scholarly journals Variability of ankle kinematics in professional cyclists: consequence on saddle height adjustment

2020 ◽  
Vol 9 (1) ◽  
pp. 25-32
Author(s):  
Geoffrey Millour ◽  
Sebastien Duc ◽  
Theo Ouvrard ◽  
Damien Segui ◽  
Frederic Puel ◽  
...  
Keyword(s):  
Coefficient Of Variation ◽  
Sagittal Plane ◽  
Knee Kinematics ◽  
Knee Extension ◽  
Individual Variability ◽  
Great Variability ◽  
Knee Angle ◽  
Optimal Range ◽  
Ankle Kinematics ◽  
Ankle Angle

Bike-fitting methods based on the knee kinematics have been developed to determine the optimal saddle height. Among them, the Ferrer-Roca method advises a knee angle between 30 and 40° in the sagittal plane when the crank arm is aligned with the seat tube while pedalling. However, the foot orientation varies between individuals and can influence the knee angle throughout the pedalling cycle. The objective of this study was to measure the inter-individual variability in joint kinematics of professional cyclists and to evaluate the influence of the ankle angle modification on the knee angle during pedalling. Seventeen professional cyclists performed a 3-min pedalling test at 150 W and 80 rpm on their personal road bike mounted on an Elite Turno® ergometer (Elite, Fontaniva, Italia). The knee and ankle angles were measured using 2D kinematic analysis. The average knee angle (38°) was in the optimal range of 30–40°, but great variability was observed between individuals (coefficient of variation of 11.8% and 9.4% for knee and ankle angles, respectively). Moreover, five of them had a knee angle greater than 40°. In addition, their ankle angle was 15% lower than that of cyclists who had a knee angle between 30 and 40° (50 ± 4° vs. 58 ± 4°, p < 0.05). The results suggest that the knee angle observed when professional cyclists use their preferred saddle height varies among individuals and is related to the foot orientation while pedalling. The maximum knee extension angle is lower for the cyclists who accentuate the dorsiflexion but greater for those who pedalled with a plantarflexion. This implies that the saddle height adjustment method based on the knee kinematics while pedalling should consider both the knee and ankle angles.

Ankle Angle but Not Knee Angle Influences Force Fluctuations During Plantar Flexion

2021 ◽  
Author(s):  
Georgios Trypidakis ◽  
Ioannis G. Amiridis ◽  
Roger Enoka ◽  
Irini Tsatsaki ◽  
Eleftherios Kellis ◽  
...  
Keyword(s):  
Knee Joint ◽  
Coefficient Of Variation ◽  
Discharge Rate ◽  
Dominant Role ◽  
Plantar Flexion ◽  
Motor Units ◽  
Medial Gastrocnemius ◽  
Knee Angle ◽  
Plantar Flexors ◽  
Ankle Angle

AbstractThe purpose of the study was to evaluate the influence of changes in ankle- and knee-joint angles on force steadiness and the discharge characteristics of motor units (MU) in soleus when the plantar flexors performed steady isometric contractions. Submaximal contractions (5, 10, 20, and 40% of maximum) were performed at two ankle angles (75° and 105°) and two knee angles (120° and 180°) by 14 young adults. The coefficient of variation of force decreased as the target force increased from 5 to 20% of maximal force, then remained unaltered at 40%. Independently of knee angle, the coefficient of variation for force at the ankle angle of 75° (long length) was always less (p<0.05) than that at 105° (shorter length). Mean discharge rate, discharge variability, and variability in neural activation of soleus motor units were less (p<0.05) at the 75° angle than at 105°. It was not possible to record MUs from medial gastrocnemius at the knee angle of 120° due to its minimal activation. The changes in knee-joint angle did not influence any of the outcome measures. The findings underscore the dominant role of the soleus muscle in the control of submaximal forces produced by the plantar flexor muscles.

scholarly journals A Comparison of Static and Dynamic Measures of Lower Limb Joint Angles in Cycling: Application to Bicycle Fitting

2016 ◽  
Vol 17 (1) ◽  
Author(s):  
Rodrigo Rico Bini ◽  
Patria Hume
Keyword(s):  
Lower Limb ◽  
Sagittal Plane ◽  
Digital Camera ◽  
Gear Ratio ◽  
Knee Angle ◽  
Joint Angles ◽  
Ankle Angle ◽  
Dynamic Measures ◽  
Potential Use ◽  
Dynamic Cycling

AbstractPurpose. Configuration of bicycle components to the cyclist (bicycle fitting) commonly uses static poses of the cyclist on the bicycle at the 6 o’clock crank position to represent dynamic cycling positions. However, the validity of this approach and the potential use of the different crank position (e.g. 3 o’clock) have not been fully explored. Therefore, this study compared lower limb joint angles of cyclists in static poses (3 and 6 o’clock) compared to dynamic cycling. Methods. Using a digital camera, right sagittal plane images were taken of thirty cyclists seated on their own bicycles mounted on a stationary trainer with the crank at 3 o’clock and 6 o’clock positions. Video was then recorded during pedalling at a self-selected gear ratio and pedalling cadence. Sagittal plane hip, knee and ankle angles were digitised. Results. Differences between static and dynamic angles were large at the 6 o’clock crank position with greater mean hip angle (4.9 ± 3°), smaller knee angle (8.2 ± 5°) and smaller ankle angle (8.2 ± 5.3°) for static angles. Differences between static and dynamic angles (< 1.4°) were trivial to small for the 3 o’clock crank position. Conclusions. To perform bicycle fitting, joint angles should be measured dynamically or with the cyclist in a static pose at the 3 o’clock crank position.

scholarly journals Angle-angle diagrams in the assessment of locomotion in persons with multiple sclerosis: A preliminary study

2022 ◽  
Author(s):  
Riccardo Di Giminiani ◽  
Davide Di Lorenzo ◽  
Luca Russo ◽  
Stefano La Greca ◽  
Francesco Masedu ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Sagittal Plane ◽  
Three Dimensional ◽  
Lower Limbs ◽  
Knee Angle ◽  
Long Term Effects ◽  
Leg Muscles ◽  
Ankle Angle ◽  
Spatiotemporal Parameters ◽  
Exercise Programmes

Gait analysis is clinically relevant in persons with multiple sclerosis (PwMS) and consists of several joint angular displace-ment-time relationships and spatiotemporal parameters. However, it lacks representation by means of diagrams in which knee angle-hip angle and knee angle-ankle angle variations are plotted against each other at the same instants of time. Three-dimensional kinematic analysis was performed on 20 subjects (10 PwMS/10 healthy controls, HCs), and the knee-angle/hip-angle and knee-angle/ankle-angle diagrams of both lower limbs were determined in the sagittal plane while walking on a motorized treadmill. The area (a quantifier of conjoint range of motion) and the perimeter (a quantifier of coordina-tion) of angle-angle diagram loops were calculated. PwMS showed reduced knee-angle/ankle-angle loops compared to HCs (P<0.05, ES = 0.80), whereas the hip-angle/ankle-angle loops between the PwMS and HCs was not significant (P> 0.05). Similarly, the activation of leg muscles showed significant differences between PwMS and HCs (p ranged from 0.05-to 0.001; ES ranged from 1.30 to 1.89). The results indicate that the proposed knee-angle/hip-angle diagram is feasible and could be applied as a reliable tool in future studies aimed at assessing the acute and long-term effects of specific exercise programmes and/or pharmacological treatment in PwMS.

Relationship Between Knee Walking Kinematics and Muscle Flexibility in Runners

2013 ◽  
Vol 22 (4) ◽  
pp. 279-287 ◽  
Author(s):  
Nathaly Gaudreault ◽  
Alex Fuentes ◽  
Neila Mezghani ◽  
Virginie O. Gauthier ◽  
Katia Turcot
Keyword(s):  
Outcome Measures ◽  
Rotation Angle ◽  
External Rotation ◽  
Three Dimensional ◽  
Knee Kinematics ◽  
Knee Extension ◽  
Iliotibial Band ◽  
Initial Contact ◽  
Knee Angle ◽  
Peak Knee

Context:Decreased flexibility in muscles and joints of lower extremities is commonly observed in runners. Understanding the effect of decreased flexibility on knee walking kinematics in runners is important because, over time, altered gait patterns can make runners vulnerable to overuse injuries or degenerative pathologies.Objectives:To compare hamstring and iliotibial-band (ITB) flexibility and knee kinematics in runners and nonrunners.Design:A descriptive, comparative laboratory study.Setting:Hamstring and ITB flexibility were measured with the active knee-extension test and the modified Ober test, respectively, in both groups of participants. Three-dimensional (3D) walking kinematic data were then recorded at the knee using a motiontracking system.Participants:18 runners and 16 nonrunners.Main Outcome Measures:Knee-extension angle (hamstring flexibility) and hip-adduction angle (ITB flexibility). Knee kinematic parameters of interest included knee angle at initial contact, peak knee angles, and knee-angle range in all planes of movement.Results:The runners had a significantly less flexible ITB than the nonrunners (hip adduction [−] and adduction [+] angles, 3.1° ± 5.6° vs −6.4° ± 4.5°; P < .001). The runners demonstrated a greater mean tibial external-rotation angle at initial contact (7.3° ± 5.8° vs 2.0° ± 4.0°; P = .01) and a smaller mean peak tibial internal-rotation angle (−1.6° ± 3.0° vs −4.2° ± 3.2°; P = .04) than the nonrunners.Conclusion:This study provides new insight into the relationship between muscle flexibility and 3D knee kinematics in runners. This supports the premise that there is an association between muscle flexibility and transverse-plane knee kinematics in this population.

scholarly journals Ground Reaction Forces of Dressage Horses Performing the Piaffe

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 436 ◽  
Author(s):  
Hilary Mary Clayton ◽  
Sarah Jane Hobbs
Keyword(s):  
Coefficient Of Variation ◽  
Three Dimensional ◽  
Individual Variability ◽  
The Other ◽  
Ground Reaction Forces ◽  
High Coefficient ◽  
Reaction Forces

The piaffe is an artificial, diagonally coordinated movement performed in the highest levels of dressage competition. The ground reaction forces (GRFs) of horses performing the piaffe do not appear to have been reported. Therefore, the objective of this study was to describe three-dimensional GRFs in ridden dressage horses performing the piaffe. In-ground force plates were used to capture fore and hindlimb GRF data from seven well-trained dressage horses. Peak vertical GRF was significantly higher in forelimbs than in the hindlimbs (7.39 ± 0.99 N/kg vs. 6.41 ± 0.64 N/kg; p < 0.001) with vertical impulse showing a trend toward higher forelimb values. Peak longitudinal forces were small with no difference in the magnitude of braking or propulsive forces between fore and hindlimbs. Peak transverse forces were similar in magnitude to longitudinal forces and were mostly directed medially in the hindlimbs. Both the intra- and inter-individual variability of longitudinal and transverse GRFs were high (coefficient of variation 25–68%). Compared with the other diagonal gaits of dressage horses, the vertical GRF somewhat shifted toward the hindlimbs. The high step-to-step variability of the horizontal GRF components is thought to reflect the challenge of balancing on one diagonal pair of limbs with no forward momentum.

Functional Data Analyses for the Assessment of Joint Power Profiles During Gait of Stroke Subjects

2014 ◽  
Vol 30 (2) ◽  
pp. 348-352 ◽  
Author(s):  
André G. P. Andrade ◽  
Janaine C. Polese ◽  
Leopoldo A. Paolucci ◽  
Hans-Joachim K. Menzel ◽  
Luci F. Teixeira-Salmela
Keyword(s):  
Power Generation ◽  
Gait Cycle ◽  
Sagittal Plane ◽  
Plantar Flexion ◽  
Knee Extension ◽  
Mathematical Function ◽  
Joint Power ◽  
Gait Biomechanics ◽  
Isolated Points ◽  
Parametric Analyses

Lower extremity kinetic data during walking of 12 people with chronic poststroke were reanalyzed, using functional analysis of variance (FANOVA). To perform the FANOVA, the whole curve is represented by a mathematical function, which spans the whole gait cycle and avoids the need to identify isolated points, as required for traditional parametric analyses of variance (ANOVA). The power variables at the ankle, knee, and hip joints, in the sagittal plane, were compared between two conditions: With and without walking sticks at comfortable and fast speeds. For the ankle joint, FANOVA demonstrated increases in plantar flexion power generation during 60–80% of the gait cycle between fast and comfortable speeds with the use of walking sticks. For the knee joint, the use of walking sticks resulted in increases in the knee extension power generation during 10–30% of the gait cycle. During both speeds, the use of walking sticks resulted in increased power generation by the hip extensors and flexors during 10–30% and 40–70% of the gait cycle, respectively. These findings demonstrated the benefits of applying the FANOVA approach to improve the knowledge regarding the effects of walking sticks on gait biomechanics and encourage its use within other clinical contexts.

Initial phase of maximal voluntary and electrically stimulated knee extension torque development at different knee angles

2004 ◽  
Vol 97 (5) ◽  
pp. 1693-1701 ◽  
Author(s):  
C. J. de Ruiter ◽  
R. D. Kooistra ◽  
M. I. Paalman ◽  
A. de Haan
Keyword(s):  
Muscle Activation ◽  
Knee Extensor ◽  
Surface Emg ◽  
Knee Extension ◽  
Voluntary Contraction ◽  
Voluntary Activation ◽  
Knee Angle ◽  
Time Integral ◽  
Voluntary Contractions ◽  
Torque Development

We investigated the capacity for torque development and muscle activation at the onset of fast voluntary isometric knee extensions at 30, 60, and 90° knee angle. Experiments were performed in subjects ( n = 7) who had high levels (>90%) of activation at the plateau of maximal voluntary contractions. During maximal electrical nerve stimulation (8 pulses at 300 Hz), the maximal rate of torque development (MRTD) and torque time integral over the first 40 ms (TTI40) changed in proportion with torque at the different knee angles (highest values at 60°). At each knee angle, voluntary MRTD and stimulated MRTD were similar ( P < 0.05), but time to voluntary MRTD was significantly longer. Voluntary TTI40 was independent ( P > 0.05) of knee angle and on average (all subjects and angles) only 40% of stimulated TTI40. However, among subjects, the averaged (across knee angles) values ranged from 10.3 ± 3.1 to 83.3 ± 3.2% and were positively related ( r2 = 0.75, P < 0.05) to the knee-extensor surface EMG at the start of torque development. It was concluded that, although all subjects had high levels of voluntary activation at the plateau of maximal voluntary contraction, among subjects and independent of knee angle, the capacity for fast muscle activation varied substantially. Moreover, in all subjects, torque developed considerably faster during maximal electrical stimulation than during maximal voluntary effort. At different knee angles, stimulated MRTD and TTI40 changed in proportion with stimulated torque, but voluntary MRTD and TTI40 changed less than maximal voluntary torque.

scholarly journals POSTURAL PROFILE OF INDIVIDUALS WITH HAM/TSP

2013 ◽  
Vol 1 (2) ◽  
Author(s):  
Maíra Carvalho Macêdo ◽  
Abrahão Fontes Baptista ◽  
Bernardo Galvão Castro-Filho ◽  
Edelvita Fernanda Duarte ◽  
Naiane Patrício ◽  
...  
Keyword(s):  
Sagittal Plane ◽  
The Body ◽  
Forward Displacement ◽  
Ankle Angle ◽  
Postural Assessment ◽  
De Medicina

Objectives:The aim of this survey was to delineate the profile of patients with HTLV-1 associated with HAM/TSP. Methods:This was cross-sectionalconducted at the HTLV Center of "EscolaBahiana de Medicina e SaúdePública,Bahia",Brazil,30 volunteerswith HAM / TSP werepairedwith 30 healthysubjects, whounderwent a postural evaluationbymeansof a Postural Assessment Software (SAPO®).Results:A trend characterized by postural projection of the trunk forward or backward, forward displacement of the body, bending the knees and ankle angle reduction was noted.Conclusion:This study demonstrates that there is a posture typical of the HAM/TSP patient which manifests itself with changes in the sagittal plane.

scholarly journals Acute effect of tendon vibration applied during isometric contraction at two knee angles on maximal knee extension force production

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242324
Author(s):  
Jonathan Harnie ◽  
Thomas Cattagni ◽  
Christophe Cornu ◽  
Peter McNair ◽  
Marc Jubeau
Keyword(s):  
Isometric Contraction ◽  
Vastus Lateralis ◽  
Force Production ◽  
Knee Extensor ◽  
Acute Effect ◽  
Knee Extension ◽  
Voluntary Contraction ◽  
Voluntary Activation ◽  
Tendon Vibration ◽  
Knee Angle

The aim of the current study was to investigate the effect of a single session of prolonged tendon vibration combined with low submaximal isometric contraction on maximal motor performance. Thirty-two young sedentary adults were assigned into two groups that differed based on the knee angle tested: 90° or 150° (180° = full knee extension). Participants performed two fatigue-inducing exercise protocols: one with three 10 min submaximal (10% of maximal voluntary contraction) knee extensor contractions and patellar tendon vibration (80 Hz) another with submaximal knee extensor contractions only. Before and after each fatigue protocol, maximal voluntary isometric contractions (MVC), voluntary activation level (assessed by the twitch interpolation technique), peak-to-peak amplitude of maximum compound action potentials of vastus medialis and vastus lateralis (assessed by electromyography with the use of electrical nerve stimulation), peak twitch amplitude and peak doublet force were measured. The knee extensor fatigue was significantly (P<0.05) greater in the 90° knee angle group (-20.6% MVC force, P<0.05) than the 150° knee angle group (-8.3% MVC force, P = 0.062). Both peripheral and central alterations could explain the reduction in MVC force at 90° knee angle. However, tendon vibration added to isometric contraction did not exacerbate the reduction in MVC force. These results clearly demonstrate that acute infrapatellar tendon vibration using a commercial apparatus operating at optimal conditions (i.e. contracted and stretched muscle) does not appear to induce knee extensor neuromuscular fatigue in young sedentary subjects.

scholarly journals Muscles Recruited During an Isometric Knee Extension is Defined by Proprioceptive Feedback

2019 ◽  
Author(s):  
Gareth York ◽  
Hugh Osborne ◽  
Piyanee Sriya ◽  
Sarah Astill ◽  
Marc de Kamps ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Conflict Of Interest ◽  
Rectus Femoris ◽  
Knee Extension ◽  
Proprioceptive Feedback ◽  
Muscle Synergy ◽  
Knee Angle ◽  
Potential Conflict ◽  
Dynamic Task ◽  
Isometric Knee Extension

AbstractProprioceptive feedback and its role in control of isometric tasks is often overlooked. In this study recordings were made from upper leg muscles during an isometric knee extension task. Internal knee angle was fixed and subjects were asked to voluntarily activate their rectus femoris muscle. Muscle synergy analysis of these recordings identified canonical temporal patterns in the data. These synergies were found to encode two separate features: one concerning the coordinated contraction of the recorded muscles and the other indicating agonistic/antagonistic interactions between these muscles. The second synergy changed with internal knee angle reflecting the influence of afferent activity. This is in contrast to previous studies of dynamic task experiments which have indicated that proprioception has a negligible effect on synergy expression. Using the MIIND neural simulation platform, we developed a spinal population model with an adjustable input representing proprioceptive feedback. The model is based on existing spinal population circuits used for dynamic tasks. When the same synergy analysis was performed on the output from the model, qualitatively similar muscle synergy patterns were observed. These results suggest proprioceptive feedback is integrated in the spinal cord to control isometric tasks via muscle synergies.Significance statementSensory feedback from muscles is a significant factor in normal motor control. It is often assumed that instantaneous muscle stretch does not influence experiments where limbs are held in a fixed position. Here, we identified patterns of muscle activity during such tasks showing that this assumption should be revisited. We also developed a computational model to propose a possible mechanism, based on a network of populations of neurons, that could explain this phenomenon. The model is based on well established neural circuits in the spinal cord and fits closely other models used to simulate more dynamic tasks like locomotion in vertebrates.Conflict of interest statementThe authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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