Fixed-support and change-in-support balance recovery strategies. On the ''fixed-support'' column, both ankle (left) and hip strategies (middle) are represented in the sagittal plane. On the ''change-in-support'' column, strategies are stepping (left) and grasping (right). Illustration adapted from Maki and McIlroy [50]. 

Contexts in source publication

Context 1

... are rapid and auto- matic movement strategies used by the CNS whenever there is a disturbance applied to a body segment that tends to cause disequilibrium or changes in postural orientation [34]. Individuals have two distinct classes of strategies to reactively recover balance: ''fixed-support'' and ''change- in-support'' strategies (see Fig. 3). They are distinguished by modification or not of the contact configuration with the environment, i.e. a limb movement modifying the BoS ...

Context 2

... -or can- not -change the size of the BoS. Two main strategies have been identified: the ankle strategy and the hip strategy [35]. A large majority of the published studies focus on these. The ankle strategy is the most commonly response used during quiet stance. In this situation, the human body mechani- cally acts like an inverted pendulum (see Fig. 3), oscillating around the ankles. It consists of creating torques that move the CoP under the feet in order to accelerate or deceler- ate the motion of the CoM [35,97]. Interestingly, this is the first -and probably the least energetically costly -human response to postural perturbations, appearing even before a significant displacement ...

Context 3

... hip strategy consists of oscillating around the hip joints in both frontal and sagittal plane (see Fig. 3) with a counter-rotation at the neck and ankle joints. This strategy mechanically allows creation of a horizontal force to accel- erate or decelerate the CoM [35]. It is usually combined with an ankle strategy [34] and mostly seen in a particular con- text, where producing ankle torque is difficult, such as if the stance platform is ...

Context 4

... function depends on strategies that individuals use to reach a steady state [27,33]. Nevertheless, the selec- tion of the response strategy depends on many information: characteristics of the external perturbation, individual's expectations, goals and prior experience, central set (auto- matic responses based on expectation of stimulus and task characteristics), initial position, given instructions and the nature of the ongoing motor task that is disturbed. The focal responses to face the perturbation are rapid and auto- matic movement strategies used by the CNS whenever there is a disturbance applied to a body segment that tends to cause disequilibrium or changes in postural orientation [34]. Individuals have two distinct classes of strategies to reactively recover balance: ''fixed-support'' and ''change- in-support'' strategies (see Fig. 3). They are distinguished by modification or not of the contact configuration with the environment, i.e. a limb movement modifying the BoS ...

Context 5

... individuals are standing quietly without any additional support, the area under and between their feet repre- sents their BoS. The so-called ''fixed-support'' strategies are performed to control the movement of the CoM with- out changing that BoS. They are usually used for very small and/or slow perturbations or particular context, in which the CNS detects that the system does not need to -or can- not -change the size of the BoS. Two main strategies have been identified: the ankle strategy and the hip strategy [35]. A large majority of the published studies focus on these. The ankle strategy is the most commonly response used during quiet stance. In this situation, the human body mechani- cally acts like an inverted pendulum (see Fig. 3), oscillating around the ankles. It consists of creating torques that move the CoP under the feet in order to accelerate or deceler- ate the motion of the CoM [35,97]. Interestingly, this is the first -and probably the least energetically costly -human response to postural perturbations, appearing even before a significant displacement of CoM [35] or stepping strategy ini- tiation [40,57]. Likewise, if the CoM is for example projected forward, the CNS will automatically respond to move the CoP forward too, in order to reduce the CoM falling torque and to try to reverse its direction of displacement to drive it closer from its initial position. However, this strategy is limited both by the size of the foot and torques developed by muscular activation, that are reduced with age ...

Context 6

... hip strategy consists of oscillating around the hip joints in both frontal and sagittal plane (see Fig. 3) with a counter-rotation at the neck and ankle joints. This strategy mechanically allows creation of a horizontal force to accel- erate or decelerate the CoM [35]. It is usually combined with an ankle strategy [34] and mostly seen in a particular con- text, where producing ankle torque is difficult, such as if the stance platform is narrow and/or the subject is instructed to not step. Nevertheless, it is not preferred when other strategies -like change-in-support -are available ...