Lower-Extremity Isokinetic Strength Profiling in Professional Rugby League and Rugby Union

2014 ◽  
Vol 9 (2) ◽  
pp. 358-361 ◽  
Author(s):  
Scott R. Brown ◽  
Matt Brughelli ◽  
Peter C. Griffiths ◽  
John B. Cronin
Keyword(s):  
Lower Extremity ◽  
Knee Flexion ◽  
Peak Torque ◽  
Rugby League ◽  
Knee Extension ◽  
Rugby Union ◽  
Joint Torque ◽  
Cross Sectional ◽  
Hip Strength ◽  
Hip Extension

Purpose:While several studies have documented isokinetic knee strength in junior and senior rugby league players, investigations of isokinetic knee and hip strength in professional rugby union players are limited. The purpose of this study was to provide lower-extremity strength profiles and compare isokinetic knee and hip strength of professional rugby league and rugby union players.Participants:32 professional rugby league and 25 professional rugby union players.Methods:Cross-sectional analysis. Isokinetic dynamometry was used to evaluate peak torque and strength ratios of the dominant and nondominant legs during seated knee-extension/flexion and supine hip-extension/flexion actions at 60°/s.Results:Forwards from both codes were taller and heavier and had a higher body-mass index than the backs of each code. Rugby union forwards produced significantly (P < .05) greater peak torque during knee flexion in the dominant and nondominant legs (ES = 1.81 and 2.02) compared with rugby league forwards. Rugby league backs produced significantly greater hip-extension peak torque in the dominant and nondominant legs (ES = 0.83 and 0.77) compared with rugby union backs. There were no significant differences in hamstring-to-quadriceps ratios between code, position, or leg. Rugby union forwards and backs produced significantly greater knee-flexion-to-hip-extension ratios in the dominant and nondominant legs (ES = 1.49–2.26) than rugby union players.Conclusions:It seems that the joint torque profiles of players from rugby league and union codes differ, which may be attributed to the different demands of each code.

Profiling Isokinetic Strength by Leg Preference and Position in Rugby Union Athletes

2016 ◽  
Vol 11 (4) ◽  
pp. 500-507 ◽  
Author(s):  
Scott R. Brown ◽  
Matt Brughelli ◽  
Lee A. Bridgeman
Keyword(s):  
Lower Extremity ◽  
Peak Torque ◽  
Knee Extension ◽  
Rugby Union ◽  
Lower Extremity Injury ◽  
Cross Sectional ◽  
Hip Strength ◽  
Lower Extremity Muscle ◽  
Lower Extremity Strength ◽  
Sectional Analysis

Context:Muscle imbalances aid in the identification of athletes at risk for lower-extremity injury. Little is known regarding the influence that leg preference or playing position may have on lower-extremity muscle strength and asymmetry.Purpose:To investigate lower-extremity strength profiles in rugby union athletes and compare isokinetic knee- and hip-strength variables between legs and positions.Methods:Thirty male academy rugby union athletes, separated into forwards (n = 15) and backs (n = 15), participated in this cross-sectional analysis. Isokinetic dynamometry was used to evaluate peak torque, angle of peak torque, and strength ratios of the preferred and nonpreferred legs during seated knee extension/flexion and supine hip extension/flexion at 60°/s.Results:Backs were older (ES = 1.6) but smaller in stature (ES = –0.47) and body mass (ES = –1.3) than the forwards. The nonpreferred leg was weaker than the preferred leg for forwards during extension (ES = –0.37) and flexion (ES = –0.21) actions and for backs during extension (ES = –0.28) actions. Backs were weaker at the knee than forwards in the preferred leg during extension (ES = –0.50) and flexion (ES = –0.66) actions. No differences were observed in strength ratios between legs or positions. Backs produced peak torque at longer muscle lengths in both legs at the knee (ES = –0.93 to –0.94) and hip (ES = –0.84 to –1.17) than the forwards.Conclusions:In this sample of male academy rugby union athletes, the preferred leg and forwards displayed superior strength compared with the nonpreferred leg and backs. These findings highlight the importance of individualized athletic assessments to detect crucial strength differences in male rugby union athletes.

Obese Youth Demonstrate Altered Landing Knee Mechanics Unrelated to Lower-Extremity Peak Torque When Compared With Healthy Weight Youth

2020 ◽  
pp. 1-9
Author(s):  
Matthew S. Briggs ◽  
Claire Spech ◽  
Rachel King ◽  
Mike McNally ◽  
Matthew Paponetti ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Knee Flexion ◽  
Peak Torque ◽  
Knee Extension ◽  
Knee Flexion Angle ◽  
Healthy Weight ◽  
Knee Mechanics ◽  
Landing Mechanics ◽  
Peak Knee ◽  
Hip Extension

Obese (OB) youth demonstrate altered knee mechanics and worse lower-extremity performance compared with healthy weight (HW) youth. Our objectives were to compare sagittal plane knee landing mechanics between OB and HW youth and to examine the associations of knee and hip extension peak torque with landing mechanics in OB youth. Twenty-four OB and 24 age- and sex-matched HW youth participated. Peak torque was measured and normalized to leg lean mass. Peak knee flexion angle and peak internal knee extension moment were measured during a single-leg hop landing. Paired t tests, Pearson correlation coefficients, and Bonferroni corrections were used. OB youth demonstrated worse performance and lower knee extension (OB: 12.76 [1.38], HW: 14.03 [2.08], P = .03) and hip extension (OB: 8.59 [3.13], HW: 11.10 [2.89], P = .005) peak torque. Furthermore, OB youth demonstrated lower peak knee flexion angles (OB: 48.89 [45.41 to 52.37], HW: 56.07 [52.59 to 59.55], P = .02) and knee extension moments (OB: −1.73 [−1.89 to −1.57], HW: −2.21 [−2.37 to −2.05], P = .0001) during landing compared with HW youth. Peak torque measures were not correlated with peak knee flexion angle nor internal knee extension moment during landing in either group (P > .01). OB youth demonstrated altered landing mechanics compared with HW youth. However, no associations among peak torque measurements and knee landing mechanics were present.

scholarly journals Three-dimensional kinematic differences between accurate and high velocity kicks in rugby union place kicking

2017 ◽  
Vol 12 (3) ◽  
pp. 371-380 ◽  
Author(s):  
J Sinclair ◽  
PJ Taylor ◽  
A Smith ◽  
J Bullen ◽  
I Bentley ◽  
...  
Keyword(s):  
Lower Extremity ◽  
External Rotation ◽  
Three Dimensional ◽  
Maximum Velocity ◽  
Knee Extension ◽  
Rugby Union ◽  
Ball Velocity ◽  
Angular Velocities ◽  
Foot Position ◽  
Hip Extension

Place kicking occurs many times during a rugby union game with more than half of all points scored coming from place kicking. Ball velocity is an important biomechanical indicator of kicking success, but it also evident that the ball must be kicked accurately to pass between the posts. This study aimed to identify biomechanical differences in rugby place kicking kinematics when kicking towards a specific target and for maximum velocity. Ten male rugby union kickers performed place kicks in two conditions: (1) for maximum velocity and (2) towards a pre-defined target. Lower extremity kinematics were obtained using an optoelectric motion capture system operating at 500 Hz. Differences in lower extremity kinematics between the two kicking conditions were examined using paired t-tests. Higher ball velocities were obtained when kicking for maximum velocity. Foot linear velocity, knee extension velocity and hip extension velocity were also found to be greater when kicking for maximum velocity. Ankle dorsiflexion and peak external rotation were found to be greater in the accuracy condition. The findings suggest that rugby kickers may have selected distinct kicking mechanics characterised by reduced joint angular velocities and a more externally rotated foot position in a deliberate attempt to improve precision, sacrificing ball velocity and thus the distance that the ball can be kicked. The specific findings from the current work have implications for coaches and applied practitioners which may facilitate improvements in kicking performance.

scholarly journals Lower Extremity Motor Impairments in Ambulatory Chronic Hemiparetic Stroke: Evidence for Lower Extremity Weakness and Abnormal Muscle and Joint Torque Coupling Patterns

2017 ◽  
Vol 31 (9) ◽  
pp. 814-826 ◽  
Author(s):  
Natalia Sánchez ◽  
Ana Maria Acosta ◽  
Roberto Lopez-Rosado ◽  
Arno H. A. Stienen ◽  
Julius P. A. Dewald
Keyword(s):  
Lower Extremity ◽  
Degrees Of Freedom ◽  
Joint Torque ◽  
Motor Impairments ◽  
Lower Extremity Weakness ◽  
Joint Torques ◽  
Hemiparetic Stroke ◽  
Chronic Hemiparetic Stroke ◽  
Hip Extension ◽  
Flexion And Extension

Although global movement abnormalities in the lower extremity poststroke have been studied, the expression of specific motor impairments such as weakness and abnormal muscle and joint torque coupling patterns have received less attention. We characterized changes in strength, muscle coactivation and associated joint torque couples in the paretic and nonparetic extremity of 15 participants with chronic poststroke hemiparesis (age 59.6 ± 15.2 years) compared with 8 age-matched controls. Participants performed isometric maximum torques in hip abduction, adduction, flexion and extension, knee flexion and extension, ankle dorsi- and plantarflexion and submaximal torques in hip extension and ankle plantarflexion. Surface electromyograms (EMGs) of 10 lower extremity muscles were measured. Relative weakness (paretic extremity compared with the nonparetic extremity) was measured in poststroke participants. Differences in EMGs and joint torques associated with maximum voluntary torques were tested using linear mixed effects models. Results indicate significant poststroke torque weakness in all degrees of freedom except hip extension and adduction, adductor coactivation during extensor tasks, in addition to synergistic muscle coactivation patterns. This was more pronounced in the paretic extremity compared with the nonparetic extremity and with controls. Results also indicated significant interjoint torque couples during maximum and submaximal hip extension in both extremities of poststroke participants and in controls only during maximal hip extension. Additionally, significant interjoint torque couples were identified only in the paretic extremity during ankle plantarflexion. A better understanding of these motor impairments is expected to lead to more effective interventions for poststroke gait and posture.

Muscle- and Region-Specific Associations Between Muscle Size and Muscular Strength During Hip Extension and Knee Flexion in the Hamstrings

2021 ◽  
pp. 1-6
Author(s):  
Raki Kawama ◽  
Masamichi Okudaira ◽  
Hirohiko Maemura ◽  
Satoru Tanigawa
Keyword(s):  
Knee Flexion ◽  
Muscular Strength ◽  
Sports Injuries ◽  
Biceps Femoris ◽  
Muscle Size ◽  
Cross Sectional ◽  
Long Head ◽  
Hip Extension ◽  
Flexion Strength ◽  
Biceps Femoris Long Head

Context: Strength deficits of the hamstrings following sports injuries decrease athletic performance and increase the risk of injury recurrence. Previous studies have shown a high correlation between the muscular strength during hip-extension and knee-flexion and total muscle size of the hamstrings. However, it remains unclear which region of the individual hamstring muscles is closely associated with muscular strength. Objective: To investigate the relationship between the size of each region of the individual hamstring muscles and muscular strength during hip extension and knee flexion. Design: Within-subject repeated measures. Setting: University laboratory. Participants: Twenty healthy young male volunteers who regularly engaged in sports activities. Outcome Measures: Anatomical cross-sectional areas were acquired from the proximal, middle, and distal regions of the biceps femoris long head, biceps femoris short head, semitendinosus, and semimembranosus. Hip-extension and knee-flexion strength were measured during maximal voluntary isometric and concentric contractions (angular velocities of 60°/s and 180°/s). Results: The anatomical cross-sectional area of the distal regions in biceps femoris long head (r = .525–.642) and semitendinosus (r = .567) were significantly correlated with hip-extension strength under all conditions and only at an angular velocity of 180°/s, respectively. Meanwhile, anatomical cross-sectional areas of the distal regions in biceps femoris short head (r = .587–.684) and semimembranosus (r = .569–.576) were closely associated with knee-flexion strength under all conditions. Conclusion: These results suggest that muscle size in the distal regions of biceps femoris long head and semitendinosus greatly contributes to the production of hip-extension strength, whereas that of biceps femoris short head and semimembranosus significantly contributes to the generation of knee-flexion strength. These findings could be useful for designing training and rehabilitation programs to efficiently improve strength deficits following sports injuries such as strain injury and anterior cruciate ligament tears.

Landing Kinematics and Isometric Hip Strength of Individuals With Chronic Ankle Instability

2019 ◽  
Vol 40 (8) ◽  
pp. 969-977 ◽  
Author(s):  
Ryan S. McCann ◽  
Masafumi Terada ◽  
Kyle B. Kosik ◽  
Phillip A. Gribble
Keyword(s):  
Lower Extremity ◽  
Ankle Instability ◽  
External Rotation ◽  
Peak Torque ◽  
Chronic Ankle Instability ◽  
Initial Contact ◽  
Level Of Evidence ◽  
Hip Strength ◽  
Hip Kinematics ◽  
Rotation Strength

Background: Chronic ankle instability (CAI) is associated with hip strength deficits and altered movement in the lower extremity. However, it remains unclear how hip strength deficits contribute to lateral ankle sprain (LAS) mechanisms. We aimed to compare lower extremity landing kinematics and isometric hip strength between individuals with and without CAI and examine associations between hip kinematics and strength. Methods: Seventy-six individuals completed 5 single-leg landings, during which we collected three-dimensional ankle, knee, and hip kinematics from 200 milliseconds pre–initial contact to 50 milliseconds post–initial contact. We calculated average peak torque (Nm/kg) from 3 trials of isometric hip extension, abduction, and external rotation strength testing. One-way analyses of variance assessed group differences (CAI, LAS coper, and control) in hip strength and kinematics. Pearson product moment correlations assessed associations between hip kinematics and strength. We adjusted the kinematic group comparisons and correlation analyses for multiple comparisons using the Benjamini-Hochberg method. Results: The CAI group exhibited less hip abduction during landing than LAS copers and controls. The CAI group had lower hip external rotation strength than LAS copers ( P = .04, d = 0.62 [0.05, 1.17]) and controls ( P < .01, d = 0.87 [0.28, 1.43]). Effect sizes suggest that the CAI group had deficits in EXT compared with controls ( d = 0.63 [0.06, 1.19]). Hip strength was not associated with hip landing kinematics for any group. Conclusion: Altered landing mechanics displayed by the CAI group may promote mechanisms of LAS, but they are not associated with isometric hip strength. However, hip strength deficits may negatively impact other functional tasks, and they should still be considered during rehabilitation. Level of Evidence: Level III, case-control study.

Linkage of myostatin pathway genes with knee strength in humans

2004 ◽  
Vol 17 (3) ◽  
pp. 264-270 ◽  
Author(s):  
W. Huygens ◽  
M. A. Thomis ◽  
M. W. Peeters ◽  
J. Aerssens ◽  
R. Janssen ◽  
...  
Keyword(s):  
Linkage Analysis ◽  
Muscle Mass ◽  
Single Point ◽  
Young Male ◽  
Peak Torque ◽  
Knee Extension ◽  
Candidate Gene Approach ◽  
Potential Candidate ◽  
Cross Sectional ◽  
Knee Strength

This study was the first to explore the potential role of the myostatin ( GDF8) pathway in relation to muscle strength and estimated muscle cross-sectional area in humans using linkage analysis with a candidate gene approach. In young male sibs ( n = 329) 11 polymorphic markers in or near 10 candidate genes from the myostatin pathway were genotyped. Muscle mass was estimated by anthropometric measurements, and maximal knee strength was evaluated using isokinetic dynamometers (Cybex NORM). Single-point nonparametric variance components and linear quantitative trait locus regression linkage analysis methods were used. Linkage patterns were observed between knee extension and flexion peak torque with markers D2S118 ( GDF8), D6S1051 ( CDKN1A), and D11S4138 ( MYOD1), and a maximum LOD score of 2.63 ( P = 0.0002) was observed with D2S118. The ratios of peak torque over muscle and bone area of the midthigh of the lower contraction velocity (60°/s) showed more frequently significant LOD scores than the torques at high velocity (240°/s). Although myostatin is physiologically more related to muscle mass through possible effects of hyperplasia and hypertrophy than it is to strength, only two estimated muscle cross-sectional areas were marginally linked (LOD 1.06 and 1.07, P = 0.01) with marker D2S118 near GDF8 (2q32.2). The present results gave suggestive evidence that the myostatin pathway might be important for strength phenotypes, and GDF8, CDKN1A, and MYOD1 are potential candidate regions for a further and denser mapping with respect to these phenotypes.

scholarly journals Role of pelvic translation and lower-extremity compensation to maintain gravity line position in spinal deformity

2016 ◽  
Vol 24 (3) ◽  
pp. 436-446 ◽  
Author(s):  
Emmanuelle Ferrero ◽  
Barthelemy Liabaud ◽  
Vincent Challier ◽  
Renaud Lafage ◽  
Bassel G. Diebo ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Spinal Deformity ◽  
Lower Limb ◽  
Knee Flexion ◽  
Large Population ◽  
Compensatory Mechanisms ◽  
The Impact ◽  
Hip Extension ◽  
Full Body

OBJECT Previous forceplate studies analyzing the impact of sagittal-plane spinal deformity on pelvic parameters have demonstrated the compensatory mechanisms of pelvis translation in addition to rotation. However, the mechanisms recruited for this pelvic rotation were not assessed. This study aims to analyze the relationship between spinopelvic and lower-extremity parameters and clarify the role of pelvic translation. METHODS This is a retrospective study of patients with spinal deformity and full-body EOS images. Patients with only stenosis or low-back pain were excluded. Patients were grouped according to T-1 spinopelvic inclination (T1SPi): sagittal forward (forward, > 0.5°), neutral (−6.3° to 0.5°), or backward (< −6.3°). Pelvic translation was quantified by pelvic shift (sagittal offset between the posterosuperior corner of the sacrum and anterior cortex of the distal tibia), hip extension was measured using the sacrofemoral angle (SFA; the angle formed by the middle of the sacral endplate and the bicoxofemoral axis and the line between the bicoxofemoral axis and the femoral axis), and chin-brow vertical angle (CBVA). Univariate and multivariate analyses were used to compare the parameters and correlation with the Oswestry Disability Index (ODI). RESULTS In total, 336 patients (71% female; mean age 57 years; mean body mass index 27 kg/m2) had mean T1SPi values of −8.8°, −3.5°, and 5.9° in the backward, neutral, and forward groups, respectively. There were significant differences in the lower-extremity and spinopelvic parameters between T1SPi groups. The backward group had a normal lumbar lordosis (LL), negative SVA and pelvic shift, and the largest hip extension. Forward patients had a small LL and an increased SVA, with a large pelvic shift creating compensatory knee flexion. Significant correlations existed between lower-limb parameter and pelvic shift, pelvic tilt, T-1 pelvic angle, T1SPi, and sagittal vertical axis (0.3 < r < 0.8; p < 0.001). ODI was significantly correlated with knee flexion and pelvic shift. CONCLUSIONS This is the first study to describe full-body alignment in a large population of patients with spinal pathologies. Furthermore, patients categorized based on T1SPi were found to have significant differences in the pelvic shift and lower-limb compensatory mechanisms. Correlations between lower-limb angles, pelvic shift, and ODI were identified. These differences in compensatory mechanisms should be considered when evaluating and planning surgical intervention for adult patients with spinal deformity.

scholarly journals Differences in the Flexion and Extension Phases during Kneeling Investigated by Kinematic and Contact Point Analyses: A Cross-sectional Study

2021 ◽  
Author(s):  
Yusuke Nakazoe ◽  
Akihiko Yonekura ◽  
Hiroyuki Takita ◽  
Takeshi Miyaji ◽  
Narihiro Okazaki ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Contact Point ◽  
Knee Extension ◽  
Cross Sectional Study ◽  
Extension Phase ◽  
3D Registration ◽  
Cross Sectional ◽  
Registration Method ◽  
Computed Tomography Images ◽  
Flexion And Extension

Abstract Background: Kneeling is necessary for certain religious and ceremonial occasions, crouching work, and gardening, which many people take part in worldwide. However, there have been few reports regarding kneeling activities. The purpose of this study was to clarify the kinematics of kneeling.Methods: The subjects were 15 healthy young males. Kneeling activity was analysed within a knee flexion angle from 100° to maximum flexion (maxflex, mean ± SD = 161.3 ± 3.2°). The kinematic and contact point (CP) analyses were performed using a 2D/3D registration method, in which a 3D bone model created from computed tomography images was matched to knee lateral fluoroscopic images and analysed on a personal computer.Results: In the kinematic analysis, the femur translated 37.5 mm posteriorly and rotated 19.8° externally relative to the tibia during the knee flexion phase. During the knee extension phase, the femur translated 36.4 mm anteriorly, which was almost the same amount as in the knee flexion phase. However, the femur rotated only 7.4° internally during the knee extension phase. In the CP analysis, the amount of anterior translation of the CP in the knee extension phase was greater in the medial CP and smaller in the lateral CP than that of posterior translation in the knee flexion phase.Conclusions: In kneeling, there was a difference in the rotational kinematics between the flexion phase and the extension phase. The kinematic difference between the flexion and extension phases may have some effect on the meniscus and articular cartilage.

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