The effects of a 7-month high impact jumping intervention on bone mass in pre-pubescent boys and girls

• Main Author: Fuchs, Robyn K.
• Other Authors: Snow, Christine
• Language: en_US
• Published: 2012
• Subjects: Jumping > Physiological aspects; Exercise for children > Physiological aspects; Bone densitometry
• Online Access: http://hdl.handle.net/1957/34070

High impact loading activities such as jumping, performed during childhood is advocated as one preventive method for increasing peak bone mass. Thus, we conducted a randomized intervention to examine the effect of high impact loading on bone mass in 34 pre-pubescent boys and girl over a seven month period. Participants meeting all inclusion criteria were randomized into either a jumping (n=18) or stretching group (n=16), both of which exercised three times per week for 15 minutes. The jumping group completed 100 jumps off 24-inch boxes each session, while the stretching group performed low impact flexibility exercises. Attrition was 85% (6 drop outs), with an overall attendance rate of 95%. Bone area and bone mineral content (BMC) was assessed using dual energy x-ray absorptiometery (Ho logic QDR 1000/W) for the left hip (femoral neck, greater trochanter, total hip), and lumbar spine (L[subscript 2-4]). Other measures were body composition (Lang skinfold calipers); physical activity (self-report questionnaire); and calcium intake (food survey). All measurements were assessed at baseline and 7 months. Significance is denoted as p<.05. Analysis of variance (ANOVA) revealed no baseline difference between groups for age, height, weight, body fat, physical activity, or calcium intake (p>.05); however, gender differences were found for FN BMC at baseline (p<.05). Repeated measures ANOVA identified significant group differences for FN BMC (p=.015), with a trend for significance for FN area (p=.055). No significant differences in BMC or bone area were found at all other skeletal sites (p>.05). No group by gender interactions were found at baseline or at the completion of the seven month intervention. No significant differences between groups were identified for body composition, physical activity, or calcium intake in repeated measures ANOVA analyses (p>.05). In conclusion, 100 jumps performed 3 times per week at approximately 8x body weight were sufficient to stimulate an osteogenic response at the femoral neck in pre-pubescent boys and girls. Implementing jumping exercises into regular physical activity programs during pre-pubescent growing years may increase peak bone mass and potentially reduce the onset of osteoporosis. === Graduation date: 1999