Tonight was Mary's first ride with the short cranks, and she thought they stressed her knees noticeably less than the regular length cranks, something she is even more sensitive to now after tearing two cartilages in her knee a few months ago. They also give a little more room when pedaling and when standing up in the foot holes to walk the trike backwards. Because her heels won't go down as far they may also permit the foot holes to be covered over (with slit spandex fabric or Velcro attached stiff panels) for better aerodynamics and more warmth in winter.