Effects of Jumping on Bone Health in Young Women
Condition: Osteoporosis, Osteopenia
MeSH terms: Osteoporosis; Bone Diseases, Metabolic
Study type: Interventional

Summary: 
      This study evaluates the longitudinal, dose-dependent effects of jumping on bone health in
      young women. The women will be divided into 9 groups of varying jump height and repetitions,
      with a tenth group serving as control.
    

Detailed description: 
      Over 1 million hip and spine fractures each year are associated with osteoporosis, a disease
      of low bone mass that contributes to increased morbidity, mortality and economic strain on
      our medical system. Effective low-cost prevention strategies such as bone-loading exercise,
      could lower the incidence of osteoporotic fractures without an increase in medical costs, and
      provide an alternative to drug therapy. Activity associated with high magnitude forces such
      as fast running and jumping, have been shown to increase hip bone mass by 1.2%-4% in
      premenopausal women which may translate into a 20-30% reduction in hip fracture risk. In
      addition, high impact exercise may also produce benefits that are maintained long-term.
      However, a specific exercise prescription for improving bone health has not been determined.

      To date, no single study has examined the interactive effects of jump magnitude (height) and
      jump number (repetitions) on bone mineral density by systematically varying the height and
      number of jumps performed. In addition, no study has evaluated the effects of loading
      exercise on multiple measures of bone health, in order to quantify the effects of exercise on
      bone strength, apart from bone mineral density. Determining the optimal dose of jump exercise
      for improving bone strength will allow the investigators to determine a specific exercise
      prescription for bone health in premenopausal women and will be useful in future projects
      that intend to employ jump training to target bone health. The long-term objective of this
      line of research is to determine how impact loading improves bone quality to ultimately
      reduce fracture risk.

      This study is a randomized, controlled, trial to compare the effects of a 9-month supervised
      exercise program using three levels of load magnitude (4", 8", 12" jump height) and three
      load repetitions (10, 50, 100 jumps per session), on three dimensions of bone health (bone
      density, remodeling and strength) in 300 premenopausal women aged 18-42y. Bone density is the
      most widely recognized dimension of bone health and clinically accepted index of fracture
      risk. Bone remodeling reflects the dynamic state of bone and can predict fracture risk
      independent of bone density. Bone strength, represented by Femur Strength Index, is a
      reflection of the geometry and structural competence of bone.

      Low-cost osteoporosis prevention strategies including jumping exercises, could lower the
      incidence of osteoporotic fractures without an increase in medical costs, and provide an
      alternative to drug therapy. This project will allow the investigators to determine the
      minimum effective dose of jumping exercise required to benefit bone health in premenopausal
      women and will lead to future research on how exercise improves bone quality and reduces
      fracture risk.
    

Intervention name(s): Jump
Intervention type(s): Other
Intervention description(s): Drop jump from step
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: jumping; bone health