Sensitivity of cycling Motion Performance Indicators (MPIs) to incremented load and their relationship with performance in professional cyclists

2021 ◽  
pp. 175433712110620
Author(s):  
Javier Courel-Ibáñez ◽  
Manuel Mateo-March ◽  
Víctor Moreno-Pérez ◽  
Rodrigo Bini
Keyword(s):  
Performance Indicators ◽  
Power Production ◽  
Cycling Performance ◽  
Cycle Ergometer ◽  
Range Of Movement ◽  
Time Motion ◽  
Graded Exercise ◽  
Measurement Units ◽  
Motion Performance ◽  
The Right

There is a lack of research assessing Motion Performance Indicators (MPIs), which have been recently made commercially available. Therefore, this study explored: (1) the influence of incremented exercise on MPIs and; (2) the relationships between MPIs and cycling performance at different intensities during a graded exercise test (GXT) in professional cyclists. Thirty-six professional cyclists performed GXT until exhaustion with their own bikes attached to a cycle ergometer. MPIs were collected using a real-time motion capture system based on inertial measurement units at 100 Hz of sample rate. Data were extracted from intensities of the GXT when lactate thresholds (LT1, LT2) and peak power (POpeak) were determined. Results showed that only Pelvic Angle ( p < 0.01, d > 1.15) and Pelvic Rotation ( p < 0.01, d > 1.37) were sensitive to increases in exercise intensity (i.e. greater inclination and increased rotation at greater power). Multivariate liner regression analyses showed that a reduced range of movement (ROM) for the upper legs at sub-maximum intensities (LT1 and LT2) was associated with greater power production ( r2 > 0.21), whilst a reduced ROM for the right foot was associated with greater POpeak ( r2 = 0.20). In conclusion, changes in movement patterns were limited to a greater inclination and rotation of the pelvis at maximum power without changes in other MPIs throughout the GXT. Cyclists who produced greater power presented less ROM for their upper legs at LT1 and LT2 whilst at POpeak and greater power production was moderately associated with less ROM for the right foot. Coaches may be able to use MPI to analyze for excess ROM, particularly at higher exercise intensities, as this seems to increase inefficiencies and limit power production.

scholarly journals The Influence of Maturation on the Oxygen Uptake Efficiency Slope

2012 ◽  
Vol 24 (3) ◽  
pp. 347-356 ◽  
Author(s):  
Michael P. Rogowski ◽  
Justin P. Guilkey ◽  
Brooke R. Stephens ◽  
Andrew S. Cole ◽  
Anthony D. Mahon
Keyword(s):  
Oxygen Uptake ◽  
Body Mass ◽  
Cycle Ergometer ◽  
Group Differences ◽  
Healthy Male ◽  
Uptake Efficiency ◽  
Graded Exercise ◽  
Oxygen Uptake Efficiency Slope ◽  
Male Subjects ◽  
One Way Anova

This study examined the influence of maturation on the oxygen uptake efficiency slope (OUES) in healthy male subjects. Seventy-six healthy male subjects (8–27 yr) were divided into groups based on maturation status: prepubertal (PP), midpubertal (MP), late-pubertal (LP), and young-adult (YA) males. Puberty status was determined by physical examination. Subjects performed a graded exercise test on a cycle ergometer to determine OUES. Group differences were assessed using a one-way ANOVA. OUES values (VO2L·min1/log10VEL·min−1) were lower in PP and MP compared with LP and YA (p < .05). When OUES was expressed relative to body mass (VO2mL·kg−1·min−1/log10VEmL·kg−1·min−1) differences between groups reversed whereby PP and MP had higher mass relative OUES values compared with LP and YA (p < .05). Adjusting OUES by measures of body mass failed to eliminate differences across maturational groups. This suggests that qualitative factors, perhaps related to oxidative metabolism, account for the responses observed in this study.

Physical Demands and Performance Indicators in Male Professional Cyclists During a Grand Tour: WorldTour Versus ProTeam Category

2021 ◽  
pp. 1-9
Author(s):  
Xabier Muriel ◽  
Pedro L. Valenzuela ◽  
Manuel Mateo-March ◽  
Jesús G. Pallarés ◽  
Alejandro Lucia ◽  
...  
Keyword(s):  
Power Output ◽  
Performance Indicators ◽  
Cycling Performance ◽  
Threshold Power ◽  
Grand Tour ◽  
Physical Demands ◽  
Physical Demand ◽  
Stress Score ◽  
And Performance ◽  
Training Stress

Purpose: To compare the physical demands and performance indicators of male professional cyclists of 2 different categories (Union Cycliste Internationale WorldTour [WT] and ProTeam [PT]) during a cycling grand tour. Methods: A WT team (n = 8, 31.4 [5.4] y) and a PT team (n = 7, 26.9 [3.3] y) that completed “La Vuelta 2020” volunteered to participate. Participants’ power output (PO) was registered, and measures of physical demand and physiological performance (kilojoules spent, training stress score, time spent at different PO bands/zones, and mean maximal PO [MMP] for different exertion durations) were computed. Results: WT achieved a higher final individual position than PT (31 [interquartile range = 33] vs 71 [59], P = .004). WT cyclists showed higher mean PO and kilojoule values than their PT peers and spent more time at high-intensity PO values (>5.25 W·kg−1) and zones (91%–120% of individualized functional threshold power) (Ps < .05). Although no differences were found for MMP values in the overall analysis (P > .05), subanalyses revealed that the between-groups gap increased through the race, with WT cyclists reaching higher MMP values for ≥5-minute efforts in the second and third weeks (Ps < .05). Conclusions: Despite the multifactorial nature of cycling performance, WT cyclists spend more time at high intensities and show higher kilojoules and mean PO than their PT referents during a grand tour. Although the highest MMP values attained during the whole race might not differentiate between WT and PT cyclists, the former achieve higher MMP values as the race progresses.

scholarly journals Effect of a Taped Filter Mask on Perceived Breathlessness, Heart Rate, Lactate and Oxygen Saturation During a Graded Exercise Test

2021 ◽  
Author(s):  
Hoi Lam Ng ◽  
Johannes Trefz ◽  
Martin Schönfelder ◽  
Henning Wackerhage
Keyword(s):  
Heart Rate ◽  
Oxygen Saturation ◽  
Exercise Test ◽  
Repeated Measures ◽  
Face Mask ◽  
Cycle Ergometer ◽  
Peripheral Oxygen Saturation ◽  
Graded Exercise Test ◽  
Graded Exercise ◽  
The Face

Abstract Background: Face masks are an effective, non-pharmacological strategy to reduce the transmission of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) and other pathogens. However, it is a challenge to keep masks sealed during exercise, as ventilation can increase from 5-10 L/min at rest to up to 200 L/min so that masks may be blown away from the face. To reduce leakage e.g. during exercise, a face mask was developed that is taped onto the face. The aim of this study was to investigate during a graded cycle ergometry test the effect of a taped mask on the perception of breathlessness, heart rate, lactate, and oxygen saturation when compared to a surgical mask and no mask.Methods: Four trained and healthy males and females each (n=8 in total) performed incremental cycle ergometer tests until voluntary exhaustion under three conditions: (1) No mask/control, (2) surgical mask or (3) taped mask. During these tests, we measured perception of breathlessness, heart rate, the concentration of blood lactate and peripheral oxygen saturation and analysed the resultant data with one or two-way repeated measures ANOVAs. We also used a questionnaire to evaluate mask comfort and analysed the data with paired t-tests. Results: When compared to wearing no mask, a taped face mask significantly reduces the maximal workload in a graded exercise test by 12±6% (p=0.001). Moreover, with a taped face mask, subjects perceive severe breathlessness at 12±9% lower workload (p=0.012) and oxygen saturation at 65% of the maximal workload is 1.5% lower (p=0.018) when compared to wearing no mask. Heart rate and the concentration of lactate were not significantly different at any workload. When compared to wearing a surgical mask, wearing a taped face mask has a significantly better wearing comfort (p=0.038), feels better on the skin (p=0.004), there is a lower sensation of moisture (p=0.026) and wearers perceive that less heat is generated (p=0.021). We found no sex/gender differences for any parameters. Conclusions: A taped mask is well tolerated during light and moderate exercise intensity but reduces maximal exercise capacity.

scholarly journals Motion-Preserving Navigated Primary Internal Fixation of Unstable C1 Fractures

2020 ◽  
Vol 14 (4) ◽  
pp. 466-474
Author(s):  
Shanmuganathan Rajasekaran ◽  
Dilip Chand Raja Soundararajan ◽  
Ajoy Prasad Shetty ◽  
Rishi Mugesh Kanna
Keyword(s):  
Neck Disability Index ◽  
Optimal Placement ◽  
Range Of Movement ◽  
Ct Guided ◽  
Duration Of Surgery ◽  
The Mean ◽  
The Right ◽  
Neck Disability ◽  
Displaced Fracture

Study Design: Prospective observational study.Purpose: To assess the safety, efficacy, and benefits of computed tomography (CT)-guided C1 fracture fixation.Overview of Literature: The surgical management of unstable C1 injuries by occipitocervical and atlantoaxial (AA) fusion compromises motion and function. Monosegmental C1 osteosynthesis negates these drawbacks and provides excellent functional outcomes.Methods: The patients were positioned in a prone position, and cranial traction was applied using Mayfield tongs to restore the C0–C2 height and obtain a reduction in the displaced fracture fragments. An intraoperative, CT-based navigation system was used to enable the optimal placement of C1 screws. A transverse rod was then placed connecting the two screws, and controlled compression was applied across the fixation. The patients were prospectively evaluated in terms of their clinical, functional, and radiological outcomes, with a minimal follow-up of 2 years.Results: A total of 10 screws were placed in five patients, with a mean follow-up of 40.8 months. The mean duration of surgery was 77±13.96 minutes, and the average blood loss was 84.4±8.04 mL. The mean combined lateral mass dislocation at presentation was 14.6±1.34 mm and following surgery, it was 5.2±1.64 mm, with a correction of 9.4±2.3 mm (<i>p</i> <0.001). The follow-up CT showed excellent placement of screws and sound healing. There were no complications and instances of AA instability. The clinical range of movement at 2 years in degrees was as follows: rotation to the right (73.6°±9.09°), rotation to the left (71.6°±5.59°), flexion (35.4°±4.5°), extension (43.8°±8.19°), and lateral bending on the right (28.4°±10.45°) and left (24.8°±11.77°). Significant improvement was observed in the functional Neck Disability Index from 78±4.4 to 1.6±1.6. All patients returned to their occupation within 3 months.Conclusions: Successful C1 reduction and fixation allows a motion-preserving option in unstable atlas fractures. CT navigation permits accurate and adequate monosegmental fixation with excellent clinical and radiological outcomes, and all patients in this study returned to their preoperative functional status.

Potential of Human Tracking in Assistive Technologies for Children with Cognitive Disabilities

2017 ◽  
pp. 245-266 ◽  
Author(s):  
Mark Tee Kit Tsun ◽  
Lau Bee Theng ◽  
Hudyjaya Siswoyo ◽  
Sian Lun Lau
Keyword(s):  
Cognitive Disabilities ◽  
Research Work ◽  
Well Being ◽  
Assistive Technologies ◽  
Human Tracking ◽  
Full Time ◽  
Tracking Systems ◽  
Measurement Units ◽  
The Right ◽  
Outdoor Localization

The development of human tracking systems has had a significant influence over the evolution of Assistive Technologies for aiding children with cognitive disabilities. Techniques that range from radio frequency, Inertial Measurement Units, and Electroencephalography to the Global Positioning System and depth-based vision systems have provided tools for researchers to incorporate indoor and outdoor localization, motion and activity tracking as well as well-being monitoring into their projects. This chapter aims to introduce the latest human tracking options to consider for implementation of future Assistive Technology projects. Some example research work is discussed with emphasis on how human tracking systems can help in gathering the right data. The chapter concludes with a discussion of a proposed hybrid vision-based system for assisting in full-time supervision of children with cognitive disabilities, utilizing the chapter's central theme of sensor fusion application.

Glucose administration before exercise modulates catecholaminergic responses in glycogen-depleted subjects

1997 ◽  
Vol 82 (1) ◽  
pp. 248-256 ◽  
Author(s):  
David Gozal ◽  
Patrice Thiriet ◽  
Jean Marie Cottet-Emard ◽  
Dieudonné Wouassi ◽  
Emmanuel Bitanga ◽  
...  
Keyword(s):  
Maximal Exercise ◽  
Serum Levels ◽  
Glucose Administration ◽  
Graded Exercise ◽  
Time Courses ◽  
The Right ◽  
To Receive ◽  
Effect Of Glucose ◽  
Slow Intravenous Infusion ◽  
Nonlinear Increase

Gozal, David, Patrice Thiriet, Jean Marie Cottet-Emard, Dieudonné Wouassi, Emmanuel Bitanga, André Geyssant, Jean Marc Pequignot, and Marcel Sagnol. Glucose administration before exercise modulates catecholaminergic responses in glycogen-depleted subjects. J. Appl. Physiol. 82(1): 248–256, 1997.—In glycogen-depleted subjects (GD) a nonlinear increase in epinephrine (Epi) and norepinephrine (NE) parallels blood lactate (La) during graded exercise. The effect of glucose (Glc) supplementation and route of administration on these relationships was studied in 26 GD athletes who were randomly assigned to receive 1.3 g/kg Glc by slow intravenous infusion (IV; n = 9), oral administration (PO; n = 9), or artificially sweetened placebo in 1 liter of water (Asp; n = 8) in the 2 h preceding a graded maximal exercise. Performance and La were similar among the three groups in normal glycogen (NG) or GD conditions. However, slightly improved performances were observed in GD compared with NG and were associated with a shift to the right in La curves. Blood Glc concentrations were higher in IV and PO before exercise, but they rapidly decreased to lowest levels in IV, gradually decreased over time in PO, and remained stable in Asp or NG. Insulin concentrations were highest in IV and lowest in Asp and NG at onset of exercise, rapidly decreasing in IV and PO although remaining at higher levels than in Asp or NG. In contrast, higher serum levels of free fatty acids were measured during exercise in Asp with no significant differences in glucagon or glycerol among the three groups. Free and sulfated NE increases were smaller in IV than in PO and Asp on exhaustion. In contrast, free and conjugated Epi were most increased in IV, with smallest increases in Asp. Dopamine levels were most increased in IV at exhaustion. We conclude that the changes of Epi and NE concentrations, associated with the activation of glucoregulatory mechanisms, including hyperinsulinemia, display different magnitude and time courses during exercise in GD subjects who receive oral vs. intravenous load of Glc before exercise. We speculate that the magnitude of insulin surge after acutely increased Glc before exercise in GD subjects may exert dissociative effects on adrenal-dependent glycogenolysis and on sympathetic responses.

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.

scholarly journals Estimation of Knee Joint Forces in Sport Movements Using Wearable Sensors and Machine Learning

Sensors ◽  
2019 ◽  
Vol 19 (17) ◽  
pp. 3690 ◽  
Author(s):  
Bernd J. Stetter ◽  
Steffen Ringhof ◽  
Frieder C. Krafft ◽  
Stefan Sell ◽  
Thorsten Stein
Keyword(s):  
Knee Joint ◽  
Wearable Sensors ◽  
Correlation Coefficients ◽  
Biomechanical Modelling ◽  
Joint Forces ◽  
Measurement Units ◽  
Artificial Neural Network Ann ◽  
The Right ◽  
Anterior Posterior ◽  
Good Agreement

Knee joint forces (KJF) are biomechanical measures used to infer the load on knee joint structures. The purpose of this study is to develop an artificial neural network (ANN) that estimates KJF during sport movements, based on data obtained by wearable sensors. Thirteen participants were equipped with two inertial measurement units (IMUs) located on the right leg. Participants performed a variety of movements, including linear motions, changes of direction, and jumps. Biomechanical modelling was carried out to determine KJF. An ANN was trained to model the association between the IMU signals and the KJF time series. The ANN-predicted KJF yielded correlation coefficients that ranged from 0.60 to 0.94 (vertical KJF), 0.64 to 0.90 (anterior–posterior KJF) and 0.25 to 0.60 (medial–lateral KJF). The vertical KJF for moderate running showed the highest correlation (0.94 ± 0.33). The summed vertical KJF and peak vertical KJF differed between calculated and predicted KJF across all movements by an average of 5.7% ± 5.9% and 17.0% ± 13.6%, respectively. The vertical and anterior–posterior KJF values showed good agreement between ANN-predicted outcomes and reference KJF across most movements. This study supports the use of wearable sensors in combination with ANN for estimating joint reactions in sports applications.

scholarly journals Real-Time Multi-person Motion Capture from Multi-view Video and IMUs

2019 ◽  
Vol 128 (6) ◽  
pp. 1594-1611
Author(s):  
Charles Malleson ◽  
John Collomosse ◽  
Adrian Hilton
Keyword(s):  
Real Time ◽  
Motion Capture ◽  
Axial Rotation ◽  
Time Motion ◽  
Background Segmentation ◽  
Measurement Units ◽  
Multi Person Tracking ◽  
Total Capture ◽  
Optical Markers ◽  
Indoor And Outdoor

AbstractA real-time motion capture system is presented which uses input from multiple standard video cameras and inertial measurement units (IMUs). The system is able to track multiple people simultaneously and requires no optical markers, specialized infra-red cameras or foreground/background segmentation, making it applicable to general indoor and outdoor scenarios with dynamic backgrounds and lighting. To overcome limitations of prior video or IMU-only approaches, we propose to use flexible combinations of multiple-view, calibrated video and IMU input along with a pose prior in an online optimization-based framework, which allows the full 6-DoF motion to be recovered including axial rotation of limbs and drift-free global position. A method for sorting and assigning raw input 2D keypoint detections into corresponding subjects is presented which facilitates multi-person tracking and rejection of any bystanders in the scene. The approach is evaluated on data from several indoor and outdoor capture environments with one or more subjects and the trade-off between input sparsity and tracking performance is discussed. State-of-the-art pose estimation performance is obtained on the Total Capture (mutli-view video and IMU) and Human 3.6M (multi-view video) datasets. Finally, a live demonstrator for the approach is presented showing real-time capture, solving and character animation using a light-weight, commodity hardware setup.

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