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Effects of fatigue on trunk stability in elite gymnasts.

van Dieën JH, Luger T, van der Eb J - Eur. J. Appl. Physiol. (2011)

Bottom Line: Nine female gymnasts participated in the study.To fatigue trunk muscles, four series of five dump handstands on the uneven bar were performed.In addition, the maximum displacement after the sudden release was increased (p = 0.009), while the rate of recovery after the perturbation was decreased (p = 0.05).

View Article: PubMed Central - PubMed

Affiliation: Faculty of Human Movement Sciences, Research Institute MOVE, VU University Amsterdam, Van der Boechorststraat 9, 1081 BT Amsterdam, The Netherlands. j.vandieen@fbw.vu.nl

ABSTRACT
The aim of the present study was to test the hypothesis that fatigue due to exercises performed in training leads to a decrement of trunk stability in elite, female gymnasts. Nine female gymnasts participated in the study. To fatigue trunk muscles, four series of five dump handstands on the uneven bar were performed. Before and after the fatigue protocol, participants performed three trials of a balancing task while sitting on a seat fixed over a hemisphere to create an unstable surface. A force plate tracked the location of the center of pressure (CoP). In addition, nine trials were performed in which the seat was backward inclined over a set angle and suddenly released after which the subject had to regain balance. Sway amplitude and frequency in unperturbed sitting were determined from the CoP time series and averaged over trials. The maximum displacement and rate of recovery of the CoP location after the sudden release were determined and averaged over trials. After the fatigue protocol, sway amplitude in the fore-aft direction was significantly increased (p = 0.03), while sway frequency was decreased (p = 0.005). In addition, the maximum displacement after the sudden release was increased (p = 0.009), while the rate of recovery after the perturbation was decreased (p = 0.05). Fatigue induced by series of exercises representing a realistic training load caused a measurable decrement in dynamic stability of the trunk in elite gymnasts.

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Schematic of the unperturbed seated balancing task (a) and the sudden release task (b)
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Fig1: Schematic of the unperturbed seated balancing task (a) and the sudden release task (b)

Mentions: For the measurements of trunk stability, subjects were seated with arms in their lap on an unstable seat, which required them to dynamically balance by trunk movement only (Fig. 1). The seat was mounted over a hemisphere (radius of hemisphere: 25 cm, height of the seat relative to the lowest point on the hemisphere: 17 cm), creating instability in all directions. To trace the center of pressure (CoP), the seat was placed on a custom-made strain gauge force plate that was sampled at 200 samples/s. The force plate was calibrated prior to each measurement session, by placing known weights on the plate. Foot supports were attached to the seat to prevent influence of leg movements. The footplate was adjusted to support the feet with the knees and hips at 90° angles. A rail was built around the seat for safety. Trunk balance was tested using two tasks. The first task required the subject to sit as still as possible and lasted 30 s. Three repetitions of this task were performed before and after the fatiguing exercise, as reliability of single measurements was previously shown to be poor (Dieën et al. 2010b). In the second task, the subject leaned back on the seat, supported by a strap around the thorax that was attached to two electromagnets on the safety rail in front of the subject. The length of the strap was adjusted to obtain a constant inclination angle for each subject. After a random interval of 3–7 s after the start of the measurement, the electromagnets were released and the subject had to regain balance as quickly as possible. Recording of data was continued for a total of 20 s. Nine repetitions were performed within a few minutes before and after the fatigue exercise.Fig. 1


Effects of fatigue on trunk stability in elite gymnasts.

van Dieën JH, Luger T, van der Eb J - Eur. J. Appl. Physiol. (2011)

Schematic of the unperturbed seated balancing task (a) and the sudden release task (b)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3299971&req=5

Fig1: Schematic of the unperturbed seated balancing task (a) and the sudden release task (b)
Mentions: For the measurements of trunk stability, subjects were seated with arms in their lap on an unstable seat, which required them to dynamically balance by trunk movement only (Fig. 1). The seat was mounted over a hemisphere (radius of hemisphere: 25 cm, height of the seat relative to the lowest point on the hemisphere: 17 cm), creating instability in all directions. To trace the center of pressure (CoP), the seat was placed on a custom-made strain gauge force plate that was sampled at 200 samples/s. The force plate was calibrated prior to each measurement session, by placing known weights on the plate. Foot supports were attached to the seat to prevent influence of leg movements. The footplate was adjusted to support the feet with the knees and hips at 90° angles. A rail was built around the seat for safety. Trunk balance was tested using two tasks. The first task required the subject to sit as still as possible and lasted 30 s. Three repetitions of this task were performed before and after the fatiguing exercise, as reliability of single measurements was previously shown to be poor (Dieën et al. 2010b). In the second task, the subject leaned back on the seat, supported by a strap around the thorax that was attached to two electromagnets on the safety rail in front of the subject. The length of the strap was adjusted to obtain a constant inclination angle for each subject. After a random interval of 3–7 s after the start of the measurement, the electromagnets were released and the subject had to regain balance as quickly as possible. Recording of data was continued for a total of 20 s. Nine repetitions were performed within a few minutes before and after the fatigue exercise.Fig. 1

Bottom Line: Nine female gymnasts participated in the study.To fatigue trunk muscles, four series of five dump handstands on the uneven bar were performed.In addition, the maximum displacement after the sudden release was increased (p = 0.009), while the rate of recovery after the perturbation was decreased (p = 0.05).

View Article: PubMed Central - PubMed

Affiliation: Faculty of Human Movement Sciences, Research Institute MOVE, VU University Amsterdam, Van der Boechorststraat 9, 1081 BT Amsterdam, The Netherlands. j.vandieen@fbw.vu.nl

ABSTRACT
The aim of the present study was to test the hypothesis that fatigue due to exercises performed in training leads to a decrement of trunk stability in elite, female gymnasts. Nine female gymnasts participated in the study. To fatigue trunk muscles, four series of five dump handstands on the uneven bar were performed. Before and after the fatigue protocol, participants performed three trials of a balancing task while sitting on a seat fixed over a hemisphere to create an unstable surface. A force plate tracked the location of the center of pressure (CoP). In addition, nine trials were performed in which the seat was backward inclined over a set angle and suddenly released after which the subject had to regain balance. Sway amplitude and frequency in unperturbed sitting were determined from the CoP time series and averaged over trials. The maximum displacement and rate of recovery of the CoP location after the sudden release were determined and averaged over trials. After the fatigue protocol, sway amplitude in the fore-aft direction was significantly increased (p = 0.03), while sway frequency was decreased (p = 0.005). In addition, the maximum displacement after the sudden release was increased (p = 0.009), while the rate of recovery after the perturbation was decreased (p = 0.05). Fatigue induced by series of exercises representing a realistic training load caused a measurable decrement in dynamic stability of the trunk in elite gymnasts.

Show MeSH
Related in: MedlinePlus