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Quadratus femoris is minimally active in a single leg bridge and single leg squat
Thursday 22 October Papers / Journal of Science and Medicine in Sport 19S (2015) e2–e32
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difference between the control and intervention groups for object control skill competency (Model 1: B = 0.671, Model 2: B = 1.345, Model 3: B = 0.696, p > 0.05 in each). Discussion: This study found that playing the Xbox Kinect does not significantly influence children’s perceived or actual object control skills, suggesting that the utility of the Xbox Kinect for developing perceived and actual object control skill competence is questionable.
Vicon and the definition of hip rotation in the Plug in Gait model in Vicon. The markerless system allows for a simple method of capturing kinematic data, but should be used only for withinsystems analysis of data.
http://dx.doi.org/10.1016/j.jsams.2015.12.418
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Quadratus femoris is minimally active in a single leg bridge and single leg squat
Are the kinematics of the lower limb and trunk captured on a markerless motion capture system comparable to traditional marker-based system? M. Perrott 1,∗ , T. Pizzari 1 , J. Cook 2 1
Department of Rehabilitation, Nutrition and Sport, La Trobe University, Australia 2 Medicine, Nursing and Health Sciences, Monash University, Australia Background: Three-dimensional motion capture is the gold standard for measuring movement. Reflective marker systems are frequently used but are time consuming for researchers and participants, limiting the number of participants in studies. Markerless systems are quicker to use but it is unclear if they produce comparable data to marker systems. The aim of the project was to compare kinematic data from two motion capture systems – Vicon (marker) and Organic Motion (markerless). Methods: Twenty recreational athletes (10 male, 10 female) aged 22–40 performed two tests: a single joint movement knee flexion test (KFT) and single leg squat (SLS). For KFT athletes stood on one leg and bent the opposite foot up behind them to touch a cord set at the height of their tibial tuberosity, performing 10 consecutive knee flexion movements. In SLS, athletes performed 5 consecutive squats. Thirteen clinically relevant joint angles were chosen for analysis in SLS. Data were analysed with paired t-test if normally distributed and otherwise by Wilcoxon signed rank test. Correlation between systems was analysed with Spearman’s correlation coefficient. Results: No significant difference was reported between systems in KFT (p = 0.33) and in SLS for knee flexion (p = 0.87), hip adduction (p = 0.22), pelvic rotation (p = 0.92), and trunk rotation (p = 0.63). There were strong correlations (r = 0.64–0.65) but significant differences in SLS for hip flexion (p < 0.01), pelvic obliquity (p < 0.01) and moderate correlations (r = 0.47–0.56) but significant differences for pelvic tilt (p < 0.01) and trunk side flexion (p < 0.01), suggesting systematic error between the systems. The systems’ reporting of ankle dorsiflexion (p = 0.01), knee valgus (p = 0.02) and rotation (p < 0.01), hip rotation (p = 0.03) and trunk flexion (p < 0.01) were significantly different and were not correlated, suggesting random differences exist for these variables. Discussion: Comparable data were produced in the more controlled KFT. In the more complex SLS test, comparable data were produced in four key kinematic measures. Four measures were moderately correlated but significantly different, indicating a systematic difference in data. Some differences are explained by the way that the two systems define the pelvis. Other differences may be related to error in placing knee alignment devices (KADs) in
http://dx.doi.org/10.1016/j.jsams.2015.12.419 Award Finalist
A. Semciw 1,∗ , D. Moore 2 , M.D. Mendis 3 , J. McClelland 2 , T. Pizzari 2 1
The University of Queensland, Australia La Trobe University, Australia 3 Australian Catholic University, Australia 2
Background: Quadratus femoris (QF) is considered an important hip joint stabiliser. Dysfunction of QF has been implicated in a range of lower limb injuries. Our theoretical understanding of the function of QF is predominantly based on radiological, biomechanical and cadaveric studies. Recently, studies using electromyography (EMG) have built on our knowledge of its direction specific action, and its role in walking and running. However, there have been no studies that have evaluated the contribution of QF to commonly prescribed lower limb rehabilitation exercises. The aim of this study was to illustrate and compare the level of activity of QF in two commonly prescribed functional rehabilitation exercises; the single leg (SL) bridge, and SL squat. This knowledge will provide evidence for the utility of these exercises in targeted QF rehabilitation. Methods: Fine-wire EMG electrodes were inserted into the QF of ten healthy young adults (mean age (range) = 23.8 (22–26) years; females = 4). Participants performed six repetitions of each exercise, timed to the beat of a metronome. This was repeated for three sets and the order of testing (SL bridge vs SL squat) was randomly assigned. An EMG profile was generated from the middle three repetitions of each set (9 repetitions in total) and averaged across all participants to generate a grand ensemble curve. These were amplitude normalized to percent of maximum voluntary isometric contraction (MVIC), and time normalized to 100 points. The peak and average EMG amplitude was recorded during the eccentric, concentric and total exercise phase, and quantitatively compared between exercises using Wilcoxon signed rank tests (˛ = 0.05). Results: The ensemble curves illustrated a single burst activity profile for each exercise. There was a ramped increase in EMG activity for the concentric phase of SL bridge, and the eccentric phase of SL squat. These peaked at the transition into the next phase. There was no significant difference in peak or average amplitude between exercises (p > 0.05). The median level of activity for both exercises can be considered as minimal (<20% MVIC). Discussion: This is the first study to document the activity of QF in lower limb rehabilitation exercises. The level of activity fell short of the 40% MVIC threshold considered important for strength training. Alternative exercises, or variations of the current exercises should be considered before prescribing a SL bridge or SL squat for targeted QF rehabilitation. http://dx.doi.org/10.1016/j.jsams.2015.12.420
e17
difference between the control and intervention groups for object control skill competency (Model 1: B = 0.671, Model 2: B = 1.345, Model 3: B = 0.696, p > 0.05 in each). Discussion: This study found that playing the Xbox Kinect does not significantly influence children’s perceived or actual object control skills, suggesting that the utility of the Xbox Kinect for developing perceived and actual object control skill competence is questionable.
Vicon and the definition of hip rotation in the Plug in Gait model in Vicon. The markerless system allows for a simple method of capturing kinematic data, but should be used only for withinsystems analysis of data.
http://dx.doi.org/10.1016/j.jsams.2015.12.418
37
36
Quadratus femoris is minimally active in a single leg bridge and single leg squat
Are the kinematics of the lower limb and trunk captured on a markerless motion capture system comparable to traditional marker-based system? M. Perrott 1,∗ , T. Pizzari 1 , J. Cook 2 1
Department of Rehabilitation, Nutrition and Sport, La Trobe University, Australia 2 Medicine, Nursing and Health Sciences, Monash University, Australia Background: Three-dimensional motion capture is the gold standard for measuring movement. Reflective marker systems are frequently used but are time consuming for researchers and participants, limiting the number of participants in studies. Markerless systems are quicker to use but it is unclear if they produce comparable data to marker systems. The aim of the project was to compare kinematic data from two motion capture systems – Vicon (marker) and Organic Motion (markerless). Methods: Twenty recreational athletes (10 male, 10 female) aged 22–40 performed two tests: a single joint movement knee flexion test (KFT) and single leg squat (SLS). For KFT athletes stood on one leg and bent the opposite foot up behind them to touch a cord set at the height of their tibial tuberosity, performing 10 consecutive knee flexion movements. In SLS, athletes performed 5 consecutive squats. Thirteen clinically relevant joint angles were chosen for analysis in SLS. Data were analysed with paired t-test if normally distributed and otherwise by Wilcoxon signed rank test. Correlation between systems was analysed with Spearman’s correlation coefficient. Results: No significant difference was reported between systems in KFT (p = 0.33) and in SLS for knee flexion (p = 0.87), hip adduction (p = 0.22), pelvic rotation (p = 0.92), and trunk rotation (p = 0.63). There were strong correlations (r = 0.64–0.65) but significant differences in SLS for hip flexion (p < 0.01), pelvic obliquity (p < 0.01) and moderate correlations (r = 0.47–0.56) but significant differences for pelvic tilt (p < 0.01) and trunk side flexion (p < 0.01), suggesting systematic error between the systems. The systems’ reporting of ankle dorsiflexion (p = 0.01), knee valgus (p = 0.02) and rotation (p < 0.01), hip rotation (p = 0.03) and trunk flexion (p < 0.01) were significantly different and were not correlated, suggesting random differences exist for these variables. Discussion: Comparable data were produced in the more controlled KFT. In the more complex SLS test, comparable data were produced in four key kinematic measures. Four measures were moderately correlated but significantly different, indicating a systematic difference in data. Some differences are explained by the way that the two systems define the pelvis. Other differences may be related to error in placing knee alignment devices (KADs) in
http://dx.doi.org/10.1016/j.jsams.2015.12.419 Award Finalist
A. Semciw 1,∗ , D. Moore 2 , M.D. Mendis 3 , J. McClelland 2 , T. Pizzari 2 1
The University of Queensland, Australia La Trobe University, Australia 3 Australian Catholic University, Australia 2
Background: Quadratus femoris (QF) is considered an important hip joint stabiliser. Dysfunction of QF has been implicated in a range of lower limb injuries. Our theoretical understanding of the function of QF is predominantly based on radiological, biomechanical and cadaveric studies. Recently, studies using electromyography (EMG) have built on our knowledge of its direction specific action, and its role in walking and running. However, there have been no studies that have evaluated the contribution of QF to commonly prescribed lower limb rehabilitation exercises. The aim of this study was to illustrate and compare the level of activity of QF in two commonly prescribed functional rehabilitation exercises; the single leg (SL) bridge, and SL squat. This knowledge will provide evidence for the utility of these exercises in targeted QF rehabilitation. Methods: Fine-wire EMG electrodes were inserted into the QF of ten healthy young adults (mean age (range) = 23.8 (22–26) years; females = 4). Participants performed six repetitions of each exercise, timed to the beat of a metronome. This was repeated for three sets and the order of testing (SL bridge vs SL squat) was randomly assigned. An EMG profile was generated from the middle three repetitions of each set (9 repetitions in total) and averaged across all participants to generate a grand ensemble curve. These were amplitude normalized to percent of maximum voluntary isometric contraction (MVIC), and time normalized to 100 points. The peak and average EMG amplitude was recorded during the eccentric, concentric and total exercise phase, and quantitatively compared between exercises using Wilcoxon signed rank tests (˛ = 0.05). Results: The ensemble curves illustrated a single burst activity profile for each exercise. There was a ramped increase in EMG activity for the concentric phase of SL bridge, and the eccentric phase of SL squat. These peaked at the transition into the next phase. There was no significant difference in peak or average amplitude between exercises (p > 0.05). The median level of activity for both exercises can be considered as minimal (<20% MVIC). Discussion: This is the first study to document the activity of QF in lower limb rehabilitation exercises. The level of activity fell short of the 40% MVIC threshold considered important for strength training. Alternative exercises, or variations of the current exercises should be considered before prescribing a SL bridge or SL squat for targeted QF rehabilitation. http://dx.doi.org/10.1016/j.jsams.2015.12.420