The effect of personalized orthopedic insoles on plantar pressure during running in subtle cavus foot.

Objective: This study aims to investigate the patterns of plantar pressure distribution during running for patients with subtle cavus foot (SCF) and determine the impact of personalized orthopedic insoles with forefoot wedge on plantar pressure distribution in patients with SCF. Methods: Sixteen undergraduate participants (8 with SCF and 8 with normal arches) were recruited based on arch height index measurements. Two full-length insoles were personalized for each SCF based on plantar pressures during running, an arch support insole (ASI) and an arch support with forefoot wedge insole (AFI). Foot pressure data collected during different insole conditions in running, analyzing ten regions of footprints for peak pressure and pressure-time integral. Results: Higher peak pressures were observed in patients with SCF at the medial forefoot (p = 0.021), medial heel (p = 0.013), and lateral heel (p = 0.025), with a higher pressure-time integral also noted at the medial forefoot (p = 0.025), medial heel (p = 0.015), and lateral heel (p = 0.047) when compared to normal arches. Compared with without-insole, both the AFI and the ASI reduced peak pressure at the medial (AFI p = 0.011; ASI p = 0.024) and lateral heel (AFI p = 0.028; ASI p = 0.032). The AFI reduced peak pressure at the medial heel (p = 0.013) compared with the ASI. Both the AFI and the ASI reduced pressure-time integral at the medial forefoot (AFI p = 0.003; ASI p = 0.026), central forefoot (AFI p = 0.005; ASI p = 0.011), medial heel (AFI p = 0.017; ASI p = 0.005), and lateral heel (AFI p = 0.017; ASI p = 0.019). Additionally, the ASI reduced pressure-time integral at the big toe (p = 0.015) compared with the without-insole. Conclusion: These findings demonstrate that during running in patients with SCF, plantar pressures are concentrated in the forefoot and heel compared to the normal arch. The personalized orthotic insoles can be used to effectively redistribute plantar pressure in patients with SCF running. Incorporating a forefoot wedge to specifically address the biomechanical abnormalities associated with SCF may enhance the effectiveness of orthopedic insoles.

Comparative Analysis of the Diagonal Stride Technique during Roller Skiing and On-Snow Skiing in Youth Cross-Country Skiers.

Roller skiing is one primary form of training method as it is an off-snow equivalent to cross-country (XC) skiing during the dry land preseason training, but the results could only be applied to on-snow skiing with appropriate caution. The aim of this present study was to investigate the similarities and differences in roller skiing and on-snow skiing with the diagonal stride (DS) technique. Six youth (age: 14.3 ± 2.9 years) skiers participated in this study. Two high-definition video camcorders and FastMove 3D Motion 2.23.3.3101 were used to obtain the three-dimensional kinematic data. The cycle characteristics and joint angle ROM of the DS technique while skiing on different surfaces were similar. Almost all joint angle-time curves that were obtained from roller skiing showed a moderate-to-high degree of similarity to the angle-time curves obtained from on-snow skiing, except the hip adduction-abduction angle. The differences between roller skiing and on-snow skiing were mainly found in the body and calf anteversion angles, and the joint angles at critical instants. DS roller skiing can simulate DS on-snow skiing to a large extent in youth athletes. The hip movement, knee flexion, and calf anteversion at ski/roller ski touchdown and take-off, pole inclination at pole touchdown, body anteversion angle, and trunk anteversion angle at pole touchdown were the points that required caution when transferring preseason practice roller skiing to on-snow skiing.

Effects of step lengths on biomechanical characteristics of lower extremity during split squat movement.

Objective: To quantify the effects of increasing the step length of the split squat on changes in kinematics, kinetics, and muscle activation of the lower extremity. Methods: Twenty male college students participated in the test (age: 23.9 ± 3.7, height: 175.1 ± 4.9). Data on kinematics, kinetics, and EMG were collected during split squat exercise at four different step lengths in a non-systematic manner. One-way repeated measurements ANOVA were used to compare characteristic variables of peak angle, moment, and RMS among the four step length conditions. Results: The step length significantly changes the peak angles of the hip (p = 0.011), knee (p = 0.001), ankle (p < 0.001) joint, and the peak extension moment of the hip (p < 0.001), knee (p = 0.002) joint, but does not affect the ankle peak extension moment (p = 0.357) during a split squat. Moreover, a significant difference was observed in the EMG of gluteus maximus (p < 0.001), vastus medialis (p = 0.013), vastus lateralis (p = 0.020), biceps femoris (p = 0.003), Semitendinosus (p < 0.001), medialis gastrocnemius (p = 0.035) and lateralis gastrocnemius (p = 0.005) during four step lengths, but no difference in rectus femoris (p = 0.16). Conclusion: Increases in step length of split squat had a greater activation on the hip extensor muscles while having a limited impact on the knee extensor muscles. The ROM, joint moment, and muscle activation of the lead limb in the split squat all should be considered in cases of individual preventative or rehabilitative prescription of the exercise. Moreover, the optimal step length for strength training in healthy adults appears to be more suitable when it is equal to the length of the individual lower extremity.