Distributions of VGRF of foot in stance phase.

<p>The blue (deep) solid line refers to the plantar VGRF of the high-arched foot while the blue (deep) ribbon presents the error bars of the plantar VGRF of the high-arched. The red (light) solid line stands for the plantar VGRF of the flat foot while the red (light) ribbon for the standard error bars of the plantar VGRF of the flat foot. The VGRF has been standardized as 1 by weight, and the stride cycle time and foot length are rated by percentage.</p

Mapping of human symmetrical bone.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032926#pone-0032926-g004" target="_blank">Fig. 4a</a> One subject's left foot first metatarsal. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032926#pone-0032926-g004" target="_blank">Fig. 4b</a> One subject's right foot first metatarsal. The cutting line is the minimal PAI of the first metatarsal. (Some sections of the head and base of the first metatarsal are not on the cutting line. As a result, these sections are not included in the map.)</p

Mapping analysis to the fourth metatarsal.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032926#pone-0032926-g005" target="_blank">Fig. 5a–5b</a> Mapping of the fourth metatarsal (left foot) of eight wrestlers and volleyball players respectively. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032926#pone-0032926-g005" target="_blank">Fig. 5c–5d</a> Mapping of the fourth metatarsal (left foot) after standardization of length and width of eight wrestlers and volleyball players, respectively. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032926#pone-0032926-g005" target="_blank">Fig. 5e–5f</a> Mapping of the fourth metatarsal (left foot) average value from eight wrestlers and volleyball players, respectively. Eq. (3) is applied to SCS of the athletes' fourth metatarsals (left foot) and then the tomography is reconstructed. Eqs. (4)–(7) are employed to develop the reconstructed tomography. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032926#pone-0032926-g005" target="_blank">Fig. 5a–5b</a>. To standardize the length and width of the metatarsal map brings the same length and width. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032926#pone-0032926-g005" target="_blank">Fig. 5c–5d</a>. Statistical analysis is conducted on the standardized metatarsal map to calculate the average value of the eight metatarsal maps at the same position. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032926#pone-0032926-g005" target="_blank">Fig. 5e–5f</a>.</p

Relationship between the footprint areas and stride time.

<p>The blue (deep) dotted lines refer to the plantar stance areas of the high-arched left and right foot while the blue (deep) solid line the sum of plantar stance area of the high-arched. The blue (deep) horizontal dotted line presents the variation range of the sum of plantar stance area of the high-arched. The red (light) dotted lines stand for the plantar stance areas of the flat left and right foot while the red (light) solid line for the sum of plantar stance area of the flat-footed. The red (light) horizontal dotted line presents the variation range of the sum of plantar stance area of the flat-footed. The footprint area is derived from the test report of Zebris FDM and the sum of plantar stance area is obtained from . According to the least-action principle in gait, , <i>T</i> stands for the stride cycle time.</p

Analysis of bone strength to the fourth metatarsal (left foot) of eight wrestlers and volleyball players, respectively.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032926#pone-0032926-g006" target="_blank">Fig. 6a</a> Comparison of bone density, volume and area of the fourth metatarsal (left foot) of eight wrestlers and volleyball players. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032926#pone-0032926-g006" target="_blank">Fig. 6b</a> Relationship between the fourth metatarsal (left foot) bone tissue density and the tissue distribution radius from eight wrestlers and volleyball players. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032926#pone-0032926-g006" target="_blank">Fig. 6c</a> Differences of the map of the fourth metatarsal (left foot) average value from eight wrestlers and volleyball players. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032926#pone-0032926-g006" target="_blank">Fig. 6d</a> P value distribution of the fourth metatarsal (left foot) map from eight wrestlers and volleyball players. In <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032926#pone-0032926-g006" target="_blank">Fig. 6a</a>, the bone's density is defined as , where , stands for the gray value of the <i>i</i>-th volume element, stands for the gray value of water. Volume and area are results from <i>Mimics</i> software. In <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032926#pone-0032926-g006" target="_blank">Fig. 6b</a>, for detailed method, see Reference 30. In <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032926#pone-0032926-g006" target="_blank">Fig. 6c</a>, when , or , is colored, where and stand for the altitude values for the positions of of the fourth metatarsal from volleyball players and wrestlers, respectively, where blue shows and red (). In <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032926#pone-0032926-g006" target="_blank">Fig. 6d</a>, the calculation is done by <i>SPSS</i>, where blue shows p<0.05 and red p<0.01.</p

Basic kinematic parameters of gait.

<p>Basic kinematic parameters of gait.</p

Tomographic reconstruction of the fourth metatarsal after using SCS.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032926#pone-0032926-g002" target="_blank">Fig. 2a</a> Tomography of the fourth metatarsal before using SCS. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032926#pone-0032926-g002" target="_blank">Fig. 2b</a> Tomography of the fourth metatarsal after using SCS. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032926#pone-0032926-g002" target="_blank">Fig. 2c</a> Tomography and sea level of the fourth metatarsal after using SCS. According to the morphological features of the fourth metatarsal, set the average value of the distance between the fourth metartasal's bone tissue to long PAI (the magnitude of principal moments of inertia is minimal) to be the radius. The central axis of the cylinder and the long PAI will superpose. The left figure shows the postures of 1st–5th metartasals before and after using SCS. If a cylinder is placed in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0032926#pone-0032926-g002" target="_blank">Fig. 2a</a>, the bone's tomography is not vertical to the central axis of the cylinder, but a reconstruction of tomography after using SCS is vertical to the central axis of the cylinder (i.e. the principal axis of minimal moment of inertia). The tomography of the non-vertical central axis of the cylinder is determined by the posture of the subject when being measured. A different posture leads to a different tomography. Without using SCS, the development of the tomographic boundary of the bone's surface map is not unique whereas using SCS brings a unique map of the bone's surface.</p

Basic information of subjects' feet.

<p>*p<0.05,</p><p>**p<0.01.</p

Detailed information of ATRs.

<p>Units in the table: height: cm; weight: kg; age: year.</p

Application of the superposition principle of the bone's COM and COS.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0028868#pone-0028868-g004" target="_blank">Fig. 4a</a> Positional relationship between the COS of the compact bone and the COS of the bone; <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0028868#pone-0028868-g004" target="_blank">Fig. 4b–m</a> Relationship between the bone tissue's density and distribution radius, where axis x stands for the tissue's density and axis y for the standardized mean distribution radius of the tissue. The data were collected from 192 pieces of foot bone of the wrestlers and 192 ones of the footballers. *p<0.05, **p<0.01. When 1.65, the bone tissue is defined as compact bone. Eqs (2) and (3) are used to calculate the compact bone's COM and COS while Eq. (4) the distance between the two points and Eq. (5) the distribution radius of bone tissue. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0028868#pone-0028868-g004" target="_blank">Fig. 4a</a> is the result of the distance between the compact bone's COM and COS standardized by the bone tissue's radius. Eq. (6) is applied to calculate same density tissue radius. Then standardize it by the bone tissue's radius. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0028868#pone-0028868-g004" target="_blank">Fig. 4b–4m</a>.</p