Effects of pedal rate and power output on cycling kinematics

2018 ◽  
pp. 23-31
Author(s):  
Nicolas Bessot
Keyword(s):  
Experimental Data ◽  
Power Output ◽  
Rate Ratio ◽  
Cycle Ergometer ◽  
Pedal Rate ◽  
Flexion Extension ◽  
Submaximal Effort ◽  
Competitive Cyclists ◽  
The Mean ◽  
Hip Flexion

The aim of this study was to examine the effect of changes in pedal rate and power output in the cycling kinematics of endurance cyclists. Nine male competitive cyclists performed 16 submaximal effort trials of 4 minutes’ duration on a cycle ergometer. Power output was imposed at 50, 100, 150, and 200 W successively for each pedal rate studied (45, 70, 95, 120 rev · min−1). The ankle, knee and hip flexion/extension, and pedal angle (pedal axis/malleolus medialis compared to the horizontal) were analysed. We observed an increase of mean pedal angle and a decrease of magnitude in pedal mobilisation when pedal rate increased or power output decreased. The mean pedal angle recorded during a crank cycle seems to depend on pedal load (power/pedal rate ratio). The supposed effect of pedal rate, power and pedal load on pedal angle was confirmed by adjusting a sin function (with pedal rate, power and power/pedal rate ratio as variables) representing the evolution of pedal angle during the crank evolution to experimental data. The modifications due to power and pedal rate change that were observed in pedal kinematics were generally transferred to the upper joints of the legs.

scholarly journals An Analysis of Variability in Power Output During Indoor and Outdoor Cycling Time Trials

2019 ◽  
Vol 14 (9) ◽  
pp. 1273-1279 ◽  
Author(s):  
Owen Jeffries ◽  
Mark Waldron ◽  
Stephen D. Patterson ◽  
Brook Galna
Keyword(s):  
Power Output ◽  
Time Trial ◽  
Mean Power ◽  
Portable Power ◽  
Output Variability ◽  
Competitive Cyclists ◽  
The Mean ◽  
Mean Power Output ◽  
Testing Protocols ◽  
Indoor And Outdoor

Purpose: Regulation of power output during cycling encompasses the integration of internal and external demands to maximize performance. However, relatively little is known about variation in power output in response to the external demands of outdoor cycling. The authors compared the mean power output and the magnitude of power-output variability and structure during a 20-min time trial performed indoors and outdoors. Methods: Twenty male competitive cyclists ( 60.4 [7.1] mL·kg−1·min−1) performed 2 randomized maximal 20-min time-trial tests: outdoors at a cycle-specific racing circuit and indoors on a laboratory-based electromagnetically braked training ergometer, 7 d apart. Power output was sampled at 1 Hz and collected on the same bike equipped with a portable power meter in both tests. Results: Twenty-minute time-trial performance indoor (280 [44] W) was not different from outdoor (284 [41] W) (P = .256), showing a strong correlation (r = .94; P < .001). Within-persons SD was greater outdoors (69 [21] W) than indoors (33 [10] W) (P < .001). Increased variability was observed across all frequencies in data from outdoor cycling compared with indoors (P < .001) except for the very slowest frequency bin (<0.0033 Hz, P = .930). Conclusions: The findings indicate a greater magnitude of variability in power output during cycling outdoors. This suggests that constraints imposed by the external environment lead to moderate- and high-frequency fluctuations in power output. Therefore, indoor testing protocols should be designed to reflect the external demands of cycling outdoors.

scholarly journals Acute ibuprofen ingestion does not attenuate fatigue during maximal intermittent knee extensor or all-out cycling exercise

2019 ◽  
Vol 44 (2) ◽  
pp. 208-215 ◽  
Author(s):  
Paul T. Morgan ◽  
Anni Vanhatalo ◽  
Joanna L. Bowtell ◽  
Andrew M. Jones ◽  
Stephen J. Bailey
Keyword(s):  
Exercise Performance ◽  
Power Output ◽  
Knee Extensor ◽  
Cycling Performance ◽  
Similar Rate ◽  
Cycle Ergometer ◽  
Knee Extensors ◽  
Mean Power ◽  
Healthy Humans ◽  
The Mean

Recent research suggests that acute consumption of pharmacological analgesics can improve exercise performance, but the ergogenic potential of ibuprofen (IBP) administration is poorly understood. This study tested the hypothesis that IBP administration would enhance maximal exercise performance. In one study, 13 physically active males completed 60 × 3-s maximal voluntary contractions (MVCs) of the knee extensors interspersed with 2-s passive recovery periods, on 2 occasions, with the critical torque (CT) estimated as the mean torque over the last 12 contractions (part A). In another study, 16 active males completed two 3-min all-out tests against a fixed resistance on an electronically braked cycle ergometer, with the critical power estimated from the mean power output over the final 30 s of the test (part B). All tests were completed 60 min after ingestion of maltodextrin (placebo, PL) or 400 mg of IBP. Peripheral nerve stimulation was administered at regular intervals and electromyography was measured throughout. For part A, mean torque (IBP: 60% ± 13% of pre-exercise MVC; PL: 58% ± 14% of pre-exercise MVC) and CT (IBP: 41% ± 16% of pre-exercise MVC; PL: 40% ± 15% of pre-exercise MVC) were not different between conditions (P > 0.05). For part B, end-test power output (IBP: 292 ± 28 W; PL: 288 ± 31 W) and work done (IBP: 65.9 ± 5.9 kJ; PL: 65.4 ± 6.4 kJ) during the 3-min all-out cycling tests were not different between conditions (all P > 0.05). For both studies, neuromuscular fatigue declined at a similar rate in both conditions (P > 0.05). In conclusion, acute ingestion of 400 mg of IBP does not improve single-leg or maximal cycling performance in healthy humans.

Short-Term Power Output in 9-Year-Old Children: Typical Error between Ergometers and Protocols

2003 ◽  
Vol 15 (3) ◽  
pp. 302-312 ◽  
Author(s):  
Craig A. Williams ◽  
Eric Doré ◽  
James Alban ◽  
Emmanuel Van Praagh
Keyword(s):  
Power Output ◽  
Peak Power ◽  
Cycle Ergometer ◽  
Short Term ◽  
Mean Power ◽  
Time To Peak ◽  
Pedal Rate ◽  
Cycle Ergometers ◽  
Power Peak ◽  
S Peak

This study investigated the differences in short-term power output (STPO) using three different cycle ergometers in 9-year-old children. A total of 31 children participated in three cycle ergometer sprint tests of 20 s duration: a modified friction braked Monark, a modified friction braked Ergomeca cycle ergometer, and a SRM isokinetic ergometer. Common indices of peak and mean power, peak pedal rate, time to peak power, and pedal rate were recorded. Indices of peak power 1 s for the Monark, Ergomeca and SRM ergometer were found to be 299 ± 55, 294 ± 55, 297 ± 53 W and mean power 20 s to be 223 ± 40, 227 ± 43 and 216 ± 34 W, respectively. The time to peak power was found to be 3 ± 2, 6 ± 2, 5 ± 3 s, respectively. The standard error of measurement was lower in mean 20-s power compared to 1-s peak power. Despite instrumentation and protocol differences these results demonstrate reproducibility in 9-year-old children that will allow researchers confidence in comparing STPO data obtained from different ergometers.

scholarly journals Hyperventilation reduces the decrease of power output in a repeated sprint training in cyclists

2018 ◽  
Vol 11 (3) ◽  
Author(s):  
J Barth ◽  
M Vaz ◽  
F Del Vecchio
Keyword(s):  
Normal Condition ◽  
Power Output ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Cycle Ergometer ◽  
Relative Power ◽  
Sprint Training ◽  
Fatigue Index ◽  
Repeated Sprint ◽  
The Mean

Objective: To evaluate the effect of hyperventilation during a repeated sprint training on a cycle ergometer. Method: Seven cyclists performed two training sessions (10 maximal sprints of 10 s, with 60 s of rest), one with free ventilatory frequency and another one with hyperventilation (the participants breathed 60 cycles per minute during the last 30 s of recovery). Power, fatigue index and blood lactate concentration were analyzed. Results: The lactate concentrations pre- and post-training did not differ between trainings. Regarding to the maximum absolute and relative power, no differences were found between sprints in the hyperventilation condition, however, the values obtained in the first four sprints were higher than the latter two (p < 0.05) in the normal condition. In relation to the mean absolute and relative power, differences were found between sprints in both conditions. In the hyperventilation condition the value of the first sprint was higher than the penultimate (p < 0.05), while in the normal condition, the value of the first sprint was greater than the last four (p < 0.05) and the value of the second sprint exceeded the last two ones (p < 0.05). For the fatigue index, both protocols showed differences from the first to the eighth sprint (p < 0.05). Conclusion: Despite the absence of differences in lactate concentration between normal condition and hyperventilation condition, hyperventilation between efforts during a repeated sprint training could reduce the decrease in power output on a cycle ergometer.

scholarly journals The influence of bicycle lean on maximal power output during sprint cycling

2021 ◽  
Author(s):  
Ross D. Wilkinson ◽  
Rodger Kram
Keyword(s):  
Power Output ◽  
Direct Evidence ◽  
Cycle Ergometer ◽  
Maximal Power ◽  
Maximal Power Output ◽  
Bicycle Dynamics ◽  
Competitive Cyclists ◽  
Sprint Cycling ◽  
Ad Libitum

Competitive cyclists typically sprint out of the saddle and alternately lean their bikes from side-to-side, away from the downstroke pedal. Yet, there is no direct evidence as to whether leaning the bicycle, or conversely, attempting to minimize lean, affects maximal power output during sprint cycling. Here, we modified a cycling ergometer so that it can lean from side-to-side but can also be locked to prevent lean. This modified ergometer made it possible to compare maximal 1-s crank power during non-seated, sprint cycling under three different conditions: locked (no lean), ad libitum lean, and minimal lean. We found that leaning the ergometer ad libitum did not enhance maximal 1-s crank power compared to a locked condition. However, trying to minimize ergometer lean decreased maximal 1-s crank power by an average of 5% compared to leaning ad libitum. IMU-derived measures of ergometer lean provided evidence that, on average, during the ad-lib condition, subjects leaned the ergometer away from the downstroke pedal as in overground cycling. This suggests that our ergometer provides a suitable emulation of lateral bicycle dynamics. Overall, we find that leaning a cycle ergometer ad libitum does not enhance maximal power output, and conversely, trying to minimize lean impairs maximal power output.

Measurement and Analysis of Lower Limb Kinematics for the Female Chinese Population During Squatting

2016 ◽  
Vol 34 (1) ◽  
pp. 59-65
Author(s):  
S. Wei ◽  
D.-M. Wang ◽  
Y.-P. Lin ◽  
X. Li ◽  
C.-T. Wang ◽  
...  
Keyword(s):  
Lower Limb ◽  
Chinese Population ◽  
Three Dimensional ◽  
Young Female ◽  
Female Group ◽  
Flexion Extension ◽  
Lower Limb Prosthesis ◽  
Limb Kinematics ◽  
The Mean ◽  
Hip Flexion

AbstractThe study investigates three-dimensional kinematics of lower limb for female Chinese population during normal squatting activity. 25 young female and 25 elder female Chinese subjects were recruited. With each subject's data collected, the means of three-dimensional rotation angles of knee, hip, and ankle joints of those two groups were calculated and analyzed. Measured results showed that the maximal eccentric range of hip flexion/extension of 128.6° for the young female group (P < 0.05) was compared with that of 158.8° for the elder female group. Thus, the elder female undergoes more hip flexion/extension angles than the young female in the posture of squatting. The mean range of motion (ROM) of knee flexion/extension was 140.2° for the young female group and 138.7° (significant level P > 0.05) for the elder female group. The mean ROM of ankle flexion/extension was 47.90° for the young female group and 31.9° (P > 0.05) for the elder female group. The ROMs obtained in the experiment during squatting were greater than the reported ones achieved after joint arthroplasty. These data may be invaluable in providing designers of lower limb prosthesis with basic mechanical parameters, and assessing the effect of kinematics of low limb on rehabilitation for the Chinese population.

Robotic-Assisted Patellofemoral Replacement—Correlation of Preoperative Planning with Intraoperative Implant Position and Early Clinical Experience: A Minimum 2-Year Follow-up

2020 ◽  
Author(s):  
Veenesh Selvaratnam ◽  
Andrew Cattell ◽  
Keith S. Eyres ◽  
Andrew D. Toms ◽  
Jonathan R. P. Phillips ◽  
...  
Keyword(s):  
Functional Outcome ◽  
Preoperative Planning ◽  
Trochlear Dysplasia ◽  
Oxford Knee Score ◽  
Implant Position ◽  
Robotic Assisted ◽  
Implant Positioning ◽  
Flexion Extension ◽  
The Mean

AbstractPatello-femoral arthroplasty (PFA) is successful in a selected group of patients and yields a good functional outcome. Robotic-assisted knee arthroplasty has been shown to provide better implant positioning and alignment. We aim to report our early outcomes and to compare Mako's (Robotic Arm Interactive Orthopaedic System [RIO]) preoperative implant planning position to our intraoperative PFA implant position. Data for this study was prospectively collected for 23 (two bilateral) patients who underwent robotic-assisted PFA between April 2017 and May 2018. All preoperative implant position planning and postoperative actual implant position were recorded. Presence of trochlear dysplasia and functional outcome scores were also collected. There were 17 (two bilateral) female and 6 male patients with a mean age of 66.5 (range: 41–89) years. The mean follow-up period was 30 (range: 24–37) months. Eighteen knees (72%) had evidence of trochlear dysplasia. The anterior trochlear line was on average, 7.71 (range: 3.3–11.3) degrees, internally rotated to the surgical transepicondylar axis and on average 2.9 (range: 0.2–6.5) degrees internally rotated to the posterior condylar line. The preoperative planning range was 4-degree internal to 4-degree external rotation, 4-degree varus to 6-degree valgus, and 7-degree flexion to 3-degree extension. The average difference between preoperative planning and intraoperative implant position was 0.43 degrees for rotation (r = 0.93), 0.99 degrees for varus/valgus (r = 0.29), 1.26 degrees for flexion/extension (r = 0.83), and 0.34 mm for proudness (r = 0.80). Six patients (24%) had a different size component from their preoperative plan (r = 0.98). The mean preoperative Oxford Knee Score (OKS) was 16 and the mean postoperative OKS was 42. No patient had implant-related revision surgery or any radiological evidence of implant loosening at final follow-up. Our early results of robotic PFA are promising. Preoperative Mako planning correlates closely with intraoperative implant positioning. Longer follow-up is needed to assess long-term patient outcomes and implant survivorship.

scholarly journals Persisting inter‐limb differences in patients following total hip arthroplasty four to five years after surgery? A preliminary cross‐sectional study

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Stefanie John ◽  
David Weizel ◽  
Anna S. Heumann ◽  
Anja Fischer ◽  
Katja Orlowski ◽  
...  
Keyword(s):  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Center Of Pressure ◽  
Operation Time ◽  
Hip Strength ◽  
Total Hip ◽  
Control Subjects ◽  
Post Surgery ◽  
Flexion Extension ◽  
Hip Flexion

Abstract Background Total hip arthroplasty (THA) is an effective procedure for patients with end-stage hip osteoarthritis. However, whether or not pre-operatively existing functional deficits are persisting several years post-surgery in the affected limb has not been thoroughly researched. Therefore, the primary aim of this preliminary study was to include patients four to five years after undergoing THA and to investigate potential differences between the operated and non-operated leg in hip strength, range of motion (ROM), balance, and gait. The secondary aim was to compare these values from the operated leg of the patients to those of the legs of healthy subjects. Methods Sixteen patients (age: 65.20 ± 5.32 years) following unilateral THA (post-operation time: 4.7 ± 0.7 years) and ten, healthy, age-matched control subjects (age: 60.85 ± 7.57 years) were examined for maximum isometric hip muscle strength, active ROM of the hip joint, balance and gait on both limbs. Paired t-tests were used to assess the inter-limb differences in the THA group. Analyses of covariance (ANCOVA) were performed to compare groups, using age as a covariate. Results The analysis of inter-limb differences in patients following THA revealed significant deficits on the operated side for hip abduction strength (p = 0.02), for hip flexion ROM (p < 0.01) and for balance in terms of the length of center of pressure (COP) (p = 0.04). Compared to values of the control subjects, the patients demonstrated significantly reduced hip strength in flexion, extension and abduction (p < 0.05) on the operated leg as well as reduced ROM measures in hip flexion, extension and abduction (p < 0.05). Conclusions The first results of this explorative study indicated that inter-limb differences as well as reduced hip strength and hip ROM compared with control subjects were still present four to five years after THA. These persisting asymmetries and deficits in patients following THA may be one explanation for the decrease in health-related quality of life (HRQoL) seen in patients over the years after surgery. Further studies are required to replicate these findings with a larger sample size. Trial registration DRKS, DRKS00016945. Registered 12 March 2019 – Retrospectively registered,

scholarly journals Are the Assioma Favero Power Meter Pedals a Reliable Tool for Monitoring Cycling Power Output?

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2789
Author(s):  
Víctor Rodríguez-Rielves ◽  
José Ramón Lillo-Beviá ◽  
Ángel Buendía-Romero ◽  
Alejandro Martínez-Cava ◽  
Alejandro Hernández-Belmonte ◽  
...  
Keyword(s):  
Power Output ◽  
Gold Standard ◽  
Cycle Ergometer ◽  
Test Reliability ◽  
Direct Drive ◽  
Validity And Reliability ◽  
Power Meter ◽  
High Workload ◽  
Vibration Stress ◽  
40 Hz

This study aimed to examine the validity and reliability of the recently developed Assioma Favero pedals under laboratory cycling conditions. In total, 12 well-trained male cyclists and triathletes (VO2max = 65.7 ± 8.7 mL·kg−1·min−1) completed five cycling tests including graded exercises tests (GXT) at different cadences (70–100 revolutions per minute, rpm), workloads (100–650 Watts, W), pedaling positions (seated and standing), vibration stress (20–40 Hz), and an 8-s maximal sprint. Tests were completed using a calibrated direct drive indoor trainer for the standing, seated, and vibration GXTs, and a friction belt cycle ergometer for the high-workload step protocol. Power output (PO) and cadence were collected from three different brand, new pedal units against the gold-standard SRM crankset. The three units of the Assioma Favero exhibited very high within-test reliability and an extremely high agreement between 100 and 250 W, compared to the gold standard (Standard Error of Measurement, SEM from 2.3–6.4 W). Greater PO produced a significant underestimating trend (p < 0.05, Effect size, ES ≥ 0.22), with pedals showing systematically lower PO than SRM (1–3%) but producing low bias for all GXT tests and conditions (1.5–7.4 W). Furthermore, vibrations ≥ 30 Hz significantly increased the differences up to 4% (p < 0.05, ES ≥ 0.24), whereas peak and mean PO differed importantly between devices during the sprints (p < 0.03, ES ≥ 0.39). These results demonstrate that the Assioma Favero power meter pedals provide trustworthy PO readings from 100 to 650 W, in either seated or standing positions, with vibrations between 20 and 40 Hz at cadences of 70, 85, and 100 rpm, or even at a free chosen cadence.

scholarly journals Application of Artificial Intelligence (AI) for Sustainable Highway and Road System

Symmetry ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 60
Author(s):  
Md Arifuzzaman ◽  
Muhammad Aniq Gul ◽  
Kaffayatullah Khan ◽  
S. M. Zakir Hossain
Keyword(s):  
Experimental Data ◽  
High Performance ◽  
Adhesion Force ◽  
Model Development ◽  
Real Life ◽  
Bayesian Optimization ◽  
Support Vector ◽  
Adhesive Properties ◽  
Bayesian Optimization Algorithm ◽  
The Mean

There are several environmental factors such as temperature differential, moisture, oxidation, etc. that affect the extended life of the modified asphalt influencing its desired adhesive properties. Knowledge of the properties of asphalt adhesives can help to provide a more resilient and durable asphalt surface. In this study, a hybrid of Bayesian optimization algorithm and support vector regression approach is recommended to predict the adhesion force of asphalt. The effects of three important variables viz., conditions (fresh, wet and aged), binder types (base, 4% SB, 5% SB, 4% SBS and 5% SBS), and Carbon Nano Tube doses (0.5%, 1.0% and 1.5%) on adhesive force are taken into consideration. Real-life experimental data (405 specimens) are considered for model development. Using atomic force microscopy, the adhesive strength of nanoscales of test specimens is determined according to functional groups on the asphalt. It is found that the model predictions overlap with the experimental data with a high R2 of 90.5% and relative deviation are scattered around zero line. Besides, the mean, median and standard deviations of experimental and the predicted values are very close. In addition, the mean absolute Error, root mean square error and fractional bias values were found to be low, indicating the high performance of the developed model.

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