The forefoot contains the toes. The big toe has two major bones and the rest have three little bones. The toes connect to the midfoot by five long bones called metatarsals, one for each toe. The metatarsals are similar to our knuckles. The hindfoot connects to the midfoot by cuneiform and cuboid bones.
When we jump, we first shift our centre of gravity in the direction we want to jump, and then we move our support base i. When you are holding onto your toes, jumping backwards is not a problem because you can use your heels to shift your weight. But to jump forward, you would have to use your toes. Unfortunately, your fingers are in the way. While sitting in a chair with your back against the chair and your feet on the floor, your centre of gravity is at your waist, supported by the chair.
When you try to stand up with your back straight, you prevent the centre of gravity from moving to a position above your feet your support base , as you would need to, to stand up. So you remain glued to your chair! When you stand straight against the wall, your centre of gravity is over your feet. When you bend forward, your centre of gravity shifts forward. In order to keep your balance, you must move your feet forward or your bum backwards. This would ensure that your centre of gravity is right above your feet to maintain stability.
Since the rules of this challenge do not allow you to move your feet and the wall is behind you, there is no way to shift your centre of gravity to maintain balance while trying to pick up the money.
If you insist on picking up the object, you will fall flat on your face. In order to move your left leg while your right side is against a wall, you need to shift your centre of gravity over your right foot. You cannot do this without moving the wall. This exercise can be used to determine the approximate location of your centre of gravity.
If you could not touch the Smartie candy without falling over, your centre of gravity is high above your belly button. When your centre of gravity is high, it will surpass your base between the knees and toes when you lean over. In order to have the model mimic a subject with diminished toe strength, Hemami and Humphrey weakened one of the sections in the computer-modeled foot, which represented a muscle located just above the big toe. This muscle helps control the foot's arch, which provides support to the body while standing.
Results indicated that in a healthy person, toes became increasingly important as the person leans forward. As the computer-modeled body leaned forward, the pressure underneath the toes increased significantly, and the pressure underneath the heel decreased in a similar fashion.
When the same tests of static balance were performed on the computer-modeled body with diminished toe strength, the pressure underneath the toes remained at zero. Initially, the pressure underneath the heel was significantly higher than in the healthy subject, and as the body leaned forward, the pressure underneath the heel only decreased by half the amount that it did in the healthy subject.
The maximum angle that a healthy computer-modeled body could lean forward from the waist without its heels lifting off the ground was nearly 12 degrees from vertical. The model with diminished toe strength could only lean forward nearly 10 degrees. The computer model supports past studies on real people, Hemami explained.
One discrepancy: his computer model was able to lean forward 12 degrees without lifting its heels, while real people were only able to lean two-thirds as much -- 8 degrees.
Hemami's colleague Laura Humphrey was one of his doctoral students, and she has since graduated from Ohio State. He will be collaborating with Ian Alexander, professor of orthopaedics at Ohio State, in the near future. Lee and Lin [18] suggested that the difference in body weight of males will result in greater CoP execution during the single-leg standing task.
However, the findings of Mickle [17] claimed that males executed greater postural sway, even though the body weight for both genders are nearly similar. According to the findings, the ML sway among females was slightly higher, but this was not significant when compared with that of the male control group during both the NS and SWT conditions Table 2. Meanwhile, the current findings show that an increased complexity of standing posture leads to an increase in the ML sway.
This finding may relate to the Q-angle. Studies have shown that females have a greater Q-angle than males due to the length of their femur and their bigger pelvis area [19] , [20]. A larger Q-angle for females may result in an increase of rotation in hip movement, since the CoM needs to be maintained within the base of support to achieve body balance [21].
As such, greater sway will be generated in the ML direction and sideways sway will increase in response to this in order to regain body equilibrium.
Maki et al. Meanwhile, the current findings show that there is an increase in the ML sway in accordance with the increasing complexity of standing posture. As such, the tendency of the ML sway was considered to be an important component for balance equilibrium when a more complex posture was applied during quiet standing. The investigation of static balance control provides normative stability data for clinicians who are concerned with this specific toe condition.
It is important to identify the changes of balance performance during SWT, since it is altered by the base of support and CoM. Some authors reported that the CoP and CoM are approximately equal only in the static or quasi-static conditions [26]. Likewise, Murray et al. From the anatomical point of view, the height of the CoM is normally lower in females than males [28]. High heel shoes tend to affect postural control by raising and shifting the CoM forward [31]. Csapo et al.
Although the current study was restricted to an investigation of static postural control during toe-extension standing activities, it would be interesting to compare the postural control between active toe-extension in healthy individuals and the passive toe-extension that can be caused by burn injuries.
Nevertheless, the investigation of static postural control has provided a normative stability data in SWT. Besides, the sample size in this study only involved young adults aged between 19 and 25 years old from one specific geographical area and, as such, the data is limited.
In conclusion, this study has demonstrated that differences between the NS and SWT conditions do not lead to differences in postural control. However, a small alteration in postural control during SWT shows a trend of greater amount of postural sway than NS, although this is not significantly different. Gender does not appear to effect static postural stability. Performed the experiments: PXK. Browse Subject Areas? Click through the PLOS taxonomy to find articles in your field.
Abstract Background Postural balance is vital for safely carrying out many daily activities, such as locomotion. Introduction Since balance is a vital prerequisite component of life for all human beings, balance control has been examined extensively in a number of studies. Participants Thirty healthy young adults 15 male and 15 female with no prior lower-limb injuries were recruited for this study. Instrumentation The BBS used in this study contained four strain gauges under a circular platform in order to measure the displacement of CoP at a sampling rate of 20 Hz.
Download: PPT. Results The descriptive statistical analysis on the demographic characteristics for all participants is tabulated in Table 1. Table 1. Descriptive and demographic characteristic for all participants. Table 2. Discussion There have been numerous studies that have investigated balance stability for various standing postures. Conclusion In conclusion, this study has demonstrated that differences between the NS and SWT conditions do not lead to differences in postural control.
Acknowledgments The assistance from Firdaus Omar is gratefully acknowledged.
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