Benefits of 3D Printed and Customized Anatomical Footwear Insoles for Plantar Pressure Distribution.

During walking, the foot is in direct contact with the insole of the footwear, and it affects the biomechanics of the whole human body. The aim of this study was to compare the plantar pressure distribution while walking in the same footwear in three different situations: with an original footwear insole, with an ethylene-vinyl acetate customized insole, and with a 3D printed anatomical insole to find out the optimal insoles for people with a normal, flat, and high arched foot according to the plantar pressure relief. Fifty-one adults were grouped into three groups (normal foot, flat foot, and high arched foot geometry). The feet of the randomly selected subjects from each group were scanned, and the insoles were designed on the basis of the foot model. These models were then used for the 3D printing. The plantar pressure distribution was observed when walking in all three different insole types for each of the three subjects with the different foot types. The peak pressure values in the forefoot, midfoot, and rearfoot and contact area were compared. The results of the study show that customized insoles influence the plantar pressure distribution mainly in people with a flat foot or with a high arched foot deformity. This influence is dependent on the type of the customized insoles, mainly in people with a high arched foot. People with a flat foot deformity have a similar plantar pressure relief in the thermoplastic insoles as those in the 3D printed insoles, and both these customized insoles can be used as a supplementary therapeutic instrument. Our study showed that the biggest attention, with regards to customizing insoles, is required by people with a high arched foot deformity, and we recommend that these people use fully customized insoles which can be guaranteed with 3D printing techniques.

Jumping performance and take-off efficiency in two different age categories of female volleyball players.

PURPOSE: Vertical jump height is recognised as a determinant factor in elite volleyball performance. In previous studies there are different opinions on whether vertical jump height performance improves during maturation or not. The aim of this study was to assess the differences in jumping abilities in two different age groups of female volleyball players and to determine the take-off efficiency during repeated jumps. METHODS: Seventeen female volleyball players from two different age categories - adults and under 16 years - participated in this study. Quattro Jump 9290BA force platform (Kistler, Winterthur, Switzerland) was used to assess the jumping performance during squat jumps, counter movement jumps, and 45-second continuous jumps. RESULTS: Jumping performance did not differ significantly between the two groups. The main efficiency of the conversion of mechanical work into mechanical energy was only 24% and it decreased during the test. CONCLUSIONS: The influence of age on the jumping performance in a group of female volleyball players was not confirmed. Take-off efficiency was in both groups quite low and it did not improve during the test.

Standing balance of professional ballet dancers and non-dancers under different conditions.

Ballet training has been reported to positively influence balance ability. It is not entirely clear how improved balance ability manifests under standing conditions with different demands on postural control. The aim of the study was to compare balance of ballet dancers and non-dancers in a unipedal stance under different conditions. Twenty-five professional ballet dancers and twenty-five controls completed four unipedal standing balance tests: firm surface with eyes open and closed; foam mat surface with eyes open; and firm surface with eyes open immediately after performing ten 360° whole-body turns. The centre of pressure (COP) data were obtained with a force platform and the direction-specific standard deviations, velocities, and sample entropy of the COP displacement were computed. A three-way analysis of variance was used to compare groups, genders, and conditions. For standing immediately after performing ten turns, the postural sway parameters were significantly larger in the control group compared to the ballet dancers in both men and women. In this stance condition the values of postural sway and COP velocities in the control group were larger in the men compared to the women. For both genders in the control group all postural sway and COP velocity parameters were larger in standing with eyes closed and standing after performing 10 turns compared to standing with eyes open on both firm and foam surface. In the ballet dancers all COP velocity parameters were larger in standing with eyes closed compared to all other conditions. The results from the present study indicate that professional ballet dancers do not have a better general balance ability than untrained subjects.

Comparison of Plantar Pressure Distribution During Walking After Two Different Surgical Treatments for Calcaneal Fracture.

The aim of our study was to compare gait in terms of foot loading and temporal variables after 2 different operative approaches (the extended lateral approach [ELA] and sinus tarsi approach). Twenty-two patients who sustained an intra-articular calcaneal fracture underwent plantar pressure distribution measurements 6 months after surgery. Measurements were performed while patients walked on the pedobarography platform. The values of dynamic variables were significantly lower on the operated limb in the ELA. In the sinus tarsi approach, no differences were observed between the operated and uninjured limbs (UIN) at peak pressure and at maximal vertical force. The values of temporal variables (contact time of the foot and of the heel) between the operated and UIN differed in the ELA. The hypothesis that differences in foot load between operated and UIN will be more significant in the ELA was confirmed. Our results showed that the differences in loading and temporal variables between the operated and the UIN persisted 6 months after surgery in both methods. The operated limb was less loaded, with the tendency to shift the load toward the midfoot and forefoot. After the less invasive sinus tarsi approach, the dynamic and temporal variables on the operated limb were nearly the same as those on the healthy one. The sinus tarsi surgical approach can be recommended for treatment of displaced calcaneal fractures.

Temporal and dynamic changes in plantar pressure distribution, as well as in posture during slow walking in flat and high-heel shoes.

PURPOSE: The aim of the study was to assess the differences in plantar pressure distribution and in posture during slow and very slow walking on the treadmill in flat and high-heeled shoes. METHODS: The Pedar-X® (Novel, Munich, Germany) measuring insoles were used to measure the plantar pressure distribution and to assess temporal parameters during walking on the treadmill with the speed v1 = 0.97 ms-1 and v2 = 0.56 ms-1 in flat shoes (FS) and HH. For postural measurement, the SonoSens Monitor Analyzer (Gefremed, Chemnitz, Germany) was used. Thirty healthy females who only occasionally wear HH volunteered to participate in the study (age: 21.8 ± 2.09 years, weight: 55.7 ± 4.05 kg, height: 1.66 ± 0.03 m). For statistical analysis the ANOVA, and paired t-test were used. RESULTS: Significant differences in walking in HH were detected in temporal and plantar pressure variables, compared to FS. The walking speed influenced the temporal variables, but not the measured dynamic parameters, in either shoes. In the sagittal plane, significant differences in all sections of the spine were identified for v1 and v2. While walking in HH, lordosis at lumbar spine decreased significantly as well as at cervical spine, and kyphosis increased in the thoracic spine. In HH statistically significant differences between the walking speeds were observed particularly in the thoracic spine. CONCLUSIONS: Walking in high heels caused a plantar pressure changes and curvature of the spine, and the slowing of walking speed did not prevent these changes.

The influence of minimalist and conventional sports shoes and lower limbs dominance on running gait.

PURPOSE: The aim of this study was to determine how minimalist running shoes (MRS), conventional running shoes (CRS) and the dominance of lower limbs influence the running gait. METHODS: Trained recreational runners (N = 13) who have been engaged in regulary running for more than one year were participants in this study. They were experienced with using MRS and CRS for more than half year and they used both types of shoes. An in-shoe pressure measuring system (Pedar-X®, Novel, Munich, Germany) was used to monitor plantar pressure and vertical force and the temporal parameters when running in MRS and CRS during the stance phase, the swing phase and over one stride. RESULTS: Running in CRS significantly prolonged stance, swing and stride phases by 2-11%, compared to MRS. In contrast, when running in MRS significantly larger values of maximum pressure (9-14%) and maximum vertical force (3-7%) than in CRS were found. CONCLUSIONS: For this reason, running in MRS could be recommended to recreational runners only with care. The effect of limb dominance on temporal characteristics was detected when running in CRS. Significantly longer stance phase for dominant limb is associated with a shorter swing. The kinematics variables were significantly higher for dominant limb than for non-dominat limb when running in MRS and CRS (by 12-23%).

The effect of climbing ability and slope inclination on vertical foot loading using a novel force sensor instrumentation system.

The aim of the study was to assess the effects of climbing ability and slope inclination on vertical loading both in terms the forces involved and physiological responses. Five novice and six intermediate female climbers completed a climbing route at three slope inclinations (85°, 90°, and 98°). The vertical loading during the climb was assessed by force-time integral using a Novel Pedar-X insole and physiological responses via oxygen uptake and heart rate. The novice climbers had a significantly lower (p < 0.05) vertical loading on foot holds and higher oxygen uptake and heart rate compared to intermediate climbers. A significant negative correlation was identified between the force-time integral and oxygen uptake (R = -0.72), and with heart rate (R = -0.64), respectively. The time-force integral decreased across the ascents with increasing slope inclination (p < 0.001). The results indicate that more advanced ability climbers make greater use of foot holds, with associated lowering in physiological response (oxygen uptake and heart rate) across all slope inclinations.