scholarly journals Physiological and Biomechanical Determinants of Sprint Ability Following Variable Intensity Exercise When Roller Ski Skating

2021 ◽  
Vol 12 ◽  
Author(s):  
Trine M. Seeberg ◽  
Jan Kocbach ◽  
Jørgen Danielsen ◽  
Dionne A. Noordhof ◽  
Knut Skovereng ◽  
...  
Keyword(s):  
Relative Intensity ◽  
Perceived Exertion ◽  
Rating Of Perceived Exertion ◽  
Variable Intensity ◽  
Gross Efficiency ◽  
Machine Learning Model ◽  
Significant Performance ◽  
Cycle Lengths ◽  
Performance Ranking ◽  
Sprint Ability

The most common race format in cross-country (XC) skiing is the mass-start event, which is under-explored in the scientific literature. To explore factors important for XC skiing mass-starts, the main purpose of this study was to investigate physiological and biomechanical determinants of sprint ability following variable intensity exercise when roller ski skating. Thirteen elite male XC skiers performed a simulated mass-start competition while roller ski skating on a treadmill. The protocol consisted of an initial 21-min bout with a varying track profile, designed as a competition track with preset inclines and speeds, directly followed by an all-out sprint (AOS) with gradually increased speed to rank their performance. The initial part was projected to simulate the “stay-in-the-group” condition during a mass-start, while the AOS was designed to assess the residual physiological capacities required to perform well during the final part of a mass-start race. Cardiorespiratory variables, kinematics and pole forces were measured continuously, and the cycles were automatically detected and classified into skating sub-techniques through a machine learning model. Better performance ranking was associated with higher VO2Max (r = 0.68) and gross efficiency (r = 0.70) measured on separate days, as well as the ability to ski on a lower relative intensity [i.e., %HRMax (r = 0.87), %VO2Max (r = 0.89), and rating of perceived exertion (r = 0.73)] during the initial 21-min of the simulated mass-start (all p-values < 0.05). Accordingly, the ability to increase HR (r = 0.76) and VO2 (r = 0.72), beyond the corresponding values achieved during the initial 21-min, in the AOS correlated positively with performance (both p < 0.05). In addition, greater utilization of the G3 sub-technique in the steepest uphill (r = 0.69, p < 0.05), as well as a trend for longer cycle lengths (CLs) during the AOS (r = 0.52, p = 0.07), were associated with performance. In conclusion, VO2Max and gross efficiency were the most significant performance-determining variables of simulated mass-start performance, enabling lower relative intensity and less accumulation of fatigue before entering the final AOS. Subsequently, better performance ranking was associated with more utilization of the demanding G3 sub-technique in the steepest uphill, and physiological reserves allowing better-performing skiers to utilize a larger portion of their aerobic potential and achieve longer CLs and higher speed during the AOS.

Carbohydrate Drink Use During 30 Minutes of Variable-Intensity Exercise Has No Effect on Exercise Performance in Premenarchal Girls

2021 ◽  
Vol 33 (2) ◽  
pp. 65-69
Author(s):  
C. Eric Heidorn ◽  
Brandon J. Dykstra ◽  
Cori A. Conner ◽  
Anthony D. Mahon
Keyword(s):  
Peak Power ◽  
Perceived Exertion ◽  
Rating Of Perceived Exertion ◽  
Fatigue Index ◽  
Mean Power ◽  
Variable Intensity ◽  
Performance Effects ◽  
Power Peak ◽  
The Mean ◽  
And Performance

Purpose: This study examined the physiological, perceptual, and performance effects of a 6% carbohydrate (CHO) drink during variable-intensity exercise (VIE) and a postexercise test in premenarchal girls. Methods: A total of 10 girls (10.4 [0.7] y) participated in the study. VO2peak was assessed, and the girls were familiarized with VIE and performance during the first visit. The trial order (CHO and placebo) was randomly assigned for subsequent visits. The drinks were given before VIE bouts and 1-minute performance (9 mL/kg total). Two 15-minute bouts of VIE were completed (10 repeated sequences of 20%, 55%, and 95% power at VO2peak and maximal sprints) before a 1-minute performance sprint. Results: The mean power, peak power, heart rate (HR), %HRpeak, and rating of perceived exertion during VIE did not differ between trials. However, the peak power decreased, and the rating of perceived exertion increased from the first to the second bout. During the 1-minute performance, there were no differences between the trial (CHO vs placebo) for HR (190 [9] vs 189 [9] bpm), %HRpeak (97.0% [3.2%] vs 96.6% [3.0%]), rating of perceived exertion (7.8 [2.3] vs 8.1 [1.9]), peak power (238 [70] vs 235 [60] W), fatigue index (54.7% [10.0%] vs 55.9% [12.8%]), or total work (9.4 [2.6] vs 9.4 [2.1] kJ). Conclusion: CHO supplementation did not alter physiological, perceptual, or performance responses during 30 minutes of VIE or postexercise sprint performance in premenarchal girls.

The Effects of Training Volume and Repetition Distance on Session Rating of Perceived Exertion and Internal Load in Swimmers

2015 ◽  
Vol 10 (7) ◽  
pp. 848-852 ◽  
Author(s):  
Renato Barroso ◽  
Diego F. Salgueiro ◽  
Everton C. do Carmo ◽  
Fábio Y. Nakamura
Keyword(s):  
Relative Intensity ◽  
Critical Speed ◽  
Perceived Exertion ◽  
Training Session ◽  
Rating Of Perceived Exertion ◽  
Training Volume ◽  
Swimming Training ◽  
Internal Load ◽  
Session Duration ◽  
M 10

Purpose:To assess swimmers’ session rating of perceived exertion (sRPE) after standardized sets of interval swimming training performed at the same relative intensity but with different total volume and repetition distance.Methods:Thirteen moderately trained swimmers (21.1 ± 1.1 y, 178 ± 6 cm, 74.1 ± 8.3 kg, 100-m freestyle 60.2 ± 2.9 s) performed 4 standardized sets (10 × 100-m, 20 × 100-m, 10 × 200-m, and 5 × 400-m) at the same relative intensity (ie, critical speed), and 1 coach (age 31 y, 7 y coaching experience) rated their efforts. Swimmers’ sRPE was assessed 30 min after the training session. Coach sRPE was collected before each training session. Internal load was calculated by multiplying sRPE by session duration.Results:When bouts with the same repetition distance and different volumes (10 × 100-m vs 20 × 100-m) are compared, sRPE and internal load are higher in 20 × 100-m bouts. When maintaining constant volume, sRPE and internal load (20 × 100-m, 10 × 200-m, and 5 × 400-m) are higher only in 5 × 400-m bouts. The coach’s and swimmers’ sRPE differed in 10 × 200-m and 5 × 400-m.Conclusions:These results indicate that sRPE in swimming is affected not only by intensity but also by volume and repetition distance. In addition, swimmers’ and the coach’s sRPE were different when longer repetition distances were used during training sessions. Therefore, care should be taken when prescribing swimming sessions with longer volume and/or longer repetition distances.

scholarly journals Comparison of Physiological and Biomechanical Responses to Flat and Uphill Cross-Country Sit-Skiing in Able-Bodied Athletes

2020 ◽  
pp. 1-7
Author(s):  
Camilla H. Carlsen ◽  
David McGhie ◽  
Julia K. Baumgart ◽  
Øyvind Sandbakk
Keyword(s):  
Oxygen Uptake ◽  
Perceived Exertion ◽  
Peak Oxygen Uptake ◽  
Work Rate ◽  
Rating Of Perceived Exertion ◽  
Physiological Variables ◽  
Gross Efficiency ◽  
Biomechanical Responses ◽  
Submaximal Work ◽  
Cross Country

Purpose: To compare peak work rate (WRpeak) and associated physiological and biomechanical performance-determining variables between flat and uphill cross-country (XC) sit-skiing. Methods: Fifteen able-bodied male XC skiers completed 2 test sessions, each comprising four 4-minute submaximal stages, followed by an incremental test to exhaustion and a verification test in a sit-ski on a roller-ski treadmill. The test sessions were counterbalanced by the incline, being either 0.5% (FLAT) or 5% (UPHILL). The authors compared WRpeak and peak oxygen uptake, as well as physiological variables, rating of perceived exertion, gross efficiency, and cycle characteristics at identical submaximal work rate, between FLAT and UPHILL. Results: In UPHILL, WRpeak was 35% higher compared to FLAT (P < .001), despite no difference in peak oxygen uptake (P = .9). The higher WRpeak in UPHILL was achieved through more work per cycle, which was enabled by the twice as long poling time, compared to FLAT (P < .001). Submaximal gross efficiency was 0.5 to 2 percentage points lower in FLAT compared to UPHILL (P < .001), with an increasing difference as work rate increased (P < .001). Neither cycle rate nor work per cycle differed between inclines when compared at identical submaximal work rate (P > .16). Conclusions: The longer poling times utilized in uphill XC sit-skiing enable more work per cycle and better gross efficiency, thereby allowing skiers to achieve a higher WRpeak compared to flat XC sit-skiing. However, the similar values of peak oxygen uptake between inclines indicate that XC sit-skiers can tax their cardiorespiratory capacity similarly in both conditions.

Prolonged Repeated-Sprint Ability Is Related to Arterial O2 Desaturation in Men

2010 ◽  
Vol 5 (2) ◽  
pp. 197-209 ◽  
Author(s):  
François Billaut ◽  
Kurt Smith
Keyword(s):  
Perceived Exertion ◽  
Vastus Lateralis ◽  
National Level ◽  
Rectus Femoris ◽  
Mechanical Work ◽  
Rating Of Perceived Exertion ◽  
Neuromuscular Activity ◽  
Repeated Sprint Ability ◽  
Repeated Sprint ◽  
Sprint Ability

The ability to repeatedly generate maximum power output is usually accompanied by neuromuscular adjustments.Purpose:This study aimed to explore the occurrence of arterial O2 desaturation during prolonged repeated-sprint ability (RSA) testing and its relationship to neuromuscular activity, as evidenced by changes in surface integrated electromyogram (iEMG).Methods:Fifteen, national-level soccer players performed twenty 5-s cycle sprints (25 s of rest). Mechanical work and surface iEMG of the vastus lateralis (VL) and rectus femoris (RF) of the dominant lower limb were recorded for every sprint. Arterial O2 saturation (S O2) was estimated via pulse oximetry and rating of perceived exertion (RPE) recorded immediately after every sprint.Results:Over the sprints, mechanical work (23.5%), iEMG (VL: 14.2%, RF: 16.4%) and S O2 (3.5%) decreased, and RPE progressed to 19 (all P < .05). There was a strong linear relationship (R2 = .83, P < .05) between the changes in mechanical output and iEMG during the sprints. More importantly, changes in S O2 accompanied changes in mechanical work, iEMG and RPE (R2 = .68, R2 = .64, R2 = .62, P < .05, respectively).Conclusion:The study suggests that in a homogenous group of athletes a progressive arterial O2 desaturation develops during a prolonged RSA test, which may contribute toward performance regulation via an effect on sense of effort and neuromuscular activity.

The Effects of Long Sprint Ability–Oriented Small-Sided Games Using Different Ratios of Players to Pitch Area on Internal and External Load in Soccer Players

2019 ◽  
Vol 14 (9) ◽  
pp. 1265-1272 ◽  
Author(s):  
Carlo Castagna ◽  
Stefano D’Ottavio ◽  
Stefano Cappelli ◽  
Susana Cristina Araújo Póvoas
Keyword(s):  
High Intensity ◽  
External Load ◽  
Perceived Exertion ◽  
Lactate Concentration ◽  
Rating Of Perceived Exertion ◽  
Soccer Players ◽  
Inverse Association ◽  
Professional Soccer ◽  
External Loads ◽  
Sprint Ability

Purpose: To examine the internal and external load imposed by long sprint ability–oriented small-sided games (SSG) using different ratios of players to pitch area (densities) in soccer players. Methods: A total of 19 professional soccer players from the same soccer club (age = 17.1 [0.3] y, height = 1.76 [0.69] m, and body mass = 69.7 [9.4] kg) participated in this study. Players performed 4 × 30-s (150 s recovery) all-out 1-vs-1 SSG considering 300, 200, and 100 m2 per player (48 h apart). Players’ external loads were tracked with global positioning technology (20 Hz). Heart rate, blood lactate concentration (BLc), and rating of perceived exertion characterized players’ internal load. Peak BLc was assessed with a 30-s all-out test on a nonmotorized treadmill (NMT). Results: SSG300 produced higher BLc than SSG200 (moderate) and SSG100 (large). The SSG300, SSG200, and SSG100 BLc were 97.8% (34.8%), trivial; 74.7% (24.9%), moderate; and 43.4% (15.7%), large, of the NMT30s peak BLc, respectively. Players covered more distance at high intensity during the SSG300 than in other SSG conditions (huge to very large differences). High-intensity deceleration distance was largely lower in SSG200 than in SSG300. SSG100 elicited very large to huge and large to very large lower external load values than SSG300 and SSG200, respectively. Conclusions: The main finding of this study showed an inverse association between ball-drill density and internal/external loads in long sprint ability–oriented SSG. The SSG300 provided BLc closer to individual maximal, thus satisfying the all-out construct assumed for the development of long sprint ability. Further studies using the SSG300 as a training intervention and/or investigating other different SSG formats using the same density are warranted.

scholarly journals Metabolic and performance responses to constant-load vs. variable-intensity exercise in trained cyclists

1999 ◽  
Vol 87 (3) ◽  
pp. 1186-1196 ◽  
Author(s):  
Garry S. Palmer ◽  
Lars B. Borghouts ◽  
Timothy D. Noakes ◽  
John A. Hawley
Keyword(s):  
Perceived Exertion ◽  
Periodic Acid ◽  
Average Power ◽  
Cardiovascular Responses ◽  
Constant Load ◽  
Rating Of Perceived Exertion ◽  
Whole Body ◽  
Average Intensity ◽  
Type I ◽  
Variable Intensity

We studied glucose oxidation (Gluox) and glycogen degradation during 140 min of constant-load [steady-state (SS)] and variable-intensity (VI) cycling of the same average power output, immediately followed by a 20-km performance ride [time trial (TT)]. Six trained cyclists each performed four trials: two experimental bouts (SS and VI) in which muscle biopsies were taken before and after 140 min of exercise for determination of glycogen and periodic acid-Schiff’s staining; and two similar trials without biopsies but incorporating the TT. During two of the experimental rides, subjects ingested a 5 g/100 ml [U-14C]glucose solution to determine rates of Gluox. Values were similar between SS and VI trials: O2 consumption (3.08 ± 0.02 vs. 3.15 ± 0.03 l/min), energy expenditure (901 ± 40 vs. 904 ± 58 J ⋅ kg−1 ⋅ min−1), heart rate (156 ± 1 vs. 160 ± 1 beats/min), and rating of perceived exertion (12.6 ± 0.6 vs. 12.7 ± 0.7). However, the area under the curve for plasma lactate concentration vs. time was significantly greater during VI than SS (29.1 ± 3.9 vs. 24.6 ± 3.7 mM/140 min; P = 0.03). VI resulted in a 49% reduction in total muscle glycogen utilization vs. 65% for SS, while total Gluoxwas higher (99.2 ± 5.3 vs. 83.9 ± 5.2 g/140 min; P < 0.05). The number of glycogen-depleted type I muscle fibers at the end of 140 min was 98% after SS but only 59% after VI. Conversely, the number of type II fibers that showed reduced periodic acid-Schiff’s staining was 1% after SS vs. 10% after VI. Despite these metabolic differences, subsequent TT performance was similar (29.14 ± 0.9 vs. 30.5 ± 0.9 min for SS vs. VI). These results indicate that whole body metabolic and cardiovascular responses to 140 min of either SS or VI exercise at the same average intensity are similar, despite differences in skeletal muscle carbohydrate metabolism and recruitment.

scholarly journals Physiological responses and cycle characteristics during double-poling versus diagonal-stride roller-skiing in junior cross-country skiers

2021 ◽  
Author(s):  
Erik P. Andersson ◽  
Irina Hämberg ◽  
Paulo Cesar Do Nascimento Salvador ◽  
Kerry McGawley
Keyword(s):  
Oxygen Uptake ◽  
Perceived Exertion ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Peak Oxygen Uptake ◽  
Submaximal Exercise ◽  
Rating Of Perceived Exertion ◽  
Time To Exhaustion ◽  
Double Poling ◽  
Cross Country

Abstract Purpose This study aimed to compare physiological factors and cycle characteristics during cross-country (XC) roller-skiing at matched inclines and speeds using the double-poling (DP) and diagonal-stride (DS) sub-techniques in junior female and male XC skiers. Methods Twenty-three well-trained junior XC skiers (11 women, 12 men; age 18.2 ± 1.2 yr.) completed two treadmill roller-skiing tests in a randomized order using either DP or DS. The exercise protocols were identical and included a 5 min warm-up, 4 × 5 min submaximal stages, and an incremental test to exhaustion, all performed at a 5° incline. Results No significant three-way interactions were observed between sex, submaximal exercise intensity, and sub-technique. For the pooled sample, higher values were observed for DP versus DS during submaximal exercise for the mean oxygen uptake kinetics response time (33%), energy cost (18%), heart rate (HR) (9%), blood lactate concentration (5.1 versus 2.1 mmol·L−1), rating of perceived exertion (12%), and cycle rate (25%), while cycle length was lower (19%) (all P < 0.001). During the time-to-exhaustion (TTE) test, peak oxygen uptake ($$\dot{V}$$ V ˙ O2peak), peak HR, and peak oxygen pulse were 8%, 2%, and 6% lower, respectively, for DP than DS, with a 29% shorter TTE during DP (pooled data, all P < 0.001). Conclusion In well-trained junior XC skiers, DP was found to exert a greater physiological load than DS during uphill XC roller-skiing at submaximal intensities. During the TTE test, both female and male athletes were able to ski for longer and reached markedly higher $$\dot{V}$$ V ˙ O2peak values when using DS compared to DP.

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