Background. Strengthening of hip and trunk muscles can modify pelvis and hip movements. However, the varus alignment of the\nfoot-ankle complex (FAC) may influence the effects of muscle strengthening, due to the relationship of FAC alignment with pelvic\nand hip kinematics. This study evaluated the effects of hip and trunk muscle strengthening on pelvis and hip kinematics during\nwalking, in subgroups with larger and smaller values of FAC varus alignment. In addition, this study evaluated the effects of hip\nand trunk muscle strengthening on hip passive and active properties, in the same subgroups. Methods. Fifty-three women, who\nwere divided into intervention and control groups, participated in this nonrandomized controlled trial. Each group was split\ninto two subgroups with larger and smaller values of FAC varus alignment. Hip and trunk muscle strengthening was performed\nthree times a week for two months, with a load of 70% to 80% of one repetition maximum. Before and after strengthening, we\nevaluated (1) pelvis and hip excursions in the frontal and transverse planes during walking, (2) isokinetic hip passive external\nrotator torque, and (3) isokinetic concentric and eccentric peak torques of the hip external rotator muscles. Mixed analyses of\nvariance (ANOVAs) were carried out for each dependent variable related to walking kinematics and isokinetic measurements\n(a= 0 05). Results. The subgroup with smaller varus alignment, of the intervention group, presented a reduction in pelvic drop\nafter strengthening (P = 0 03). The subgroup with larger varus alignment increased pelvic drop after strengthening, with a\nmarginal significance (P = 0 06). The other kinematic excursions did not change (pelvic anterior rotation P = 0 30, hip internal\nrotation P = 0 54, and hip adduction P = 0 43). The intervention group showed increases in passive torque (P = 0 002), peak\nconcentric torque (P < 0 001), and peak eccentric torque (P < 0 001), independently of FAC alignment. These results suggest\nthat FAC varus alignment influences the effects of strengthening and should be considered when hip and trunk muscle\nstrengthening is used to reduce pelvic drop during walking.
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