Preventing Stress Fractures and Low Bone Density

Bones Matter!

By Susie Bond, Physiotherapist for Dancers. November 2020

You can Prevent Development of Stress Fractures and Low Bone Density

Stress Fractures in lower limb, foot or lumbar spine may affect dancers at some stage in their career.  Girls and women may be more susceptible to stress fractures and low bone density, because of the perceived requirements of a lean body aesthetic and their rigorous training schedule.

Common bones affected are the 2^nd metatarsal (near ball of foot), navicular or cuneiform bone on the inside foot arch, the lower inside shin (Tibia) and the outside ankle (Lateral malleoli of the lower fibula).  Lumbar ‘pars’ stress fractures can also affect dancers and gymnasts who do excessive uncontrolled back extensions.

Repeated strain on some bones can lead to a spectrum of irritation of the surface of the bone (periosteum) right through to actual small cracks or fractures in the bone. These fractures are painful but may not initially show up on Xray. A bone scan or MRI can be ordered by the doctor or sports physician to confirm the diagnosis.

Signs and Symptoms

• Persistent pain on weight bearing or jump take off and landing.
• Pain diminishes with rest
• Aching at night
• Specific points of Bony tenderness
• Warmth over the painful area
• Redness, Mild Swelling  

Many dance teachers and health practitioners look to prevent bone injury by knowing common Risk Factors for bone stress fracture development.

1.       Physical Overuse Issues.

(Normal Bone exposed to increased, repeated Stress, causing local bending Fatigue that the bone cannot recover from quickly enough)

• Excessive Foot pronation during running and jump landing
• Pushing lower leg turn out without adequate pelvis and hip external rotation control, causing less than ideal twisting of the knee/ lower leg/ ankle/foot
• General muscular weakness and poor spinal or leg alignment control
• Dancing in shoes with inadequate support (including ‘dead’ pointe shoes)
• Dancing on hard non sprung floors or outdoor concrete surfaces
• Restricted movement in part of the foot or ankle. eg. Tight soleus calf muscle, with decreased plie depth, causing more ‘rolling in’ of foot arch
•  Sudden Increased Dance Intensity and hours eg. After long holidays or coming back to dance after Covid lock down
• Poor sleep and general fatigue

Dancers who danced greater than 5 hours per day were significantly more likely to have a stress fracture than those dancing less than 5 hours per day.

Picture of Dancer with inside Foot arches rolling

2.       Other Underlying Nutritional and Hormonal Issues

(Abnormal bone and body metabolic problems increasing the risk of bone stress) 

• Delayed, irregular or absent periods for females
• Decreased bone mineral density
• Reduced daily nutritional intake so the dancer does not get enough calories to support body energy requirements
• Low amount of calcium in diet
• Vitamin D deficiency

Normal bone is a dynamic living tissue which slowly responds to the forces we put through them. Bone metabolism is a complicated body function. Interestingly bone will adapt to increased forces, or it will become less dense with less force. An astronaut loses bone density up in space without gravity.

When we stop growing, the cartilage ‘growth plates’ in our bones calcify and close. We have reached our adult height. Bone mineral density is a measure of the thickness of the bone. Calcium and phosphorous ae examples of minerals stored in bone to make it strong. Low bone density is known as osteopenia or osteoporosis. Low bone density increases the risk of bone fractures or breaks.

Did you know that people reach their ‘peak bone density’ between the age of 18 and 25 generally?

It is very important to reach your best peak bone density in your teenage years, before the age of 20, to prevent problems later in life. This is especially the case for ladies, who have a sudden decrease in bone density as menopause occurs, with decreased oestrogen hormone protection. I am one of those people who now has to contend with managing osteoporosis! I wonder if my bone density would have been different if my diet had included more calcium as a teenager eg. Milk, more cheese, yoghurt.

I have been concerned about dance students, who have taken on a vegan diet during their teenage years. While this has many health and environmental responsibility benefits, a young dancer needs to be extremely careful to get their daily nutritional needs, to support body energy requirements for demanding dance class and performance loads.

 I asked a dietician specialising in dancer’s health to comment on this concern:

She says: ‘Dancers, especially in their growing years, have extremely high energy and nutritional requirements. In the recent years, I have seen an increase in dancers present to my clinic with repeated stress fractures, slow wound healing, amenorrhoea (absence of period) and/or eating disorders, while following a vegan diet that is significantly deficient in energy and macro- and micro-nutrients; protein, carbohydrates, essential fatty acids, vitamin D, vitamin B’s (especially B12), iron, and zinc, only to name a few.

Remember that everyone’s bodies are different. Some bodies can tolerate being vegan while some bodies can’t. And that doesn’t mean either is superior or inferior. What’s more important is for you, as a dancer, to understand your body and nourish it fully to ensure optimum growth, development and performance.’

Female Dancers are at risk of low bone density and a particularly dangerous condition known as ‘Female Athletic Triad’ or ‘RED-s’ (Reduced Energy Deficiency in Sport) due to their aspirations for a lean physical body shape and often huge work load. This can lead to some irreversible body problems, so prevention is essential.

 Watch for symptoms of the “female athletic triad” to prevent potentially irreversible body issues:

1. Abnormal eating so the athlete or dancer may not be getting the proper nutrition. 
2. Menstrual dysfunction: Hormonal changes that stop menstrual periods (amenorrhea) may be caused by poor nutrition, low calorie intake, excessive exercise, stress or low body fat levels. ‘Amenorrhea’ is defined as no menstrual cycle for 3 months or more. 
3. Low bone density for one’s age: When female athletes don’t have their periods, there is reduced oestrogen production which can lead the body’s bone-building process being disrupted, making bones more likely to break.

 If any of these three things is happening, talk to your doctor.

SO YOU CAN REDUCE RISK!
Recovery from a stress fracture can involve complete rest for 6 to 10 weeks. It is important to recognize possible signs and risk factors to avoid bone damage and unnecessary time off dance.

• Avoid rapid increase in dance intensity
• Regulate pointe work and jumping intensity, especially after holiday breaks
• Avoid dancing on hard flooring
• Wear protective shoes inside and outside of dance
• Refer suspected dancers for nutritional consult to address restricted eating and vitamin deficiencies
• Work in correct alignment
• Improve dance specific flexibility, endurance, balance control, and strength
  

References:
IADMS:  http://c.ymcdn.com/sites/www.iadms.org/resource/resmgr/resource_papers/bone_health_female_dancers.pdf;