Skeletal Flexibility
Your tendons and joints are pliable, making basic tasks like sitting upright or moving painful. You take (IE) × 10 percent less damage from all bludgeoning damage. Your movement rate is reduced by (IE) × 10 percent, and you have a +(IE) bonus on all saving throws against bludgeoning, force, or thunder damage, but when you take bludgeoning, force, or thunder damage, you must succeed on a Dexterity saving throw to avoid falling prone as your joints buckle. The DC equals 8 + (IE) or half the damage you take, whichever number is higher. If you take damage from multiple sources, such as a club and a ram, you make a separate saving throw for each source of damage. You also can benefit from a +(IE) bonus to all rolls against being restrained or grappled, although this also causes (IE) psychic damage if you use this bonus due to the pain. You’ve learned a lot about your own bones and joints, so you have a +(IE) bonus to Wisdom (Medicine) checks related to bones and joints. If you have multiple traits, you may choose Dislocation and Hyperelasticity as one or more of them.
Real-world Examples
Ehlers-Danlos Syndrome, Joint Hypermobility Syndrome, Hypophosphatasia, Osteoporosis
Assistive Options
Braces over your limbs and joints can give you a +1 to the Dexterity saving throws to avoid falling prone but also cause a −1 penalty on all Dexterity (Acrobatics) checks.