فهرست مطالب zahra bassiri

The purpose of this study was to determine the effect of three different ankle braces using the Maximum Lyapunov exponent on local dynamical stability of individuals with chronic ankle instability during running. Twelve subjects with chronic ankle instability as injured group and 12 healthy individuals participated in this study. Injured group performed 70 strides of treadmill running in shoe and rigid, semi-rigid and soft braces as well as no-brace conditions. The healthy group performed the test only in no-brace condition. Kinematics data were used to calculate the short time (λ_S) and long time (λ_L) maximum Lyapunov exponent. The results showed that λ_S of running in semi-rigid brace is significantly different with running in other braces in chronic ankle instability group; but it was not different with the control group. It seems running in semi-rigid brace in chronic ankle instability group provides stability like healthy control group.

The effect of silica nanoparticles (SNPs) in sport shoes outsoles on the parameters related to anterior cruciate ligament (ACL) Injury has not been investigated. The aim of this study was to investigate the effect of shoes outsole containing a composite of thermoplastic elastomer based on styrene-butadiene and silica nanoparticles (TPEN shoe) on Knee Valgus Angle (KVA) as a risk factor of ACL injuries during landing Fourteen active healthy women without knee injuries and disorders performed bilateral drop jump (DJ) and single leg drop landing (SLL) tasks in barefoot, wearing shoes fabricated with polyvinyl chloride outsole (PVC shoe) and TPEN shoes conditions, randomly. The knee valgus angle values of right and left legs were calculated in the landing conditions. Two factors repeated measures ANOVA were used to investigate the effect of landing and footwear conditions on KVA of right and left legs. For both left and right limbs, the KVA was at maximum and minimum values during landing with barefoot and TPEN shoes, respectively. PVC shoe significantly reduced the knee valgus by 3.84% in left and 4.18% in right knee (P<0.05) as compared to barefoot landing. In a similar pattern, TPEN shoe significantly reduced the knee valgus compared to barefoot by 7.82% and 9.71% in left and right limbs, respectively. Moreover, the knee valgus during DJ was significantly increased as compared to SLL condition (P<0.05). Shod landing and specially TPEN shoe decreases KVA compared to barefoot. Our results suggested that using SNPs could produce some viscoelasticity property and a better joint movement control in shoe outsoles which can reduce KVA and consequent reduction of ACL Injury.

The popularity of running and consequently of running injuries has increased tends to develop shoe sole constructions aiming at preventing different injuries. The purpose of this study was to investigate the effect of shoe outsole containing nanoclay particles on knee joint power during stance phase of running. Fourteen healthy male shod runners run 3 times at 3.5 m.s-1 under three shoe conditions manufactured by polyurethane (PU), 1% Polyurethanes-clay nano-composites (NPU1) and 2% Polyurethanes-clay nano-composites (NPU2). The joint power (Pj) was calculated by multiplying the joint moment (Mj) and the joint angular velocity (ωj). Knee joint peak power in the three dimensional planes were compared between the shod conditions during the stance phase of running using repeated measurement ANOVA (P< 0.05). The results showed that the negative peak of knee joint power in sagittal plane was significantly different between the PU and NPU2 conditions. No significant differences were noted in other positive and negative peaks. It is concluded that using Polyurethanes-clay nano-composites can change shock absorbing ability of knee joint​.