I think Shawn Fears said it best.
Using hand weight and ankle weights certainly increases the intensity of the workout when walking, and may help increase heart rate for those who cannot run or jog, but the added weight is too insignificant to really see an improvement in bone density or bone health… better results can be had through traditional strength training.
Adding weight to the hands or ankles may also significantly alter the natural gait of the participant as well; definitely not a good idea for anyone, especially those that train intensely or competitively.
A better idea to increase intensity (without having to run) would be to add a weight vest, add incline, or perhaps throw in some walking lunges or stationary squats every “x” number of minutes/miles/etc.
Any type of walking will have the pizoelectric effect, in fact sitting in an improper posture will also have that affect due to the body fighting gravity.
If I am reading this right what you are asking is in reference to Wolf’s Law where bone density is directly proportional to the stress placed on it. The addition of a couple of pounds will have no bearing on her goals, but jogging/running will have a better effect as the forces of impact are much greater than that of walking with weights, better yet sprinting will increase the stress place on the skelatal system even more(of course these may be contraindicated).
If the need to add external load during locamotion is absolutely set in her mind then an adjustable weight vest would be your best be. With that being said, plain ‘ol resistance training should provide the necessary stress for bone remodeling.
In regard to walking with a weighted vest, this is often recommended for people without a diagnosis of osteoporosis in the spine, however, if you have a client with this condition, loading the spine is not recommended.
I agree that walking with ankle weights and hand weights is contra-indicated. I’ve seen people with wrist and elbow issues related to holding hand weights (or even, in the day, a Walkman).
Relative to bone building. Any movement that requires impact will benefit the skeletal structure. Is the relationship linear with weight, meaning do we increase bone building linear with increased impact (through wearing ankle weights) I believe it would be safe to say YES. However, I would rather bypass the weights in avoiding unnecessary strain upon knees, hips and ankles.