This study will compare the ability of two types of long term (12 months) weight-bearing exercise treatments (1. high-intensity jumping and 2. weight lifting) to increase bone mass of the total body, spine and hip in physically active men with osteopenia.

The overall goal of this project is to determine the efficacy of chronic (12 months) plyometric jump training exercise on bone mineral density (BMD) and markers of bone turnover in physically active males cyclists diagnosed with osteopenia below normal bone mineral density of the lumbar spine or hip.

Inclusion Criteria:

• Male
• Age 25-60 years
• No symptoms of disease
• Currently participating in cycling activities an average of 4 hr/wk for the previous 24 months
• Osteopenia of the lumbar spine and/or hip (T score < -1.0 and > -2.5 )

Exclusion Criteria:

• Medications or supplements that affect bone metabolism or prevent exercise
• Previous or current medical condition affecting bone health
• Osteoporosis of the lumbar spine and/or hip (T score > -1.0 or < -2.5)
• Cardiovascular disease
• Metallic implants
• Current smoker
• Current regular participation in high-intensity resistance training and/or plyometrics