1
|
Gueugneau N, Martin A, Gaveau J, Papaxanthis C. Gravity-efficient motor control is associated with contraction-dependent intracortical inhibition. iScience 2023; 26:107150. [PMID: 37534144 PMCID: PMC10391940 DOI: 10.1016/j.isci.2023.107150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 06/04/2023] [Accepted: 06/12/2023] [Indexed: 08/04/2023] Open
Abstract
In humans, moving efficiently along the gravity axis requires shifts in muscular contraction modes. Raising the arm up involves shortening contractions of arm flexors, whereas the reverse movement can rely on lengthening contractions with the help of gravity. Although this control mode is universal, the neuromuscular mechanisms that drive gravity-oriented movements remain unknown. Here, we designed neurophysiological experiments that aimed to track the modulations of cortical, spinal, and muscular outputs of arm flexors during vertical movements with specific kinematics (i.e., optimal motor commands). We report a specific drop of corticospinal excitability during lengthening versus shortening contractions, with an increase of intracortical inhibition and no change in spinal motoneuron responsiveness. We discuss these contraction-dependent modulations of the supraspinal motor output in the light of feedforward mechanisms that may support gravity-tuned motor control. Generally, these results shed a new perspective on the neural policy that optimizes movement control along the gravity axis.
Collapse
Affiliation(s)
- Nicolas Gueugneau
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, 21000 Dijon, France
| | - Alain Martin
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, 21000 Dijon, France
| | - Jérémie Gaveau
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, 21000 Dijon, France
| | - Charalambos Papaxanthis
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, 21000 Dijon, France
| |
Collapse
|
2
|
Ruas CV, Latella C, Taylor JL, Haff GG, Nosaka K. Comparison between Eccentric-Only and Coupled Concentric-Eccentric Contractions for Neuromuscular Fatigue and Muscle Damage. Med Sci Sports Exerc 2022; 54:1635-1646. [PMID: 36106831 DOI: 10.1249/mss.0000000000002959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE Eccentric contractions induce muscle damage, but less is known about the effects of preceding concentric contractions to eccentric contractions on muscle damage. We compared eccentric-only (ECC) and coupled concentric and eccentric contractions (CON-ECC) of the knee extensors for parameters of neuromuscular fatigue and muscle damage. METHODS Twenty participants (age, 19-36 yr) were randomly placed into an ECC or a CON-ECC group (n = 10 per group), without significant (P > 0.06) differences in baseline neuromuscular variables between groups. The ECC group performed six sets of eight ECC at 80% of ECC one-repetition maximum (1-RMecc), whereas the CON-ECC group performed six sets of eight alternating concentric (CON) and ECC (16 contractions per set) at 80% of CON 1-RM and 1-RMecc, respectively. Maximal voluntary isometric contraction force, rate of force development, resting twitch force, maximal M-wave (MMAX), voluntary activation, motor evoked potentials, corticospinal silent period, short interval intracortical inhibition, and muscle soreness were measured before, immediately after, and 1-3 d after exercise. RESULTS No significant (P ≥ 0.09) differences between ECC and CON-ECC were observed for changes in any variables after exercise. However, maximal voluntary isometric contraction force decreased immediately after exercise (ECC: -20.7% ± 12.8%, CON-ECC: -23.6% ± 23.3%) and was still reduced 3 d after exercise (ECC: -13.6% ± 13.4%, CON-ECC: -3.3% ± 21.2%). Rate of force development at 0-30 ms reduced immediately after exercise (ECC: -38.3% ± 33.9%, CON-ECC: -30.7% ± 38.3%). Voluntary activation, resting twitch force, and motor evoked potential/MMAX decreased and corticospinal silent period increased after exercise (all P ≤ 0.03), but short interval intracortical inhibition and MMAX did not change. Muscle soreness developed (P < 0.001) similarly for both groups (peak, 38.5 ± 29.5 mm). CONCLUSIONS CON-ECC did not exacerbate neuromuscular fatigue and muscle damage when compared with ECC, despite twice as many contractions performed. Thus, eccentric contractions (n = 48 in both groups) seemed to mainly mediate the neuromuscular responses observed.
Collapse
Affiliation(s)
| | | | | | | | - Kazunori Nosaka
- Centre for Human Performance, School of Medical and Health Sciences, Edith Cowan University, Joondalup, AUSTRALIA
| |
Collapse
|
3
|
Zeng X, Xie Z, Zhong G, Chen Y, Wen B, Li Y, Ma L, Huang W, Yang T, Zhang Y. The 6DOF knee kinematics of healthy subjects during sloped walking compared to level walking. Gait Posture 2022; 95:198-203. [PMID: 35526472 DOI: 10.1016/j.gaitpost.2022.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/23/2022] [Accepted: 05/02/2022] [Indexed: 02/02/2023]
Abstract
BACKGROUND Level Walking is a frequent functional movement during daily life. However, sloped walking is also common. Exploring 6DOF knee kinematics during sloped walking is important. It provides a reference for the rehabilitation, safety, and knee health of patients with knee diseases walking on sloped surfaces. RESEARCH QUESTION The study aimed to explore 6DOF knee kinematics characteristics during sloped walking compared to level walking. We hypothesized that tibial anteroposterior translation and flexion angle (the sagittal plane) were significantly different from those of level walking. METHODS One hundred young, healthy adults (50 males and 50 females) were recruited for this study. A three-dimensional gait analysis system was used to collect 6DOF knee kinematics during level and sloped walking. The slope was set to ± 15% when the sloped walking was performed. RESULTS Sloped walking mainly increased knee flexion angle (upslope, 2.5-26.2°, 1-100% gait cycle (GC), p < 0.05; downslope, 1.7-11.9°, 15-95% GC, p < 0.05) and anterior tibial translation (upslope, 0.7-4.1 mm, 3-54% GC & 0.6-2.1 mm, 80-94% GC; downslope, 1.0-2.2 mm, 21-69% GC) in the participants' knees. However, participants' other 4DOF knee kinematics during sloped walking were significantly different from those during level walking (p < 0.05). Participants had 'drastically changeable' knee kinematic alterations in the transverse and coronal plane (the other 4DOF knee kinematics) during sloped walking compared to level walking. SIGNIFICANCE Our results confirmed the hypothesis. Sloped walking significantly increased anterior tibial translation (in most GC) and flexion angle. These kinematic changes in healthy subjects should be evaluated and further explored for patients with knee diseases, such as anterior cruciate ligament deficiency. Our findings are meaningful for their rehabilitation or safety or knee health while walking on sloped surfaces. Our study may provide a pilot reference for the 6DOF knee kinematic exploration of sloped walking.
Collapse
Affiliation(s)
- Xiaolong Zeng
- School of Medicine, South China University of Technology, Guangzhou 510006, Guangdong, China; Department of Orthopaedics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, Guangdong, China
| | - Zhenyan Xie
- Department of Orthopaedics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, Guangdong, China; Shantou Central Hospital, Shantou 515000, Guangdong, China
| | - Guoqing Zhong
- Department of Orthopaedics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, Guangdong, China; Shantou Central Hospital, Shantou 515000, Guangdong, China
| | - Ying Chen
- Shantou Central Hospital, Shantou 515000, Guangdong, China
| | - Baohong Wen
- Shantou Central Hospital, Shantou 515000, Guangdong, China
| | - Yixi Li
- School of Public Health, Guangdong Pharmaceutical University, Guangzhou 510000, Guangdong, China
| | - Limin Ma
- Department of Orthopaedics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, Guangdong, China
| | - Wenhan Huang
- Department of Orthopaedics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, Guangdong, China
| | - Tao Yang
- School of Medicine, South China University of Technology, Guangzhou 510006, Guangdong, China; Department of Orthopaedics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, Guangdong, China
| | - Yu Zhang
- School of Medicine, South China University of Technology, Guangzhou 510006, Guangdong, China; Department of Orthopaedics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, Guangdong, China.
| |
Collapse
|
4
|
Ruas CV, Latella C, Taylor JL, Haff GG, Nosaka K. Early Detection of Prolonged Decreases in Maximal Voluntary Contraction Force after Eccentric Exercise of the Knee Extensors. Med Sci Sports Exerc 2022; 54:267-279. [PMID: 35029591 DOI: 10.1249/mss.0000000000002797] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
PURPOSE We examined whether the magnitude of muscle damage indicated by changes in maximal voluntary isometric contraction (MVIC) strength 1 to 3 d after unaccustomed eccentric exercise (ECC) was correlated with changes in central and peripheral neuromuscular parameters immediately post-ECC. METHODS Twenty participants (19-36 yr) performed six sets of eight eccentric contractions of the knee extensors. Rate of force development (RFD) during knee extensor MVIC, twitch force, rate of force development (RFDRT) and rate of relaxation (RRRT) of the resting twitch, maximal M-wave (MMAX), voluntary activation, silent period duration, motor-evoked potentials (MEP) and short-interval intracortical inhibition were assessed before, immediately after, and 1 to 3 d post-ECC. Relationships between changes in these variables immediately post-ECC and changes in MVIC strength at 1 to 3 d post-ECC were examined by Pearson product-moment (r) or Spearman correlations. RESULTS Maximal voluntary isometric contraction strength decreased (-22.2% ± 18.4%) immediately postexercise, and remained below baseline at 1 (-16.3% ± 15.2%), 2 (-14.7% ± 13.2%) and 3 d post-ECC (-8.6% ± 15.7%). Immediately post-ECC, RFD (0-30-ms: -38.3% ± 31.4%), twitch force (-45.9% ± 22.4%), RFDRT (-32.5% ± 40.7%), RRRT (-38.0% ± 39.7%), voluntary activation (-21.4% ± 16.5%) and MEP/MMAX at rest (-42.5% ± 23.3%) also decreased, whereas the silent period duration at 10%-MVIC increased by 26.0% ± 12.2% (P < 0.05). Decreases in RFD at 0 to 30 ms, 0 to 50 ms, and 0 to 100 ms immediately post-ECC were correlated (P < 0.05) with changes in MVIC strength at 1 d (r = 0.56-0.60) and 2 d post-ECC (r = 0.53-0.63). Changes in MEP/MMAX at 10%-MVIC immediately post-ECC were correlated with changes in MVIC strength at 1 d (r = -0.53) and 2 d (r = -0.54) post-ECC (P < 0.05). CONCLUSIONS The magnitude of decrease in MVIC strength at 1 to 3 d after ECC was associated with the magnitude of changes in RFD and MEP/MMAX immediately post-ECC. However, based on individual data, these markers were not sensitive for the practical detection of muscle damage.
Collapse
Affiliation(s)
| | | | | | | | - Kazunori Nosaka
- Centre for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, AUSTRALIA
| |
Collapse
|
5
|
Clos P, Mater A, Laroche D, Lepers R. Concentric versus eccentric cycling at equal power output or effort perception: Neuromuscular alterations and muscle pain. Scand J Med Sci Sports 2021; 32:45-59. [PMID: 34533875 DOI: 10.1111/sms.14053] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 06/16/2021] [Accepted: 09/14/2021] [Indexed: 12/24/2022]
Abstract
This study aimed to compare neuromuscular alterations and perceptions of effort and muscle pain induced by concentric and eccentric cycling performed at the same power output or effort perception. Fifteen participants completed three 30-min sessions: one in concentric at 60% peak power output (CON) and two in eccentric, at the same power output (ECCPOWER ) or same perceived effort (ECCEFFORT ). Muscle pain, perception of effort, oxygen uptake as well as rectus femoris and vastus lateralis electromyographic activities were collected when pedaling. The knee extensors maximal voluntary contraction (MVC) torque, the torque evoked by double stimulations at 100 Hz and 10 Hz (Dt100; Dt10), and the voluntary activation level (VAL) were evaluated before and after exercise. Power output was higher in ECCEFFORT than CON (89.1 ± 23.3% peak power). Muscle pain and effort perception were greater in CON than ECCPOWER (p < 0.03) while muscle pain was similar in CON and ECCEFFORT (p > 0.43). MVC torque, Dt100, and VAL dropped in all conditions (p < 0.04). MVC torque (p < 0.001) and the Dt10/ Dt100 ratio declined further in ECCEFFORT (p < 0.001). Eccentric cycling perceived as difficult as concentric cycling caused similar muscle pain but more MVC torque decrease. A given power output induced lower perceptions of pain and effort in eccentric than in concentric yet similar MVC torque decline. While neural impairments were similar in all conditions, eccentric cycling seemed to alter excitation-contraction coupling. Clinicians should thus be cautious when setting eccentric cycling intensity based on effort perception.
Collapse
Affiliation(s)
- Pierre Clos
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, Dijon, France
| | - Adrien Mater
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, Dijon, France
| | - Davy Laroche
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, Dijon, France
| | - Romuald Lepers
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, Dijon, France
| |
Collapse
|
6
|
Clos P, Lepers R, Garnier YM. Locomotor activities as a way of inducing neuroplasticity: insights from conventional approaches and perspectives on eccentric exercises. Eur J Appl Physiol 2021; 121:697-706. [PMID: 33389143 DOI: 10.1007/s00421-020-04575-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 11/30/2020] [Indexed: 12/13/2022]
Abstract
Corticospinal excitability, and particularly the balance between cortical inhibitory and excitatory processes (assessed in a muscle using single and paired-pulse transcranial magnetic stimulation), are affected by neurodegenerative pathologies or following a stroke. This review describes how locomotor exercises may counterbalance these neuroplastic alterations, either when performed under its conventional form (e.g., walking or cycling) or when comprising eccentric (i.e., active lengthening) muscle contractions. Non-fatiguing conventional locomotor exercise decreases intracortical inhibition and/or increases intracortical facilitation. These modifications notably seem to be a consequence of neurotrophic factors (e.g., brain-derived neurotrophic factor) resulting from the hemodynamic solicitation. Furthermore, it can be inferred from non-invasive brain and peripheral stimulation studies that repeated activation of neural networks can endogenously shape neuroplasticity. Such mechanisms could also occur following eccentric exercises (lengthening of the muscle), during which motor-related cortical potential (electroencephalography) is of greater magnitude and lasts longer than during concentric exercises (i.e., muscle shortening). As single-joint eccentric exercise decreased short- and long-interval intracortical inhibition and increased intracortical facilitation, locomotor eccentric exercise (e.g., downhill walking or eccentric cycling) may be even more potent by adding hemodynamic-related neuroplastic processes to endogenous processes. Besides, eccentric exercise is especially useful to develop relatively high force levels at low cardiorespiratory and perceived intensities, which can be a training goal alongside the induction of neuroplastic changes. Even though indirect evidence let us think that locomotor eccentric exercise could shape neuroplasticity in ways relevant to neurorehabilitation, its efficacy remains speculative. We provide future research directions on the neuroplastic effects and underlying mechanisms of locomotor exercise.
Collapse
Affiliation(s)
- Pierre Clos
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, 21000, Dijon, France.
| | - Romuald Lepers
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, 21000, Dijon, France
| | - Yoann M Garnier
- Clermont-Auvergne University, AME2P, Clermont-Ferrand, France
| |
Collapse
|
7
|
DA Silva F, Monjo F, Zghal F, Chorin F, Guérin O, Colson SS. Altered Position Sense after Submaximal Eccentric Exercise-inducing Central Fatigue. Med Sci Sports Exerc 2021; 53:218-227. [PMID: 32694369 DOI: 10.1249/mss.0000000000002444] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE The purpose of this study was to concomitantly investigate the acute and delayed effects of a submaximal eccentric-induced muscle fatigue on the position sense and the neuromuscular function of the right knee extensor muscles. METHODS Thirteen young and physically active participants performed a unilateral isokinetic eccentric exercise of their right lower limb until a decrease in maximal voluntary isometric contraction (MVIC) of 20% was reached. Neuromuscular (i.e., MVIC, voluntary activation (VA) level, and evoked contractile properties [DB100 and DB10]) and psychophysical evaluations (i.e., bilateral position-matching task, perceived muscle soreness, and perceived fatigue) were performed at four time points: before (PRE), immediately after (POST), 24 (POST24), and 48 (POST48) the exercise. RESULTS The acute 20% MVIC reduction (P < 0.001) was associated with both central (i.e., -13% VA decrease, P < 0.01) and peripheral (i.e., -18% and -42% reduction of DB100 and DB10, respectively, P < 0.001) fatigue. In the following days (POST24 and POST48), VA levels had recovered despite the presence of a persisting peripheral fatigue and delayed-onset muscle soreness. Knee position sense, as revealed by position errors, was significantly altered only at POST (P < 0.05) with participants overestimating the length of their knee extensor. Position errors and VA deficits were significantly correlated at POST (r = -0.60, P = 0.03). Position errors returned to nonsignificant control values in the following days. CONCLUSION The acute central fatigue induced by the eccentric exercise contributes to the position sense disturbances. Central fatigue might lead to alterations in the sensory structures responsible for the integration and the processing of position-related sensory inputs.
Collapse
Affiliation(s)
| | | | - Firas Zghal
- Université Côte d'Azur, LAMHESS, Nice, FRANCE
| | | | | | | |
Collapse
|
8
|
Clos P, Garnier Y, Martin A, Lepers R. Corticospinal excitability is altered similarly following concentric and eccentric maximal contractions. Eur J Appl Physiol 2020; 120:1457-1469. [PMID: 32347373 DOI: 10.1007/s00421-020-04377-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 04/13/2020] [Indexed: 01/24/2023]
Abstract
PURPOSE To examine corticospinal excitability and neuromuscular function following the completion of eccentric (ECC) or concentric (CON) maximal exercises of same mechanical work. METHODS Ten males (29.9 ± 11.8 years) performed maximal isokinetic knee extensor contractions in four experimental sessions. The two first sessions (one in ECC and one in CON) ended with a dynamic peak torque loss of 20%. The work completed in each contraction type was then achieved in the other contraction type. Neuromuscular function- maximal voluntary isometric contraction (MVIC), voluntary activation level (VAL), potentiated doublet (Dt), M-wave- and corticospinal excitability- motor evoked potential (MEP) amplitude and silent period (SP)-were assessed in the vastus lateralis (VL) and rectus femoris (RF) muscles at 20% MVIC before and immediately after exercise. RESULTS To lose 20% of dynamic peak torque subjects performed 1.8 times more work in ECC than CON (P = 0.03), inducing a non-different decline in MVIC (P = 0.15). VAL dropped after the ECC sessions only (- 8.5 ± 6.7%; all P < 0.027). Only, the CON session featuring the greatest work affected Dt amplitude (- 9.4 ± 23.8%; P = 0.047). In both muscles, MEP amplitude decreased (all P < 0.001) and MEP SP stayed constant (all P > 0.45), irrespective of contraction type (all P > 0.15). CONCLUSION Same-work maximal ECC and CON exercises induced similar fatigue level but from different origins (preferentially central for ECC vs peripheral for CON). Yet, net corticospinal excitability did not depend on contraction type.
Collapse
Affiliation(s)
- Pierre Clos
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, 21000, Dijon, France.
| | - Yoann Garnier
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, 21000, Dijon, France
- Clermont-Auvergne University, AME2P, Clermont-Ferrand, France
| | - Alain Martin
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, 21000, Dijon, France
| | - Romuald Lepers
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, 21000, Dijon, France
| |
Collapse
|
9
|
Walsh JA, Stapley PJ, Shemmell JBH, Lepers R, McAndrew DJ. Global Corticospinal Excitability as Assessed in A Non-Exercised Upper Limb Muscle Compared Between Concentric and Eccentric Modes of Leg Cycling. Sci Rep 2019; 9:19212. [PMID: 31844115 PMCID: PMC6915732 DOI: 10.1038/s41598-019-55858-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 12/03/2019] [Indexed: 02/04/2023] Open
Abstract
This study investigated the effects of eccentric (ECC) and concentric (CON) semi-recumbent leg cycling on global corticospinal excitability (CSE), assessed through the activity of a non-exercised hand muscle. Thirteen healthy male adults completed two 30-min bouts of moderate intensity ECC and CON recumbent cycling on separate days. Power output (POutput), heart rate (HR) and cadence were monitored during cycling. Global CSE was assessed using transcranial magnetic stimulation to elicit motor-evoked potentials (MEP) in the right first dorsal interosseous muscle before (‘Pre’), interleaved (at 10 and 20 mins, t10 and t20, respectively), immediately after (post, P0), and 30-min post exercise (P30). Participants briefly stopped pedalling (no more than 60 s) while stimulation was applied at the t10 and t20 time-points of cycling. Mean POutput, and rate of perceived exertion (RPE) did not differ between ECC and CON cycling and HR was significantly lower during ECC cycling (P = 0.01). Group mean MEP amplitudes were not significantly different between ECC and CON cycling at P0, t10, t20, and P30 and CON (at P > 0.05). Individual participant ratios of POutput and MEP amplitude showed large variability across the two modes of cycling, as did changes in slope of stimulus-response curves. These results suggest that compared to ‘Pre’ values, group mean CSE is not significantly affected by low-moderate intensity leg cycling in both modes. However, POutput and CSE show wide inter-participant variability which has implications for individual neural responses to CON and ECC cycling and rates of adaptation to a novel (ECC) mode. The study of CSE should therefore be analysed for each participant individually in relation to relevant physiological variables and account for familiarisation to semi-recumbent ECC leg cycling.
Collapse
Affiliation(s)
- Joel A Walsh
- Neural Control of Movement Laboratory, School of Medicine, Faculty of Science, Medicine and Health, University of Wollongong, New South Wales, Australia. .,Illawarra Health and Medical Research Institute (IHMRI) University of Wollongong, New South Wales, Australia.
| | - Paul J Stapley
- Neural Control of Movement Laboratory, School of Medicine, Faculty of Science, Medicine and Health, University of Wollongong, New South Wales, Australia.,Illawarra Health and Medical Research Institute (IHMRI) University of Wollongong, New South Wales, Australia
| | - Jonathan B H Shemmell
- Neural Control of Movement Laboratory, School of Medicine, Faculty of Science, Medicine and Health, University of Wollongong, New South Wales, Australia.,Neuromotor Adaptation Laboratory, School of Medicine, Faculty of Science, Medicine and Health, University of Wollongong, New South Wales, Australia.,Illawarra Health and Medical Research Institute (IHMRI) University of Wollongong, New South Wales, Australia
| | - Romuald Lepers
- INSERM UMR1093-CAPS, Université Bourgogne Franche-Comté, UFR des Sciences du Sport, Dijon, France
| | - Darryl J McAndrew
- Neural Control of Movement Laboratory, School of Medicine, Faculty of Science, Medicine and Health, University of Wollongong, New South Wales, Australia.,Discipline of Graduate Medicine, School of Medicine, Faculty of Science, Medicine and Health, University of Wollongong, New South Wales, Australia.,Illawarra Health and Medical Research Institute (IHMRI) University of Wollongong, New South Wales, Australia
| |
Collapse
|