The purpose of this research is to develop a circuit box jumping exercise program and to examine the effects of the
circuit box jumping exercise program on bone formation, bone resorption, health related to physical fitness and balance of the
premenopausal females. The samples consisted of 57 female volunteers from Chulalongkorn University, aged between 35-45.
The subjects were divided into two groups: 28 females in the experimental group and 29 females in the control group by the
simple random sampling method. The experimental group participated in the circuit box jumping exercise program while
wearing heart rate monitors. The exercise speed was determined by the rhythm of the music. The experimental group
completed two circuits of jumping at 6 stations with 10 jumps per station three times per week, for a period of twelve weeks.
Each jumping box at Station 1 and 4 was 10 cm. high; the boxes at Station 2 and 5 were 15 cm. high; and at Station 3 and 6,
the boxes were 20 cm. in height. The intensity is 60%-80% of a maximum heart rate. The control group did not participate in
the circuit box jumping exercise program. The collected data before and after the experiment were the results of the physiology
test, the biochemical bone markers, the health related physical fitness and the balance ability. The collected data were
compared and analyzed by the mean and standard deviation. The differences of the tests are statistically significant at the .05
level.

The results of the present study are as follows;

1. After the 12-week experiment training, the findings indicated that the mean scores on bone resorption (β-
Crosslaps) of the experimental group and the control group were significantly different at 0.05 level. In addition, the findings
showed that the percentage changes on bone resorption (β-Crosslaps) variance of the experiment group reduced by -25.6528
%, while that of the control group reduced by -0.5933 %. Bone formation (PINP/β-Crosslaps) in the circuit box jumping
subjects was significantly higher after the training intervention (p < 0.05).

2. The general physiological data in the circuit box jumping subjects after the training intervention was significantly
lower in weight, resting heart rate and systolic blood pressure (p < 0.05).

3. The health-related to physical fitness in the circuit box jumping subjects after the training intervention was
significantly lower in waist/hip ratio, body fat and fat in percent while skeleton muscle mass, leg strength, flexibility and
VO2max were significantly higher after the training intervention (p < 0.05).

4. The balance in the circuit box jumping subjects after the training intervention was significantly better after the
training intervention (p < 0.05).

The circuit box jumping training has the positive effects on slowing down the bone resorption and consequently the
bone formation increased. It can be concluded that the circuit box jumping training reduces some risks of osteoporosis in the
premenopausal women. Additionally, it promotes the better health-related to physical fitness and balance.

Keywords: Biological marker, Bone resorption (beta CTx), Premenopause, Circuit box jumping training, Health-related
physical fitness, Balance