scholarly journals Effects of Exercise Intensity on Pedal Force Asymmetry during Cycling

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1449
Author(s):  
John Wayland Farrell ◽  
Brian A. Pribble ◽  
Rebecca D. Larson
Keyword(s):  
Blood Lactate ◽  
Exercise Intensity ◽  
Test Group ◽  
Asymmetry Index ◽  
Lower Limbs ◽  
Absolute Difference ◽  
Peak Power Output ◽  
Pedal Force ◽  
Main Effect ◽  
Power Outputs

The purpose of the current investigation was to examine the effects of exercise intensity and a participant’s cycling experience on asymmetry in pedal forces during cycling. Participants were classified as cycling experienced (CE) or non-cycling experienced (NCE) based on self-reported training history. Participants completed an incremental cycling test via a cycle ergometer with inspired and expired gases, capillary blood lactate and pedaling forces collected throughout the test. Group X exercise intensity comparisons were analyzed at workloads corresponding to 2 mmol/L and 4 mmol/L for the blood lactate accumulation and peak power output, respectively. No Group X exercise intensity interactions for any variables (p > 0.05) were observed. The main effect on the exercise intensity was observed for absolute (p = 0.000, η2 = 0.836) and relative (p = 0.000, η2 = 0.752) power outputs and pedal force effectiveness (PFE) (p = 0.000, η2 = 0.728). The main effect for the group was observed for absolute (p = 0.007, η2 = 0.326) and relative (p = 0.001, η2 = 0.433) power outputs, the absolute difference between the lower limbs in power production (p = 0.047, η2 = 0.191), the peak crank torque asymmetry index (p = 0.031, η2 = 0.222) and the PFE (p = 0.014, η2 = 0.280). The exercise intensity was observed to have no impact on asymmetry in pedaling forces during cycling.

O2 uptake kinetics and the O2 deficit as related to exercise intensity and blood lactate

1993 ◽  
Vol 75 (2) ◽  
pp. 755-762 ◽  
Author(s):  
T. J. Barstow ◽  
R. Casaburi ◽  
K. Wasserman
Keyword(s):  
Blood Lactate ◽  
Time Constant ◽  
Exercise Intensity ◽  
Power Output ◽  
Cycle Ergometer ◽  
O2 Uptake ◽  
Ergometer Exercise ◽  
Lactate Levels ◽  
Power Outputs ◽  
O2 Deficit

The dynamic responses of O2 uptake (VO2) to a range of constant power output levels were related to exercise intensity [as percent maximal VO2 and as below vs. above lactic acid threshold (LAT)] and to the associated end-exercise lactate in three groups of subjects: group I, untrained subjects performing leg cycle ergometer exercise; group II, the same subjects performing arm cycle exercise; and group III, trained cyclists performing leg cycle ergometer exercise. Responses were described by a double-exponential equation, with each component having an independent time delay, which reduced to a monoexponential description for moderate (below-LAT) exercise. When a second exponential component to the VO2 response was present, it did not become evident until approximately 80–100 s into exercise. An overall time constant (tau T, determined as O2 deficit for the total response divided by net end-exercise VO2) and a primary time constant (tau P, determined from the O2 deficit and the amplitude for the early primary VO2 response) were compared. The tau T rose with power output and end-exercise lactate levels, but tau P was virtually invariant, even at high end-exercise lactate levels. Moreover the gain of the primary exponential component (as delta VO2/delta W) was constant across power outputs and blood lactate levels, suggesting that the primary VO2 response reflects a linear system, even at higher power outputs. These results suggest that elevated end-exercise lactate is not associated with any discernible slowing of the primary rise in VO2.(ABSTRACT TRUNCATED AT 250 WORDS)

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 Analyzing the Magnitude of Interlimb Asymmetries in Young Female Soccer Players: A Preliminary Study

2021 ◽  
Vol 18 (2) ◽  
pp. 475
Author(s):  
Javier Raya-González ◽  
Filipe Manuel Clemente ◽  
Daniel Castillo
Keyword(s):  
Range Of Motion ◽  
Muscle Mass ◽  
Injury Risk ◽  
Young Female ◽  
Asymmetry Index ◽  
Lower Limbs ◽  
Soccer Players ◽  
Countermovement Jump ◽  
Change Of Direction ◽  
Jump Ability

Although asymmetries in lower limbs have been linked with players’ performance in male soccer players, literature that has been published addressing female soccer is scarce. Thus, the aim of this study was twofold: (i) describe the asymmetries of women soccer players during jumping, change-of-direction and range-of-motion tests; and (ii) test possible relationships between asymmetries and injury risk in female soccer players. Sixteen female players (15.5 ± 1.5 years) performed a battery of fitness tests (i.e., jump ability, change-of-direction ability and passive range-of-motion) and muscle mass analysis via dual-energy X-ray absorptiometry, through which the specific asymmetry index and the related injury risk were calculated. Significant (p < 0.05) lower asymmetries in the change-of-direction test were observed in comparison to those observed in jumping and range-of-motion tests; significant (p < 0.05) lower asymmetries in muscle mass were also reported compared to those found in the change-of-direction and countermovement jump tests. Additionally, increased injury risk for countermovement jump and hip flexion with extended knee range-of-motion (relating to asymmetry values) and for ankle flexion with flexed knee range-of-motion in both legs (relating to reference range-of-motion values), as well as increased individual injury risk values, were observed across all tests. These findings suggest the necessity to implement individual approaches for asymmetry and injury risk analyses.

scholarly journals Exercise intensity during official soccer matches

2016 ◽  
Vol 18 (6) ◽  
pp. 621 ◽  
Author(s):  
Daniel Barbosa Coelho ◽  
Rodney Coelho da Paixão ◽  
Emerson Cruz de Oliveira ◽  
Lenice Kappes Becker ◽  
João Batista Ferreira-Júnior ◽  
...  
Keyword(s):  
Heart Rate ◽  
Blood Lactate ◽  
Field Test ◽  
Exercise Intensity ◽  
Intermediate Phase ◽  
Age Groups ◽  
Soccer Players ◽  
Blood Lactate Accumulation ◽  
Intensity Of Exercise ◽  
In The Beginning

DOI: http://dx.doi.org/10.5007/1980-0037.2016v18n6p621 The aims of the study were: 1) to analyze the exercise intensity in several phases (six phases of 15 min) of soccer matches; 2) to compare the match time spent above anaerobic threshold (AT) between different age groups (U-17 and U-20); and 3) to compare the match time spent above AT between players’ positions (backs, midfielders, forwards and wingabcks). Forty-four male soccer players were analyzed. To express players’ effort, the heart rate (HR) was continuously monitored in 29 official matches. Further, HR corresponding to the intensity at the onset of blood lactate accumulation (OBLA) was obtained in a field test. The highest exercise intensity during match was observed in the 15-30 min period of the first half (p< 0.05). Match time spent above AT was not different between players from U-17 and U-20. In the comparison among players’ positions, wingbacks showed lower time above AT (p< 0.05) than players of other positions. The intensity of effort is higher in the 15 to 30 minutes of play (intermediate phase), probably because the players are more rested in the beginning and wearing out is progressive throughout the game. It is also noteworthy that the intensity of exercise (HR and time above AT) of wingbacks was lower, probably because they usually are required to run a larger number of sprints and need more time below the AT to recover. 

Seasonal changes in aerobic fitness indices in elite cyclists

2008 ◽  
Vol 33 (4) ◽  
pp. 735-742 ◽  
Author(s):  
Aldo Sassi ◽  
Franco M. Impellizzeri ◽  
Andrea Morelli ◽  
Paolo Menaspà ◽  
Ermanno Rampinini
Keyword(s):  
Oxygen Consumption ◽  
Aerobic Fitness ◽  
Power Output ◽  
Seasonal Changes ◽  
Peak Power Output ◽  
Time To Exhaustion ◽  
Absolute Maximum ◽  
Maximum Oxygen Consumption ◽  
Main Effect ◽  
Elite Cyclists

The primary purpose of this study was to compare seasonal changes in cycling gross efficiency (GE) and economy (EC) with changes in other aerobic fitness indices. The secondary aim was to assess the relationship between maximum oxygen consumption, GE, and EC among elite cyclists. The relationships of maximum oxygen consumption with GE and EC were studied in 13 cyclists (8 professional road cyclists and 5 mountain bikers). Seasonal changes in GE and EC, predicted time to exhaustion (pTE), maximum oxygen consumption, and respiratory compensation point (RCP) were examined in a subgroup of 8 subjects, before (TREST) and after (TPRECOMP) the pre-competitive winter training, and during the competitive period (TCOMP). GE and EC were assessed during a constant power test at 75% of peak power output (PPO). Significant main effect for time was found for maximum oxygen consumption (4.623 ± 0.675, 4.879 ± 0.727, and 5.010 ± 0.663 L·min–1; p = 0.028), PPO (417.8 ± 46.5, 443.0 ± 48.0, and 455 ± 48 W; p < 0.001), oxygen uptake at RCP (3.866 ± 0.793, 4.041 ± 0.685, and 4.143 ± 0.643 L·min–1; p = 0.049), power output at RCP (330 ± 64, 354 ± 52, and 361 ± 50 W; p < 0.001), and pTE (17 ± 4, 30 ± 8, and 46 ± 17 min; p < 0.001). No significant main effect for time was found in GE (p = 0.097) or EC (p = 0.225), despite within-subject seasonal changes. No significant correlations were found between absolute maximum oxygen consumption and GE (r = –0.276; p = 0.359) or EC (r = –0.328; p = 0.272). However, cyclists with high maximum oxygen consumption values (i.e., over 80 mL·kg–1·min–1), showed low efficiency rates. Despite within-subject seasonal waves in cycling efficiency, changes in GE and EC should not be expected as direct consequence of changes in other maximal and submaximal parameters of aerobic fitness (i.e., maximum oxygen consumption and RCP).

scholarly journals Influence of COVID-19 Restrictions on Training and Physiological Characteristics in U23 Elite Cyclists

2021 ◽  
Vol 7 (1) ◽  
pp. 1
Author(s):  
Peter Leo ◽  
Iñigo Mujika ◽  
Justin Lawley
Keyword(s):  
Power Output ◽  
Ventilatory Threshold ◽  
Training Load ◽  
Peak Power Output ◽  
Physiological Performance ◽  
Performance Variables ◽  
Elite Level ◽  
And Performance ◽  
Power Outputs ◽  
Elite Cyclists

PURPOSE: The COVID-19 pandemic and its associated mobility restrictions caused many athletes to adjust or reduce their usual training load. The aim of this study was to investigate how the COVID-19 restrictions affected training and performance physiology measures in U23 elite cyclists. METHODS: Twelve U23 elite cyclists (n = 12) participated in this study (mean ± SD: Age 21.2 ± 1.2 years; height 182.9 ± 4.7 cm; body mass 71.4 ± 6.5 kg). Training characteristics were assessed between 30 days pre, during, and post COVID-19 restrictions, respectively. The physiological assessment in the laboratory was 30 days pre and post COVID-19 restrictions and included maximum oxygen uptake (V̇O2max), peak power output for sprint (SprintPmax), and ramp incremental graded exercise (GXTPmax), as well as power output at ventilatory threshold (VT) and respiratory compensation point (RCP). RESULTS: Training load characteristics before, during, and after the lockdown remained statistically unchanged (p > 0.05) despite large effects (>0.8) with mean reductions of 4.7 to 25.0% during COVID-19 restrictions. There were no significant differences in maximal and submaximal power outputs, as well as relative and absolute V̇O2max between pre and post COVID-19 restrictions (p > 0.05) with small to moderate effects. DISCUSSION: These results indicate that COVID-19 restrictions did not negatively affect training characteristics and physiological performance measures in U23 elite cyclists for a period of <30 days. In contrast with recent reports on professional cyclists and other elite level athletes, these findings reveal that as long as athletes are able to maintain and/or slightly adapt their training routine, physiological performance variables remain stable.

scholarly journals Physiological aspects and energetic contribution in 20s:10s high-intensity interval exercise at different intensities

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9791
Author(s):  
Gabriel V. Protzen ◽  
Charles Bartel ◽  
Victor S. Coswig ◽  
Paulo Gentil ◽  
Fabricio B. Del Vecchio
Keyword(s):  
Heart Rate ◽  
Blood Lactate ◽  
Power Output ◽  
High Intensity ◽  
Interval Training ◽  
Random Order ◽  
Peak Power Output ◽  
Maximal Heart Rate ◽  
Work Intensity ◽  
High Intensity Interval

Background One of the most popular high-intensity interval exercises is the called “Tabata Protocol”. However, most investigations have limitations in describing the work intensity, and this fact appears to be due to the protocol unfeasibility. Furthermore, the physiological demands and energetic contribution during this kind of exercise remain unclear. Methods Eight physically active students (21.8 ± 3.7 years) and eight well-trained cycling athletes (27.8 ± 6.4 years) were enrolled. In the first visit, we collected descriptive data and the peak power output (PPO). On the next three visits, in random order, participants performed interval training with the same time structure (effort:rest 20s:10s) but using different intensities (115%, 130%, and 170% of PPO). We collected the number of sprints, power output, oxygen consumption, blood lactate, and heart rate. Results The analysis of variance for multivariate test (number of sprints, power output, blood lactate, peak heart rate and percentage of maximal heart rate) showed significant differences between groups (F = 9.62; p = 0.001) and intensities (F = 384.05; p < 0.001), with no interactions (F = 0.94; p = 0.57). All three energetic contributions and intensities were different between protocols. The higher contribution was aerobic, followed by alactic and lactic. The aerobic contribution was higher at 115%PPO, while the alactic system showed higher contribution at 130%PPO. In conclusion, the aerobic system was predominant in the three exercise protocols, and we observed a higher contribution at lower intensities.

Relationship of potassium ions and blood lactate to ventilation during exercise

2010 ◽  
Vol 35 (5) ◽  
pp. 691-698
Author(s):  
Robert G. McMurray ◽  
Matthew S. Tenan
Keyword(s):  
Blood Lactate ◽  
Exercise Intensity ◽  
Minute Ventilation ◽  
Potassium Ions ◽  
Ventilatory Control ◽  
Volitional Fatigue ◽  
Relationship Of ◽  
Glycogen Stores ◽  
The Relationship ◽  
Recent Attention

Ventilatory control during exercise is a complex network of neural and humoral signals. One humoral input that has received little recent attention in the exercise literature is potassium ions [K+]. The purpose of this study was to examine the relationship between [K+] and ventilation during an incremental cycle test and to determine if the relationship between [K+] and ventilation differs when blood lactate [lac–] is manipulated. Eight experienced triathletes (4 of each sex) completed 2 incremental, progressive (5-min stages) cycle tests to volitional fatigue: 1 with normal glycogen stores and 1 with reduced glycogen. Minute ventilation was measured during the final minute of each stage, and blood [lac–] and [K+] were measured at the end of each exercise stage. Minute ventilation and [K+] increased with exercise intensity and were similar between trials (p > 0.5), despite lower [lac–] during the reduced-glycogen trial. The concordance correlations (Rc) between [lac–] and minute ventilation were stronger for both trials (Rc = ~0.88–0.96), but the slopes of the relationships were different than the relationships between [K+] and minute ventilation (Rc = ~0.76–0.89). The slope of the relationship between [lac–] and minute ventilation was not as steep during the reduced-glycogen trial, compared with the normal trial (p = 0.002). Conversely, the slope of the relationships between [K+] and minute ventilation did not change between trials (p = 0.454). The consistent relationship of minute ventilation and blood [K+] during exercise suggests a role for this ion in the control of ventilation during exercise. Conversely, the inconsistent relationship between blood lactate and ventilation brings into question the importance of the relationship between lactate and ventilation during exercise.

scholarly journals Aerobic exercise intensity does not affect the anabolic signaling following resistance exercise in endurance athletes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
T. W. Jones ◽  
L. Eddens ◽  
J. Kupusarevic ◽  
D. C. M. Simoes ◽  
M. J. W. Furber ◽  
...  
Keyword(s):  
Resistance Exercise ◽  
Exercise Intensity ◽  
Endurance Athletes ◽  
Moderate Intensity ◽  
Concurrent Training ◽  
Signaling Proteins ◽  
Main Effect ◽  
High Intensity Interval ◽  
Interval Cycling ◽  
Muscle Biopsies

AbstractThis study examined whether intensity of endurance stimulus within a concurrent training paradigm influenced the phosphorylation of signaling proteins associated with the mTOR and AMPK networks. Eight male cyclists completed (1) resistance exercise (RES), 6 × 8 squats at 80% 1-RM; (2) resistance exercise and moderate intensity cycling of 40 min at 65% V̇O2peak, (RES + MIC); (3) resistance exercise and high intensity interval cycling of 40 min with 6 alternating 3 min intervals of 85 and 45% V̇O2peak (RES + HIIC), in a cross-over design. Muscle biopsies were collected at rest and 3 h post-RES. There was a main effect of condition for mTORS2448 (p = 0.043), with a greater response in the RES + MIC relative to RES condition (p = 0.033). There was a main effect of condition for AMPKα2T172 (p = 0.041), with a greater response in RES + MIC, relative to both RES + HIIC (p = 0.026) and RES (p = 0.046). There were no other condition effects for the remaining protein kinases assessed (p > 0.05). These data do not support a molecular interference effect in cyclists under controlled conditions. There was no intensity-dependent regulation of AMPK, nor differential activation of anabolism with the manipulation of endurance exercise intensity.

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