1. Are there physical similarities between, for example, those who sustain low back injuries?
The answer to this is an unqualified _yes._ There are genetic tendencies, within families, for the development of specific body types. Some body types are more often associated with predisposing vulnerability to certain types of injuries.
Thus, a tall, slender father who has sustained a lumbar injury may, indeed, produce a tall slender son who is vulnerable to the same injury.
Also, it is not unusual for descendants to engage in similar work as their parents. A mother who performed production work or a father who did construction work are more likely to produce children who work in similar vocations. They would be similarly vulnerable in high injury-risk occupations.
2. But I suspect you were also asking whether there are families with disabled members who produce successive generations of disabled individuals. And, again, the answer is _yes._
A father disabled by the time he is 30 may well produce children who view disability as either an inevitable outcome of life_or certainly not an unusual outcome. A child raised on workers_ compensation income, whose home was purchased by a workers_ compensation settlement, and whose same sex role-model was continually obtunded by pain is more likely to reproduce that pattern in a subsequent generation.
One example that always comes to mind was a tall thin, male who had sustained a mild back injury but perceived himself as permanently disabled. His father and two brothers were both permanently disabled. He was twenty-two years of age. His father and brothers had been disabled before age twenty-eight. He tearfully stated that he had always hoped to lead a long and productive career in construction, _working until I was maybe even thirty._
