scholarly journals Optimizing Interval Training Through Power-Output Variation Within the Work Intervals

2020 ◽  
Vol 15 (7) ◽  
pp. 982-989
Author(s):  
Arthur H. Bossi ◽  
Cristian Mesquida ◽  
Louis Passfield ◽  
Bent R. Rønnestad ◽  
James G. Hopker

Purpose: Maximal oxygen uptake () is a key determinant of endurance performance. Therefore, devising high-intensity interval training (HIIT) that maximizes stress of the oxygen-transport and -utilization systems may be important to stimulate further adaptation in athletes. The authors compared physiological and perceptual responses elicited by work intervals matched for duration and mean power output but differing in power-output distribution. Methods: Fourteen cyclists ( 69.2 [6.6] mL·kg−1·min−1) completed 3 laboratory visits for a performance assessment and 2 HIIT sessions using either varied-intensity or constant-intensity work intervals. Results: Cyclists spent more time at during HIIT with varied-intensity work intervals (410 [207] vs 286 [162] s, P = .02), but there were no differences between sessions in heart-rate- or perceptual-based training-load metrics (all P ≥ .1). When considering individual work intervals, minute ventilation () was higher in the varied-intensity mode (F = 8.42, P = .01), but not respiratory frequency, tidal volume, blood lactate concentration [La], ratings of perceived exertion, or cadence (all F ≤ 3.50, ≥ .08). Absolute changes (Δ) between HIIT sessions were calculated per work interval, and Δ total oxygen uptake was moderately associated with (r = .36, P = .002). Conclusions: In comparison with an HIIT session with constant-intensity work intervals, well-trained cyclists sustain higher fractions of when work intervals involved power-output variations. This effect is partially mediated by an increased oxygen cost of hyperpnea and not associated with a higher [La], perceived exertion, or training-load metrics.

Author(s):  
Kirstie J Turner ◽  
Anthony J Rice

Stationary cycling is a common training mode of rowers, used to provide variety in training programs and prevent overuse injuries commonly associated with the repetitive nature of the rowing stroke. The purpose of this study was to investigate the differences in physiological responses on a Concept II BikeErg (Concept II BikeErg; Concept2 Inc., US) and Concept II RowErg (Concept II Model D; Concept2 Inc., US) at matched submaximal workloads so training load can be appropriately prescribed for stationary cycling. Ten well-trained, male rowers completed 6 min of exercise at four submaximal workloads (50%, 62.5%, 75% and 87.5% of their most recent 2000 m RowErg score) interspersed with 2-minute recovery periods on both ergometers in a single day. Ergometer order was randomised and balanced between groups. At matched power output (PO) results while on the RowErg were significantly higher across all workloads for rate of oxygen consumption ([Formula: see text]), rate of carbon dioxide production ([Formula: see text]), minute ventilation ([Formula: see text]) and heart rate (HR) (p < 0.05) and across the final two workloads for Rating of Perceived Exertion (RPE) and blood lactate concentration (BLa) (p < 0.05). When oxygen uptake at a fixed value ([Formula: see text] = 3.5 L.min−1) was matched between groups results while on the RowErg were significantly lower for PO, BLa, [Formula: see text], RER and RPE whereas [Formula: see text] and HR were similar to the BikeErg. These results support the understanding that displayed power output on the RowErg does not account for all work done during the rowing stroke cycle, specifically during the recovery phase. In conclusion, the physiological responses on the Concept II BikeErg are no more closely aligned to the Concept II RowErg than previously shown for similar cycle ergometers from different manufacturers. Due to the lack of consistency between Concept II BikeErg and Concept II RowErg PO, HR is better suited for the prescription of training loads on the BikeErg.


Author(s):  
Erik P. Andersson ◽  
Irina Hämberg ◽  
Paulo Cesar Do Nascimento Salvador ◽  
Kerry McGawley

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.


Author(s):  
Nicola Giovanelli ◽  
Lara Mari ◽  
Asia Patini ◽  
Stefano Lazzer

Purpose: To compare energetics and spatiotemporal parameters of steep uphill pole walking on a treadmill and overground. Methods: First, the authors evaluated 6 male trail runners during an incremental graded test on a treadmill. Then, they performed a maximal overground test with poles and an overground test at 80% (OG80) of vertical velocity of maximal overground test with poles on an uphill mountain path (length = 1.3 km, elevation gain = 433 m). Finally, they covered the same elevation gain using poles on a customized treadmill at the average vertical velocity of the OG80. During all the tests, the authors measured oxygen uptake, carbon dioxide production, heart rate, blood lactate concentration, and rate of perceived exertion. Results: Treadmills required lower metabolic power (15.3 [1.9] vs 16.6 [2.0] W/kg, P = .002) and vertical cost of transport (49.6 [2.7] vs 53.7 [2.1] J/kg·m, P < .001) compared with OG80. Also, oxygen uptake was lower on a treadmill (41.7 [5.0] vs 46.2 [5.0] mL/kg·min, P = .001). Conversely, respiratory quotient was higher on TR80 compared with OG80 (0.98 [0.02] vs 0.89 [0.04], P = .032). In addition, rate of perceived exertion was higher on a treadmill and increased with elevation (P < .001). The authors did not detect any differences in other physiological measurements or in spatiotemporal parameters. Conclusions: Researchers, coaches, and athletes should be aware that steep treadmill pole walking requires lower energy consumption but same heart rate and rate of perceived exertion than overground pole walking at the same average intensity.


2019 ◽  
Vol 44 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Alessandro Piras ◽  
Francesco Campa ◽  
Stefania Toselli ◽  
Rocco Di Michele ◽  
Milena Raffi

This investigation examined the effect of partial-body cryostimulation (PBC) performed in the recovery time between a strength training and an interval running (IR) session. Nine rugby players (age, 23.7 ± 3.6 years; body mass index, 28.0 ± 2.6 kg·m−2) were randomly exposed to 2 different conditions: (i) PBC: 3 min at −160 °C, and (ii) passive recovery at 21 °C. We performed the bioelectrical impedance analysis (BIA) and recorded temperature and cardiac autonomic variables at 3 time points: at baseline, after strength training, and after 90 min of recovery. In addition, blood lactate concentration was measured 1 min before and 2.5 min after the IR. Heart rate (HR), energy cost, minute ventilation, oxygen uptake, and metabolic power were assessed during the IR. Homeostatic hydration status was affected by the execution of an intense strength training subsession. Then, after PBC, the BIA vector was restored close to normohydration status. Autonomic variables changed over time in both conditions, although the mean differences and effect sizes were greater in the PBC condition. During IR, HR was 3.5% lower after PBC, and the same result was observed for oxygen uptake (∼4.9% lower) and ventilation (∼6.5% lower). The energy cost measured after cryotherapy was ∼9.0% lower than after passive recovery. Cryotherapy enhances recovery after a single strength training session, and during subsequent IR, it shows a reduction in cardiorespiratory and metabolic parameters. PBC may be useful for those athletes who compete or train more than once in the same day, to improve recovery between successive training sessions or competitions.


2012 ◽  
Vol 7 (2) ◽  
pp. 121-129 ◽  
Author(s):  
Andrew Renfree ◽  
Julia West ◽  
Mark Corbett ◽  
Clare Rhoden ◽  
Alan St Clair Gibson

Purpose:This study examined the determinants of pacing strategy and performance during self-paced maximal exercise.Methods:Eight well-trained cyclists completed two 20-km time trials. Power output, rating of perceived exertion (RPE), positive and negative affect, and iEMG activity of the active musculature were recorded every 0.5 km, confidence in achieving preexercise goals was assessed every 5 km, and blood lactate and pH were measured postexercise. Differences in all parameters were assessed between fastest (FAST) and slowest (SLOW) trials performed.Results:Mean power output was significantly higher during the initial 90% of FAST, but not the final 10%, and blood lactate concentration was significantly higher and pH significantly lower following FAST. Mean iEMG activity was significantly higher throughout SLOW. Rating of perceived exertion was similar throughout both trials, but participants had significantly more positive affect and less negative affect throughout FAST. Participants grew less confident in their ability to achieve their goals throughout SLOW.Conclusions:The results suggest that affect may be the primary psychological regulator of pacing strategy and that higher levels of positivity and lower levels of negativity may have been associated with a more aggressive strategy during FAST. Although the exact mechanisms through which affect acts to influence performance are unclear, it may determine the degree of physiological disruption that can be tolerated, or be reflective of peripheral physiological status in relation to the still to be completed exercise task.


2000 ◽  
Vol 89 (5) ◽  
pp. 1744-1752 ◽  
Author(s):  
Helen Carter ◽  
Andrew M. Jones ◽  
Thomas J. Barstow ◽  
Mark Burnley ◽  
Craig Williams ◽  
...  

The purpose of this study was to examine the effect of endurance training on oxygen uptake (V˙o 2) kinetics during moderate [below the lactate threshold (LT)] and heavy (above LT) treadmill running. Twenty-three healthy physical education students undertook 6 wk of endurance training that involved continuous and interval running training 3–5 days per week for 20–30 min per session. Before and after the training program, the subjects performed an incremental treadmill test to exhaustion for determination of the LT and the V˙o 2 max and a series of 6-min square-wave transitions from rest to running speeds calculated to require 80% of the LT and 50% of the difference between LT and maximal V˙o 2. The training program caused small (3–4%) but significant increases in LT and maximalV˙o 2 ( P < 0.05). TheV˙o 2 kinetics for moderate exercise were not significantly affected by training. For heavy exercise, the time constant and amplitude of the fast component were not significantly affected by training, but the amplitude of theV˙o 2 slow component was significantly reduced from 321 ± 32 to 217 ± 23 ml/min ( P< 0.05). The reduction in the slow component was not significantly correlated to the reduction in blood lactate concentration ( r = 0.39). Although the reduction in the slow component was significantly related to the reduction in minute ventilation ( r = 0.46; P < 0.05), it was calculated that only 9–14% of the slow component could be attributed to the change in minute ventilation. We conclude that theV˙o 2 slow component during treadmill running can be attenuated with a short-term program of endurance running training.


Author(s):  
Carl Foster ◽  
Daniel Boullosa ◽  
Michael McGuigan ◽  
Andrea Fusco ◽  
Cristina Cortis ◽  
...  

The session rating of perceived exertion (sRPE) method was developed 25 years ago as a modification of the Borg concept of rating of perceived exertion (RPE), designed to estimate the intensity of an entire training session. It appears to be well accepted as a marker of the internal training load. Early studies demonstrated that sRPE correlated well with objective measures of internal training load, such as the percentage of heart rate reserve and blood lactate concentration. It has been shown to be useful in a wide variety of exercise activities ranging from aerobic to resistance to games. It has also been shown to be useful in populations ranging from patients to elite athletes. The sRPE is a reasonable measure of the average RPE acquired across an exercise session. Originally designed to be acquired ∼30 minutes after a training bout to prevent the terminal elements of an exercise session from unduly influencing the rating, sRPE has been shown to be temporally robust across periods ranging from 1 minute to 14 days following an exercise session. Within the training impulse concept, sRPE, or other indices derived from sRPE, has been shown to be able to account for both positive and negative training outcomes and has contributed to our understanding of how training is periodized to optimize training outcomes and to understand maladaptations such as overtraining syndrome. The sRPE as a method of monitoring training has the advantage of extreme simplicity. While it is not ideal for the precise recording of the details of the external training load, it has large advantages relative to evaluating the internal training load.


2021 ◽  
pp. 1-10
Author(s):  
Jeanette M. Ricci ◽  
Katharine D. Currie ◽  
Todd A. Astorino ◽  
Karin A. Pfeiffer

Girls’ acute responses to group-based high-intensity interval exercise (HIIE) are not well characterized. Purpose: To compare acute responses to treadmill-based HIIE (TM) and body-weight resistance exercise circuit (CIRC) and to CIRC performed in a small-group setting (group CIRC). Method: Nineteen girls (9.1 [1.1] y) completed exercise testing on a TM to determine peak oxygen uptake, peak heart rate (HRpeak), and maximal aerobic speed. The TM involved eight 30-second sprints at 100% maximal aerobic speed. The CIRC consisted of 8 exercises of maximal repetitions performed for 30 seconds. Each exercise bout was followed by 30 seconds of active recovery. The blood lactate concentration was assessed preexercise and postexercise. The ratings of perceived exertion, affective valence, and enjoyment were recorded at preexercise, Intervals 3 and 6, and postexercise. Results: The mean heart rate was higher during group CIRC (92% [7%] HRpeak) than CIRC (86% [7%] HRpeak) and TM (85% [4%] HRpeak) ( = .49). The mean oxygen uptake equaled 76% (11%) of the peak oxygen uptake for CIRC and did not differ from TM (d = 0.02). The CIRC elicited a greater postexercise blood lactate concentration versus TM (5.8 [1.7] vs 1.4 [0.4] mM, d = 3.61). The perceptual responses were similar among conditions (P > .05), and only the rating of perceived exertion increased during exercise ( = .78). Conclusion: Whether performed individually or in a small group, CIRC represents HIIE and may be a feasible alternative to running-based HIIE.


1978 ◽  
Vol 46 (3) ◽  
pp. 683-698 ◽  
Author(s):  
Kent B. Pandolf

The literature suggests two major factors determine rated perceived exertion during physical work. These two factors are a local factor, i.e., sensations or feelings of strain in the working muscles and/or joints; and a central factor, i.e., sensations or feelings primarily associated with the cardio-respiratory systems. In some experiments heart rate and minute ventilation (central factors) appear to be the dominant cues for rated perceived exertion, while in others, local factors such as blood lactate concentration and muscular discomfort seem to be the prominent cues. However, it appears that when a particular cue is accentuated by either elevated rate, concentration or value over others it can dominate the over-all rating of perceived exertion. After evaluating the existing literature, a model has been introduced to evaluate differentiated ratings of perceived exertion (local and central) in comparison to the over-all measure. This model may help aid in a better understanding of the mechanisms by which the subjective perception of exertion is determined during different types of physical work.


Author(s):  
Bent R. Rønnestad ◽  
Sjur J. Øfsteng ◽  
Fabio Zambolin ◽  
Truls Raastad ◽  
Daniel Hammarström

Purpose: To compare the effects of a 1-week high-intensity aerobic-training shock microcycle composed of either 5 short-interval sessions (SI; n = 9, 5 series with 12 × 30-s work intervals interspersed with 15-s recovery and 3-min recovery between series) or 5 long-interval sessions (LI; n = 8, 6 series of 5-min work intervals with 2.5-min recovery between series) on indicators of endurance performance in well-trained cyclists. Methods: Before and following 6 days with standardized training loads after the 1-week high-intensity aerobic-training shock microcycle, both groups were tested in physiological determinants of endurance performance. Results: From pretraining to posttraining, SI achieved a larger improvement than LI in maximal oxygen uptake (5.7%; 95% confidence interval, 1.3–10.3; P = .015) and power output at a blood lactate concentration of 4 mmol·L−1 (3.8%; 95% confidence interval, 0.2–7.4; P = .038). There were no group differences in changes of fractional use of maximal oxygen uptake at a workload corresponding to a blood lactate concentration of 4 mmol·L−1, gross efficiency, or the 1-minute peak power output from the maximal-oxygen-uptake test. Conclusion: The SI protocol may induce superior changes in indicators of endurance performance compared with the LI protocol, indicating that SI can be a good strategy during a 1-week high-intensity aerobic-training shock microcycle in well-trained cyclists.


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