Exercise as it relates to Disease/Dancing your way to stronger bones

This page has been written for a university assignment for the unit: Health, Disease and Exercise at the University of Canberra.

This analysis of the article "Simple, novel physical activity maintains proximal femur bone mineral density, and improves muscle strength and balance in sedentary, post-menopausal Caucasian women." From the Osteoporosis International journal on October 2007, Volume 18, Issue 10, pp 1379–1387.

What is the background to this research?

Bone density is defined as “the amount of bone tissue in a particular volume of bone.” Bone density starts to reduce from our late twenties and is sped up by:

• • Osteopenia
• • Osteoporosis
• • Not achieving the recommended amounts of Calcium or Vitamin D in their daily diet
• • Rheumatoid arthritis

Low impact exercises such as walking have shown to have minimal effects on bone density. High impact exercise that causes a great amount of impact on the skeletal system have shown to improve bone density however with people whom already have low bone density; participating in high magnitude exercises have a great risk. Strength training will also incidentally improve bone density and prevent falls due to having increase muscle control and coordination.

Prevalence

A study in 2011-12 showed that approximately 726,000; 3.3% of Australians self-reported having osteoporosis. Women over the age of 50 made up 15% of the statistics.

Where is the research from?

This study was approved by the Human Research Ethics Committee at Griffith University, Gold Coast, Australia in 2003.

What kind of research was this?

This research was a yearlong study which baseline results for bone density were taken at 6 and 12 months. All other tests in this study were taken at 12 months only.

What did the research involve?

45 women whom were sedentary, in good health, were at least 5 years post-menopausal, volunteered and gave written consent for the study and were randomly sorted into one of 3 groups; Line dancing, line dancing and squats and line dancing, squats and foot stamping. Many participants were unavailable for follow up testing causing the participant numbers to decrease to 31. This study looked at how many participants were compliant to the exercises given and for the amount of repetitions or time spent doing the activities. Collecting participant information such as height, weight, years since the onset of menopause, amount of daily exercise completed and calcium consumption were also necessary for this study.

What were the basic results?

Outcome	Group 1 (LD)	Group 2 (LDS)	Group 3 (LDSS)	Mean
BUA (dB/MHz)	0.43 ± 4.4	2.3 ± 4.4	−2.6 ± 3.1	−0.07 ± 4.4
PF BMD (g/cm2)	−0.026 ± 0.03	−0.009 ± 0.03	−0.004 ± 0.04	−0.012 ± 0.03
LS BMD (g/cm2)	0.0048 ± 0.05	0.0004 ± 0.04	−0.011 ± 0.43	−0.006 ± 0.44
Squats (amount)	12 ± 12	21 ± 20	39 ± 26	14 ± 11
Single leg stance (s)	15 ± 13	13 ± 1	13 ± 11	13 ± 11
Timed up and go (s	−2 ± 1	−2 ± 2	−2 ± 1	−2 ± 2
Forward step velocity (m/s)	0.22 ± 0.56	0.31 ± 0.88	−0.3 ± 0.85	0.036 ± 0.82
Lateral step velocity (m/s)	0.36 ± 0.55	0.36 ± 0.34	0.13 ± 0.66	0.27 ± 0.53

Average changes after 1 year of specifically assigned exercises

LD= Line dancing, LDS=Line dancing and squats, LDSS= Line dancing, squats and stamping BUA =broadband ultrasound attenuation, PF=proximal femur, LS=lumbar spine, BMD=bone mineral density

How did the researchers interpret the results?

Between the groups, there were minimal differences for bone mineral density at both lumbar spine and proximal femur however in those in the LDSS group, there was a more significant and positive correlation to the compliance to doing the stamping exercise. All groups showed improvement with the squat task and a positive correlation between squat compliance and functional squats capacity was shown.

What conclusions should be taken away from this research?

Exercising once a week in a dance class helped the participants maintained bone density as well as gaining improvements to lower body strength and better dynamic and static balance. Home based exercises also improved these traits and reduced musculoskeletal precursors to hip fracture. Exercising more using the lower extremities such as foot stamping and squats allow for greater muscular gain and bone mineral maintenance as well as a further reduced falling chance by improving the participants balance. Whole heel drops proved to have little impact on the proximal femur however it is hypothesized that with a higher magnitude force or ipsilateral stamping may lead to an increased stimuli and improvement on bone mineral density for the proximal femur. Differing tasks of varying forces are known to cause further bone growth than the same activity being consistently repeated.

What are the implications of this research?

This research had no control group for dancing and the group participating only in the line dancing session was used as the control group for stamping and squatting. There was a drop-out rate of 32% which altered the data. All groups started with 15 participants and by the testing the group 1 dropped to 10 people, group 2 to 9 people and group 3 to 12 people. Group 2 which had the additional squatting exercise amount of participation. Intermittent knee pains caused participants to stop their task in both groups 2 and 3 and was shown to be higher in group 2 due to participants being heavier. Compliance to the activities was another issue as there was no complete activity compliance within the study. Average squatting compliance was the lowest at 65%, Line dancing compliance was 70%, and stamp compliance was 80%. This shows that activities which involve little amounts of effort were of the highest compliance rates compared to the more full body exercises.