The Effect of Different Degrees of Ankle Dorsiflexion Restriction on the Biomechanics of the Lower Extremity in Stop-Jumping

Purpose

The functional status of the ankle joint is critical during dynamic movements in high-intensity sports like basketball and volleyball, particularly when performing actions such as stopping jumps. Limited ankle dorsiflexion is associated with increased injury risk and biomechanical changes during stop-jump tasks. Therefore, this study aims to investigate how restricting ankle dorsiflexion affects lower extremity biomechanics during the stop-jump phase, with a focus on the adaptive changes that occur in response to this restriction. Initially, 18 participants during stop-jumping with no wedge plate (NW), 10° wedge plate (10 W), and 20° wedge plate (20 W) using dominant leg data were collected to explore the relationship between limiting ankle mobility and lower extremity biomechanics. Following this, a musculoskeletal model was developed to simulate and calculate biomechanical data. Finally, one-dimensional parametric statistical mapping (SPM1D) was utilized to evaluate between-group variation in outcome variables using a one-way repeated measures analysis of variance (ANOVA).

Results

As the ankle restriction angle increased, knee external rotation angles, knee extension angular velocities, hip extension angle, and angular velocity increased and were significantly different at different ankle restriction angles (p  < 0.001 and p=0.001), coactivation of the peripatellar muscles (BF/RF and BF/VM) increased progressively, and patellofemoral joint contact force (PTF) increased progressively during the 3%-8% phase (p=0.015). These results highlight the influence of ankle joint restriction on lower limb kinematics and patellofemoral joint loading during the stop-jump maneuver.

Conclusion

As the angle of ankle restriction increased, there was an increase in coactivation of the peripatellar muscles and an increase in PTF, possibly because a person is unable to adequately adjust their body for balance when the ankle valgus angle is restricted. The increased coactivation of the peripatellar muscles and increased patellofemoral contact force may be a compensatory response to the body's adaptation to balance adjustments.

Effectiveness of Shock-Absorbing Insole for High-Heeled Shoes on Gait: Randomized Controlled Trials

This study was carried out to identify the influence of a shock-absorbing insole, developed by the author for use with high-heeled shoes, on walking. The research design included single-blind randomized parallel groups; namely, a group of 26 participants who wore the shock-absorbing insoles and another group of 26 participants who did not wear the insoles, both carried out walking while wearing 7 cm high-heels. During walking, plantar pressure analysis (via in-shoe plantar pressure measurements), surface electrode electromyography (surface EMG), gait analysis, subjective comfort evaluation, and functional movement (functional mobility) analysis were carried out. In order to compare the two groups, statistical verification (paired t-test) was performed. Wearing the shock-absorbing insole with the high-heeled shoes improved posture stability during walking, as well as increasing the walking speed. In addition, the heel pressure, the pressure of the front foot at the inner side, and the shock ability were decreased. For these reasons, the wearers reported higher comfort. Changes in the muscle activities of the tibialis anterior muscle (TA) and the gastrocnemius muscle (GA) heightened the stability of the ankle joints. Overall, the proposed shock-absorbing insole for use with high-heeled shoes improved the postural stability when walking, as well as improving the distribution of pressure on the soles. A decrease in the diverse side-effects of wearing high-heeled shoes can thus be expected.