The effect of walking program on bone mass density in thin girls

Purpose: This study aims to investigate the effect of walking program on bone mass density in
order to prevent bone loss and osteoporosis in thin girls.
Methods: Twenty untrained thin girls (19-25 year) took part in this study and were divided randomly
into two experimental (n=10; BMI, 17.73±1.05 kg/m2) and control group (n=10; BMI, 17.51±1.21
kg/m2). Initially, bone mass density in both hip and spinal (L2-L4) areas were determined by using dual
energy X-ray absorptiometry (DEXA) and bloods parameter were measured by routine laboratory test.
Then the experimental group started to perform an exercise program that involved 30 minutes walking
at an intensity corresponding to 50%-75% of heart rate, 3 sessions per week for 2 months. After 2
months all measurements were repeated. Data were analyzed by student t- test (pre-post) at the level of
P<0.05. Results: The results showed that walking program had no effect on bone mass density in thin
girls, and had no effect on serum calcium and phosphorus, but the level of serum estrogen in the
experimental group was more than the control group (P=0.004). Although, there was no significant
change in total body weight in the experimental groups, lean mass were significantly increased and the
percent of body fat as well as fat mass were significantly decreased in them (P=0.0005). Conclusions:
Therefore, it could be concluded that short term walking program does not effect on bone mass density
in thin girls and it means that they are still at risk of osteoporosis and it seems more studies in
preventing of this illness in thin girls are needed.