Cardiorespiratory and Autonomic Nervous System Responses to Prolonged Eccentric Cycling

Background: This study tested muscle activity (EMG) and perception of effort in eccentric (ECC) and concentric (CON) cycling before and after four sessions of both. Methods: Twelve volunteers naïve to ECC cycling attended the laboratory six times. On day 1, they performed a CON cycling peak power output (PPO) test. They then carried-out four sessions comprising two sets of 1 to 1.5-min cycling bouts at 5 intensities (30, 45, 60, 75, and 90% PPO) in ECC and CON cycling. On day 2 and day 6 (two weeks apart), EMG root mean square of the vastus lateralis (VL), rectus femoris (RF), biceps femoris (BF), and soleus (SOL) muscles, was averaged from 15 to 30 s within each 1-min bout and perception of effort was asked after 45 s. Results: Before the four cycling sessions, while VL EMG was lower in ECC than CON cycling, most variables were not different. Afterwards, ECC cycling exhibited lower RF EMG at 75 and 90% PPO (all p < 0.02), lower VL and BF EMG at all exercise intensities (all p < 0.02), and inferior SOL EMG (all p < 0.04) except at 45% PPO (p = 0.07). Perception of effort was lower in ECC cycling at all exercise intensities (all p < 0.03) but 60% PPO (p = 0.11). Conclusions: After four short sessions of ECC cycling, the activity of four leg muscles and perception of effort became lower in ECC than in CON cycling at most of five power outputs, while they were similar before.

Section: Introductionmentioning

confidence: 99%

Leg Muscle Activity and Perception of Effort before and after Four Short Sessions of Submaximal Eccentric Cycling

Clos

Lepers

2020

“…In view of the potential usage of this type of exercise for cardiac disease rehabilitation [ 26 ], a clinically relevant question is whether an unaccustomed bout of moderate duration ECC may lead to a change in DFA a1 compared to CON. Since ECC may trigger higher sympathetic activity than CON [ 1 , 8 ], along with complex interaction between mechanoreceptors, metaboreceptors and baroreceptors, a greater decline in DFA a1 was anticipated. In this study, the initial workload was set to have the same HR at the beginning of CON and ECC (54% of HR MAX ).…”

Section: Discussionmentioning

confidence: 99%

“…Unfortunately, recommendations for ECC training intensity are problematic. At the same VO 2 , ECC may lead to a higher heart rate (HR), making suggestions based on common HR based formulas unreliable [ 1 , 5 , 8 ]. Many of the ideal candidates for an ECC program may be taking medications that can affect HR, such as beta-adrenergic blocking agents, further obscuring HR related intensity target formulas.…”

Section: Introductionmentioning

confidence: 99%

“…As exercise intensity rises, there is a withdrawal of parasympathetic and enhancement of sympathetic influence that leads to a decline in DFA a1 [ 10 , 16 ]. On the other hand, it has been shown that, for the same VO 2 or HR, ECC is associated with an increased muscle tension and sympathetic stress [ 1 , 8 ], especially when participants are not accustomed to eccentric exercise, and ECC should produce the greatest degree of muscle soreness. However, to the best of our knowledge, it is not known whether this is accompanied by a more pronounced decrease in DFA a1.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Fractal Correlation Properties of Heart Rate Variability during an Initial Session of Eccentric Cycling

Rogers

Gronwald

Mourot

2021

Self Cite

Eccentric cycling (ECC) has attracted attention as a method to improve muscle strength and aerobic fitness in populations unable to tolerate conventional methods. However, agreement on exercise prescription targets have been problematic. The current report is an initial exploration of a potentially useful tool, a nonlinear heart rate (HR) variability (HRV) index based on the short-term scaling exponent alpha1 of detrended fluctuation analysis (DFA a1), which has been previously shown to correspond to exercise intensity. Eleven male volunteers performed 45 min of concentric (CON) cycling and ECC separated by 1 month. Work rates were matched for HR (~50% of the maximal HR) during the first 5 min and remained stable thereafter. HRV, HR, oxygen consumption (VO2), and cycling power were monitored and evaluated at elapsed times of 10 (T10) and 45 (T45) minutes duration. HR significantly increased between ECC T10 and ECC T45 (p = 0.003, d = 1.485), while DFA a1 significantly decreased (p = 0.004, d = 1.087). During CON, HR significantly increased (p < 0.001 d = 1.570) without significant DFA a1 change (p = 0.48, d = 0.22). Significantly higher HR was observed at T45 in ECC than in CON (p = 0.047, d = 1.059). A session of unaccustomed ECC lead to decreased values of DFA a1 at T45 in comparison to that seen with CON at similar VO2. ECC lead to altered autonomic nervous system balance as reflected by the loss of correlation properties compared to CON.

“…This specific characteristic could be interesting for diverse populations of athletes or patients under specific circumstances (e.g., coronary and pulmonary patients). However, when non-adequately designed, eccentric cycling may result into altered autonomic nervous system responses that could adversely reduce the safety of patients [9]. Most studies on eccentric cycling have been completed at continuous submaximal intensities, with few studies examining eccentric HIT [10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Acute and Delayed Effects of Time-Matched Very Short “All Out” Efforts in Concentric vs. Eccentric Cycling

Boullosa

Dragutinovic

Deutsch

et al. 2021

Background: To the authors’ knowledge, there have been no studies comparing the acute responses to “all out” efforts in concentric (isoinertial) vs. eccentric (isovelocity) cycling. Methods: After two familiarization sessions, 12 physically active men underwent the experimental protocols consisting of a 2-min warm-up and 8 maximal efforts of 5 s, separated by 55 s of active recovery at 80 rpm, in concentric vs. eccentric cycling. Comparisons between protocols were conducted during, immediately after, and 24-h post-sessions. Results: Mechanical (Work: 82,824 ± 6350 vs. 60,602 ± 8904 J) and cardiometabolic responses (mean HR: 68.8 ± 6.6 vs. 51.3 ± 5.7% HRmax, lactate: 4.9 ± 2.1 vs. 1.8 ± 0.6 mmol/L) were larger in concentric cycling (p < 0.001). The perceptual responses to both protocols were similarly low. Immediately after concentric cycling, vertical jump was potentiated (p = 0.028). Muscle soreness (VAS; p = 0.016) and thigh circumference (p = 0.045) were slightly increased only 24-h after eccentric cycling. Serum concentrations of CK, BAG3, and MMP-13 did not change significantly post-exercise. Conclusions: These results suggest the appropriateness of the eccentric cycling protocol used as a time-efficient (i.e., ~60 kJ in 10 min) and safe (i.e., without exercise-induced muscle damage) alternative to be used with different populations in future longitudinal interventions.