 2004). In addition, longer femur length means body pressure is distributed to wider surface, allows amputees to tolerate the tension at stump better during prosthesis side stance phase. If high pressure …show more content…
Aforementioned, hip extensors strength is affected as the result of the above knee amputation, however, iliopsoas remains intact and it is the main hip flexors. This explains the presentation of limited hip extension range and hip flexors tightness at amputated side (Gottschalk, 1999). The reduction in iliopsoas muscle length will increase lumbar lordosis as it attaches to vertebral bodies T12 – L5, meanwhile hamstrings are weakened during amputation and are incapable hindering pelvic anterior tilt, thus lumbar lordosis increases (Gaunaurd et al., 2011). There is a close relationship among hip flexors, back extensors, hamstrings and abdominal muscles in hyperlordotic postures (Diagram 2). Abdominal muscles are maintained in lengthened position and this will lead to a reduction of force that can be generated secondary to the contact between actin and myosin filaments reduce when the sarcomere is stretched (Rassier et al., 1999). Conversely, hip and back extensors will be shortened. Tight hip flexors and back extensors encourage pelvic innominate inclination at the operated side (Gaunaurd et al., 2011). All these factors will cause TFAs to generate greater transverse plane rotation at the spine as the compensatory strategy to generate propulsive force during mid-swing (Morgenroth et al., 2010). Axial rotation of spine may expose TFAs to suffer from low back pain earlier as this movement put a high strain on annulus fibre strain (Schmidt et al., 2007). Again,
force can be generated by gluteus maximus is reduced if femur residue length is shorter. Therefore, amputees need to recruit more motor units in order to generate adequate force in walking. This can rationalise energy expenditure on walking increases with higher level amputations (Perry, 2004). In addition, longer femur length means body pressure is distributed to wider surface, allows amputees to tolerate the tension at stump better during prosthesis side stance phase. If high pressure …show more content…
Aforementioned, hip extensors strength is affected as the result of the above knee amputation, however, iliopsoas remains intact and it is the main hip flexors. This explains the presentation of limited hip extension range and hip flexors tightness at amputated side (Gottschalk, 1999). The reduction in iliopsoas muscle length will increase lumbar lordosis as it attaches to vertebral bodies T12 – L5, meanwhile hamstrings are weakened during amputation and are incapable hindering pelvic anterior tilt, thus lumbar lordosis increases (Gaunaurd et al., 2011). There is a close relationship among hip flexors, back extensors, hamstrings and abdominal muscles in hyperlordotic postures (Diagram 2). Abdominal muscles are maintained in lengthened position and this will lead to a reduction of force that can be generated secondary to the contact between actin and myosin filaments reduce when the sarcomere is stretched (Rassier et al., 1999). Conversely, hip and back extensors will be shortened. Tight hip flexors and back extensors encourage pelvic innominate inclination at the operated side (Gaunaurd et al., 2011). All these factors will cause TFAs to generate greater transverse plane rotation at the spine as the compensatory strategy to generate propulsive force during mid-swing (Morgenroth et al., 2010). Axial rotation of spine may expose TFAs to suffer from low back pain earlier as this movement put a high strain on annulus fibre strain (Schmidt et al., 2007). Again,