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The role of tibialis posterior fatigue on foot kinematics during walking.

Pohl MB, Rabbito M, Ferber R - J Foot Ankle Res (2010)

Bottom Line: It was also postulated that the magnitude of the change in rearfoot motion would be associated with standing anatomical rearfoot posture.These data indicate that reduced force output of the tibialis posterior muscle did not alter rearfoot and forefoot motion during gait.The anatomical structure of the rearfoot was not associated with the dependence of muscular activity that an individual requires to maintain normal rearfoot kinematics during gait.

View Article: PubMed Central - HTML - PubMed

Affiliation: Running Injury Clinic, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada. mbpohl@ucalgary.ca.

ABSTRACT

Background: The purpose of this study was to investigate the effect of localised tibialis posterior muscle fatigue on foot kinematics during walking. It was hypothesised that following fatigue, subjects would demonstrate greater forefoot and rearfoot motion during walking. It was also postulated that the magnitude of the change in rearfoot motion would be associated with standing anatomical rearfoot posture.

Methods: Twenty-nine subjects underwent an exercise fatigue protocol aimed at reducing the force output of tibialis posterior. An eight camera motion analysis system was used to evaluate 3D foot kinematics during treadmill walking both pre- and post-fatigue. The anatomical rearfoot angle was measured during standing prior to the fatigue protocol using a goniometer.

Results: Peak rearfoot eversion remained unchanged following the fatigue protocol. Although increases in rearfoot eversion excursion were observed following fatigue, these changes were of a magnitude of questionable clinical significance (<1.0 degrees ). The magnitude of the change in rearfoot eversion due to fatigue was not associated with the anatomical measurement of standing rearfoot angle. No substantial changes in forefoot kinematics were observed following the fatigue protocol.

Conclusions: These data indicate that reduced force output of the tibialis posterior muscle did not alter rearfoot and forefoot motion during gait. The anatomical structure of the rearfoot was not associated with the dependence of muscular activity that an individual requires to maintain normal rearfoot kinematics during gait.

No MeSH data available.


Related in: MedlinePlus

Setup for the fatigue-inducing exercise and measurement of MVCs. The complete setup is shown in (A) with the subject strapped into a chair with ball placement and leg straps included. The foot is positioned on a sliding foot plate (1) and foot adduction is achieved by the subject pushing their 1st metatarsal head against the dynamometer (3). The MVCs were measured by locking the foot plate while the subject pushed isometrically against the dynamometer. A pulley system that allowed the placement of weights (2) provided adjustable resistance while the subject performed the fatiguing exercise through a 30° range of motion (B).
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Figure 1: Setup for the fatigue-inducing exercise and measurement of MVCs. The complete setup is shown in (A) with the subject strapped into a chair with ball placement and leg straps included. The foot is positioned on a sliding foot plate (1) and foot adduction is achieved by the subject pushing their 1st metatarsal head against the dynamometer (3). The MVCs were measured by locking the foot plate while the subject pushed isometrically against the dynamometer. A pulley system that allowed the placement of weights (2) provided adjustable resistance while the subject performed the fatiguing exercise through a 30° range of motion (B).

Mentions: In the present study, muscle fatigue was defined as a reduction in the capacity of the muscle to perform work or generate force [10]. Tibialis posterior was fatigued using closed chain resisted foot adduction motion. This exercise was chosen since previous MRI research indicated that tibialis posterior was selectively activated during its performance compared to open chain inversion [11]. Subjects were seated in a chair while their right foot was placed in a custom built device (Figure 1a) that allowed them to perform concentric/eccentric foot adduction contractions with adjustable resistance, similar to Kulig et al. [18]. The subjects legs were stabilised by placing a ball (diameter = 16 cm) between their knees and then strapping both lower legs together and both thighs to the chair (Figure 1a). The custom built device also contained a dynamometer (Lafayette Instrument, Lafayette, USA: Model 01163)) which was fixed against the 1st metatarsal head of the subject to enable the measurement of a maximal voluntary contraction (MVC) during isometric foot adduction. Prior to the commencement of the fatigue-inducing exercise, the mean of three MVC trials were taken to represent force output for the PRE conditions. Then with the ankle positioned in 20° plantarflexion, subjects performed sets of 50 concentric/eccentric contractions at 50% MVC through a 30° range of motion (Figure 1b). The subjects were allowed 10 seconds of rest between each set and after every four sets, MVCs were performed (Figure 2). The sets were continued until subjects MVCs had dropped below 70% of the PRE values or they were unable to complete two consecutive sets. A final set of MVCs were taken immediately following the post-fatigue walk (within 2 minutes) to determine whether subjects had recovered in terms of force output during the walking trial.


The role of tibialis posterior fatigue on foot kinematics during walking.

Pohl MB, Rabbito M, Ferber R - J Foot Ankle Res (2010)

Setup for the fatigue-inducing exercise and measurement of MVCs. The complete setup is shown in (A) with the subject strapped into a chair with ball placement and leg straps included. The foot is positioned on a sliding foot plate (1) and foot adduction is achieved by the subject pushing their 1st metatarsal head against the dynamometer (3). The MVCs were measured by locking the foot plate while the subject pushed isometrically against the dynamometer. A pulley system that allowed the placement of weights (2) provided adjustable resistance while the subject performed the fatiguing exercise through a 30° range of motion (B).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2864206&req=5

Figure 1: Setup for the fatigue-inducing exercise and measurement of MVCs. The complete setup is shown in (A) with the subject strapped into a chair with ball placement and leg straps included. The foot is positioned on a sliding foot plate (1) and foot adduction is achieved by the subject pushing their 1st metatarsal head against the dynamometer (3). The MVCs were measured by locking the foot plate while the subject pushed isometrically against the dynamometer. A pulley system that allowed the placement of weights (2) provided adjustable resistance while the subject performed the fatiguing exercise through a 30° range of motion (B).
Mentions: In the present study, muscle fatigue was defined as a reduction in the capacity of the muscle to perform work or generate force [10]. Tibialis posterior was fatigued using closed chain resisted foot adduction motion. This exercise was chosen since previous MRI research indicated that tibialis posterior was selectively activated during its performance compared to open chain inversion [11]. Subjects were seated in a chair while their right foot was placed in a custom built device (Figure 1a) that allowed them to perform concentric/eccentric foot adduction contractions with adjustable resistance, similar to Kulig et al. [18]. The subjects legs were stabilised by placing a ball (diameter = 16 cm) between their knees and then strapping both lower legs together and both thighs to the chair (Figure 1a). The custom built device also contained a dynamometer (Lafayette Instrument, Lafayette, USA: Model 01163)) which was fixed against the 1st metatarsal head of the subject to enable the measurement of a maximal voluntary contraction (MVC) during isometric foot adduction. Prior to the commencement of the fatigue-inducing exercise, the mean of three MVC trials were taken to represent force output for the PRE conditions. Then with the ankle positioned in 20° plantarflexion, subjects performed sets of 50 concentric/eccentric contractions at 50% MVC through a 30° range of motion (Figure 1b). The subjects were allowed 10 seconds of rest between each set and after every four sets, MVCs were performed (Figure 2). The sets were continued until subjects MVCs had dropped below 70% of the PRE values or they were unable to complete two consecutive sets. A final set of MVCs were taken immediately following the post-fatigue walk (within 2 minutes) to determine whether subjects had recovered in terms of force output during the walking trial.

Bottom Line: It was also postulated that the magnitude of the change in rearfoot motion would be associated with standing anatomical rearfoot posture.These data indicate that reduced force output of the tibialis posterior muscle did not alter rearfoot and forefoot motion during gait.The anatomical structure of the rearfoot was not associated with the dependence of muscular activity that an individual requires to maintain normal rearfoot kinematics during gait.

View Article: PubMed Central - HTML - PubMed

Affiliation: Running Injury Clinic, Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada. mbpohl@ucalgary.ca.

ABSTRACT

Background: The purpose of this study was to investigate the effect of localised tibialis posterior muscle fatigue on foot kinematics during walking. It was hypothesised that following fatigue, subjects would demonstrate greater forefoot and rearfoot motion during walking. It was also postulated that the magnitude of the change in rearfoot motion would be associated with standing anatomical rearfoot posture.

Methods: Twenty-nine subjects underwent an exercise fatigue protocol aimed at reducing the force output of tibialis posterior. An eight camera motion analysis system was used to evaluate 3D foot kinematics during treadmill walking both pre- and post-fatigue. The anatomical rearfoot angle was measured during standing prior to the fatigue protocol using a goniometer.

Results: Peak rearfoot eversion remained unchanged following the fatigue protocol. Although increases in rearfoot eversion excursion were observed following fatigue, these changes were of a magnitude of questionable clinical significance (<1.0 degrees ). The magnitude of the change in rearfoot eversion due to fatigue was not associated with the anatomical measurement of standing rearfoot angle. No substantial changes in forefoot kinematics were observed following the fatigue protocol.

Conclusions: These data indicate that reduced force output of the tibialis posterior muscle did not alter rearfoot and forefoot motion during gait. The anatomical structure of the rearfoot was not associated with the dependence of muscular activity that an individual requires to maintain normal rearfoot kinematics during gait.

No MeSH data available.


Related in: MedlinePlus