A foot support device, adapted for attachment to a leg of a user, for therapeutically treating plantar fasciitis in the foot in said leg of said user so as to dynamically control and maintain consistent dorsiflexion of the plantar fascia with the user simultaneously permitted to be mobile during treatment, the foot support device comprises: a foot assembly comprising a sock adapted for placement over the foot in said leg to undergo treatment, and a guide member affixed to the sock proximate the ball of the foot with said guide member having a passageway extending therethrough; a knee assembly comprising a first and second adjustable strap (11, 12) in a relationship above and below the kneecap of the knee in said leg, and a material section interconnecting the first adjustable strap to the second adjustable strap such that upon attachment of the foot support device to said leg the knee assembly forms a brace for the knee which engages and surrounds the knee, a tension assembly comprising a tension strap (3, 4) having open ends with the tension strap (3, 4) extending through the passageway of said guide member to form a continuous loop extending from one side of the knee assembly through the passageway in said guide member to the opposite side of said knee assembly; characterized in that the foot support device further comprises: coupling members (7, 8; 17 - 20) for interconnecting each of the open ends of said tension strap (3, 4) to the material section of the knee assembly, at points of connection to the knee assembly located on opposite sides of the knee in substantial alignment with a longitudinal axis extending through the rotatable joint of the knee, such that tension in said tension strap (3, 4) is maintained constant whether the user is mobile or stationary and with said tension strap (3, 4) being slidably movable within the passageway of the guide member in response to mobility of the treated leg for dynamically providing consistent dorsiflexion of the plantar fascia during treatment; and means for adjusting tension in said tension strap (3, 4) to apply consistent and uniform pressure to the ball of the foot undergoing treatment wherein the tension strap (3, 4) adjustably slides within the passageway of said guide member to maintain consistency in tension in said tension strap (3, 4) in response to movement of the leg or foot of the user. a foot assembly comprising a sock adapted for placement over the foot in said leg to undergo treatment, and a guide member affixed to the sock proximate the ball of the foot with said guide member having a passageway extending therethrough; a knee assembly comprising a first and second adjustable strap (11, 12) in a relationship above and below the kneecap of the knee in said leg, and a material section interconnecting the first adjustable strap to the second adjustable strap such that upon attachment of the foot support device to said leg the knee assembly forms a brace for the knee which engages and surrounds the knee, a tension assembly comprising a tension strap (3, 4) having open ends with the tension strap (3, 4) extending through the passageway of said guide member to form a continuous loop extending from one side of the knee assembly through the passageway in said guide member to the opposite side of said knee assembly; coupling members (7, 8; 17 - 20) for interconnecting each of the open ends of said tension strap (3, 4) to the material section of the knee assembly, at points of connection to the knee assembly located on opposite sides of the knee in substantial alignment with a longitudinal axis extending through the rotatable joint of the knee, such that tension in said tension strap (3, 4) is maintained constant whether the user is mobile or stationary and with said tension strap (3, 4) being slidably movable within the passageway of the guide member in response to mobility of the treated leg for dynamically providing consistent dorsiflexion of the plantar fascia during treatment; and means for adjusting tension in said tension strap (3, 4) to apply consistent and uniform pressure to the ball of the foot undergoing treatment wherein the tension strap (3, 4) adjustably slides within the passageway of said guide member to maintain consistency in tension in said tension strap (3, 4) in response to movement of the leg or foot of the user.