Assessment of Bilateral Asymmetry in Cycling Using a Commercial Instrumented Crank System and Instrumented Pedals

2014 ◽  
Vol 9 (5) ◽  
pp. 876-881 ◽  
Author(s):  
Rodrigo R. Bini ◽  
Patria A. Hume
Keyword(s):  
Power Output ◽  
Lower Limb ◽  
Peak Torque ◽  
Asymmetry Index ◽  
Effect Sizes ◽  
Bilateral Asymmetry ◽  
Cycling Test ◽  
Torque Measurements ◽  
Higher Power ◽  
Competitive Cyclists

The accuracy of commercial instrumented crank systems for symmetry assessment in cycling has not been fully explored. Therefore, the authors’ aims were to compare peak crank torque between a commercial instrumented crank system and instrumented pedals and to assess the effect of power output on bilateral asymmetries during cycling. Ten competitive cyclists performed an incremental cycling test to exhaustion. Forces and pedal angles were recorded using right and left instrumented pedals synchronized with crank-torque measurements using an instrumented crank system. Differences in right (dominant) and left (nondominant) peak torque and asymmetry index were assessed using effect sizes. In the 100- to 250-W power-output range, the instrumented pedal system recorded larger peak torque (dominant 55–122%, nondominant 23–99%) than the instrumented crank system. There was an increase in differences between dominant and nondominant crank torque as power output increased using the instrumented crank system (7% to 33%) and the instrumented pedals (9% to 66%). Lower-limb asymmetries in peak torque increased at higher power-output levels in favor of the dominant leg. Limitations in design of the instrumented crank system may preclude the use of this system to assess peak crank-torque symmetry.

scholarly journals The Comparison between Isokinetic Knee Muscles Strength in the Ipsilateral and Contralateral Limbs and Correlating with Function of Patients with Stroke

2019 ◽  
Vol 10 (04) ◽  
pp. 683-689
Author(s):  
Fayaz Khan ◽  
Haris Anjamparuthikal ◽  
Mohamed Faisal Chevidikunnan
Keyword(s):  
Lower Limb ◽  
Knee Flexion ◽  
Peak Torque ◽  
Lower Limbs ◽  
Isokinetic Strength ◽  
Isokinetic Dynamometer ◽  
Knee Strength ◽  
Torque Measurements ◽  
Significant Difference ◽  
Knee Muscle

Abstract Objective The aim of this study is to compare the isokinetic knee muscles peak torque measurements and proprioception between the affected and intact limbs of patients with stroke, in addition to finding the correlation between knee muscles strength and lower limb function. Methods Twelve patients with stroke (mean age 64.33 ± 6.140 years), with 3 to 7 months poststroke who can walk 25 feet independently without using or using assistive devices and full passive range of motion were included in the study. Biodex isokinetic dynamometer was used for measuring isokinetic strength at 90°/s, 120°/s, and 150°/s and isometric strength at 60°/s in both flexors and extensors of the knee, whereas proprioception was measured at 45°/s knee flexion, all for affected and intact limbs. Functional measurements were assessed using the Fugl-Meyer Assessment for Lower Limb scale and Barthel Index (BI). Results The differences shown were found to be statistically significant between affected and intact limbs in isokinetic 90°/s flexion (p = 0.005), extension (p = 0.0013), and isometric at 60°/s flexion (p < 0.0001) knee muscle strengths and also the proprioception (p = 0.05). Significant positive correlation was found between isokinetic affected side knee flexion at 90°/s (r = 0.903) with BI (r = 0.704). Conclusion There is a significant difference in peak torque measurements between affected and normal lower limbs of poststroke patients, as well as a significant correlation between the knee strength and lower limb functions. Furthermore, it can also be concluded that the differences in knee proprioception between the affected and intact limbs were shown to be significant.

scholarly journals Re-esterified DHA improves ventilatory threshold 2 in competitive amateur cyclists

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Vicente Ávila-Gandía ◽  
Antonio Torregrosa-García ◽  
Antonio J. Luque-Rubia ◽  
María Salud Abellán-Ruiz ◽  
Desirée Victoria-Montesinos ◽  
...  
Keyword(s):  
Power Output ◽  
Ventilatory Threshold ◽  
Heart Rate Recovery ◽  
Recovery Phase ◽  
Lactate Clearance ◽  
Mean Power ◽  
Double Blind ◽  
Cycling Test ◽  
Competitive Cyclists ◽  
Mean Power Output

Abstract Background Fish oils were studied as ergogenic aids in a number of mixed physical trial designs showing promising results. However, the heterogeneous purity of the studied supplements, combined with the variety of physical tests employed call for more studies to confirm these findings, ideally with standardised supplements. Our aim was to test a supplement highly concentrated in DHA (DHA:EPA ratio equal to approximately 8:1) on a maximal cycling test to elucidate performance improvements mainly due to DHA. Methods A double-blind, placebo controlled, randomised balanced, parallel design, in competitive amateur cyclists was employed. They were all male, older than 18 years old, with training routine of 2 to 4 sessions per week lasting at least one hour each. A ramp cycling test to exhaustion with a subsequent 5 min recovery phase was employed before and after treatment to analyse aerobic metabolism and lactate clearance after the bout. After 30 days of supplementation with 975 mg of re-esterified DHA, the thirty-eight cyclist who completed the study were finally included for statistical analysis. Results Mean power output at ventilatory threshold 2 (VT2) improved after DHA supplementation both as absolute (△DHA versus △PLA: 6.33–26.54 Watts; CI 95%) and relative (p=0.006) values, paralleled with higher oxygen consumption at VT2 both for absolute (DHA 2729.4 ±304.5, 3045.9 ±335.0; PLA 2792.3 ±339.5, 2845.5 ±357.1; ml·min−1 baseline versus post p=0.025) and relative values (DHA 36.6 ±5.0, 41.2 ±5.4; PLA 37.2 ±5.7, 38.1 ±5.2; ml·kg−1·min−1 baseline versus post p=0.024). Heart rate recovery rate improved during the recovery phase in the DHA group compared to PLA (p=0.005). Conclusion DHA is capable of improving mean power output at the ventilatory threshold 2 (anaerobic ventilatory threshold) in amateur competitive cyclists. It is unclear if these findings are the result of the specific DHA supplement blend or another factor.

scholarly journals Índice de asimetría bilateral similar de las manifestaciones de la fuerza muscular de extremidades inferiores en jóvenes universitarios (Similar bilateral asymmetry index of the expressions of muscle strength in lower limbs in university students)

Retos ◽  
2017 ◽  
pp. 34-36
Author(s):  
Ramón Candia Luján ◽  
Beatríz Anai Núñez Escudero ◽  
Karen Ileana Carreón Santa Cruz ◽  
Lidia Guillermina De León Fierro ◽  
Caudia Esther Carrasco Legleu ◽  
...  
Keyword(s):  
Muscle Strength ◽  
University Students ◽  
Lower Limb ◽  
Statistical Difference ◽  
Muscle Power ◽  
Asymmetry Index ◽  
Lower Limbs ◽  
Bilateral Asymmetry ◽  
Las Mujeres ◽  
Estudiantes Universitarios

El objetivo del presente estudio fue determinar la asimetría bilateral y comparar el índice de asimetría (IA) de las manifestaciones de la fuerza muscular de las extremidades inferiores. Participaron 16 hombres y 14 mujeres con una edad de 22.5 ± 2 años, todos ellos estudiantes universitarios, se les midió la fuerza muscular máxima dinámica, la fuerza máxima isométrica y la potencia muscular de cada extremidad inferior con la sentadilla unilateral. El IA presentado por los sujetos fue entre 2.8 ± 3.0 y 4.0 ± 4.3 % en las diferentes manifestaciones de la fuerza muscular, cuando se compararon dichas manifestaciones no hubo diferencia entre ellas. Por último las mujeres presentaron entre un 2.5 ± 2.7 y un 4.0 ± 4.1 % de IA de las manifestaciones de la fuerza mientras que para los hombres fue entre un 3.0 ± 3.4 y 5.0 ± 4.6 %, sin diferencia cuando se comparó por género. Por lo que se concluye que la asimetría bilateral de las manifestaciones de la fuerza está presente en los sujetos evaluados, siendo similar el IA de las manifestaciones evaluadas así como entre hombres y mujeres.Abstract. The aim of this study was to determine the bilateral asymmetry, and to compare the asymmetry index (AI) of muscle strength expressions in the lower limbs. A total 30 university students (16 men and 14 women) with a mean age of 22.5 ± 2 years participated in the study. Maximum dynamic muscle strength, maximum isometric strength, and muscle power in unilateral lower limb squat were assessed. The IA presented by the subjects ranged from 2.8 ± 3.0 and 4.0 ± 4.3 % in the different manifestations of muscle strength. The comparison of these manifestations revealed no differences. In addition, women scored between 2.5 ± 2.7 and 4.0 ± 4.1 % AI of expression of strength, whereas in men this value ranged between 3.0 ± 3.4 and 5.0 ± 4.6 %. No statistical difference was found comparing by gender. Therefore, we can conclude that there exists a bilateral asymmetry in the manifestations of strength in our sample, at the same time their IA is similar both considering the overall sample and assessing it by gender.

scholarly journals Effects of workload level on muscle recruitment in cycling

2014 ◽  
Vol 15 (1) ◽  
Author(s):  
Jose I. Priego ◽  
Rodrigo R. Bini ◽  
F.J. Lanferdini ◽  
Felipe P. Carpes
Keyword(s):  
Motor Unit ◽  
Power Output ◽  
Lower Limb ◽  
Muscle Activation ◽  
Aerobic Power ◽  
Lower Limb Muscle ◽  
Limb Muscle ◽  
Frequency Content ◽  
Competitive Cyclists ◽  
Aerobic Power Output

AbstractPurpose. Despite the volume of studies addressing muscle activation during pedaling, it is unclear whether changes in workload level during cycling could dictate motor unit recruitment. The present study investigated the frequency content of lower limb muscle activation during submaximal workloads. Methods. Twelve male competitive cyclists pedaled at three workload levels: (1) maximum aerobic power output (PO

scholarly journals Influence of saddle height and exercise intensity on pedalling asymmetries in cyclists

2016 ◽  
Vol 18 (4) ◽  
pp. 411 ◽  
Author(s):  
Fernando Diefenthaeler ◽  
Joscelito De Oliveira Berneira ◽  
Vanderson Luis Moro ◽  
Felipe Pivetta Carpes
Keyword(s):  
Exercise Intensity ◽  
Power Output ◽  
Practical Implication ◽  
Pubic Symphysis ◽  
Constant Load ◽  
Asymmetry Index ◽  
Lower Limbs ◽  
Cycle Asymmetry ◽  
Competitive Cyclists ◽  
Body Positioning

DOI: http://dx.doi.org/10.5007/1980-0037.2016v18n4p411 Pedaling asymmetries quantified during stationary cycling, when cyclist body positioning and intensity remain unchanged, may not fully reproduce the training and competition situations, in which cyclists experience different intensities and may opt for different saddle positioning aiming at power output optimization. Previous studies showed that torque and power can be asymmetric in cyclists. It is not clear whether changes in saddle height and exercise intensity may affect asymmetries. The aim of the present study was to determine pedaling asymmetries during cycling at different saddle heights and different exercise intensities. Twelve competitive cyclists performed an incremental maximal test, a constant-load (“heavy” intensity domain), and a Wingate test. Constant load and the Wingate tests were repeated using three different saddle heights (reference and lower or higher by 2.5% of the distance from the pubic symphysis to the ground). Crank torque was recorded throughout the pedaling cycle. Asymmetry (higher torque for the preferred limb) was found in all saddle heights (p<0.001) in both intensities. Asymmetry index was similar across the saddle positions (p>0.05) in both intensities. Our results suggest that asymmetric cyclists present a consistent pattern regardless of small changes in the saddle height or in exercise intensity. For practical implication, cyclists producing asymmetric torque may be adapted to this condition so they are continuously exposed to asymmetric effort and overload on the lower limbs.

scholarly journals Cu2Se-based thermoelectric cellular architectures for efficient and durable power generation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Seungjun Choo ◽  
Faizan Ejaz ◽  
Hyejin Ju ◽  
Fredrick Kim ◽  
Jungsoo Lee ◽  
...  
Keyword(s):  
Power Generation ◽  
3D Printing ◽  
Power Output ◽  
Waste Heat ◽  
Computational Simulation ◽  
Mechanical Stiffness ◽  
Higher Power ◽  
Printing Inks ◽  
Binder Free ◽  
Sustainable Power

AbstractThermoelectric power generation offers a promising way to recover waste heat. The geometrical design of thermoelectric legs in modules is important to ensure sustainable power generation but cannot be easily achieved by traditional fabrication processes. Herein, we propose the design of cellular thermoelectric architectures for efficient and durable power generation, realized by the extrusion-based 3D printing process of Cu2Se thermoelectric materials. We design the optimum aspect ratio of a cuboid thermoelectric leg to maximize the power output and extend this design to the mechanically stiff cellular architectures of hollow hexagonal column- and honeycomb-based thermoelectric legs. Moreover, we develop organic binder-free Cu2Se-based 3D-printing inks with desirable viscoelasticity, tailored with an additive of inorganic Se82− polyanion, fabricating the designed topologies. The computational simulation and experimental measurement demonstrate the superior power output and mechanical stiffness of the proposed cellular thermoelectric architectures to other designs, unveiling the importance of topological designs of thermoelectric legs toward higher power and longer durability.

scholarly journals Reliability of a New Portable Dynamometer for Assessing Hip and Lower Limb Strength

2021 ◽  
Vol 11 (8) ◽  
pp. 3391
Author(s):  
Jan Marušič ◽  
Goran Marković ◽  
Nejc Šarabon
Keyword(s):  
Lower Limb ◽  
External Rotation ◽  
Peak Torque ◽  
Knee Extension ◽  
Lower Limb Muscles ◽  
Lower Limb Strength ◽  
Flexion Extension ◽  
Strength Tests ◽  
Hip Abduction ◽  
Maximal Peak

The purpose of this study was to evaluate intra- and inter-session reliability of the new, portable, and externally fixated dynamometer called MuscleBoard® for assessing the strength of hip and lower limb muscles. Hip abduction, adduction, flexion, extension, internal and external rotation, knee extension, ankle plantarflexion, and Nordic hamstring exercise strength were measured in three sessions (three sets of three repetitions for each test) on 24 healthy and recreationally active participants. Average and maximal value of normalized peak torque (Nm/kg) from three repetitions in each set and agonist:antagonist ratios (%) were statistically analyzed; the coefficient of variation and intra-class correlation coefficient (ICC2,k) were calculated to assess absolute and relative reliability, respectively. Overall, the results display high to excellent intra- and inter-session reliability with low to acceptable within-individual variation for average and maximal peak torques in all bilateral strength tests, while the reliability of unilateral strength tests was moderate to good. Our findings indicate that using the MuscleBoard® dynamometer can be a reliable device for assessing and monitoring bilateral and certain unilateral hip and lower limb muscle strength, while some unilateral strength tests require some refinement and more extensive familiarization.

Bilateral asymmetries in professional cyclists during a Grand Tour

2020 ◽  
pp. 1-7
Author(s):  
Alejandro Javaloyes ◽  
Manuel Mateo-March ◽  
Felipe P. Carpes ◽  
Manuel Moya-Ramon ◽  
Raúl Lopez-Grueso ◽  
...  
Keyword(s):  
Injury Prevention ◽  
Intensity Distribution ◽  
Power Output ◽  
Lower Limb ◽  
Overuse Injury ◽  
Power Balance ◽  
Grand Tour ◽  
Race Time ◽  
Potential Link

BACKGROUND: Pedalling asymmetries are a topic of interest to cycling coaches and athletes due to a potential link with performance and injury prevention. OBJECTIVES: The aim of this study is to describe the bilateral asymmetry of professional cyclists during two editions of a Grand Tour. METHODS: Here we set out to determine the power balance (power produced by each lower limb) between stronger and weaker leg (dominant vs. non-dominant) of 12 UCI professional cyclists competing at two Giro d’Italia editions. Power data were recorded during competition stages. Further analysis considered power data clustered into individual intensity zones (from Z1 to Z7). RESULTS: Higher intensity elicited better power balance (lower asymmetry) regardless of the stage profile. Intensity distribution analysed according to the role of the cyclist was lower for climbers in Z2 (p= 0.006) and Z7 (p= 0.002) and higher in Z5 (p= 0.023) compared to team helpers. Power balance ranged from 0 to 9 % across the different athletes. CONCLUSIONS: Increase in power output improves power balance, especially in team helpers, and the lower power balance at lower exercise intensities, which are most of the race time, may elicit significant cumulative loading on a given leg of the cyclists, which requires further attention regarding risks of overuse injury.

Power output and fatigue of human muscle in maximal cycling exercise

1983 ◽  
Vol 55 (1) ◽  
pp. 218-224 ◽  
Author(s):  
N. McCartney ◽  
G. J. Heigenhauser ◽  
N. L. Jones
Keyword(s):  
Power Output ◽  
Fiber Type ◽  
Average Power ◽  
Lactate Concentration ◽  
Peak Torque ◽  
Muscle Volume ◽  
Thigh Muscle ◽  
Peak Power Output ◽  
Maximal Power ◽  
Maximal Power Output

We studied maximal torque-velocity relationships and fatigue during short-term maximal exercise on a constant velocity cycle ergometer in 13 healthy male subjects. Maximum torque showed an inverse linear relationship to crank velocity between 60 and 160 rpm, and a direct relationship to thigh muscle volume measured by computerized tomography. Peak torque per liter thigh muscle volume (PT, N X ml-1) was related to crank velocity (CV, rpm) in the following equation: PT = 61.7 - 0.234 CV (r = 0.99). Peak power output was a parabolic function of crank velocity in individual subjects, but maximal power output was achieved at varying crank velocities in different subjects. Fiber type distribution was measured in the two subjects showing the greatest differences and demonstrated that a high proportion of type II fibers may be one factor associated with a high crank velocity for maximal power output. The decline in average power during 30 s of maximal effort was least at 60 rpm (23.7 +/- 4.6% of initial maximal power) and greatest at 140 rpm (58.7 +/- 6.5%). At 60 rpm the decline in power over 30 s was inversely related to maximal oxygen uptake (ml X min-1 X kg-1) (r = 0.69). Total work performed and plasma lactate concentration 3 min after completion of 30-s maximum effort were similar for each crank velocity.

Slight power output manipulations around the maximal lactate steady state have an impact on fatigue in females and males.

2021 ◽  
Author(s):  
Rafael de Almeida Azevedo ◽  
Jonas Forot ◽  
Danilo Iannetta ◽  
Martin J. MacInnis ◽  
Guillaume Y. Millet ◽  
...  
Keyword(s):  
Steady State ◽  
Power Output ◽  
Contractile Function ◽  
Femoral Nerve ◽  
Peak Torque ◽  
Knee Extensors ◽  
Time To Exhaustion ◽  
Maximal Lactate Steady State ◽  
Subsequent Performance ◽  
Single Twitch

Neuromuscular fatigue (NMF) and exercise performance are affected by exercise intensity and sex differences. However, whether slight changes in power output (PO) below and above the maximal lactate steady-state (MLSS) impact NMF and subsequent performance (time to exhaustion, TTE) is unknown. Purpose: This study compared NMF and TTE in females and males in response to exercise performed at MLSS, 10 W below (MLSS-10) and above (MLSS+10). Methods: Twenty participants (9 females) performed three 30-min constant-PO exercise bouts followed (1 min delay) by a TTE at 80% of the peak-PO. NMF was characterized by isometric maximal voluntary contractions (IMVC) and femoral nerve electrical stimulation of knee extensors [e.g. peak torque of potentiated high-frequency (Db100) and single twitch (TwPt)] before and immediately after the constant-PO and TTE bouts. Results: IMVC declined less after MLSS-10 (-18±10%) compared to MLSS (-26±14%) and MLSS+10 (-31±11%) (all p<0.05), and the Db100 decline was greater after MLSS+10 (-24±14%) compared to the other intensities (MLSS-10: -15±9%; MLSS: -18±11%) (all p<0.05). Females showed smaller reductions in IMVC and TwPt compared to males after constant-PO bouts (all p<0.05), this difference being not dependant on intensity. TTE was negatively impacted by increasing the PO in the constant-PO (p<0.001), with no differences in end-exercise NMF (p>0.05). Conclusion: Slight changes in PO around MLSS elicited great changes in the reduction of maximal voluntary force and impairments in contractile function. Although NMF was lower in females compared to males, the changes in PO around the MLSS impacted both sexes similarly.

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