Proper height measurements of child along with father and mother is needed. We can then calculate mid parental height. And with help of growth charts can see , if actually your baby is short or it is just your apprehension.
If your baby is actually short as per chart, than need to investigate properly.
Hanging on bars will not make too much of difference.
Next Steps
best things which you can do is provide nutritious diet rich in protein and consult Pediatrician or Pediatric endocrinologist.