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Gomez-Guerrero G, Avela J, Jussila I, Pihlajamäki E, Deng FY, Kidgell DJ, Ahtiainen JP, Walker S. Cortical and spinal responses to short-term strength training and detraining in young and older adults in rectus femoris muscle. Eur J Appl Physiol 2024; 124:2209-2223. [PMID: 38441691 PMCID: PMC11199260 DOI: 10.1007/s00421-024-05443-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 02/14/2024] [Indexed: 06/27/2024]
Abstract
INTRODUCTION Strength training mitigates the age-related decline in strength and muscle activation but limited evidence exists on specific motor pathway adaptations. METHODS Eleven young (22-34 years) and ten older (66-80 years) adults underwent five testing sessions where lumbar-evoked potentials (LEPs) and motor-evoked potentials (MEPs) were measured during 20 and 60% of maximum voluntary contraction (MVC). Ten stimulations, randomly delivered, targeted 25% of maximum compound action potential for LEPs and 120, 140, and 160% of active motor threshold (aMT) for MEPs. The 7-week whole-body resistance training intervention included five exercises, e.g., knee extension (5 sets) and leg press (3 sets), performed twice weekly and was followed by 4 weeks of detraining. RESULTS Young had higher MVC (~ 63 N·m, p = 0.006), 1-RM (~ 50 kg, p = 0.002), and lower aMT (~ 9%, p = 0.030) than older adults at baseline. Young increased 1-RM (+ 18 kg, p < 0.001), skeletal muscle mass (SMM) (+ 0.9 kg, p = 0.009), and LEP amplitude (+ 0.174, p < 0.001) during 20% MVC. Older adults increased MVC (+ 13 N·m, p = 0.014), however, they experienced decreased LEP amplitude (- 0.241, p < 0.001) during 20% MVC and MEP amplitude reductions at 120% (- 0.157, p = 0.034), 140% (- 0.196, p = 0.026), and 160% (- 0.210, p = 0.006) aMT during 60% MVC trials. After detraining, young and older adults decreased 1-RM, while young adults decreased SMM. CONCLUSION Higher aMT and MEP amplitude in older adults were concomitant with lower baseline strength. Training increased strength in both groups, but divergent modifications in cortico-spinal activity occurred. Results suggest that the primary locus of adaptation occurs at the spinal level.
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Affiliation(s)
- Gonzalo Gomez-Guerrero
- Faculty of Sport and Health Sciences, NeuroMuscular Research Center, Viveca, VIV221, University of Jyväskylä, 40700, Jyväskylä, Finland.
| | - Janne Avela
- Faculty of Sport and Health Sciences, NeuroMuscular Research Center, Viveca, VIV221, University of Jyväskylä, 40700, Jyväskylä, Finland
| | - Ilkka Jussila
- Faculty of Sport and Health Sciences, NeuroMuscular Research Center, Viveca, VIV221, University of Jyväskylä, 40700, Jyväskylä, Finland
| | - Esa Pihlajamäki
- Faculty of Sport and Health Sciences, NeuroMuscular Research Center, Viveca, VIV221, University of Jyväskylä, 40700, Jyväskylä, Finland
| | - Fu-Yu Deng
- Faculty of Sport and Health Sciences, NeuroMuscular Research Center, Viveca, VIV221, University of Jyväskylä, 40700, Jyväskylä, Finland
| | - Dawson J Kidgell
- Monash Exercise Neuroplasticity Research Unit, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia
| | - Juha P Ahtiainen
- Faculty of Sport and Health Sciences, NeuroMuscular Research Center, Viveca, VIV221, University of Jyväskylä, 40700, Jyväskylä, Finland
| | - Simon Walker
- Faculty of Sport and Health Sciences, NeuroMuscular Research Center, Viveca, VIV221, University of Jyväskylä, 40700, Jyväskylä, Finland
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Norbury R, Grant I, Woodhead A, Hughes L, Tallent J, Patterson SD. Acute hypoalgesic, neurophysiological and perceptual responses to low-load blood flow restriction exercise and high-load resistance exercise. Exp Physiol 2024; 109:672-688. [PMID: 38578259 PMCID: PMC11061633 DOI: 10.1113/ep091705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 03/13/2024] [Indexed: 04/06/2024]
Abstract
This study compared the acute hypoalgesic and neurophysiological responses to low-load resistance exercise with and without blood flow restriction (BFR), and free-flow, high-load exercise. Participants performed four experimental conditions where they completed baseline measures of pain pressure threshold (PPT), maximum voluntary force (MVF) with peripheral nerve stimulation to determine central and peripheral fatigue. Corticospinal excitability (CSE), corticospinal inhibition and short interval intracortical inhibition (SICI) were estimated with transcranial magnetic stimulation. Participants then performed low-load leg press exercise at 30% of one-repetition maximum (LL); low-load leg press with BFR at 40% (BFR40) or 80% (BFR80) of limb occlusion pressure; or high-load leg press of four sets of 10 repetitions at 70% one-repetition maximum (HL). Measurements were repeated at 5, 45 min and 24 h post-exercise. There were no differences in CSE or SICI between conditions (all P > 0.05); however, corticospinal inhibition was reduced to a greater extent (11%-14%) in all low-load conditions compared to HL (P < 0.005). PPTs were 12%-16% greater at 5 min post-exercise in BFR40, BFR80 and HL compared to LL (P ≤ 0.016). Neuromuscular fatigue displayed no clear difference in the magnitude or time course between conditions (all P > 0.05). In summary, low-load BFR resistance exercise does not induce different acute neurophysiological responses to low-load, free-flow exercise but it does promote a greater degree of hypoalgesia and reduces corticospinal inhibition more than high-load exercise, making it a useful rehabilitation tool. The changes in neurophysiology following exercise were not related to changes in PPT.
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Affiliation(s)
- Ryan Norbury
- Faculty of Sport, Technology and Health SciencesSt Mary's UniversityTwickenhamUK
| | - Ian Grant
- Faculty of Sport, Technology and Health SciencesSt Mary's UniversityTwickenhamUK
| | - Alex Woodhead
- Faculty of Sport, Technology and Health SciencesSt Mary's UniversityTwickenhamUK
| | - Luke Hughes
- Department of Sport, Exercise and RehabilitationNorthumbria UniversityNewcastle‐Upon TyneUK
| | - Jamie Tallent
- School of Sport, Rehabilitation and Exercise SciencesUniversity of EssexColchesterUK
- Monash Exercise Neuroplasticity Research Unit, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health ScienceMonash UniversityMelbourneVAAustralia
| | - Stephen D. Patterson
- Faculty of Sport, Technology and Health SciencesSt Mary's UniversityTwickenhamUK
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Vallance P, Malliaras P, Vicenzino B, Kidgell DJ. Determining intracortical, corticospinal and alpha motoneurone excitability in athletes with patellar tendinopathy compared to asymptomatic controls. Scand J Med Sci Sports 2024; 34:e14579. [PMID: 38332685 DOI: 10.1111/sms.14579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 01/22/2024] [Accepted: 01/29/2024] [Indexed: 02/10/2024]
Abstract
BACKGROUND Lower capacity to generate knee extension maximal voluntary force (MVF) has been observed in individuals affected with patellar tendinopathy (PT) compared to asymptomatic controls. This MVF deficit is hypothesized to emanate from alterations in corticospinal excitability (CSE). The modulation of CSE is intricately linked to the excitability levels at multiple sites, encompassing neurones within the corticospinal tract (CST), intracortical neurones within the primary motor cortex (M1), and the alpha motoneurone. The aim of this investigation was to examine the excitability of intracortical neurones, CST neurones, and the alpha motoneurone, and compare these between volleyball and basketball athletes with PT and matched asymptomatic controls. METHOD Nineteen athletes with PT and 18 asymptomatic controls participated in this cross-sectional study. Transcranial magnetic stimulation was utilized to assess CST excitability, corticospinal inhibition (silent period, and short-interval cortical inhibition). Peripheral nerve stimulation was used to evaluate lumbar spine and alpha motoneurone excitability, including the evocation of lumbar-evoked potentials and maximal compound muscle action potential (MMAX ), and CSE with central activation ratio (CAR). Knee extension MVF was also assessed. RESULTS Athletes with PT exhibited longer silent period duration and greater electrical stimulator output for MMAX , as well as lower MVF, compared to asymptomatic controls (p < 0.05). CONCLUSION These findings indicate volleyball and basketball athletes with PT exhibit reduced excitability of the alpha motoneurone or the neuromuscular junction, which may be linked to lower MVF. Subtle alterations at specific sites may represent compensatory changes to excitability aiming to maintain efferent drive to the knee extensors.
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Affiliation(s)
- Patrick Vallance
- Monash Musculoskeletal Research Unit, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, Victoria, Australia
- Monash Exercise Neuroplasticity Research Unit, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, Victoria, Australia
| | - Peter Malliaras
- Monash Musculoskeletal Research Unit, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, Victoria, Australia
| | - Bill Vicenzino
- School of Health and Rehabilitation Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Dawson J Kidgell
- Monash Exercise Neuroplasticity Research Unit, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, Victoria, Australia
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