High heels and Women's Health

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Original Editor - Kapil Narale

Top Contributors - Kapil Narale and Kim Jackson  

Introduction

Its a popular notion that high heels can increase a Woman's physical attractiveness, thus enhancing her health and fertility.

Many Women (59% of Women) are seen to be wearing high heels for social or professional reasons, anywhere from 1 to 8 hours a day.

Legs in high heels are seen to be more attractive than legs without high heels. Legs that are in heels are perceived to be longer than those not in heels. The longer leg length is seen to be more sexually attractive to the opposite sex. The use of high heels give the perception that Women are being safeguarded by their partners. Women feel more sexually attractive as well.

High heels are seen to superficially increase Women's attractiveness to Men through altering their gait, reducing their stride length, and increasing their pelvic tilt and hip rotation. In addition, the curve in Women's lumbar spine is increased, which also increases attractiveness.

High heels do have psychosexual benefits which make their use more preferred, however there are many detrimental effects associated with high heels, making their use a public health challenge.

There is an association between psychosexual benefits and the negative effects on musculoskeletal health, which makes high heels a social and controversial issue. These effects and aspects will be discussed.

Musculoskeletal Health

A biomechanical review has found that there are incorrect variations to the neuromechanics of walking gait, and kinematics and kinetics of structures within the body from the spine to the toes, which can create a risk for various conditions such as musculoskeletal pain, hallux valgus, ankle inversion injuries, and osteoarthritis. There can also be deviations in foot and ankle kinematics, kinetics, knee and hip flexion, gait, posture, and balance. Increased lumbar lordosis due to an increased pelvic tilt can be associated with the risk of low back pain.

It is seen that the use of high heels in adolescents, individuals ranging from 10-19 years old, can lead to postural impairments, which affect head positioning, the back, pelvis, and the knee. Heel height and width are primary contributors to postural changes, and boy imbalance.

High heels are also seen to increase lumbar lordosis. They also increase the height of the body's Center of Mass, therefore decreasing postural stability. Due to these changes, there is an adjusted increase in erector spinae activity, to maintain the deviated posture. The increased muscle activity can lead to increased discomfort and muscle fatigue. This would help explain the onset of low back pain in individuals who use high-heels for an extended period.

Trunk Muscles

It is found that the activity of trunk muscles increase as heel height increases, thus resulting in fatigue and discomfort of back muscles in women wearing high heels.

However, it is interesting to note that there may be a heel height where the trunk muscles cannot adjust for changes in ground reaction forces or alterations in the CoM.

Muscle Activation and Joint Loading

There are various muscles that have an altered activation with the use of high heels. The study by Simonsen et al (2012) made note of eight of these muscles. When women walked with a 9cm high heel, compared to barefoot, there was a difference in:

• Doubling of the knee extensor moment peak in the first half of stance phase, likely due to the increased flexion in the first half of stance. This could be caused by the increased knee joint flexion during stance phase and increased EMG in the quadriceps
• The knee extensor moment in midstance has a statistically significant difference to walking barefoot
• Pronounced and increased flexion of the knee during the first half of stance phase
• A marked increase in the knee joint abductor moment and the hip joint abductor moment, in the frontal plane
• There was an increase in knee extensor joint moment in midstance, while the hip joint angle remained unchanged
• Higher ankle dorsiflexor moment after heel strike
• The reduction of the peak plantarflexor moment of the ankle join at push off
• A significantly increased external extensor moment at the knee joint, during midstance - with respect to internal muscle moments this represents a flexor moment.

The increased flexion of the knee joint is seen to produce an increase knee joint extensor moment.

As a result of the increased knee joint extensor moment during walking with high heels, there are increased bone-on-bone forces in the knee joint. This may help explain the increase in the onset of knee osteoarthritis in women.

It is seen that there is an increased pressure distribution under the foot with the use of of high heels and with increasing heel height.

There was an increased ankle angle with wearing and walking in shoes, as opposed to high heels. As the ankle should, it was driven into a plantarflexed position at the end of stance. With shoes, the knee joint was also flexed more during heel strike and early stance.

There was decrease in the ankle joint moment with high-heel waking, compared to barefoot walking. This may be due to a decrease muscle fiber length and moment arm at the achilles tendon with a more plantarflexed position with barefoot walking. This reduction in net joint moment during push-off may be caused by the fact that the ankle is already plantarflexed, and there is less of a need for a large plantarflexor moment.

Feel free to see Figure 5 in Simonsen et al 2012, for a comparison of EMG between barefoot and high-heeled walking for tibialis anterior soleus, vastus lateralis, rectus femoris, biceps femoris, semimembranosus, and gamellus muscles.

However, knee joint loading could be unchanged, in the sagittal plane, between barefoot walking and the use of high heels, since the extensor moment peaks during stance are unchanged between barefoot walking and with high heels. Thought there was an increase in the external varus knee joint moment in the frontal plane.

Other studies found a reduced internal ankle joint moment, an unchanged internal extensor knee joint moment in the sagittal plane, and a greater varus external knee joint moment in the frontal plane. The use of high heels do cause a greater varus and valgus moments at the knee joint, with the extensor moment at the knee joint remaining unchanged.

Walking Speed

It is noted that walking speed may be 65 lower than generally normal walking speed when wearing high heels.

The knee joint moment, as discussed above, is affected by walking speed. The knee joint moment having an increased extensor dominance is affected by the reduced ankle joint plantarflexor moment.

Erector Spinae Activity and Pelvis Kinematics

The increased heel height produces an altered activation timing of the erector spinae muscles. A study showed that there was an early activation of the erector spinae muscle. This goes to show that foot wedging can produce distinctive changes in the timing of muscle activation in the low back and pelvis, during gait. This may be clinically significant since an even short increase in EMG activity of the back muscles can lead to chronic overload and fatigue.

A study measured the EMG of the erector spinae and pelvis kinematics, in normal walking speeds, of younger Women and middle-aged Women, in three conditions: without shoes, in low-heeled shoes (4cm), and high heeled shoes (10cm). It is seen that as heel height increases, erector spinae EMG activity increases.

As can be seen throughout various studies, there are biomechanical differences according to the age range of individuals. The lumbar spine absorbs and transmits the weight of the body. Differences are seen since, the spinal column undergoes physical changes as individuals age. The curvature of women's spines gradually and moderately decrease from the late 2s to the 30s, with a decrease beginning thereafter. A second decrease in curvature begins once women reach 50 years.

In younger women, within the three conditions of increasing heel height, there was an increased EMG activity recorded during gait at initial ground contact (heel strike), and at toe off. However, EMG activity did not differ much between wearing high heels and low heels. In addition, with high heels, there was a greater pelvic range of motion in the sagittal plane, compared to low heels and no heels. It is seen that younger individuals have a pronounced anterior pelvic tilt, and an increased spine lumbar lordosis. The increased lumbar lordosis, in younger women, does assist the spine in absorbing the increased vertical shock. However, this may lead to hyperlordosis with long-term use caused by changes in postural muscle activity.

In middle aged Women, there was a significantly higher lumbar erector spinae EMG activity between wearing high heels and with no heels. There was no significant difference between wearing low heels and no heels. They are seen to have a pronounced posterior pelvic tilt, and a reduced spine lordosis. With a posteriorly tilted pelvis, the hamstrings may become lax, which may lead to the loss of muscle tone in the hamstrings, and ongoing iliopsoas muscle activity, causing an anterior shift of the pelvis, and thus the hyperlordotic lumbar spine.

Its interesting to note these differences since these changes in middle-aged Women can increase soft tissue mechanical loading, which can facilitate degenerative changes. This can be noticed in those individuals with low back and knee concerns. The increased lumbar erector spinae EMG activity has the potential to cause muscle overuse, which could to low back problems.

The lower pelvic range of motion in middle aged Women, compared to younger Women, can signify that tissues in the lumbopelvic region become more rigid as one ages. Thus, the harmful effects of high heels on posture and spinal tissues may be more apparent with age.

It is seen that changes in body tissue and structure due to ageing, such as worsening of tissue elasticity or tissue perfusion, alters the biomechanical adjustments brought on by wearing high heeled or stiletto type shoes. Thus differences are noticed between young women and middle-aged women.

Pelvic range of motion did not display a significant difference with heel height in the frontal or transverse planes, in both the young women and middle-aged women groups. However, the values were significantly lower in the middle-aged women group. In addition, heel height showed no significant effect on pelvic alignment angle, in both young and middle-aged women, in the sagittal, frontal, or transverse planes, during the initial contact and toe off phases of gait. Pelvic tilt angle, between young and middle-aged women, had no significant difference.

It is interesting to note that gait velocity were not significantly different between young women and middle-aged women, and between the conditions of wearing no heels, low heels, and high heels.

As noted, there is a large difference in lumbar spinae erector muscle activity between high heels and low heels, and high heels and no heels. Therefore, it is safe to say that EMG activity increases as heel height increases.

Here is a video to explain the effects on the erector spinae:

Gait Disturbances

Studies have shown that gait with high heels is less energy efficient, which can increase fatigue, reducing reflex and voluntary movement responses, in addition to change in rate of muscle activation and strength.

The use of high heel shoes aligns the foot in plantarflexion, which produces increased ground reaction forces that have an effect on the spine. Initial ground contact at the beginning of the gait cycle, induces a force caused by an increased ground reaction force, which is transmitted up the spine. This can pose as a danger of low back pain, as related to heel height. It is possible that loads absorbed by tissues during gait may further aggravate low back pain symptoms. However, the increased loads can in fact be dampened by alterations in the kinematics of the body, or through direct absorption by the soft tissues.

Increased lumbar lordosis which occurs with the use of high heeled shoes has a purpose of absorbing the vertical loads. Thus, repetitive strain injuries can be caused by tissue overload that is not accommodated for in high heeled gait.

Local muscle fatigue can be triggered by increased back muscle activity with high heeled gait. The accumulated muscle fatigue can lead to structural soft tissue impairments, such as swelling or restricted movement. In fact this low intensity repetitive strain, at 2% of maximal load, of the lumbar muscles has been shown to reduce tissue oxygenation. Prolonged isometric muscle contraction at this intensity can also lead to repetitive strain injury in the lumbar region. Contrarily it is said that the chance of musculoskeletal injury can be reduced if the muscles can rest at levels below the 1-2% of maximal load. However, the fatigue can have an effect on the timing of lumbar muscle activation and lead to spinal tissue damage. Muscle fatigue and instability of the lumbar spine can be seen to be a cause and effect of low back pain. Therefore, these microtrauma stresses that would occur to individuals who wear high heels for prolonged periods could lead to various deformities, and impairments, and compensations.

The use of high heels causes the body's CoM to move anteriorly and superiorly. This shift in the CoM may necessitate an earlier onset and greater activation of the erector spinae muscle activity to maintain balance and stability in the lumbopelvic region during gait. This increased contraction of the erector spinae muscles may cause an extension movement of the lumbar spine. This would lead to a posterior shift of the CoM balancing the anterior displacement caused by an increased heel height.

Also, walking on harder surfaces causes a increased level of peak acceleration of ground reaction forces in the lumbar region.

Osteoarthritis

Various biomechanical reviews show evidence that there is a risk of osteoarthritis, though there isn't evidence of epidemiological studies.

a positive knee joint moment in the frontal plane, termed a valgus moment, may be crucial for joint deterioration dur to osteoarthritis. When the knee joint is directed into a varus position, there will be an 'opening' of the lateral compartment, and the entire loading will be focused on the articular surfaces of the medial compartment.

The knee joint abductor moment in the frontal plane was dominant with barefoot walking. This increased by 10% when wearing high heels, and showed a large increase in bone-on-bone forces. Since there is a 1% increase in knee joint abductor moment increases the risk of osteoarthritis progression by 6.46 times.

Fertility and Pregnancy

Similar to an increased body mass index, pregnant women have an anteriorly tilted pelvis, due to their altered mass distribution. The adjustment for the shift in center of gravity from the increased body mass causes postural changes, which affect the position of the head, the neck, and the trunk.

Second-party Injury

An injury, caused by another person, due to the mechanism of a stiletto (heels that are higher than 1 inch) is very possible, and can lead to temporary or more long-term impairments or damages, especially when involved in stepping on another individual or used in a fight.

Resources

Here are some brief fun yet informative videos explaining the health effects of high heels, and where caution should be taken .

8 reasons not to wear high heels

This is a very technical video of the effects on the spine .