Limits...
Alteration in global motor strategy following lateral ankle sprain.

Bastien M, Moffet H, Bouyer LJ, Perron M, Hébert LJ, Leblond J - BMC Musculoskelet Disord (2014)

Bottom Line: The global body centre of mass variables were significantly correlated to SEBT performance (MRD).Modifications in global motor strategies were found in participants with LAS as well as a decreased performance on the SEBT for the injured and uninjured lower limbs.These results support the hypothesis that following LAS, there may be a maladaptive reorganization of the central motor commands. 3b.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Medicine, Rehabilitation Department, Laval University, Quebec, QC, Canada. Helene.Moffet@rea.ulaval.ca.

ABSTRACT

Background: Lateral ankle sprain (LAS) has often been considered an injury leading to localized joint impairments affecting the musculoskeletal system. Persistent chronic ankle instability and bilateral alterations in motor control after a first ankle sprain episode suggest that the origin of relapses might be a maladaptive reorganization of central motor commands. The objectives of this study were (1) to compare the quality of motor control through motor strategy variables of two groups (with and without LAS) from a military population (n = 10/group), (2) to evaluate the contribution of the lower limbs and the trunk to global body strategy and (3) to identify which global variable best estimates performance on the Star Excursion Balance Test (SEBT) for each group, reaching direction, and lower limb.

Methods: Personal and clinical characteristics of the participants of both groups were collected. Their functional ability was measured using questionnaires and they performed a series of functional tests including the SEBT. During this test, the maximal reach distance (MRD) and biomechanical data were collected to characterize whole body and segmental strategies using a 3D motion capture system.

Results: At maximal lower limb reach, participants with LAS had a smaller variation in their vertical velocity in lowering-straightening and lowered the body centre of mass less for all injured limb conditions and some conditions with the uninjured lower limb. The global body centre of mass variables were significantly correlated to SEBT performance (MRD).

Conclusion: Modifications in global motor strategies were found in participants with LAS as well as a decreased performance on the SEBT for the injured and uninjured lower limbs. These results support the hypothesis that following LAS, there may be a maladaptive reorganization of the central motor commands.

Level of evidence: 3b.

Show MeSH

Related in: MedlinePlus

Kinematics variables during the SEBT task, experimental setting and description of subtasks and events. Illustration of the six conditions at the SEBT (3 reaching directions per limb; AM: anteromedial, M: medial, PM: posteromedial) and profiles (mean ± 1 standard deviation; n = 3 trials) of the vertical position of the reaching foot (A), global body CoM (CoMgl) (B and C) and joint amplitude of motion of the stance limb (D) in a typical healthy subject in the PM reaching direction. The central grey rectangle, called the central phase around foot contact, represents the critical period used for the analyses. The lowest vertical position of the tip of the reaching foot was used to subdivide the task, which corresponds to the “foot contact” event (vertical line at 50% of the task). The first subtask is characterized by body lowering (B and D) and alignment of the reaching limb for foot contact (A). In the second subtask which occurred after foot contact, a rapid straightening up of the entire body (B and C) is performed while returning from perturbation in single-limb stance. The transition between subtasks represents a highly challenging period for stability and motor control as a change in movement direction takes place at the perceived limits of stability. This transition period, called the central phase, was defined as -1 s to +1 s after foot contact. Further analysis about the quality of motor control was performed during this phase.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4300726&req=5

Fig1: Kinematics variables during the SEBT task, experimental setting and description of subtasks and events. Illustration of the six conditions at the SEBT (3 reaching directions per limb; AM: anteromedial, M: medial, PM: posteromedial) and profiles (mean ± 1 standard deviation; n = 3 trials) of the vertical position of the reaching foot (A), global body CoM (CoMgl) (B and C) and joint amplitude of motion of the stance limb (D) in a typical healthy subject in the PM reaching direction. The central grey rectangle, called the central phase around foot contact, represents the critical period used for the analyses. The lowest vertical position of the tip of the reaching foot was used to subdivide the task, which corresponds to the “foot contact” event (vertical line at 50% of the task). The first subtask is characterized by body lowering (B and D) and alignment of the reaching limb for foot contact (A). In the second subtask which occurred after foot contact, a rapid straightening up of the entire body (B and C) is performed while returning from perturbation in single-limb stance. The transition between subtasks represents a highly challenging period for stability and motor control as a change in movement direction takes place at the perceived limits of stability. This transition period, called the central phase, was defined as -1 s to +1 s after foot contact. Further analysis about the quality of motor control was performed during this phase.

Mentions: During the SEBT, the participant had to: (1) touch the floor as far as possible with the tip of the foot of the reaching limb in three different directions with respect to the stance limb (anteromedial [AM], medial [M] and posteromedial [PM] directions) and (2) return to unipedal stance after each reaching movement while maintaining balance on the stance limb with the hands resting on the iliac crests. The AM, M and PM directions were the ones proposed by Hertel et al. [62] because these directions were able to identify significant reach deficits associated with chronic ankle instability and provided complementary and non-redundant information. After a practice session [37, 63] (six trials/direction followed by a five-minute rest period), three successful trials, separated by a ten-second rest period, were recorded for each direction (Figure 1). Trials were rejected according to the criteria used in previous studies [62, 64, 65] (1) weight-bearing by the reaching limb, (2) displacement of the stance limb, or (3) loss of balance. As shown in Figure 1, the directions to be followed by the reaching limb during the tests were clearly marked on the floor using graduated tape. The order of test conditions (two legs and three directions) was determined as follows: first the leg order was randomly selected, then a test direction was randomly determined. All conditions for one leg were completed starting with the determined direction followed by the next anticlockwise direction (right leg) or clockwise direction (left leg). The same condition order was then used for the second leg.Figure 1


Alteration in global motor strategy following lateral ankle sprain.

Bastien M, Moffet H, Bouyer LJ, Perron M, Hébert LJ, Leblond J - BMC Musculoskelet Disord (2014)

Kinematics variables during the SEBT task, experimental setting and description of subtasks and events. Illustration of the six conditions at the SEBT (3 reaching directions per limb; AM: anteromedial, M: medial, PM: posteromedial) and profiles (mean ± 1 standard deviation; n = 3 trials) of the vertical position of the reaching foot (A), global body CoM (CoMgl) (B and C) and joint amplitude of motion of the stance limb (D) in a typical healthy subject in the PM reaching direction. The central grey rectangle, called the central phase around foot contact, represents the critical period used for the analyses. The lowest vertical position of the tip of the reaching foot was used to subdivide the task, which corresponds to the “foot contact” event (vertical line at 50% of the task). The first subtask is characterized by body lowering (B and D) and alignment of the reaching limb for foot contact (A). In the second subtask which occurred after foot contact, a rapid straightening up of the entire body (B and C) is performed while returning from perturbation in single-limb stance. The transition between subtasks represents a highly challenging period for stability and motor control as a change in movement direction takes place at the perceived limits of stability. This transition period, called the central phase, was defined as -1 s to +1 s after foot contact. Further analysis about the quality of motor control was performed during this phase.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4300726&req=5

Fig1: Kinematics variables during the SEBT task, experimental setting and description of subtasks and events. Illustration of the six conditions at the SEBT (3 reaching directions per limb; AM: anteromedial, M: medial, PM: posteromedial) and profiles (mean ± 1 standard deviation; n = 3 trials) of the vertical position of the reaching foot (A), global body CoM (CoMgl) (B and C) and joint amplitude of motion of the stance limb (D) in a typical healthy subject in the PM reaching direction. The central grey rectangle, called the central phase around foot contact, represents the critical period used for the analyses. The lowest vertical position of the tip of the reaching foot was used to subdivide the task, which corresponds to the “foot contact” event (vertical line at 50% of the task). The first subtask is characterized by body lowering (B and D) and alignment of the reaching limb for foot contact (A). In the second subtask which occurred after foot contact, a rapid straightening up of the entire body (B and C) is performed while returning from perturbation in single-limb stance. The transition between subtasks represents a highly challenging period for stability and motor control as a change in movement direction takes place at the perceived limits of stability. This transition period, called the central phase, was defined as -1 s to +1 s after foot contact. Further analysis about the quality of motor control was performed during this phase.
Mentions: During the SEBT, the participant had to: (1) touch the floor as far as possible with the tip of the foot of the reaching limb in three different directions with respect to the stance limb (anteromedial [AM], medial [M] and posteromedial [PM] directions) and (2) return to unipedal stance after each reaching movement while maintaining balance on the stance limb with the hands resting on the iliac crests. The AM, M and PM directions were the ones proposed by Hertel et al. [62] because these directions were able to identify significant reach deficits associated with chronic ankle instability and provided complementary and non-redundant information. After a practice session [37, 63] (six trials/direction followed by a five-minute rest period), three successful trials, separated by a ten-second rest period, were recorded for each direction (Figure 1). Trials were rejected according to the criteria used in previous studies [62, 64, 65] (1) weight-bearing by the reaching limb, (2) displacement of the stance limb, or (3) loss of balance. As shown in Figure 1, the directions to be followed by the reaching limb during the tests were clearly marked on the floor using graduated tape. The order of test conditions (two legs and three directions) was determined as follows: first the leg order was randomly selected, then a test direction was randomly determined. All conditions for one leg were completed starting with the determined direction followed by the next anticlockwise direction (right leg) or clockwise direction (left leg). The same condition order was then used for the second leg.Figure 1

Bottom Line: The global body centre of mass variables were significantly correlated to SEBT performance (MRD).Modifications in global motor strategies were found in participants with LAS as well as a decreased performance on the SEBT for the injured and uninjured lower limbs.These results support the hypothesis that following LAS, there may be a maladaptive reorganization of the central motor commands. 3b.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Medicine, Rehabilitation Department, Laval University, Quebec, QC, Canada. Helene.Moffet@rea.ulaval.ca.

ABSTRACT

Background: Lateral ankle sprain (LAS) has often been considered an injury leading to localized joint impairments affecting the musculoskeletal system. Persistent chronic ankle instability and bilateral alterations in motor control after a first ankle sprain episode suggest that the origin of relapses might be a maladaptive reorganization of central motor commands. The objectives of this study were (1) to compare the quality of motor control through motor strategy variables of two groups (with and without LAS) from a military population (n = 10/group), (2) to evaluate the contribution of the lower limbs and the trunk to global body strategy and (3) to identify which global variable best estimates performance on the Star Excursion Balance Test (SEBT) for each group, reaching direction, and lower limb.

Methods: Personal and clinical characteristics of the participants of both groups were collected. Their functional ability was measured using questionnaires and they performed a series of functional tests including the SEBT. During this test, the maximal reach distance (MRD) and biomechanical data were collected to characterize whole body and segmental strategies using a 3D motion capture system.

Results: At maximal lower limb reach, participants with LAS had a smaller variation in their vertical velocity in lowering-straightening and lowered the body centre of mass less for all injured limb conditions and some conditions with the uninjured lower limb. The global body centre of mass variables were significantly correlated to SEBT performance (MRD).

Conclusion: Modifications in global motor strategies were found in participants with LAS as well as a decreased performance on the SEBT for the injured and uninjured lower limbs. These results support the hypothesis that following LAS, there may be a maladaptive reorganization of the central motor commands.

Level of evidence: 3b.

Show MeSH
Related in: MedlinePlus