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Biomechanical symmetry in elite rugby union players during dynamic tasks: an investigation using discrete and continuous data analysis techniques.

Marshall B, Franklyn-Miller A, Moran K, King E, Richter C, Gore S, Strike S, Falvey É - BMC Sports Sci Med Rehabil (2015)

Bottom Line: The majority of variables were found to be symmetrical with a total of 57/60 variables displaying symmetry in the discrete point analysis and 55/60 in the ACP.The five variables that were found to be asymmetrical were hip abductor moment in the drop landing (p = 0.02), pelvis lift/drop in the drop landing (p = 0.04) and hurdle hop (p = 0.02), ankle internal rotation moment in the cut (p = 0.04) and ankle dorsiflexion angle also in the cut (p = 0.01).When examining symmetry it is recommended to incorporate continuous data analysis techniques rather than a discrete point analysis alone; a discrete point analysis was unable to detect two of the five asymmetries identified.

View Article: PubMed Central - PubMed

Affiliation: Sports Medicine Department, Sports Surgery Clinic, Santry Demesne, Dublin, Ireland ; School of Health and Human Performance, Dublin City University, Dublin, Ireland ; Insight Centre for Data Analytics, Dublin City University, Dublin, Ireland.

ABSTRACT

Background: While measures of asymmetry may provide a means of identifying individuals predisposed to injury, normative asymmetry values for challenging sport specific movements in elite athletes are currently lacking in the literature. In addition, previous studies have typically investigated symmetry using discrete point analyses alone. This study examined biomechanical symmetry in elite rugby union players using both discrete point and continuous data analysis techniques.

Methods: Twenty elite injury free international rugby union players (mean ± SD: age 20.4 ± 1.0 years; height 1.86 ± 0.08 m; mass 98.4 ± 9.9 kg) underwent biomechanical assessment. A single leg drop landing, a single leg hurdle hop, and a running cut were analysed. Peak joint angles and moments were examined in the discrete point analysis while analysis of characterising phases (ACP) techniques were used to examine the continuous data. Dominant side was compared to non-dominant side using dependent t-tests for normally distributed data or Wilcoxon signed-rank test for non-normally distributed data. The significance level was set at α = 0.05.

Results: The majority of variables were found to be symmetrical with a total of 57/60 variables displaying symmetry in the discrete point analysis and 55/60 in the ACP. The five variables that were found to be asymmetrical were hip abductor moment in the drop landing (p = 0.02), pelvis lift/drop in the drop landing (p = 0.04) and hurdle hop (p = 0.02), ankle internal rotation moment in the cut (p = 0.04) and ankle dorsiflexion angle also in the cut (p = 0.01). The ACP identified two additional asymmetries not identified in the discrete point analysis.

Conclusions: Elite injury free rugby union players tended to exhibit bi-lateral symmetry across a range of biomechanical variables in a drop landing, hurdle hop and cut. This study provides useful normative values for inter-limb symmetry in these movement tests. When examining symmetry it is recommended to incorporate continuous data analysis techniques rather than a discrete point analysis alone; a discrete point analysis was unable to detect two of the five asymmetries identified.

No MeSH data available.


Related in: MedlinePlus

Group mean wave-forms for kinetic and kinematic variables in the hurdle hop. Sagittal angles: ankle dorsiflexion (+)/plantarflexion (−); knee flexion (+)/extension (−); hip flexion (+)/extension (−); pelvis anterior tilt (+)/posterior tilt(−); thorax flexion (+)/thorax extension (−). Frontal angles: ankle eversion (+)/inversion (−); knee varus (+)/valgus (−); hip adduction (+)/abduction (−); pelvis contralateral drop (+)/contralateral lift (−); thorax lateral flexion (+)/ medial flexion (−) Sagittal moments: ankle plantarflexion (+)/dorsiflexion (−); knee extension (+)/flexion (−); hip extension (+)/flexion (−). Frontal moments: ankle eversion (+)/inversion (−); knee valgus (+)/varus (−); hip abduction (+)/ adduction (−)
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Fig3: Group mean wave-forms for kinetic and kinematic variables in the hurdle hop. Sagittal angles: ankle dorsiflexion (+)/plantarflexion (−); knee flexion (+)/extension (−); hip flexion (+)/extension (−); pelvis anterior tilt (+)/posterior tilt(−); thorax flexion (+)/thorax extension (−). Frontal angles: ankle eversion (+)/inversion (−); knee varus (+)/valgus (−); hip adduction (+)/abduction (−); pelvis contralateral drop (+)/contralateral lift (−); thorax lateral flexion (+)/ medial flexion (−) Sagittal moments: ankle plantarflexion (+)/dorsiflexion (−); knee extension (+)/flexion (−); hip extension (+)/flexion (−). Frontal moments: ankle eversion (+)/inversion (−); knee valgus (+)/varus (−); hip abduction (+)/ adduction (−)

Mentions: For the ACP, Figs. 2, 3, 4 and 5 display group mean wave-forms for all variables in the drop landing, hurdle hop and cut, respectively. Areas of the wave-form that displayed significant differences between dominant and non-dominant leg are highlighted. The majority of variables under examination displayed no significant asymmetries in the drop landing (13/15), hurdle hop (16/17) or cut (26/28). Those variables that did display significant differences (p < 0.05) are summarised in Table 5. For the drop landing on the dominant leg there was significantly greater hip abductor moments early in the eccentric phase (p = 0.02, effect size = 0.62) and more pelvis contralateral lift from 52 % of the movement onwards (p = 0.04, effect size = 0.66). There was significantly greater contralateral pelvic drop on the non-dominant side throughout the hop test (p = 0.01 - 0.02, effect size = 0.88). In the cut, ankle internal rotation moments were significantly greater in the non-dominant ankle (p = 0.02 – 0.04, effect size = 0.52) from 23-38 % of the movement. The ankle joint was also significantly more dorsi-flexed on the non-dominant side during the latter stages (78–94 %) of the cut push-off (p = 0.011, effect size = 0.57).Fig. 2


Biomechanical symmetry in elite rugby union players during dynamic tasks: an investigation using discrete and continuous data analysis techniques.

Marshall B, Franklyn-Miller A, Moran K, King E, Richter C, Gore S, Strike S, Falvey É - BMC Sports Sci Med Rehabil (2015)

Group mean wave-forms for kinetic and kinematic variables in the hurdle hop. Sagittal angles: ankle dorsiflexion (+)/plantarflexion (−); knee flexion (+)/extension (−); hip flexion (+)/extension (−); pelvis anterior tilt (+)/posterior tilt(−); thorax flexion (+)/thorax extension (−). Frontal angles: ankle eversion (+)/inversion (−); knee varus (+)/valgus (−); hip adduction (+)/abduction (−); pelvis contralateral drop (+)/contralateral lift (−); thorax lateral flexion (+)/ medial flexion (−) Sagittal moments: ankle plantarflexion (+)/dorsiflexion (−); knee extension (+)/flexion (−); hip extension (+)/flexion (−). Frontal moments: ankle eversion (+)/inversion (−); knee valgus (+)/varus (−); hip abduction (+)/ adduction (−)
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4940714&req=5

Fig3: Group mean wave-forms for kinetic and kinematic variables in the hurdle hop. Sagittal angles: ankle dorsiflexion (+)/plantarflexion (−); knee flexion (+)/extension (−); hip flexion (+)/extension (−); pelvis anterior tilt (+)/posterior tilt(−); thorax flexion (+)/thorax extension (−). Frontal angles: ankle eversion (+)/inversion (−); knee varus (+)/valgus (−); hip adduction (+)/abduction (−); pelvis contralateral drop (+)/contralateral lift (−); thorax lateral flexion (+)/ medial flexion (−) Sagittal moments: ankle plantarflexion (+)/dorsiflexion (−); knee extension (+)/flexion (−); hip extension (+)/flexion (−). Frontal moments: ankle eversion (+)/inversion (−); knee valgus (+)/varus (−); hip abduction (+)/ adduction (−)
Mentions: For the ACP, Figs. 2, 3, 4 and 5 display group mean wave-forms for all variables in the drop landing, hurdle hop and cut, respectively. Areas of the wave-form that displayed significant differences between dominant and non-dominant leg are highlighted. The majority of variables under examination displayed no significant asymmetries in the drop landing (13/15), hurdle hop (16/17) or cut (26/28). Those variables that did display significant differences (p < 0.05) are summarised in Table 5. For the drop landing on the dominant leg there was significantly greater hip abductor moments early in the eccentric phase (p = 0.02, effect size = 0.62) and more pelvis contralateral lift from 52 % of the movement onwards (p = 0.04, effect size = 0.66). There was significantly greater contralateral pelvic drop on the non-dominant side throughout the hop test (p = 0.01 - 0.02, effect size = 0.88). In the cut, ankle internal rotation moments were significantly greater in the non-dominant ankle (p = 0.02 – 0.04, effect size = 0.52) from 23-38 % of the movement. The ankle joint was also significantly more dorsi-flexed on the non-dominant side during the latter stages (78–94 %) of the cut push-off (p = 0.011, effect size = 0.57).Fig. 2

Bottom Line: The majority of variables were found to be symmetrical with a total of 57/60 variables displaying symmetry in the discrete point analysis and 55/60 in the ACP.The five variables that were found to be asymmetrical were hip abductor moment in the drop landing (p = 0.02), pelvis lift/drop in the drop landing (p = 0.04) and hurdle hop (p = 0.02), ankle internal rotation moment in the cut (p = 0.04) and ankle dorsiflexion angle also in the cut (p = 0.01).When examining symmetry it is recommended to incorporate continuous data analysis techniques rather than a discrete point analysis alone; a discrete point analysis was unable to detect two of the five asymmetries identified.

View Article: PubMed Central - PubMed

Affiliation: Sports Medicine Department, Sports Surgery Clinic, Santry Demesne, Dublin, Ireland ; School of Health and Human Performance, Dublin City University, Dublin, Ireland ; Insight Centre for Data Analytics, Dublin City University, Dublin, Ireland.

ABSTRACT

Background: While measures of asymmetry may provide a means of identifying individuals predisposed to injury, normative asymmetry values for challenging sport specific movements in elite athletes are currently lacking in the literature. In addition, previous studies have typically investigated symmetry using discrete point analyses alone. This study examined biomechanical symmetry in elite rugby union players using both discrete point and continuous data analysis techniques.

Methods: Twenty elite injury free international rugby union players (mean ± SD: age 20.4 ± 1.0 years; height 1.86 ± 0.08 m; mass 98.4 ± 9.9 kg) underwent biomechanical assessment. A single leg drop landing, a single leg hurdle hop, and a running cut were analysed. Peak joint angles and moments were examined in the discrete point analysis while analysis of characterising phases (ACP) techniques were used to examine the continuous data. Dominant side was compared to non-dominant side using dependent t-tests for normally distributed data or Wilcoxon signed-rank test for non-normally distributed data. The significance level was set at α = 0.05.

Results: The majority of variables were found to be symmetrical with a total of 57/60 variables displaying symmetry in the discrete point analysis and 55/60 in the ACP. The five variables that were found to be asymmetrical were hip abductor moment in the drop landing (p = 0.02), pelvis lift/drop in the drop landing (p = 0.04) and hurdle hop (p = 0.02), ankle internal rotation moment in the cut (p = 0.04) and ankle dorsiflexion angle also in the cut (p = 0.01). The ACP identified two additional asymmetries not identified in the discrete point analysis.

Conclusions: Elite injury free rugby union players tended to exhibit bi-lateral symmetry across a range of biomechanical variables in a drop landing, hurdle hop and cut. This study provides useful normative values for inter-limb symmetry in these movement tests. When examining symmetry it is recommended to incorporate continuous data analysis techniques rather than a discrete point analysis alone; a discrete point analysis was unable to detect two of the five asymmetries identified.

No MeSH data available.


Related in: MedlinePlus