The report noted that although many cyclists did strength training during the off-season this was not enough to maintain bone mineral density (BMD) and that the large number of hours riding a bike was having some sort of negative effect on bone health.
It is possible that the large amount of non-weight-bearing training conducted by the athletes in the present study attenuated the osteogenic effect elicited by the resistance training. Most studies documenting a beneficial effect of resistance training on bone mass are longitudinal studies, lasting for minimum 7–12 months, with two to three sessions per week. Usually, cyclists perform strength training during off-season, which is the winter months from October to January. Thus, 2–4 months of strength training might not be sufficient to elicit the bone modelling process.
The report made reference to previous studies which showed the positive effect of strength training to increase bone mineral density (BMD).
A 1999 study stated: "The research completed to date indicates that resistance training is positively associated with high BMD in both young and older adults and that the effect of resistive exercise is relatively site specific to the working muscles and the bones to which they attach" In other words, hiking and skipping are not going to increase BMD at the wrist, arms and shoulders. But an exercise like a bench press or overhead press will.
"Although aerobic exercise and weight bearing physical activity are important in maintaining overall health and healthy bone, resistance training exercise seems to have a more potent impact on bone density." So skipping and hiking may have beneficial effect on hips and lumbar spine but lifting a weight while standing (such as squat, dead lift and overhead press) will have a greater effect.
I was diagnosed with osteopenia about 10 years ago (in my mid-40s) after I broke my hip. (My T numbers averaged -1.2 for hip and lumbar spine.) I now do strength training all year round. I also increased my body weight from a relatively skinny 67kg to a more healthy 79kg. I'm 186cms / 6' 1". (A lot of that is fat, by the way.) Comparative scans of my hip and lumbar spine before and after indicate that I have halted the decline in BMD but as yet have not reversed it. I do a programme of four barbell exercises: squat, deadlift, bench press, and overhead press three times a week. Although during the summer months I am reluctant to go to the gym more than once a week as I'd rather be outside enjoying myself